diff options
Diffstat (limited to 'fs/netfs')
| -rw-r--r-- | fs/netfs/Kconfig | 39 | ||||
| -rw-r--r-- | fs/netfs/Makefile | 22 | ||||
| -rw-r--r-- | fs/netfs/buffered_read.c | 237 | ||||
| -rw-r--r-- | fs/netfs/buffered_write.c | 1258 | ||||
| -rw-r--r-- | fs/netfs/direct_read.c | 125 | ||||
| -rw-r--r-- | fs/netfs/direct_write.c | 174 | ||||
| -rw-r--r-- | fs/netfs/fscache_cache.c | 429 | ||||
| -rw-r--r-- | fs/netfs/fscache_cookie.c | 1180 | ||||
| -rw-r--r-- | fs/netfs/fscache_internal.h | 14 | ||||
| -rw-r--r-- | fs/netfs/fscache_io.c | 287 | ||||
| -rw-r--r-- | fs/netfs/fscache_main.c | 108 | ||||
| -rw-r--r-- | fs/netfs/fscache_proc.c | 47 | ||||
| -rw-r--r-- | fs/netfs/fscache_stats.c | 103 | ||||
| -rw-r--r-- | fs/netfs/fscache_volume.c | 520 | ||||
| -rw-r--r-- | fs/netfs/internal.h | 284 | ||||
| -rw-r--r-- | fs/netfs/io.c | 217 | ||||
| -rw-r--r-- | fs/netfs/iterator.c | 97 | ||||
| -rw-r--r-- | fs/netfs/locking.c | 216 | ||||
| -rw-r--r-- | fs/netfs/main.c | 109 | ||||
| -rw-r--r-- | fs/netfs/misc.c | 260 | ||||
| -rw-r--r-- | fs/netfs/objects.c | 59 | ||||
| -rw-r--r-- | fs/netfs/output.c | 478 | ||||
| -rw-r--r-- | fs/netfs/stats.c | 42 |
23 files changed, 6213 insertions, 92 deletions
diff --git a/fs/netfs/Kconfig b/fs/netfs/Kconfig index b4db21022c..bec805e0c4 100644 --- a/fs/netfs/Kconfig +++ b/fs/netfs/Kconfig @@ -21,3 +21,42 @@ config NETFS_STATS multi-CPU system these may be on cachelines that keep bouncing between CPUs. On the other hand, the stats are very useful for debugging purposes. Saying 'Y' here is recommended. + +config FSCACHE + bool "General filesystem local caching manager" + depends on NETFS_SUPPORT + help + This option enables a generic filesystem caching manager that can be + used by various network and other filesystems to cache data locally. + Different sorts of caches can be plugged in, depending on the + resources available. + + See Documentation/filesystems/caching/fscache.rst for more information. + +config FSCACHE_STATS + bool "Gather statistical information on local caching" + depends on FSCACHE && PROC_FS + select NETFS_STATS + help + This option causes statistical information to be gathered on local + caching and exported through file: + + /proc/fs/fscache/stats + + The gathering of statistics adds a certain amount of overhead to + execution as there are a quite a few stats gathered, and on a + multi-CPU system these may be on cachelines that keep bouncing + between CPUs. On the other hand, the stats are very useful for + debugging purposes. Saying 'Y' here is recommended. + + See Documentation/filesystems/caching/fscache.rst for more information. + +config FSCACHE_DEBUG + bool "Debug FS-Cache" + depends on FSCACHE + help + This permits debugging to be dynamically enabled in the local caching + management module. If this is set, the debugging output may be + enabled by setting bits in /sys/modules/fscache/parameter/debug. + + See Documentation/filesystems/caching/fscache.rst for more information. diff --git a/fs/netfs/Makefile b/fs/netfs/Makefile index 386d6fb927..d4d1d79981 100644 --- a/fs/netfs/Makefile +++ b/fs/netfs/Makefile @@ -2,11 +2,29 @@ netfs-y := \ buffered_read.o \ + buffered_write.o \ + direct_read.o \ + direct_write.o \ io.o \ iterator.o \ + locking.o \ main.o \ - objects.o + misc.o \ + objects.o \ + output.o netfs-$(CONFIG_NETFS_STATS) += stats.o -obj-$(CONFIG_NETFS_SUPPORT) := netfs.o +netfs-$(CONFIG_FSCACHE) += \ + fscache_cache.o \ + fscache_cookie.o \ + fscache_io.o \ + fscache_main.o \ + fscache_volume.o + +ifeq ($(CONFIG_PROC_FS),y) +netfs-$(CONFIG_FSCACHE) += fscache_proc.o +endif +netfs-$(CONFIG_FSCACHE_STATS) += fscache_stats.o + +obj-$(CONFIG_NETFS_SUPPORT) += netfs.o diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c index 2cd3ccf4c4..3298c29b55 100644 --- a/fs/netfs/buffered_read.c +++ b/fs/netfs/buffered_read.c @@ -16,6 +16,7 @@ void netfs_rreq_unlock_folios(struct netfs_io_request *rreq) { struct netfs_io_subrequest *subreq; + struct netfs_folio *finfo; struct folio *folio; pgoff_t start_page = rreq->start / PAGE_SIZE; pgoff_t last_page = ((rreq->start + rreq->len) / PAGE_SIZE) - 1; @@ -63,6 +64,7 @@ void netfs_rreq_unlock_folios(struct netfs_io_request *rreq) break; } if (!folio_started && test_bit(NETFS_SREQ_COPY_TO_CACHE, &subreq->flags)) { + trace_netfs_folio(folio, netfs_folio_trace_copy_to_cache); folio_start_fscache(folio); folio_started = true; } @@ -86,11 +88,20 @@ void netfs_rreq_unlock_folios(struct netfs_io_request *rreq) if (!pg_failed) { flush_dcache_folio(folio); + finfo = netfs_folio_info(folio); + if (finfo) { + trace_netfs_folio(folio, netfs_folio_trace_filled_gaps); + if (finfo->netfs_group) + folio_change_private(folio, finfo->netfs_group); + else + folio_detach_private(folio); + kfree(finfo); + } folio_mark_uptodate(folio); } if (!test_bit(NETFS_RREQ_DONT_UNLOCK_FOLIOS, &rreq->flags)) { - if (folio_index(folio) == rreq->no_unlock_folio && + if (folio->index == rreq->no_unlock_folio && test_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags)) _debug("no unlock"); else @@ -147,6 +158,15 @@ static void netfs_rreq_expand(struct netfs_io_request *rreq, } } +/* + * Begin an operation, and fetch the stored zero point value from the cookie if + * available. + */ +static int netfs_begin_cache_read(struct netfs_io_request *rreq, struct netfs_inode *ctx) +{ + return fscache_begin_read_operation(&rreq->cache_resources, netfs_i_cookie(ctx)); +} + /** * netfs_readahead - Helper to manage a read request * @ractl: The description of the readahead request @@ -180,11 +200,9 @@ void netfs_readahead(struct readahead_control *ractl) if (IS_ERR(rreq)) return; - if (ctx->ops->begin_cache_operation) { - ret = ctx->ops->begin_cache_operation(rreq); - if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS) - goto cleanup_free; - } + ret = netfs_begin_cache_read(rreq, ctx); + if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS) + goto cleanup_free; netfs_stat(&netfs_n_rh_readahead); trace_netfs_read(rreq, readahead_pos(ractl), readahead_length(ractl), @@ -192,6 +210,10 @@ void netfs_readahead(struct readahead_control *ractl) netfs_rreq_expand(rreq, ractl); + /* Set up the output buffer */ + iov_iter_xarray(&rreq->iter, ITER_DEST, &ractl->mapping->i_pages, + rreq->start, rreq->len); + /* Drop the refs on the folios here rather than in the cache or * filesystem. The locks will be dropped in netfs_rreq_unlock(). */ @@ -199,6 +221,7 @@ void netfs_readahead(struct readahead_control *ractl) ; netfs_begin_read(rreq, false); + netfs_put_request(rreq, false, netfs_rreq_trace_put_return); return; cleanup_free: @@ -223,12 +246,13 @@ EXPORT_SYMBOL(netfs_readahead); */ int netfs_read_folio(struct file *file, struct folio *folio) { - struct address_space *mapping = folio_file_mapping(folio); + struct address_space *mapping = folio->mapping; struct netfs_io_request *rreq; struct netfs_inode *ctx = netfs_inode(mapping->host); + struct folio *sink = NULL; int ret; - _enter("%lx", folio_index(folio)); + _enter("%lx", folio->index); rreq = netfs_alloc_request(mapping, file, folio_file_pos(folio), folio_size(folio), @@ -238,15 +262,64 @@ int netfs_read_folio(struct file *file, struct folio *folio) goto alloc_error; } - if (ctx->ops->begin_cache_operation) { - ret = ctx->ops->begin_cache_operation(rreq); - if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS) - goto discard; - } + ret = netfs_begin_cache_read(rreq, ctx); + if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS) + goto discard; netfs_stat(&netfs_n_rh_readpage); trace_netfs_read(rreq, rreq->start, rreq->len, netfs_read_trace_readpage); - return netfs_begin_read(rreq, true); + + /* Set up the output buffer */ + if (folio_test_dirty(folio)) { + /* Handle someone trying to read from an unflushed streaming + * write. We fiddle the buffer so that a gap at the beginning + * and/or a gap at the end get copied to, but the middle is + * discarded. + */ + struct netfs_folio *finfo = netfs_folio_info(folio); + struct bio_vec *bvec; + unsigned int from = finfo->dirty_offset; + unsigned int to = from + finfo->dirty_len; + unsigned int off = 0, i = 0; + size_t flen = folio_size(folio); + size_t nr_bvec = flen / PAGE_SIZE + 2; + size_t part; + + ret = -ENOMEM; + bvec = kmalloc_array(nr_bvec, sizeof(*bvec), GFP_KERNEL); + if (!bvec) + goto discard; + + sink = folio_alloc(GFP_KERNEL, 0); + if (!sink) + goto discard; + + trace_netfs_folio(folio, netfs_folio_trace_read_gaps); + + rreq->direct_bv = bvec; + rreq->direct_bv_count = nr_bvec; + if (from > 0) { + bvec_set_folio(&bvec[i++], folio, from, 0); + off = from; + } + while (off < to) { + part = min_t(size_t, to - off, PAGE_SIZE); + bvec_set_folio(&bvec[i++], sink, part, 0); + off += part; + } + if (to < flen) + bvec_set_folio(&bvec[i++], folio, flen - to, to); + iov_iter_bvec(&rreq->iter, ITER_DEST, bvec, i, rreq->len); + } else { + iov_iter_xarray(&rreq->iter, ITER_DEST, &mapping->i_pages, + rreq->start, rreq->len); + } + + ret = netfs_begin_read(rreq, true); + if (sink) + folio_put(sink); + netfs_put_request(rreq, false, netfs_rreq_trace_put_return); + return ret < 0 ? ret : 0; discard: netfs_put_request(rreq, false, netfs_rreq_trace_put_discard); @@ -387,14 +460,12 @@ retry: ret = PTR_ERR(rreq); goto error; } - rreq->no_unlock_folio = folio_index(folio); + rreq->no_unlock_folio = folio->index; __set_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags); - if (ctx->ops->begin_cache_operation) { - ret = ctx->ops->begin_cache_operation(rreq); - if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS) - goto error_put; - } + ret = netfs_begin_cache_read(rreq, ctx); + if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS) + goto error_put; netfs_stat(&netfs_n_rh_write_begin); trace_netfs_read(rreq, pos, len, netfs_read_trace_write_begin); @@ -405,6 +476,10 @@ retry: ractl._nr_pages = folio_nr_pages(folio); netfs_rreq_expand(rreq, &ractl); + /* Set up the output buffer */ + iov_iter_xarray(&rreq->iter, ITER_DEST, &mapping->i_pages, + rreq->start, rreq->len); + /* We hold the folio locks, so we can drop the references */ folio_get(folio); while (readahead_folio(&ractl)) @@ -413,6 +488,7 @@ retry: ret = netfs_begin_read(rreq, true); if (ret < 0) goto error; + netfs_put_request(rreq, false, netfs_rreq_trace_put_return); have_folio: ret = folio_wait_fscache_killable(folio); @@ -434,3 +510,124 @@ error: return ret; } EXPORT_SYMBOL(netfs_write_begin); + +/* + * Preload the data into a page we're proposing to write into. + */ +int netfs_prefetch_for_write(struct file *file, struct folio *folio, + size_t offset, size_t len) +{ + struct netfs_io_request *rreq; + struct address_space *mapping = folio->mapping; + struct netfs_inode *ctx = netfs_inode(mapping->host); + unsigned long long start = folio_pos(folio); + size_t flen = folio_size(folio); + int ret; + + _enter("%zx @%llx", flen, start); + + ret = -ENOMEM; + + rreq = netfs_alloc_request(mapping, file, start, flen, + NETFS_READ_FOR_WRITE); + if (IS_ERR(rreq)) { + ret = PTR_ERR(rreq); + goto error; + } + + rreq->no_unlock_folio = folio->index; + __set_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags); + ret = netfs_begin_cache_read(rreq, ctx); + if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS) + goto error_put; + + netfs_stat(&netfs_n_rh_write_begin); + trace_netfs_read(rreq, start, flen, netfs_read_trace_prefetch_for_write); + + /* Set up the output buffer */ + iov_iter_xarray(&rreq->iter, ITER_DEST, &mapping->i_pages, + rreq->start, rreq->len); + + ret = netfs_begin_read(rreq, true); + netfs_put_request(rreq, false, netfs_rreq_trace_put_return); + return ret; + +error_put: + netfs_put_request(rreq, false, netfs_rreq_trace_put_discard); +error: + _leave(" = %d", ret); + return ret; +} + +/** + * netfs_buffered_read_iter - Filesystem buffered I/O read routine + * @iocb: kernel I/O control block + * @iter: destination for the data read + * + * This is the ->read_iter() routine for all filesystems that can use the page + * cache directly. + * + * The IOCB_NOWAIT flag in iocb->ki_flags indicates that -EAGAIN shall be + * returned when no data can be read without waiting for I/O requests to + * complete; it doesn't prevent readahead. + * + * The IOCB_NOIO flag in iocb->ki_flags indicates that no new I/O requests + * shall be made for the read or for readahead. When no data can be read, + * -EAGAIN shall be returned. When readahead would be triggered, a partial, + * possibly empty read shall be returned. + * + * Return: + * * number of bytes copied, even for partial reads + * * negative error code (or 0 if IOCB_NOIO) if nothing was read + */ +ssize_t netfs_buffered_read_iter(struct kiocb *iocb, struct iov_iter *iter) +{ + struct inode *inode = file_inode(iocb->ki_filp); + struct netfs_inode *ictx = netfs_inode(inode); + ssize_t ret; + + if (WARN_ON_ONCE((iocb->ki_flags & IOCB_DIRECT) || + test_bit(NETFS_ICTX_UNBUFFERED, &ictx->flags))) + return -EINVAL; + + ret = netfs_start_io_read(inode); + if (ret == 0) { + ret = filemap_read(iocb, iter, 0); + netfs_end_io_read(inode); + } + return ret; +} +EXPORT_SYMBOL(netfs_buffered_read_iter); + +/** + * netfs_file_read_iter - Generic filesystem read routine + * @iocb: kernel I/O control block + * @iter: destination for the data read + * + * This is the ->read_iter() routine for all filesystems that can use the page + * cache directly. + * + * The IOCB_NOWAIT flag in iocb->ki_flags indicates that -EAGAIN shall be + * returned when no data can be read without waiting for I/O requests to + * complete; it doesn't prevent readahead. + * + * The IOCB_NOIO flag in iocb->ki_flags indicates that no new I/O requests + * shall be made for the read or for readahead. When no data can be read, + * -EAGAIN shall be returned. When readahead would be triggered, a partial, + * possibly empty read shall be returned. + * + * Return: + * * number of bytes copied, even for partial reads + * * negative error code (or 0 if IOCB_NOIO) if nothing was read + */ +ssize_t netfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter) +{ + struct netfs_inode *ictx = netfs_inode(iocb->ki_filp->f_mapping->host); + + if ((iocb->ki_flags & IOCB_DIRECT) || + test_bit(NETFS_ICTX_UNBUFFERED, &ictx->flags)) + return netfs_unbuffered_read_iter(iocb, iter); + + return netfs_buffered_read_iter(iocb, iter); +} +EXPORT_SYMBOL(netfs_file_read_iter); diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c new file mode 100644 index 0000000000..267b622d92 --- /dev/null +++ b/fs/netfs/buffered_write.c @@ -0,0 +1,1258 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Network filesystem high-level write support. + * + * Copyright (C) 2023 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include <linux/export.h> +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/pagemap.h> +#include <linux/slab.h> +#include <linux/pagevec.h> +#include "internal.h" + +/* + * Determined write method. Adjust netfs_folio_traces if this is changed. + */ +enum netfs_how_to_modify { + NETFS_FOLIO_IS_UPTODATE, /* Folio is uptodate already */ + NETFS_JUST_PREFETCH, /* We have to read the folio anyway */ + NETFS_WHOLE_FOLIO_MODIFY, /* We're going to overwrite the whole folio */ + NETFS_MODIFY_AND_CLEAR, /* We can assume there is no data to be downloaded. */ + NETFS_STREAMING_WRITE, /* Store incomplete data in non-uptodate page. */ + NETFS_STREAMING_WRITE_CONT, /* Continue streaming write. */ + NETFS_FLUSH_CONTENT, /* Flush incompatible content. */ +}; + +static void netfs_cleanup_buffered_write(struct netfs_io_request *wreq); + +static void netfs_set_group(struct folio *folio, struct netfs_group *netfs_group) +{ + if (netfs_group && !folio_get_private(folio)) + folio_attach_private(folio, netfs_get_group(netfs_group)); +} + +#if IS_ENABLED(CONFIG_FSCACHE) +static void netfs_folio_start_fscache(bool caching, struct folio *folio) +{ + if (caching) + folio_start_fscache(folio); +} +#else +static void netfs_folio_start_fscache(bool caching, struct folio *folio) +{ +} +#endif + +/* + * Decide how we should modify a folio. We might be attempting to do + * write-streaming, in which case we don't want to a local RMW cycle if we can + * avoid it. If we're doing local caching or content crypto, we award that + * priority over avoiding RMW. If the file is open readably, then we also + * assume that we may want to read what we wrote. + */ +static enum netfs_how_to_modify netfs_how_to_modify(struct netfs_inode *ctx, + struct file *file, + struct folio *folio, + void *netfs_group, + size_t flen, + size_t offset, + size_t len, + bool maybe_trouble) +{ + struct netfs_folio *finfo = netfs_folio_info(folio); + loff_t pos = folio_file_pos(folio); + + _enter(""); + + if (netfs_folio_group(folio) != netfs_group) + return NETFS_FLUSH_CONTENT; + + if (folio_test_uptodate(folio)) + return NETFS_FOLIO_IS_UPTODATE; + + if (pos >= ctx->zero_point) + return NETFS_MODIFY_AND_CLEAR; + + if (!maybe_trouble && offset == 0 && len >= flen) + return NETFS_WHOLE_FOLIO_MODIFY; + + if (file->f_mode & FMODE_READ) + goto no_write_streaming; + if (test_bit(NETFS_ICTX_NO_WRITE_STREAMING, &ctx->flags)) + goto no_write_streaming; + + if (netfs_is_cache_enabled(ctx)) { + /* We don't want to get a streaming write on a file that loses + * caching service temporarily because the backing store got + * culled. + */ + if (!test_bit(NETFS_ICTX_NO_WRITE_STREAMING, &ctx->flags)) + set_bit(NETFS_ICTX_NO_WRITE_STREAMING, &ctx->flags); + goto no_write_streaming; + } + + if (!finfo) + return NETFS_STREAMING_WRITE; + + /* We can continue a streaming write only if it continues on from the + * previous. If it overlaps, we must flush lest we suffer a partial + * copy and disjoint dirty regions. + */ + if (offset == finfo->dirty_offset + finfo->dirty_len) + return NETFS_STREAMING_WRITE_CONT; + return NETFS_FLUSH_CONTENT; + +no_write_streaming: + if (finfo) { + netfs_stat(&netfs_n_wh_wstream_conflict); + return NETFS_FLUSH_CONTENT; + } + return NETFS_JUST_PREFETCH; +} + +/* + * Grab a folio for writing and lock it. Attempt to allocate as large a folio + * as possible to hold as much of the remaining length as possible in one go. + */ +static struct folio *netfs_grab_folio_for_write(struct address_space *mapping, + loff_t pos, size_t part) +{ + pgoff_t index = pos / PAGE_SIZE; + fgf_t fgp_flags = FGP_WRITEBEGIN; + + if (mapping_large_folio_support(mapping)) + fgp_flags |= fgf_set_order(pos % PAGE_SIZE + part); + + return __filemap_get_folio(mapping, index, fgp_flags, + mapping_gfp_mask(mapping)); +} + +/** + * netfs_perform_write - Copy data into the pagecache. + * @iocb: The operation parameters + * @iter: The source buffer + * @netfs_group: Grouping for dirty pages (eg. ceph snaps). + * + * Copy data into pagecache pages attached to the inode specified by @iocb. + * The caller must hold appropriate inode locks. + * + * Dirty pages are tagged with a netfs_folio struct if they're not up to date + * to indicate the range modified. Dirty pages may also be tagged with a + * netfs-specific grouping such that data from an old group gets flushed before + * a new one is started. + */ +ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, + struct netfs_group *netfs_group) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file_inode(file); + struct address_space *mapping = inode->i_mapping; + struct netfs_inode *ctx = netfs_inode(inode); + struct writeback_control wbc = { + .sync_mode = WB_SYNC_NONE, + .for_sync = true, + .nr_to_write = LONG_MAX, + .range_start = iocb->ki_pos, + .range_end = iocb->ki_pos + iter->count, + }; + struct netfs_io_request *wreq = NULL; + struct netfs_folio *finfo; + struct folio *folio; + enum netfs_how_to_modify howto; + enum netfs_folio_trace trace; + unsigned int bdp_flags = (iocb->ki_flags & IOCB_SYNC) ? 0: BDP_ASYNC; + ssize_t written = 0, ret, ret2; + loff_t i_size, pos = iocb->ki_pos, from, to; + size_t max_chunk = PAGE_SIZE << MAX_PAGECACHE_ORDER; + bool maybe_trouble = false; + + if (unlikely(test_bit(NETFS_ICTX_WRITETHROUGH, &ctx->flags) || + iocb->ki_flags & (IOCB_DSYNC | IOCB_SYNC)) + ) { + wbc_attach_fdatawrite_inode(&wbc, mapping->host); + + ret = filemap_write_and_wait_range(mapping, pos, pos + iter->count); + if (ret < 0) { + wbc_detach_inode(&wbc); + goto out; + } + + wreq = netfs_begin_writethrough(iocb, iter->count); + if (IS_ERR(wreq)) { + wbc_detach_inode(&wbc); + ret = PTR_ERR(wreq); + wreq = NULL; + goto out; + } + if (!is_sync_kiocb(iocb)) + wreq->iocb = iocb; + wreq->cleanup = netfs_cleanup_buffered_write; + } + + do { + size_t flen; + size_t offset; /* Offset into pagecache folio */ + size_t part; /* Bytes to write to folio */ + size_t copied; /* Bytes copied from user */ + + ret = balance_dirty_pages_ratelimited_flags(mapping, bdp_flags); + if (unlikely(ret < 0)) + break; + + offset = pos & (max_chunk - 1); + part = min(max_chunk - offset, iov_iter_count(iter)); + + /* Bring in the user pages that we will copy from _first_ lest + * we hit a nasty deadlock on copying from the same page as + * we're writing to, without it being marked uptodate. + * + * Not only is this an optimisation, but it is also required to + * check that the address is actually valid, when atomic + * usercopies are used below. + * + * We rely on the page being held onto long enough by the LRU + * that we can grab it below if this causes it to be read. + */ + ret = -EFAULT; + if (unlikely(fault_in_iov_iter_readable(iter, part) == part)) + break; + + folio = netfs_grab_folio_for_write(mapping, pos, part); + if (IS_ERR(folio)) { + ret = PTR_ERR(folio); + break; + } + + flen = folio_size(folio); + offset = pos & (flen - 1); + part = min_t(size_t, flen - offset, part); + + if (signal_pending(current)) { + ret = written ? -EINTR : -ERESTARTSYS; + goto error_folio_unlock; + } + + /* See if we need to prefetch the area we're going to modify. + * We need to do this before we get a lock on the folio in case + * there's more than one writer competing for the same cache + * block. + */ + howto = netfs_how_to_modify(ctx, file, folio, netfs_group, + flen, offset, part, maybe_trouble); + _debug("howto %u", howto); + switch (howto) { + case NETFS_JUST_PREFETCH: + ret = netfs_prefetch_for_write(file, folio, offset, part); + if (ret < 0) { + _debug("prefetch = %zd", ret); + goto error_folio_unlock; + } + break; + case NETFS_FOLIO_IS_UPTODATE: + case NETFS_WHOLE_FOLIO_MODIFY: + case NETFS_STREAMING_WRITE_CONT: + break; + case NETFS_MODIFY_AND_CLEAR: + zero_user_segment(&folio->page, 0, offset); + break; + case NETFS_STREAMING_WRITE: + ret = -EIO; + if (WARN_ON(folio_get_private(folio))) + goto error_folio_unlock; + break; + case NETFS_FLUSH_CONTENT: + trace_netfs_folio(folio, netfs_flush_content); + from = folio_pos(folio); + to = from + folio_size(folio) - 1; + folio_unlock(folio); + folio_put(folio); + ret = filemap_write_and_wait_range(mapping, from, to); + if (ret < 0) + goto error_folio_unlock; + continue; + } + + if (mapping_writably_mapped(mapping)) + flush_dcache_folio(folio); + + copied = copy_folio_from_iter_atomic(folio, offset, part, iter); + + flush_dcache_folio(folio); + + /* Deal with a (partially) failed copy */ + if (copied == 0) { + ret = -EFAULT; + goto error_folio_unlock; + } + + trace = (enum netfs_folio_trace)howto; + switch (howto) { + case NETFS_FOLIO_IS_UPTODATE: + case NETFS_JUST_PREFETCH: + netfs_set_group(folio, netfs_group); + break; + case NETFS_MODIFY_AND_CLEAR: + zero_user_segment(&folio->page, offset + copied, flen); + netfs_set_group(folio, netfs_group); + folio_mark_uptodate(folio); + break; + case NETFS_WHOLE_FOLIO_MODIFY: + if (unlikely(copied < part)) { + maybe_trouble = true; + iov_iter_revert(iter, copied); + copied = 0; + goto retry; + } + netfs_set_group(folio, netfs_group); + folio_mark_uptodate(folio); + break; + case NETFS_STREAMING_WRITE: + if (offset == 0 && copied == flen) { + netfs_set_group(folio, netfs_group); + folio_mark_uptodate(folio); + trace = netfs_streaming_filled_page; + break; + } + finfo = kzalloc(sizeof(*finfo), GFP_KERNEL); + if (!finfo) { + iov_iter_revert(iter, copied); + ret = -ENOMEM; + goto error_folio_unlock; + } + finfo->netfs_group = netfs_get_group(netfs_group); + finfo->dirty_offset = offset; + finfo->dirty_len = copied; + folio_attach_private(folio, (void *)((unsigned long)finfo | + NETFS_FOLIO_INFO)); + break; + case NETFS_STREAMING_WRITE_CONT: + finfo = netfs_folio_info(folio); + finfo->dirty_len += copied; + if (finfo->dirty_offset == 0 && finfo->dirty_len == flen) { + if (finfo->netfs_group) + folio_change_private(folio, finfo->netfs_group); + else + folio_detach_private(folio); + folio_mark_uptodate(folio); + kfree(finfo); + trace = netfs_streaming_cont_filled_page; + } + break; + default: + WARN(true, "Unexpected modify type %u ix=%lx\n", + howto, folio->index); + ret = -EIO; + goto error_folio_unlock; + } + + trace_netfs_folio(folio, trace); + + /* Update the inode size if we moved the EOF marker */ + i_size = i_size_read(inode); + pos += copied; + if (pos > i_size) { + if (ctx->ops->update_i_size) { + ctx->ops->update_i_size(inode, pos); + } else { + i_size_write(inode, pos); +#if IS_ENABLED(CONFIG_FSCACHE) + fscache_update_cookie(ctx->cache, NULL, &pos); +#endif + } + } + written += copied; + + if (likely(!wreq)) { + folio_mark_dirty(folio); + } else { + if (folio_test_dirty(folio)) + /* Sigh. mmap. */ + folio_clear_dirty_for_io(folio); + /* We make multiple writes to the folio... */ + if (!folio_test_writeback(folio)) { + folio_wait_fscache(folio); + folio_start_writeback(folio); + folio_start_fscache(folio); + if (wreq->iter.count == 0) + trace_netfs_folio(folio, netfs_folio_trace_wthru); + else + trace_netfs_folio(folio, netfs_folio_trace_wthru_plus); + } + netfs_advance_writethrough(wreq, copied, + offset + copied == flen); + } + retry: + folio_unlock(folio); + folio_put(folio); + folio = NULL; + + cond_resched(); + } while (iov_iter_count(iter)); + +out: + if (unlikely(wreq)) { + ret2 = netfs_end_writethrough(wreq, iocb); + wbc_detach_inode(&wbc); + if (ret2 == -EIOCBQUEUED) + return ret2; + if (ret == 0) + ret = ret2; + } + + iocb->ki_pos += written; + _leave(" = %zd [%zd]", written, ret); + return written ? written : ret; + +error_folio_unlock: + folio_unlock(folio); + folio_put(folio); + goto out; +} +EXPORT_SYMBOL(netfs_perform_write); + +/** + * netfs_buffered_write_iter_locked - write data to a file + * @iocb: IO state structure (file, offset, etc.) + * @from: iov_iter with data to write + * @netfs_group: Grouping for dirty pages (eg. ceph snaps). + * + * This function does all the work needed for actually writing data to a + * file. It does all basic checks, removes SUID from the file, updates + * modification times and calls proper subroutines depending on whether we + * do direct IO or a standard buffered write. + * + * The caller must hold appropriate locks around this function and have called + * generic_write_checks() already. The caller is also responsible for doing + * any necessary syncing afterwards. + * + * This function does *not* take care of syncing data in case of O_SYNC write. + * A caller has to handle it. This is mainly due to the fact that we want to + * avoid syncing under i_rwsem. + * + * Return: + * * number of bytes written, even for truncated writes + * * negative error code if no data has been written at all + */ +ssize_t netfs_buffered_write_iter_locked(struct kiocb *iocb, struct iov_iter *from, + struct netfs_group *netfs_group) +{ + struct file *file = iocb->ki_filp; + ssize_t ret; + + trace_netfs_write_iter(iocb, from); + + ret = file_remove_privs(file); + if (ret) + return ret; + + ret = file_update_time(file); + if (ret) + return ret; + + return netfs_perform_write(iocb, from, netfs_group); +} +EXPORT_SYMBOL(netfs_buffered_write_iter_locked); + +/** + * netfs_file_write_iter - write data to a file + * @iocb: IO state structure + * @from: iov_iter with data to write + * + * Perform a write to a file, writing into the pagecache if possible and doing + * an unbuffered write instead if not. + * + * Return: + * * Negative error code if no data has been written at all of + * vfs_fsync_range() failed for a synchronous write + * * Number of bytes written, even for truncated writes + */ +ssize_t netfs_file_write_iter(struct kiocb *iocb, struct iov_iter *from) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file->f_mapping->host; + struct netfs_inode *ictx = netfs_inode(inode); + ssize_t ret; + + _enter("%llx,%zx,%llx", iocb->ki_pos, iov_iter_count(from), i_size_read(inode)); + + if (!iov_iter_count(from)) + return 0; + + if ((iocb->ki_flags & IOCB_DIRECT) || + test_bit(NETFS_ICTX_UNBUFFERED, &ictx->flags)) + return netfs_unbuffered_write_iter(iocb, from); + + ret = netfs_start_io_write(inode); + if (ret < 0) + return ret; + + ret = generic_write_checks(iocb, from); + if (ret > 0) + ret = netfs_buffered_write_iter_locked(iocb, from, NULL); + netfs_end_io_write(inode); + if (ret > 0) + ret = generic_write_sync(iocb, ret); + return ret; +} +EXPORT_SYMBOL(netfs_file_write_iter); + +/* + * Notification that a previously read-only page is about to become writable. + * Note that the caller indicates a single page of a multipage folio. + */ +vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_group) +{ + struct folio *folio = page_folio(vmf->page); + struct file *file = vmf->vma->vm_file; + struct inode *inode = file_inode(file); + vm_fault_t ret = VM_FAULT_RETRY; + int err; + + _enter("%lx", folio->index); + + sb_start_pagefault(inode->i_sb); + + if (folio_wait_writeback_killable(folio)) + goto out; + + if (folio_lock_killable(folio) < 0) + goto out; + + /* Can we see a streaming write here? */ + if (WARN_ON(!folio_test_uptodate(folio))) { + ret = VM_FAULT_SIGBUS | VM_FAULT_LOCKED; + goto out; + } + + if (netfs_folio_group(folio) != netfs_group) { + folio_unlock(folio); + err = filemap_fdatawait_range(inode->i_mapping, + folio_pos(folio), + folio_pos(folio) + folio_size(folio)); + switch (err) { + case 0: + ret = VM_FAULT_RETRY; + goto out; + case -ENOMEM: + ret = VM_FAULT_OOM; + goto out; + default: + ret = VM_FAULT_SIGBUS; + goto out; + } + } + + if (folio_test_dirty(folio)) + trace_netfs_folio(folio, netfs_folio_trace_mkwrite_plus); + else + trace_netfs_folio(folio, netfs_folio_trace_mkwrite); + netfs_set_group(folio, netfs_group); + file_update_time(file); + ret = VM_FAULT_LOCKED; +out: + sb_end_pagefault(inode->i_sb); + return ret; +} +EXPORT_SYMBOL(netfs_page_mkwrite); + +/* + * Kill all the pages in the given range + */ +static void netfs_kill_pages(struct address_space *mapping, + loff_t start, loff_t len) +{ + struct folio *folio; + pgoff_t index = start / PAGE_SIZE; + pgoff_t last = (start + len - 1) / PAGE_SIZE, next; + + _enter("%llx-%llx", start, start + len - 1); + + do { + _debug("kill %lx (to %lx)", index, last); + + folio = filemap_get_folio(mapping, index); + if (IS_ERR(folio)) { + next = index + 1; + continue; + } + + next = folio_next_index(folio); + + trace_netfs_folio(folio, netfs_folio_trace_kill); + folio_clear_uptodate(folio); + if (folio_test_fscache(folio)) + folio_end_fscache(folio); + folio_end_writeback(folio); + folio_lock(folio); + generic_error_remove_folio(mapping, folio); + folio_unlock(folio); + folio_put(folio); + + } while (index = next, index <= last); + + _leave(""); +} + +/* + * Redirty all the pages in a given range. + */ +static void netfs_redirty_pages(struct address_space *mapping, + loff_t start, loff_t len) +{ + struct folio *folio; + pgoff_t index = start / PAGE_SIZE; + pgoff_t last = (start + len - 1) / PAGE_SIZE, next; + + _enter("%llx-%llx", start, start + len - 1); + + do { + _debug("redirty %llx @%llx", len, start); + + folio = filemap_get_folio(mapping, index); + if (IS_ERR(folio)) { + next = index + 1; + continue; + } + + next = folio_next_index(folio); + trace_netfs_folio(folio, netfs_folio_trace_redirty); + filemap_dirty_folio(mapping, folio); + if (folio_test_fscache(folio)) + folio_end_fscache(folio); + folio_end_writeback(folio); + folio_put(folio); + } while (index = next, index <= last); + + balance_dirty_pages_ratelimited(mapping); + + _leave(""); +} + +/* + * Completion of write to server + */ +static void netfs_pages_written_back(struct netfs_io_request *wreq) +{ + struct address_space *mapping = wreq->mapping; + struct netfs_folio *finfo; + struct netfs_group *group = NULL; + struct folio *folio; + pgoff_t last; + int gcount = 0; + + XA_STATE(xas, &mapping->i_pages, wreq->start / PAGE_SIZE); + + _enter("%llx-%llx", wreq->start, wreq->start + wreq->len); + + rcu_read_lock(); + + last = (wreq->start + wreq->len - 1) / PAGE_SIZE; + xas_for_each(&xas, folio, last) { + WARN(!folio_test_writeback(folio), + "bad %zx @%llx page %lx %lx\n", + wreq->len, wreq->start, folio->index, last); + + if ((finfo = netfs_folio_info(folio))) { + /* Streaming writes cannot be redirtied whilst under + * writeback, so discard the streaming record. + */ + folio_detach_private(folio); + group = finfo->netfs_group; + gcount++; + trace_netfs_folio(folio, netfs_folio_trace_clear_s); + kfree(finfo); + } else if ((group = netfs_folio_group(folio))) { + /* Need to detach the group pointer if the page didn't + * get redirtied. If it has been redirtied, then it + * must be within the same group. + */ + if (folio_test_dirty(folio)) { + trace_netfs_folio(folio, netfs_folio_trace_redirtied); + goto end_wb; + } + if (folio_trylock(folio)) { + if (!folio_test_dirty(folio)) { + folio_detach_private(folio); + gcount++; + trace_netfs_folio(folio, netfs_folio_trace_clear_g); + } else { + trace_netfs_folio(folio, netfs_folio_trace_redirtied); + } + folio_unlock(folio); + goto end_wb; + } + + xas_pause(&xas); + rcu_read_unlock(); + folio_lock(folio); + if (!folio_test_dirty(folio)) { + folio_detach_private(folio); + gcount++; + trace_netfs_folio(folio, netfs_folio_trace_clear_g); + } else { + trace_netfs_folio(folio, netfs_folio_trace_redirtied); + } + folio_unlock(folio); + rcu_read_lock(); + } else { + trace_netfs_folio(folio, netfs_folio_trace_clear); + } + end_wb: + if (folio_test_fscache(folio)) + folio_end_fscache(folio); + xas_advance(&xas, folio_next_index(folio) - 1); + folio_end_writeback(folio); + } + + rcu_read_unlock(); + netfs_put_group_many(group, gcount); + _leave(""); +} + +/* + * Deal with the disposition of the folios that are under writeback to close + * out the operation. + */ +static void netfs_cleanup_buffered_write(struct netfs_io_request *wreq) +{ + struct address_space *mapping = wreq->mapping; + + _enter(""); + + switch (wreq->error) { + case 0: + netfs_pages_written_back(wreq); + break; + + default: + pr_notice("R=%08x Unexpected error %d\n", wreq->debug_id, wreq->error); + fallthrough; + case -EACCES: + case -EPERM: + case -ENOKEY: + case -EKEYEXPIRED: + case -EKEYREJECTED: + case -EKEYREVOKED: + case -ENETRESET: + case -EDQUOT: + case -ENOSPC: + netfs_redirty_pages(mapping, wreq->start, wreq->len); + break; + + case -EROFS: + case -EIO: + case -EREMOTEIO: + case -EFBIG: + case -ENOENT: + case -ENOMEDIUM: + case -ENXIO: + netfs_kill_pages(mapping, wreq->start, wreq->len); + break; + } + + if (wreq->error) + mapping_set_error(mapping, wreq->error); + if (wreq->netfs_ops->done) + wreq->netfs_ops->done(wreq); +} + +/* + * Extend the region to be written back to include subsequent contiguously + * dirty pages if possible, but don't sleep while doing so. + * + * If this page holds new content, then we can include filler zeros in the + * writeback. + */ +static void netfs_extend_writeback(struct address_space *mapping, + struct netfs_group *group, + struct xa_state *xas, + long *_count, + loff_t start, + loff_t max_len, + bool caching, + size_t *_len, + size_t *_top) +{ + struct netfs_folio *finfo; + struct folio_batch fbatch; + struct folio *folio; + unsigned int i; + pgoff_t index = (start + *_len) / PAGE_SIZE; + size_t len; + void *priv; + bool stop = true; + + folio_batch_init(&fbatch); + + do { + /* Firstly, we gather up a batch of contiguous dirty pages + * under the RCU read lock - but we can't clear the dirty flags + * there if any of those pages are mapped. + */ + rcu_read_lock(); + + xas_for_each(xas, folio, ULONG_MAX) { + stop = true; + if (xas_retry(xas, folio)) + continue; + if (xa_is_value(folio)) + break; + if (folio->index != index) { + xas_reset(xas); + break; + } + + if (!folio_try_get_rcu(folio)) { + xas_reset(xas); + continue; + } + + /* Has the folio moved or been split? */ + if (unlikely(folio != xas_reload(xas))) { + folio_put(folio); + xas_reset(xas); + break; + } + + if (!folio_trylock(folio)) { + folio_put(folio); + xas_reset(xas); + break; + } + if (!folio_test_dirty(folio) || + folio_test_writeback(folio) || + folio_test_fscache(folio)) { + folio_unlock(folio); + folio_put(folio); + xas_reset(xas); + break; + } + + stop = false; + len = folio_size(folio); + priv = folio_get_private(folio); + if ((const struct netfs_group *)priv != group) { + stop = true; + finfo = netfs_folio_info(folio); + if (finfo->netfs_group != group || + finfo->dirty_offset > 0) { + folio_unlock(folio); + folio_put(folio); + xas_reset(xas); + break; + } + len = finfo->dirty_len; + } + + *_top += folio_size(folio); + index += folio_nr_pages(folio); + *_count -= folio_nr_pages(folio); + *_len += len; + if (*_len >= max_len || *_count <= 0) + stop = true; + + if (!folio_batch_add(&fbatch, folio)) + break; + if (stop) + break; + } + + xas_pause(xas); + rcu_read_unlock(); + + /* Now, if we obtained any folios, we can shift them to being + * writable and mark them for caching. + */ + if (!folio_batch_count(&fbatch)) + break; + + for (i = 0; i < folio_batch_count(&fbatch); i++) { + folio = fbatch.folios[i]; + trace_netfs_folio(folio, netfs_folio_trace_store_plus); + + if (!folio_clear_dirty_for_io(folio)) + BUG(); + folio_start_writeback(folio); + netfs_folio_start_fscache(caching, folio); + folio_unlock(folio); + } + + folio_batch_release(&fbatch); + cond_resched(); + } while (!stop); +} + +/* + * Synchronously write back the locked page and any subsequent non-locked dirty + * pages. + */ +static ssize_t netfs_write_back_from_locked_folio(struct address_space *mapping, + struct writeback_control *wbc, + struct netfs_group *group, + struct xa_state *xas, + struct folio *folio, + unsigned long long start, + unsigned long long end) +{ + struct netfs_io_request *wreq; + struct netfs_folio *finfo; + struct netfs_inode *ctx = netfs_inode(mapping->host); + unsigned long long i_size = i_size_read(&ctx->inode); + size_t len, max_len; + bool caching = netfs_is_cache_enabled(ctx); + long count = wbc->nr_to_write; + int ret; + + _enter(",%lx,%llx-%llx,%u", folio->index, start, end, caching); + + wreq = netfs_alloc_request(mapping, NULL, start, folio_size(folio), + NETFS_WRITEBACK); + if (IS_ERR(wreq)) { + folio_unlock(folio); + return PTR_ERR(wreq); + } + + if (!folio_clear_dirty_for_io(folio)) + BUG(); + folio_start_writeback(folio); + netfs_folio_start_fscache(caching, folio); + + count -= folio_nr_pages(folio); + + /* Find all consecutive lockable dirty pages that have contiguous + * written regions, stopping when we find a page that is not + * immediately lockable, is not dirty or is missing, or we reach the + * end of the range. + */ + trace_netfs_folio(folio, netfs_folio_trace_store); + + len = wreq->len; + finfo = netfs_folio_info(folio); + if (finfo) { + start += finfo->dirty_offset; + if (finfo->dirty_offset + finfo->dirty_len != len) { + len = finfo->dirty_len; + goto cant_expand; + } + len = finfo->dirty_len; + } + + if (start < i_size) { + /* Trim the write to the EOF; the extra data is ignored. Also + * put an upper limit on the size of a single storedata op. + */ + max_len = 65536 * 4096; + max_len = min_t(unsigned long long, max_len, end - start + 1); + max_len = min_t(unsigned long long, max_len, i_size - start); + + if (len < max_len) + netfs_extend_writeback(mapping, group, xas, &count, start, + max_len, caching, &len, &wreq->upper_len); + } + +cant_expand: + len = min_t(unsigned long long, len, i_size - start); + + /* We now have a contiguous set of dirty pages, each with writeback + * set; the first page is still locked at this point, but all the rest + * have been unlocked. + */ + folio_unlock(folio); + wreq->start = start; + wreq->len = len; + + if (start < i_size) { + _debug("write back %zx @%llx [%llx]", len, start, i_size); + + /* Speculatively write to the cache. We have to fix this up + * later if the store fails. + */ + wreq->cleanup = netfs_cleanup_buffered_write; + + iov_iter_xarray(&wreq->iter, ITER_SOURCE, &mapping->i_pages, start, + wreq->upper_len); + __set_bit(NETFS_RREQ_UPLOAD_TO_SERVER, &wreq->flags); + ret = netfs_begin_write(wreq, true, netfs_write_trace_writeback); + if (ret == 0 || ret == -EIOCBQUEUED) + wbc->nr_to_write -= len / PAGE_SIZE; + } else { + _debug("write discard %zx @%llx [%llx]", len, start, i_size); + + /* The dirty region was entirely beyond the EOF. */ + fscache_clear_page_bits(mapping, start, len, caching); + netfs_pages_written_back(wreq); + ret = 0; + } + + netfs_put_request(wreq, false, netfs_rreq_trace_put_return); + _leave(" = 1"); + return 1; +} + +/* + * Write a region of pages back to the server + */ +static ssize_t netfs_writepages_begin(struct address_space *mapping, + struct writeback_control *wbc, + struct netfs_group *group, + struct xa_state *xas, + unsigned long long *_start, + unsigned long long end) +{ + const struct netfs_folio *finfo; + struct folio *folio; + unsigned long long start = *_start; + ssize_t ret; + void *priv; + int skips = 0; + + _enter("%llx,%llx,", start, end); + +search_again: + /* Find the first dirty page in the group. */ + rcu_read_lock(); + + for (;;) { + folio = xas_find_marked(xas, end / PAGE_SIZE, PAGECACHE_TAG_DIRTY); + if (xas_retry(xas, folio) || xa_is_value(folio)) + continue; + if (!folio) + break; + + if (!folio_try_get_rcu(folio)) { + xas_reset(xas); + continue; + } + + if (unlikely(folio != xas_reload(xas))) { + folio_put(folio); + xas_reset(xas); + continue; + } + + /* Skip any dirty folio that's not in the group of interest. */ + priv = folio_get_private(folio); + if ((const struct netfs_group *)priv != group) { + finfo = netfs_folio_info(folio); + if (finfo->netfs_group != group) { + folio_put(folio); + continue; + } + } + + xas_pause(xas); + break; + } + rcu_read_unlock(); + if (!folio) + return 0; + + start = folio_pos(folio); /* May regress with THPs */ + + _debug("wback %lx", folio->index); + + /* At this point we hold neither the i_pages lock nor the page lock: + * the page may be truncated or invalidated (changing page->mapping to + * NULL), or even swizzled back from swapper_space to tmpfs file + * mapping + */ +lock_again: + if (wbc->sync_mode != WB_SYNC_NONE) { + ret = folio_lock_killable(folio); + if (ret < 0) + return ret; + } else { + if (!folio_trylock(folio)) + goto search_again; + } + + if (folio->mapping != mapping || + !folio_test_dirty(folio)) { + start += folio_size(folio); + folio_unlock(folio); + goto search_again; + } + + if (folio_test_writeback(folio) || + folio_test_fscache(folio)) { + folio_unlock(folio); + if (wbc->sync_mode != WB_SYNC_NONE) { + folio_wait_writeback(folio); +#ifdef CONFIG_FSCACHE + folio_wait_fscache(folio); +#endif + goto lock_again; + } + + start += folio_size(folio); + if (wbc->sync_mode == WB_SYNC_NONE) { + if (skips >= 5 || need_resched()) { + ret = 0; + goto out; + } + skips++; + } + goto search_again; + } + + ret = netfs_write_back_from_locked_folio(mapping, wbc, group, xas, + folio, start, end); +out: + if (ret > 0) + *_start = start + ret; + _leave(" = %zd [%llx]", ret, *_start); + return ret; +} + +/* + * Write a region of pages back to the server + */ +static int netfs_writepages_region(struct address_space *mapping, + struct writeback_control *wbc, + struct netfs_group *group, + unsigned long long *_start, + unsigned long long end) +{ + ssize_t ret; + + XA_STATE(xas, &mapping->i_pages, *_start / PAGE_SIZE); + + do { + ret = netfs_writepages_begin(mapping, wbc, group, &xas, + _start, end); + if (ret > 0 && wbc->nr_to_write > 0) + cond_resched(); + } while (ret > 0 && wbc->nr_to_write > 0); + + return ret > 0 ? 0 : ret; +} + +/* + * write some of the pending data back to the server + */ +int netfs_writepages(struct address_space *mapping, + struct writeback_control *wbc) +{ + struct netfs_group *group = NULL; + loff_t start, end; + int ret; + + _enter(""); + + /* We have to be careful as we can end up racing with setattr() + * truncating the pagecache since the caller doesn't take a lock here + * to prevent it. + */ + + if (wbc->range_cyclic && mapping->writeback_index) { + start = mapping->writeback_index * PAGE_SIZE; + ret = netfs_writepages_region(mapping, wbc, group, + &start, LLONG_MAX); + if (ret < 0) + goto out; + + if (wbc->nr_to_write <= 0) { + mapping->writeback_index = start / PAGE_SIZE; + goto out; + } + + start = 0; + end = mapping->writeback_index * PAGE_SIZE; + mapping->writeback_index = 0; + ret = netfs_writepages_region(mapping, wbc, group, &start, end); + if (ret == 0) + mapping->writeback_index = start / PAGE_SIZE; + } else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) { + start = 0; + ret = netfs_writepages_region(mapping, wbc, group, + &start, LLONG_MAX); + if (wbc->nr_to_write > 0 && ret == 0) + mapping->writeback_index = start / PAGE_SIZE; + } else { + start = wbc->range_start; + ret = netfs_writepages_region(mapping, wbc, group, + &start, wbc->range_end); + } + +out: + _leave(" = %d", ret); + return ret; +} +EXPORT_SYMBOL(netfs_writepages); + +/* + * Deal with the disposition of a laundered folio. + */ +static void netfs_cleanup_launder_folio(struct netfs_io_request *wreq) +{ + if (wreq->error) { + pr_notice("R=%08x Laundering error %d\n", wreq->debug_id, wreq->error); + mapping_set_error(wreq->mapping, wreq->error); + } +} + +/** + * netfs_launder_folio - Clean up a dirty folio that's being invalidated + * @folio: The folio to clean + * + * This is called to write back a folio that's being invalidated when an inode + * is getting torn down. Ideally, writepages would be used instead. + */ +int netfs_launder_folio(struct folio *folio) +{ + struct netfs_io_request *wreq; + struct address_space *mapping = folio->mapping; + struct netfs_folio *finfo = netfs_folio_info(folio); + struct netfs_group *group = netfs_folio_group(folio); + struct bio_vec bvec; + unsigned long long i_size = i_size_read(mapping->host); + unsigned long long start = folio_pos(folio); + size_t offset = 0, len; + int ret = 0; + + if (finfo) { + offset = finfo->dirty_offset; + start += offset; + len = finfo->dirty_len; + } else { + len = folio_size(folio); + } + len = min_t(unsigned long long, len, i_size - start); + + wreq = netfs_alloc_request(mapping, NULL, start, len, NETFS_LAUNDER_WRITE); + if (IS_ERR(wreq)) { + ret = PTR_ERR(wreq); + goto out; + } + + if (!folio_clear_dirty_for_io(folio)) + goto out_put; + + trace_netfs_folio(folio, netfs_folio_trace_launder); + + _debug("launder %llx-%llx", start, start + len - 1); + + /* Speculatively write to the cache. We have to fix this up later if + * the store fails. + */ + wreq->cleanup = netfs_cleanup_launder_folio; + + bvec_set_folio(&bvec, folio, len, offset); + iov_iter_bvec(&wreq->iter, ITER_SOURCE, &bvec, 1, len); + __set_bit(NETFS_RREQ_UPLOAD_TO_SERVER, &wreq->flags); + ret = netfs_begin_write(wreq, true, netfs_write_trace_launder); + +out_put: + folio_detach_private(folio); + netfs_put_group(group); + kfree(finfo); + netfs_put_request(wreq, false, netfs_rreq_trace_put_return); +out: + folio_wait_fscache(folio); + _leave(" = %d", ret); + return ret; +} +EXPORT_SYMBOL(netfs_launder_folio); diff --git a/fs/netfs/direct_read.c b/fs/netfs/direct_read.c new file mode 100644 index 0000000000..ad4370b393 --- /dev/null +++ b/fs/netfs/direct_read.c @@ -0,0 +1,125 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Direct I/O support. + * + * Copyright (C) 2023 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include <linux/export.h> +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/pagemap.h> +#include <linux/slab.h> +#include <linux/uio.h> +#include <linux/sched/mm.h> +#include <linux/task_io_accounting_ops.h> +#include <linux/netfs.h> +#include "internal.h" + +/** + * netfs_unbuffered_read_iter_locked - Perform an unbuffered or direct I/O read + * @iocb: The I/O control descriptor describing the read + * @iter: The output buffer (also specifies read length) + * + * Perform an unbuffered I/O or direct I/O from the file in @iocb to the + * output buffer. No use is made of the pagecache. + * + * The caller must hold any appropriate locks. + */ +static ssize_t netfs_unbuffered_read_iter_locked(struct kiocb *iocb, struct iov_iter *iter) +{ + struct netfs_io_request *rreq; + ssize_t ret; + size_t orig_count = iov_iter_count(iter); + bool async = !is_sync_kiocb(iocb); + + _enter(""); + + if (!orig_count) + return 0; /* Don't update atime */ + + ret = kiocb_write_and_wait(iocb, orig_count); + if (ret < 0) + return ret; + file_accessed(iocb->ki_filp); + + rreq = netfs_alloc_request(iocb->ki_filp->f_mapping, iocb->ki_filp, + iocb->ki_pos, orig_count, + NETFS_DIO_READ); + if (IS_ERR(rreq)) + return PTR_ERR(rreq); + + netfs_stat(&netfs_n_rh_dio_read); + trace_netfs_read(rreq, rreq->start, rreq->len, netfs_read_trace_dio_read); + + /* If this is an async op, we have to keep track of the destination + * buffer for ourselves as the caller's iterator will be trashed when + * we return. + * + * In such a case, extract an iterator to represent as much of the the + * output buffer as we can manage. Note that the extraction might not + * be able to allocate a sufficiently large bvec array and may shorten + * the request. + */ + if (user_backed_iter(iter)) { + ret = netfs_extract_user_iter(iter, rreq->len, &rreq->iter, 0); + if (ret < 0) + goto out; + rreq->direct_bv = (struct bio_vec *)rreq->iter.bvec; + rreq->direct_bv_count = ret; + rreq->direct_bv_unpin = iov_iter_extract_will_pin(iter); + rreq->len = iov_iter_count(&rreq->iter); + } else { + rreq->iter = *iter; + rreq->len = orig_count; + rreq->direct_bv_unpin = false; + iov_iter_advance(iter, orig_count); + } + + // TODO: Set up bounce buffer if needed + + if (async) + rreq->iocb = iocb; + + ret = netfs_begin_read(rreq, is_sync_kiocb(iocb)); + if (ret < 0) + goto out; /* May be -EIOCBQUEUED */ + if (!async) { + // TODO: Copy from bounce buffer + iocb->ki_pos += rreq->transferred; + ret = rreq->transferred; + } + +out: + netfs_put_request(rreq, false, netfs_rreq_trace_put_return); + if (ret > 0) + orig_count -= ret; + if (ret != -EIOCBQUEUED) + iov_iter_revert(iter, orig_count - iov_iter_count(iter)); + return ret; +} + +/** + * netfs_unbuffered_read_iter - Perform an unbuffered or direct I/O read + * @iocb: The I/O control descriptor describing the read + * @iter: The output buffer (also specifies read length) + * + * Perform an unbuffered I/O or direct I/O from the file in @iocb to the + * output buffer. No use is made of the pagecache. + */ +ssize_t netfs_unbuffered_read_iter(struct kiocb *iocb, struct iov_iter *iter) +{ + struct inode *inode = file_inode(iocb->ki_filp); + ssize_t ret; + + if (!iter->count) + return 0; /* Don't update atime */ + + ret = netfs_start_io_direct(inode); + if (ret == 0) { + ret = netfs_unbuffered_read_iter_locked(iocb, iter); + netfs_end_io_direct(inode); + } + return ret; +} +EXPORT_SYMBOL(netfs_unbuffered_read_iter); diff --git a/fs/netfs/direct_write.c b/fs/netfs/direct_write.c new file mode 100644 index 0000000000..bee047e20f --- /dev/null +++ b/fs/netfs/direct_write.c @@ -0,0 +1,174 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Unbuffered and direct write support. + * + * Copyright (C) 2023 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include <linux/export.h> +#include <linux/uio.h> +#include "internal.h" + +static void netfs_cleanup_dio_write(struct netfs_io_request *wreq) +{ + struct inode *inode = wreq->inode; + unsigned long long end = wreq->start + wreq->len; + + if (!wreq->error && + i_size_read(inode) < end) { + if (wreq->netfs_ops->update_i_size) + wreq->netfs_ops->update_i_size(inode, end); + else + i_size_write(inode, end); + } +} + +/* + * Perform an unbuffered write where we may have to do an RMW operation on an + * encrypted file. This can also be used for direct I/O writes. + */ +static ssize_t netfs_unbuffered_write_iter_locked(struct kiocb *iocb, struct iov_iter *iter, + struct netfs_group *netfs_group) +{ + struct netfs_io_request *wreq; + unsigned long long start = iocb->ki_pos; + unsigned long long end = start + iov_iter_count(iter); + ssize_t ret, n; + bool async = !is_sync_kiocb(iocb); + + _enter(""); + + /* We're going to need a bounce buffer if what we transmit is going to + * be different in some way to the source buffer, e.g. because it gets + * encrypted/compressed or because it needs expanding to a block size. + */ + // TODO + + _debug("uw %llx-%llx", start, end); + + wreq = netfs_alloc_request(iocb->ki_filp->f_mapping, iocb->ki_filp, + start, end - start, + iocb->ki_flags & IOCB_DIRECT ? + NETFS_DIO_WRITE : NETFS_UNBUFFERED_WRITE); + if (IS_ERR(wreq)) + return PTR_ERR(wreq); + + { + /* If this is an async op and we're not using a bounce buffer, + * we have to save the source buffer as the iterator is only + * good until we return. In such a case, extract an iterator + * to represent as much of the the output buffer as we can + * manage. Note that the extraction might not be able to + * allocate a sufficiently large bvec array and may shorten the + * request. + */ + if (async || user_backed_iter(iter)) { + n = netfs_extract_user_iter(iter, wreq->len, &wreq->iter, 0); + if (n < 0) { + ret = n; + goto out; + } + wreq->direct_bv = (struct bio_vec *)wreq->iter.bvec; + wreq->direct_bv_count = n; + wreq->direct_bv_unpin = iov_iter_extract_will_pin(iter); + wreq->len = iov_iter_count(&wreq->iter); + } else { + wreq->iter = *iter; + } + + wreq->io_iter = wreq->iter; + } + + /* Copy the data into the bounce buffer and encrypt it. */ + // TODO + + /* Dispatch the write. */ + __set_bit(NETFS_RREQ_UPLOAD_TO_SERVER, &wreq->flags); + if (async) + wreq->iocb = iocb; + wreq->cleanup = netfs_cleanup_dio_write; + ret = netfs_begin_write(wreq, is_sync_kiocb(iocb), + iocb->ki_flags & IOCB_DIRECT ? + netfs_write_trace_dio_write : + netfs_write_trace_unbuffered_write); + if (ret < 0) { + _debug("begin = %zd", ret); + goto out; + } + + if (!async) { + trace_netfs_rreq(wreq, netfs_rreq_trace_wait_ip); + wait_on_bit(&wreq->flags, NETFS_RREQ_IN_PROGRESS, + TASK_UNINTERRUPTIBLE); + + ret = wreq->error; + _debug("waited = %zd", ret); + if (ret == 0) { + ret = wreq->transferred; + iocb->ki_pos += ret; + } + } else { + ret = -EIOCBQUEUED; + } + +out: + netfs_put_request(wreq, false, netfs_rreq_trace_put_return); + return ret; +} + +/** + * netfs_unbuffered_write_iter - Unbuffered write to a file + * @iocb: IO state structure + * @from: iov_iter with data to write + * + * Do an unbuffered write to a file, writing the data directly to the server + * and not lodging the data in the pagecache. + * + * Return: + * * Negative error code if no data has been written at all of + * vfs_fsync_range() failed for a synchronous write + * * Number of bytes written, even for truncated writes + */ +ssize_t netfs_unbuffered_write_iter(struct kiocb *iocb, struct iov_iter *from) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file->f_mapping->host; + struct netfs_inode *ictx = netfs_inode(inode); + unsigned long long end; + ssize_t ret; + + _enter("%llx,%zx,%llx", iocb->ki_pos, iov_iter_count(from), i_size_read(inode)); + + if (!iov_iter_count(from)) + return 0; + + trace_netfs_write_iter(iocb, from); + netfs_stat(&netfs_n_rh_dio_write); + + ret = netfs_start_io_direct(inode); + if (ret < 0) + return ret; + ret = generic_write_checks(iocb, from); + if (ret <= 0) + goto out; + ret = file_remove_privs(file); + if (ret < 0) + goto out; + ret = file_update_time(file); + if (ret < 0) + goto out; + ret = kiocb_invalidate_pages(iocb, iov_iter_count(from)); + if (ret < 0) + goto out; + end = iocb->ki_pos + iov_iter_count(from); + if (end > ictx->zero_point) + ictx->zero_point = end; + + fscache_invalidate(netfs_i_cookie(ictx), NULL, i_size_read(inode), + FSCACHE_INVAL_DIO_WRITE); + ret = netfs_unbuffered_write_iter_locked(iocb, from, NULL); +out: + netfs_end_io_direct(inode); + return ret; +} +EXPORT_SYMBOL(netfs_unbuffered_write_iter); diff --git a/fs/netfs/fscache_cache.c b/fs/netfs/fscache_cache.c new file mode 100644 index 0000000000..9397ed39b0 --- /dev/null +++ b/fs/netfs/fscache_cache.c @@ -0,0 +1,429 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* FS-Cache cache handling + * + * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#define FSCACHE_DEBUG_LEVEL CACHE +#include <linux/export.h> +#include <linux/slab.h> +#include "internal.h" + +static LIST_HEAD(fscache_caches); +DECLARE_RWSEM(fscache_addremove_sem); +EXPORT_SYMBOL(fscache_addremove_sem); +DECLARE_WAIT_QUEUE_HEAD(fscache_clearance_waiters); +EXPORT_SYMBOL(fscache_clearance_waiters); + +static atomic_t fscache_cache_debug_id; + +/* + * Allocate a cache cookie. + */ +static struct fscache_cache *fscache_alloc_cache(const char *name) +{ + struct fscache_cache *cache; + + cache = kzalloc(sizeof(*cache), GFP_KERNEL); + if (cache) { + if (name) { + cache->name = kstrdup(name, GFP_KERNEL); + if (!cache->name) { + kfree(cache); + return NULL; + } + } + refcount_set(&cache->ref, 1); + INIT_LIST_HEAD(&cache->cache_link); + cache->debug_id = atomic_inc_return(&fscache_cache_debug_id); + } + return cache; +} + +static bool fscache_get_cache_maybe(struct fscache_cache *cache, + enum fscache_cache_trace where) +{ + bool success; + int ref; + + success = __refcount_inc_not_zero(&cache->ref, &ref); + if (success) + trace_fscache_cache(cache->debug_id, ref + 1, where); + return success; +} + +/* + * Look up a cache cookie. + */ +struct fscache_cache *fscache_lookup_cache(const char *name, bool is_cache) +{ + struct fscache_cache *candidate, *cache, *unnamed = NULL; + + /* firstly check for the existence of the cache under read lock */ + down_read(&fscache_addremove_sem); + + list_for_each_entry(cache, &fscache_caches, cache_link) { + if (cache->name && name && strcmp(cache->name, name) == 0 && + fscache_get_cache_maybe(cache, fscache_cache_get_acquire)) + goto got_cache_r; + if (!cache->name && !name && + fscache_get_cache_maybe(cache, fscache_cache_get_acquire)) + goto got_cache_r; + } + + if (!name) { + list_for_each_entry(cache, &fscache_caches, cache_link) { + if (cache->name && + fscache_get_cache_maybe(cache, fscache_cache_get_acquire)) + goto got_cache_r; + } + } + + up_read(&fscache_addremove_sem); + + /* the cache does not exist - create a candidate */ + candidate = fscache_alloc_cache(name); + if (!candidate) + return ERR_PTR(-ENOMEM); + + /* write lock, search again and add if still not present */ + down_write(&fscache_addremove_sem); + + list_for_each_entry(cache, &fscache_caches, cache_link) { + if (cache->name && name && strcmp(cache->name, name) == 0 && + fscache_get_cache_maybe(cache, fscache_cache_get_acquire)) + goto got_cache_w; + if (!cache->name) { + unnamed = cache; + if (!name && + fscache_get_cache_maybe(cache, fscache_cache_get_acquire)) + goto got_cache_w; + } + } + + if (unnamed && is_cache && + fscache_get_cache_maybe(unnamed, fscache_cache_get_acquire)) + goto use_unnamed_cache; + + if (!name) { + list_for_each_entry(cache, &fscache_caches, cache_link) { + if (cache->name && + fscache_get_cache_maybe(cache, fscache_cache_get_acquire)) + goto got_cache_w; + } + } + + list_add_tail(&candidate->cache_link, &fscache_caches); + trace_fscache_cache(candidate->debug_id, + refcount_read(&candidate->ref), + fscache_cache_new_acquire); + up_write(&fscache_addremove_sem); + return candidate; + +got_cache_r: + up_read(&fscache_addremove_sem); + return cache; +use_unnamed_cache: + cache = unnamed; + cache->name = candidate->name; + candidate->name = NULL; +got_cache_w: + up_write(&fscache_addremove_sem); + kfree(candidate->name); + kfree(candidate); + return cache; +} + +/** + * fscache_acquire_cache - Acquire a cache-level cookie. + * @name: The name of the cache. + * + * Get a cookie to represent an actual cache. If a name is given and there is + * a nameless cache record available, this will acquire that and set its name, + * directing all the volumes using it to this cache. + * + * The cache will be switched over to the preparing state if not currently in + * use, otherwise -EBUSY will be returned. + */ +struct fscache_cache *fscache_acquire_cache(const char *name) +{ + struct fscache_cache *cache; + + ASSERT(name); + cache = fscache_lookup_cache(name, true); + if (IS_ERR(cache)) + return cache; + + if (!fscache_set_cache_state_maybe(cache, + FSCACHE_CACHE_IS_NOT_PRESENT, + FSCACHE_CACHE_IS_PREPARING)) { + pr_warn("Cache tag %s in use\n", name); + fscache_put_cache(cache, fscache_cache_put_cache); + return ERR_PTR(-EBUSY); + } + + return cache; +} +EXPORT_SYMBOL(fscache_acquire_cache); + +/** + * fscache_put_cache - Release a cache-level cookie. + * @cache: The cache cookie to be released + * @where: An indication of where the release happened + * + * Release the caller's reference on a cache-level cookie. The @where + * indication should give information about the circumstances in which the call + * occurs and will be logged through a tracepoint. + */ +void fscache_put_cache(struct fscache_cache *cache, + enum fscache_cache_trace where) +{ + unsigned int debug_id; + bool zero; + int ref; + + if (IS_ERR_OR_NULL(cache)) + return; + + debug_id = cache->debug_id; + zero = __refcount_dec_and_test(&cache->ref, &ref); + trace_fscache_cache(debug_id, ref - 1, where); + + if (zero) { + down_write(&fscache_addremove_sem); + list_del_init(&cache->cache_link); + up_write(&fscache_addremove_sem); + kfree(cache->name); + kfree(cache); + } +} + +/** + * fscache_relinquish_cache - Reset cache state and release cookie + * @cache: The cache cookie to be released + * + * Reset the state of a cache and release the caller's reference on a cache + * cookie. + */ +void fscache_relinquish_cache(struct fscache_cache *cache) +{ + enum fscache_cache_trace where = + (cache->state == FSCACHE_CACHE_IS_PREPARING) ? + fscache_cache_put_prep_failed : + fscache_cache_put_relinquish; + + cache->ops = NULL; + cache->cache_priv = NULL; + fscache_set_cache_state(cache, FSCACHE_CACHE_IS_NOT_PRESENT); + fscache_put_cache(cache, where); +} +EXPORT_SYMBOL(fscache_relinquish_cache); + +/** + * fscache_add_cache - Declare a cache as being open for business + * @cache: The cache-level cookie representing the cache + * @ops: Table of cache operations to use + * @cache_priv: Private data for the cache record + * + * Add a cache to the system, making it available for netfs's to use. + * + * See Documentation/filesystems/caching/backend-api.rst for a complete + * description. + */ +int fscache_add_cache(struct fscache_cache *cache, + const struct fscache_cache_ops *ops, + void *cache_priv) +{ + int n_accesses; + + _enter("{%s,%s}", ops->name, cache->name); + + BUG_ON(fscache_cache_state(cache) != FSCACHE_CACHE_IS_PREPARING); + + /* Get a ref on the cache cookie and keep its n_accesses counter raised + * by 1 to prevent wakeups from transitioning it to 0 until we're + * withdrawing caching services from it. + */ + n_accesses = atomic_inc_return(&cache->n_accesses); + trace_fscache_access_cache(cache->debug_id, refcount_read(&cache->ref), + n_accesses, fscache_access_cache_pin); + + down_write(&fscache_addremove_sem); + + cache->ops = ops; + cache->cache_priv = cache_priv; + fscache_set_cache_state(cache, FSCACHE_CACHE_IS_ACTIVE); + + up_write(&fscache_addremove_sem); + pr_notice("Cache \"%s\" added (type %s)\n", cache->name, ops->name); + _leave(" = 0 [%s]", cache->name); + return 0; +} +EXPORT_SYMBOL(fscache_add_cache); + +/** + * fscache_begin_cache_access - Pin a cache so it can be accessed + * @cache: The cache-level cookie + * @why: An indication of the circumstances of the access for tracing + * + * Attempt to pin the cache to prevent it from going away whilst we're + * accessing it and returns true if successful. This works as follows: + * + * (1) If the cache tests as not live (state is not FSCACHE_CACHE_IS_ACTIVE), + * then we return false to indicate access was not permitted. + * + * (2) If the cache tests as live, then we increment the n_accesses count and + * then recheck the liveness, ending the access if it ceased to be live. + * + * (3) When we end the access, we decrement n_accesses and wake up the any + * waiters if it reaches 0. + * + * (4) Whilst the cache is caching, n_accesses is kept artificially + * incremented to prevent wakeups from happening. + * + * (5) When the cache is taken offline, the state is changed to prevent new + * accesses, n_accesses is decremented and we wait for n_accesses to + * become 0. + */ +bool fscache_begin_cache_access(struct fscache_cache *cache, enum fscache_access_trace why) +{ + int n_accesses; + + if (!fscache_cache_is_live(cache)) + return false; + + n_accesses = atomic_inc_return(&cache->n_accesses); + smp_mb__after_atomic(); /* Reread live flag after n_accesses */ + trace_fscache_access_cache(cache->debug_id, refcount_read(&cache->ref), + n_accesses, why); + if (!fscache_cache_is_live(cache)) { + fscache_end_cache_access(cache, fscache_access_unlive); + return false; + } + return true; +} + +/** + * fscache_end_cache_access - Unpin a cache at the end of an access. + * @cache: The cache-level cookie + * @why: An indication of the circumstances of the access for tracing + * + * Unpin a cache after we've accessed it. The @why indicator is merely + * provided for tracing purposes. + */ +void fscache_end_cache_access(struct fscache_cache *cache, enum fscache_access_trace why) +{ + int n_accesses; + + smp_mb__before_atomic(); + n_accesses = atomic_dec_return(&cache->n_accesses); + trace_fscache_access_cache(cache->debug_id, refcount_read(&cache->ref), + n_accesses, why); + if (n_accesses == 0) + wake_up_var(&cache->n_accesses); +} + +/** + * fscache_io_error - Note a cache I/O error + * @cache: The record describing the cache + * + * Note that an I/O error occurred in a cache and that it should no longer be + * used for anything. This also reports the error into the kernel log. + * + * See Documentation/filesystems/caching/backend-api.rst for a complete + * description. + */ +void fscache_io_error(struct fscache_cache *cache) +{ + if (fscache_set_cache_state_maybe(cache, + FSCACHE_CACHE_IS_ACTIVE, + FSCACHE_CACHE_GOT_IOERROR)) + pr_err("Cache '%s' stopped due to I/O error\n", + cache->name); +} +EXPORT_SYMBOL(fscache_io_error); + +/** + * fscache_withdraw_cache - Withdraw a cache from the active service + * @cache: The cache cookie + * + * Begin the process of withdrawing a cache from service. This stops new + * cache-level and volume-level accesses from taking place and waits for + * currently ongoing cache-level accesses to end. + */ +void fscache_withdraw_cache(struct fscache_cache *cache) +{ + int n_accesses; + + pr_notice("Withdrawing cache \"%s\" (%u objs)\n", + cache->name, atomic_read(&cache->object_count)); + + fscache_set_cache_state(cache, FSCACHE_CACHE_IS_WITHDRAWN); + + /* Allow wakeups on dec-to-0 */ + n_accesses = atomic_dec_return(&cache->n_accesses); + trace_fscache_access_cache(cache->debug_id, refcount_read(&cache->ref), + n_accesses, fscache_access_cache_unpin); + + wait_var_event(&cache->n_accesses, + atomic_read(&cache->n_accesses) == 0); +} +EXPORT_SYMBOL(fscache_withdraw_cache); + +#ifdef CONFIG_PROC_FS +static const char fscache_cache_states[NR__FSCACHE_CACHE_STATE] = "-PAEW"; + +/* + * Generate a list of caches in /proc/fs/fscache/caches + */ +static int fscache_caches_seq_show(struct seq_file *m, void *v) +{ + struct fscache_cache *cache; + + if (v == &fscache_caches) { + seq_puts(m, + "CACHE REF VOLS OBJS ACCES S NAME\n" + "======== ===== ===== ===== ===== = ===============\n" + ); + return 0; + } + + cache = list_entry(v, struct fscache_cache, cache_link); + seq_printf(m, + "%08x %5d %5d %5d %5d %c %s\n", + cache->debug_id, + refcount_read(&cache->ref), + atomic_read(&cache->n_volumes), + atomic_read(&cache->object_count), + atomic_read(&cache->n_accesses), + fscache_cache_states[cache->state], + cache->name ?: "-"); + return 0; +} + +static void *fscache_caches_seq_start(struct seq_file *m, loff_t *_pos) + __acquires(fscache_addremove_sem) +{ + down_read(&fscache_addremove_sem); + return seq_list_start_head(&fscache_caches, *_pos); +} + +static void *fscache_caches_seq_next(struct seq_file *m, void *v, loff_t *_pos) +{ + return seq_list_next(v, &fscache_caches, _pos); +} + +static void fscache_caches_seq_stop(struct seq_file *m, void *v) + __releases(fscache_addremove_sem) +{ + up_read(&fscache_addremove_sem); +} + +const struct seq_operations fscache_caches_seq_ops = { + .start = fscache_caches_seq_start, + .next = fscache_caches_seq_next, + .stop = fscache_caches_seq_stop, + .show = fscache_caches_seq_show, +}; +#endif /* CONFIG_PROC_FS */ diff --git a/fs/netfs/fscache_cookie.c b/fs/netfs/fscache_cookie.c new file mode 100644 index 0000000000..bce2492186 --- /dev/null +++ b/fs/netfs/fscache_cookie.c @@ -0,0 +1,1180 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* netfs cookie management + * + * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * See Documentation/filesystems/caching/netfs-api.rst for more information on + * the netfs API. + */ + +#define FSCACHE_DEBUG_LEVEL COOKIE +#include <linux/module.h> +#include <linux/slab.h> +#include "internal.h" + +struct kmem_cache *fscache_cookie_jar; + +static void fscache_cookie_lru_timed_out(struct timer_list *timer); +static void fscache_cookie_lru_worker(struct work_struct *work); +static void fscache_cookie_worker(struct work_struct *work); +static void fscache_unhash_cookie(struct fscache_cookie *cookie); +static void fscache_perform_invalidation(struct fscache_cookie *cookie); + +#define fscache_cookie_hash_shift 15 +static struct hlist_bl_head fscache_cookie_hash[1 << fscache_cookie_hash_shift]; +static LIST_HEAD(fscache_cookies); +static DEFINE_RWLOCK(fscache_cookies_lock); +static LIST_HEAD(fscache_cookie_lru); +static DEFINE_SPINLOCK(fscache_cookie_lru_lock); +DEFINE_TIMER(fscache_cookie_lru_timer, fscache_cookie_lru_timed_out); +static DECLARE_WORK(fscache_cookie_lru_work, fscache_cookie_lru_worker); +static const char fscache_cookie_states[FSCACHE_COOKIE_STATE__NR] = "-LCAIFUWRD"; +static unsigned int fscache_lru_cookie_timeout = 10 * HZ; + +void fscache_print_cookie(struct fscache_cookie *cookie, char prefix) +{ + const u8 *k; + + pr_err("%c-cookie c=%08x [fl=%lx na=%u nA=%u s=%c]\n", + prefix, + cookie->debug_id, + cookie->flags, + atomic_read(&cookie->n_active), + atomic_read(&cookie->n_accesses), + fscache_cookie_states[cookie->state]); + pr_err("%c-cookie V=%08x [%s]\n", + prefix, + cookie->volume->debug_id, + cookie->volume->key); + + k = (cookie->key_len <= sizeof(cookie->inline_key)) ? + cookie->inline_key : cookie->key; + pr_err("%c-key=[%u] '%*phN'\n", prefix, cookie->key_len, cookie->key_len, k); +} + +static void fscache_free_cookie(struct fscache_cookie *cookie) +{ + if (WARN_ON_ONCE(!list_empty(&cookie->commit_link))) { + spin_lock(&fscache_cookie_lru_lock); + list_del_init(&cookie->commit_link); + spin_unlock(&fscache_cookie_lru_lock); + fscache_stat_d(&fscache_n_cookies_lru); + fscache_stat(&fscache_n_cookies_lru_removed); + } + + if (WARN_ON_ONCE(test_bit(FSCACHE_COOKIE_IS_HASHED, &cookie->flags))) { + fscache_print_cookie(cookie, 'F'); + return; + } + + write_lock(&fscache_cookies_lock); + list_del(&cookie->proc_link); + write_unlock(&fscache_cookies_lock); + if (cookie->aux_len > sizeof(cookie->inline_aux)) + kfree(cookie->aux); + if (cookie->key_len > sizeof(cookie->inline_key)) + kfree(cookie->key); + fscache_stat_d(&fscache_n_cookies); + kmem_cache_free(fscache_cookie_jar, cookie); +} + +static void __fscache_queue_cookie(struct fscache_cookie *cookie) +{ + if (!queue_work(fscache_wq, &cookie->work)) + fscache_put_cookie(cookie, fscache_cookie_put_over_queued); +} + +static void fscache_queue_cookie(struct fscache_cookie *cookie, + enum fscache_cookie_trace where) +{ + fscache_get_cookie(cookie, where); + __fscache_queue_cookie(cookie); +} + +/* + * Initialise the access gate on a cookie by setting a flag to prevent the + * state machine from being queued when the access counter transitions to 0. + * We're only interested in this when we withdraw caching services from the + * cookie. + */ +static void fscache_init_access_gate(struct fscache_cookie *cookie) +{ + int n_accesses; + + n_accesses = atomic_read(&cookie->n_accesses); + trace_fscache_access(cookie->debug_id, refcount_read(&cookie->ref), + n_accesses, fscache_access_cache_pin); + set_bit(FSCACHE_COOKIE_NO_ACCESS_WAKE, &cookie->flags); +} + +/** + * fscache_end_cookie_access - Unpin a cache at the end of an access. + * @cookie: A data file cookie + * @why: An indication of the circumstances of the access for tracing + * + * Unpin a cache cookie after we've accessed it and bring a deferred + * relinquishment or withdrawal state into effect. + * + * The @why indicator is provided for tracing purposes. + */ +void fscache_end_cookie_access(struct fscache_cookie *cookie, + enum fscache_access_trace why) +{ + int n_accesses; + + smp_mb__before_atomic(); + n_accesses = atomic_dec_return(&cookie->n_accesses); + trace_fscache_access(cookie->debug_id, refcount_read(&cookie->ref), + n_accesses, why); + if (n_accesses == 0 && + !test_bit(FSCACHE_COOKIE_NO_ACCESS_WAKE, &cookie->flags)) + fscache_queue_cookie(cookie, fscache_cookie_get_end_access); +} +EXPORT_SYMBOL(fscache_end_cookie_access); + +/* + * Pin the cache behind a cookie so that we can access it. + */ +static void __fscache_begin_cookie_access(struct fscache_cookie *cookie, + enum fscache_access_trace why) +{ + int n_accesses; + + n_accesses = atomic_inc_return(&cookie->n_accesses); + smp_mb__after_atomic(); /* (Future) read state after is-caching. + * Reread n_accesses after is-caching + */ + trace_fscache_access(cookie->debug_id, refcount_read(&cookie->ref), + n_accesses, why); +} + +/** + * fscache_begin_cookie_access - Pin a cache so data can be accessed + * @cookie: A data file cookie + * @why: An indication of the circumstances of the access for tracing + * + * Attempt to pin the cache to prevent it from going away whilst we're + * accessing data and returns true if successful. This works as follows: + * + * (1) If the cookie is not being cached (ie. FSCACHE_COOKIE_IS_CACHING is not + * set), we return false to indicate access was not permitted. + * + * (2) If the cookie is being cached, we increment its n_accesses count and + * then recheck the IS_CACHING flag, ending the access if it got cleared. + * + * (3) When we end the access, we decrement the cookie's n_accesses and wake + * up the any waiters if it reaches 0. + * + * (4) Whilst the cookie is actively being cached, its n_accesses is kept + * artificially incremented to prevent wakeups from happening. + * + * (5) When the cache is taken offline or if the cookie is culled, the flag is + * cleared to prevent new accesses, the cookie's n_accesses is decremented + * and we wait for it to become 0. + * + * The @why indicator are merely provided for tracing purposes. + */ +bool fscache_begin_cookie_access(struct fscache_cookie *cookie, + enum fscache_access_trace why) +{ + if (!test_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags)) + return false; + __fscache_begin_cookie_access(cookie, why); + if (!test_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags) || + !fscache_cache_is_live(cookie->volume->cache)) { + fscache_end_cookie_access(cookie, fscache_access_unlive); + return false; + } + return true; +} + +static inline void wake_up_cookie_state(struct fscache_cookie *cookie) +{ + /* Use a barrier to ensure that waiters see the state variable + * change, as spin_unlock doesn't guarantee a barrier. + * + * See comments over wake_up_bit() and waitqueue_active(). + */ + smp_mb(); + wake_up_var(&cookie->state); +} + +/* + * Change the state a cookie is at and wake up anyone waiting for that. Impose + * an ordering between the stuff stored in the cookie and the state member. + * Paired with fscache_cookie_state(). + */ +static void __fscache_set_cookie_state(struct fscache_cookie *cookie, + enum fscache_cookie_state state) +{ + smp_store_release(&cookie->state, state); +} + +static void fscache_set_cookie_state(struct fscache_cookie *cookie, + enum fscache_cookie_state state) +{ + spin_lock(&cookie->lock); + __fscache_set_cookie_state(cookie, state); + spin_unlock(&cookie->lock); + wake_up_cookie_state(cookie); +} + +/** + * fscache_cookie_lookup_negative - Note negative lookup + * @cookie: The cookie that was being looked up + * + * Note that some part of the metadata path in the cache doesn't exist and so + * we can release any waiting readers in the certain knowledge that there's + * nothing for them to actually read. + * + * This function uses no locking and must only be called from the state machine. + */ +void fscache_cookie_lookup_negative(struct fscache_cookie *cookie) +{ + set_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags); + fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_CREATING); +} +EXPORT_SYMBOL(fscache_cookie_lookup_negative); + +/** + * fscache_resume_after_invalidation - Allow I/O to resume after invalidation + * @cookie: The cookie that was invalidated + * + * Tell fscache that invalidation is sufficiently complete that I/O can be + * allowed again. + */ +void fscache_resume_after_invalidation(struct fscache_cookie *cookie) +{ + fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_ACTIVE); +} +EXPORT_SYMBOL(fscache_resume_after_invalidation); + +/** + * fscache_caching_failed - Report that a failure stopped caching on a cookie + * @cookie: The cookie that was affected + * + * Tell fscache that caching on a cookie needs to be stopped due to some sort + * of failure. + * + * This function uses no locking and must only be called from the state machine. + */ +void fscache_caching_failed(struct fscache_cookie *cookie) +{ + clear_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags); + fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_FAILED); + trace_fscache_cookie(cookie->debug_id, refcount_read(&cookie->ref), + fscache_cookie_failed); +} +EXPORT_SYMBOL(fscache_caching_failed); + +/* + * Set the index key in a cookie. The cookie struct has space for a 16-byte + * key plus length and hash, but if that's not big enough, it's instead a + * pointer to a buffer containing 3 bytes of hash, 1 byte of length and then + * the key data. + */ +static int fscache_set_key(struct fscache_cookie *cookie, + const void *index_key, size_t index_key_len) +{ + void *buf; + size_t buf_size; + + buf_size = round_up(index_key_len, sizeof(__le32)); + + if (index_key_len > sizeof(cookie->inline_key)) { + buf = kzalloc(buf_size, GFP_KERNEL); + if (!buf) + return -ENOMEM; + cookie->key = buf; + } else { + buf = cookie->inline_key; + } + + memcpy(buf, index_key, index_key_len); + cookie->key_hash = fscache_hash(cookie->volume->key_hash, + buf, buf_size); + return 0; +} + +static bool fscache_cookie_same(const struct fscache_cookie *a, + const struct fscache_cookie *b) +{ + const void *ka, *kb; + + if (a->key_hash != b->key_hash || + a->volume != b->volume || + a->key_len != b->key_len) + return false; + + if (a->key_len <= sizeof(a->inline_key)) { + ka = &a->inline_key; + kb = &b->inline_key; + } else { + ka = a->key; + kb = b->key; + } + return memcmp(ka, kb, a->key_len) == 0; +} + +static atomic_t fscache_cookie_debug_id = ATOMIC_INIT(1); + +/* + * Allocate a cookie. + */ +static struct fscache_cookie *fscache_alloc_cookie( + struct fscache_volume *volume, + u8 advice, + const void *index_key, size_t index_key_len, + const void *aux_data, size_t aux_data_len, + loff_t object_size) +{ + struct fscache_cookie *cookie; + + /* allocate and initialise a cookie */ + cookie = kmem_cache_zalloc(fscache_cookie_jar, GFP_KERNEL); + if (!cookie) + return NULL; + fscache_stat(&fscache_n_cookies); + + cookie->volume = volume; + cookie->advice = advice; + cookie->key_len = index_key_len; + cookie->aux_len = aux_data_len; + cookie->object_size = object_size; + if (object_size == 0) + __set_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags); + + if (fscache_set_key(cookie, index_key, index_key_len) < 0) + goto nomem; + + if (cookie->aux_len <= sizeof(cookie->inline_aux)) { + memcpy(cookie->inline_aux, aux_data, cookie->aux_len); + } else { + cookie->aux = kmemdup(aux_data, cookie->aux_len, GFP_KERNEL); + if (!cookie->aux) + goto nomem; + } + + refcount_set(&cookie->ref, 1); + cookie->debug_id = atomic_inc_return(&fscache_cookie_debug_id); + spin_lock_init(&cookie->lock); + INIT_LIST_HEAD(&cookie->commit_link); + INIT_WORK(&cookie->work, fscache_cookie_worker); + __fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_QUIESCENT); + + write_lock(&fscache_cookies_lock); + list_add_tail(&cookie->proc_link, &fscache_cookies); + write_unlock(&fscache_cookies_lock); + fscache_see_cookie(cookie, fscache_cookie_new_acquire); + return cookie; + +nomem: + fscache_free_cookie(cookie); + return NULL; +} + +static inline bool fscache_cookie_is_dropped(struct fscache_cookie *cookie) +{ + return READ_ONCE(cookie->state) == FSCACHE_COOKIE_STATE_DROPPED; +} + +static void fscache_wait_on_collision(struct fscache_cookie *candidate, + struct fscache_cookie *wait_for) +{ + enum fscache_cookie_state *statep = &wait_for->state; + + wait_var_event_timeout(statep, fscache_cookie_is_dropped(wait_for), + 20 * HZ); + if (!fscache_cookie_is_dropped(wait_for)) { + pr_notice("Potential collision c=%08x old: c=%08x", + candidate->debug_id, wait_for->debug_id); + wait_var_event(statep, fscache_cookie_is_dropped(wait_for)); + } +} + +/* + * Attempt to insert the new cookie into the hash. If there's a collision, we + * wait for the old cookie to complete if it's being relinquished and an error + * otherwise. + */ +static bool fscache_hash_cookie(struct fscache_cookie *candidate) +{ + struct fscache_cookie *cursor, *wait_for = NULL; + struct hlist_bl_head *h; + struct hlist_bl_node *p; + unsigned int bucket; + + bucket = candidate->key_hash & (ARRAY_SIZE(fscache_cookie_hash) - 1); + h = &fscache_cookie_hash[bucket]; + + hlist_bl_lock(h); + hlist_bl_for_each_entry(cursor, p, h, hash_link) { + if (fscache_cookie_same(candidate, cursor)) { + if (!test_bit(FSCACHE_COOKIE_RELINQUISHED, &cursor->flags)) + goto collision; + wait_for = fscache_get_cookie(cursor, + fscache_cookie_get_hash_collision); + break; + } + } + + fscache_get_volume(candidate->volume, fscache_volume_get_cookie); + atomic_inc(&candidate->volume->n_cookies); + hlist_bl_add_head(&candidate->hash_link, h); + set_bit(FSCACHE_COOKIE_IS_HASHED, &candidate->flags); + hlist_bl_unlock(h); + + if (wait_for) { + fscache_wait_on_collision(candidate, wait_for); + fscache_put_cookie(wait_for, fscache_cookie_put_hash_collision); + } + return true; + +collision: + trace_fscache_cookie(cursor->debug_id, refcount_read(&cursor->ref), + fscache_cookie_collision); + pr_err("Duplicate cookie detected\n"); + fscache_print_cookie(cursor, 'O'); + fscache_print_cookie(candidate, 'N'); + hlist_bl_unlock(h); + return false; +} + +/* + * Request a cookie to represent a data storage object within a volume. + * + * We never let on to the netfs about errors. We may set a negative cookie + * pointer, but that's okay + */ +struct fscache_cookie *__fscache_acquire_cookie( + struct fscache_volume *volume, + u8 advice, + const void *index_key, size_t index_key_len, + const void *aux_data, size_t aux_data_len, + loff_t object_size) +{ + struct fscache_cookie *cookie; + + _enter("V=%x", volume->debug_id); + + if (!index_key || !index_key_len || index_key_len > 255 || aux_data_len > 255) + return NULL; + if (!aux_data || !aux_data_len) { + aux_data = NULL; + aux_data_len = 0; + } + + fscache_stat(&fscache_n_acquires); + + cookie = fscache_alloc_cookie(volume, advice, + index_key, index_key_len, + aux_data, aux_data_len, + object_size); + if (!cookie) { + fscache_stat(&fscache_n_acquires_oom); + return NULL; + } + + if (!fscache_hash_cookie(cookie)) { + fscache_see_cookie(cookie, fscache_cookie_discard); + fscache_free_cookie(cookie); + return NULL; + } + + trace_fscache_acquire(cookie); + fscache_stat(&fscache_n_acquires_ok); + _leave(" = c=%08x", cookie->debug_id); + return cookie; +} +EXPORT_SYMBOL(__fscache_acquire_cookie); + +/* + * Prepare a cache object to be written to. + */ +static void fscache_prepare_to_write(struct fscache_cookie *cookie) +{ + cookie->volume->cache->ops->prepare_to_write(cookie); +} + +/* + * Look up a cookie in the cache. + */ +static void fscache_perform_lookup(struct fscache_cookie *cookie) +{ + enum fscache_access_trace trace = fscache_access_lookup_cookie_end_failed; + bool need_withdraw = false; + + _enter(""); + + if (!cookie->volume->cache_priv) { + fscache_create_volume(cookie->volume, true); + if (!cookie->volume->cache_priv) { + fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_QUIESCENT); + goto out; + } + } + + if (!cookie->volume->cache->ops->lookup_cookie(cookie)) { + if (cookie->state != FSCACHE_COOKIE_STATE_FAILED) + fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_QUIESCENT); + need_withdraw = true; + _leave(" [fail]"); + goto out; + } + + fscache_see_cookie(cookie, fscache_cookie_see_active); + spin_lock(&cookie->lock); + if (test_and_clear_bit(FSCACHE_COOKIE_DO_INVALIDATE, &cookie->flags)) + __fscache_set_cookie_state(cookie, + FSCACHE_COOKIE_STATE_INVALIDATING); + else + __fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_ACTIVE); + spin_unlock(&cookie->lock); + wake_up_cookie_state(cookie); + trace = fscache_access_lookup_cookie_end; + +out: + fscache_end_cookie_access(cookie, trace); + if (need_withdraw) + fscache_withdraw_cookie(cookie); + fscache_end_volume_access(cookie->volume, cookie, trace); +} + +/* + * Begin the process of looking up a cookie. We offload the actual process to + * a worker thread. + */ +static bool fscache_begin_lookup(struct fscache_cookie *cookie, bool will_modify) +{ + if (will_modify) { + set_bit(FSCACHE_COOKIE_LOCAL_WRITE, &cookie->flags); + set_bit(FSCACHE_COOKIE_DO_PREP_TO_WRITE, &cookie->flags); + } + if (!fscache_begin_volume_access(cookie->volume, cookie, + fscache_access_lookup_cookie)) + return false; + + __fscache_begin_cookie_access(cookie, fscache_access_lookup_cookie); + __fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_LOOKING_UP); + set_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags); + set_bit(FSCACHE_COOKIE_HAS_BEEN_CACHED, &cookie->flags); + return true; +} + +/* + * Start using the cookie for I/O. This prevents the backing object from being + * reaped by VM pressure. + */ +void __fscache_use_cookie(struct fscache_cookie *cookie, bool will_modify) +{ + enum fscache_cookie_state state; + bool queue = false; + int n_active; + + _enter("c=%08x", cookie->debug_id); + + if (WARN(test_bit(FSCACHE_COOKIE_RELINQUISHED, &cookie->flags), + "Trying to use relinquished cookie\n")) + return; + + spin_lock(&cookie->lock); + + n_active = atomic_inc_return(&cookie->n_active); + trace_fscache_active(cookie->debug_id, refcount_read(&cookie->ref), + n_active, atomic_read(&cookie->n_accesses), + will_modify ? + fscache_active_use_modify : fscache_active_use); + +again: + state = fscache_cookie_state(cookie); + switch (state) { + case FSCACHE_COOKIE_STATE_QUIESCENT: + queue = fscache_begin_lookup(cookie, will_modify); + break; + + case FSCACHE_COOKIE_STATE_LOOKING_UP: + case FSCACHE_COOKIE_STATE_CREATING: + if (will_modify) + set_bit(FSCACHE_COOKIE_LOCAL_WRITE, &cookie->flags); + break; + case FSCACHE_COOKIE_STATE_ACTIVE: + case FSCACHE_COOKIE_STATE_INVALIDATING: + if (will_modify && + !test_and_set_bit(FSCACHE_COOKIE_LOCAL_WRITE, &cookie->flags)) { + set_bit(FSCACHE_COOKIE_DO_PREP_TO_WRITE, &cookie->flags); + queue = true; + } + /* + * We could race with cookie_lru which may set LRU_DISCARD bit + * but has yet to run the cookie state machine. If this happens + * and another thread tries to use the cookie, clear LRU_DISCARD + * so we don't end up withdrawing the cookie while in use. + */ + if (test_and_clear_bit(FSCACHE_COOKIE_DO_LRU_DISCARD, &cookie->flags)) + fscache_see_cookie(cookie, fscache_cookie_see_lru_discard_clear); + break; + + case FSCACHE_COOKIE_STATE_FAILED: + case FSCACHE_COOKIE_STATE_WITHDRAWING: + break; + + case FSCACHE_COOKIE_STATE_LRU_DISCARDING: + spin_unlock(&cookie->lock); + wait_var_event(&cookie->state, + fscache_cookie_state(cookie) != + FSCACHE_COOKIE_STATE_LRU_DISCARDING); + spin_lock(&cookie->lock); + goto again; + + case FSCACHE_COOKIE_STATE_DROPPED: + case FSCACHE_COOKIE_STATE_RELINQUISHING: + WARN(1, "Can't use cookie in state %u\n", state); + break; + } + + spin_unlock(&cookie->lock); + if (queue) + fscache_queue_cookie(cookie, fscache_cookie_get_use_work); + _leave(""); +} +EXPORT_SYMBOL(__fscache_use_cookie); + +static void fscache_unuse_cookie_locked(struct fscache_cookie *cookie) +{ + clear_bit(FSCACHE_COOKIE_DISABLED, &cookie->flags); + if (!test_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags)) + return; + + cookie->unused_at = jiffies; + spin_lock(&fscache_cookie_lru_lock); + if (list_empty(&cookie->commit_link)) { + fscache_get_cookie(cookie, fscache_cookie_get_lru); + fscache_stat(&fscache_n_cookies_lru); + } + list_move_tail(&cookie->commit_link, &fscache_cookie_lru); + + spin_unlock(&fscache_cookie_lru_lock); + timer_reduce(&fscache_cookie_lru_timer, + jiffies + fscache_lru_cookie_timeout); +} + +/* + * Stop using the cookie for I/O. + */ +void __fscache_unuse_cookie(struct fscache_cookie *cookie, + const void *aux_data, const loff_t *object_size) +{ + unsigned int debug_id = cookie->debug_id; + unsigned int r = refcount_read(&cookie->ref); + unsigned int a = atomic_read(&cookie->n_accesses); + unsigned int c; + + if (aux_data || object_size) + __fscache_update_cookie(cookie, aux_data, object_size); + + /* Subtract 1 from counter unless that drops it to 0 (ie. it was 1) */ + c = atomic_fetch_add_unless(&cookie->n_active, -1, 1); + if (c != 1) { + trace_fscache_active(debug_id, r, c - 1, a, fscache_active_unuse); + return; + } + + spin_lock(&cookie->lock); + r = refcount_read(&cookie->ref); + a = atomic_read(&cookie->n_accesses); + c = atomic_dec_return(&cookie->n_active); + trace_fscache_active(debug_id, r, c, a, fscache_active_unuse); + if (c == 0) + fscache_unuse_cookie_locked(cookie); + spin_unlock(&cookie->lock); +} +EXPORT_SYMBOL(__fscache_unuse_cookie); + +/* + * Perform work upon the cookie, such as committing its cache state, + * relinquishing it or withdrawing the backing cache. We're protected from the + * cache going away under us as object withdrawal must come through this + * non-reentrant work item. + */ +static void fscache_cookie_state_machine(struct fscache_cookie *cookie) +{ + enum fscache_cookie_state state; + bool wake = false; + + _enter("c=%x", cookie->debug_id); + +again: + spin_lock(&cookie->lock); +again_locked: + state = cookie->state; + switch (state) { + case FSCACHE_COOKIE_STATE_QUIESCENT: + /* The QUIESCENT state is jumped to the LOOKING_UP state by + * fscache_use_cookie(). + */ + + if (atomic_read(&cookie->n_accesses) == 0 && + test_bit(FSCACHE_COOKIE_DO_RELINQUISH, &cookie->flags)) { + __fscache_set_cookie_state(cookie, + FSCACHE_COOKIE_STATE_RELINQUISHING); + wake = true; + goto again_locked; + } + break; + + case FSCACHE_COOKIE_STATE_LOOKING_UP: + spin_unlock(&cookie->lock); + fscache_init_access_gate(cookie); + fscache_perform_lookup(cookie); + goto again; + + case FSCACHE_COOKIE_STATE_INVALIDATING: + spin_unlock(&cookie->lock); + fscache_perform_invalidation(cookie); + goto again; + + case FSCACHE_COOKIE_STATE_ACTIVE: + if (test_and_clear_bit(FSCACHE_COOKIE_DO_PREP_TO_WRITE, &cookie->flags)) { + spin_unlock(&cookie->lock); + fscache_prepare_to_write(cookie); + spin_lock(&cookie->lock); + } + if (test_bit(FSCACHE_COOKIE_DO_LRU_DISCARD, &cookie->flags)) { + __fscache_set_cookie_state(cookie, + FSCACHE_COOKIE_STATE_LRU_DISCARDING); + wake = true; + goto again_locked; + } + fallthrough; + + case FSCACHE_COOKIE_STATE_FAILED: + if (test_and_clear_bit(FSCACHE_COOKIE_DO_INVALIDATE, &cookie->flags)) + fscache_end_cookie_access(cookie, fscache_access_invalidate_cookie_end); + + if (atomic_read(&cookie->n_accesses) != 0) + break; + if (test_bit(FSCACHE_COOKIE_DO_RELINQUISH, &cookie->flags)) { + __fscache_set_cookie_state(cookie, + FSCACHE_COOKIE_STATE_RELINQUISHING); + wake = true; + goto again_locked; + } + if (test_bit(FSCACHE_COOKIE_DO_WITHDRAW, &cookie->flags)) { + __fscache_set_cookie_state(cookie, + FSCACHE_COOKIE_STATE_WITHDRAWING); + wake = true; + goto again_locked; + } + break; + + case FSCACHE_COOKIE_STATE_LRU_DISCARDING: + case FSCACHE_COOKIE_STATE_RELINQUISHING: + case FSCACHE_COOKIE_STATE_WITHDRAWING: + if (cookie->cache_priv) { + spin_unlock(&cookie->lock); + cookie->volume->cache->ops->withdraw_cookie(cookie); + spin_lock(&cookie->lock); + } + + if (test_and_clear_bit(FSCACHE_COOKIE_DO_INVALIDATE, &cookie->flags)) + fscache_end_cookie_access(cookie, fscache_access_invalidate_cookie_end); + + switch (state) { + case FSCACHE_COOKIE_STATE_RELINQUISHING: + fscache_see_cookie(cookie, fscache_cookie_see_relinquish); + fscache_unhash_cookie(cookie); + __fscache_set_cookie_state(cookie, + FSCACHE_COOKIE_STATE_DROPPED); + wake = true; + goto out; + case FSCACHE_COOKIE_STATE_LRU_DISCARDING: + fscache_see_cookie(cookie, fscache_cookie_see_lru_discard); + break; + case FSCACHE_COOKIE_STATE_WITHDRAWING: + fscache_see_cookie(cookie, fscache_cookie_see_withdraw); + break; + default: + BUG(); + } + + clear_bit(FSCACHE_COOKIE_NEEDS_UPDATE, &cookie->flags); + clear_bit(FSCACHE_COOKIE_DO_WITHDRAW, &cookie->flags); + clear_bit(FSCACHE_COOKIE_DO_LRU_DISCARD, &cookie->flags); + clear_bit(FSCACHE_COOKIE_DO_PREP_TO_WRITE, &cookie->flags); + set_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags); + __fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_QUIESCENT); + wake = true; + goto again_locked; + + case FSCACHE_COOKIE_STATE_DROPPED: + break; + + default: + WARN_ONCE(1, "Cookie %x in unexpected state %u\n", + cookie->debug_id, state); + break; + } + +out: + spin_unlock(&cookie->lock); + if (wake) + wake_up_cookie_state(cookie); + _leave(""); +} + +static void fscache_cookie_worker(struct work_struct *work) +{ + struct fscache_cookie *cookie = container_of(work, struct fscache_cookie, work); + + fscache_see_cookie(cookie, fscache_cookie_see_work); + fscache_cookie_state_machine(cookie); + fscache_put_cookie(cookie, fscache_cookie_put_work); +} + +/* + * Wait for the object to become inactive. The cookie's work item will be + * scheduled when someone transitions n_accesses to 0 - but if someone's + * already done that, schedule it anyway. + */ +static void __fscache_withdraw_cookie(struct fscache_cookie *cookie) +{ + int n_accesses; + bool unpinned; + + unpinned = test_and_clear_bit(FSCACHE_COOKIE_NO_ACCESS_WAKE, &cookie->flags); + + /* Need to read the access count after unpinning */ + n_accesses = atomic_read(&cookie->n_accesses); + if (unpinned) + trace_fscache_access(cookie->debug_id, refcount_read(&cookie->ref), + n_accesses, fscache_access_cache_unpin); + if (n_accesses == 0) + fscache_queue_cookie(cookie, fscache_cookie_get_end_access); +} + +static void fscache_cookie_lru_do_one(struct fscache_cookie *cookie) +{ + fscache_see_cookie(cookie, fscache_cookie_see_lru_do_one); + + spin_lock(&cookie->lock); + if (cookie->state != FSCACHE_COOKIE_STATE_ACTIVE || + time_before(jiffies, cookie->unused_at + fscache_lru_cookie_timeout) || + atomic_read(&cookie->n_active) > 0) { + spin_unlock(&cookie->lock); + fscache_stat(&fscache_n_cookies_lru_removed); + } else { + set_bit(FSCACHE_COOKIE_DO_LRU_DISCARD, &cookie->flags); + spin_unlock(&cookie->lock); + fscache_stat(&fscache_n_cookies_lru_expired); + _debug("lru c=%x", cookie->debug_id); + __fscache_withdraw_cookie(cookie); + } + + fscache_put_cookie(cookie, fscache_cookie_put_lru); +} + +static void fscache_cookie_lru_worker(struct work_struct *work) +{ + struct fscache_cookie *cookie; + unsigned long unused_at; + + spin_lock(&fscache_cookie_lru_lock); + + while (!list_empty(&fscache_cookie_lru)) { + cookie = list_first_entry(&fscache_cookie_lru, + struct fscache_cookie, commit_link); + unused_at = cookie->unused_at + fscache_lru_cookie_timeout; + if (time_before(jiffies, unused_at)) { + timer_reduce(&fscache_cookie_lru_timer, unused_at); + break; + } + + list_del_init(&cookie->commit_link); + fscache_stat_d(&fscache_n_cookies_lru); + spin_unlock(&fscache_cookie_lru_lock); + fscache_cookie_lru_do_one(cookie); + spin_lock(&fscache_cookie_lru_lock); + } + + spin_unlock(&fscache_cookie_lru_lock); +} + +static void fscache_cookie_lru_timed_out(struct timer_list *timer) +{ + queue_work(fscache_wq, &fscache_cookie_lru_work); +} + +static void fscache_cookie_drop_from_lru(struct fscache_cookie *cookie) +{ + bool need_put = false; + + if (!list_empty(&cookie->commit_link)) { + spin_lock(&fscache_cookie_lru_lock); + if (!list_empty(&cookie->commit_link)) { + list_del_init(&cookie->commit_link); + fscache_stat_d(&fscache_n_cookies_lru); + fscache_stat(&fscache_n_cookies_lru_dropped); + need_put = true; + } + spin_unlock(&fscache_cookie_lru_lock); + if (need_put) + fscache_put_cookie(cookie, fscache_cookie_put_lru); + } +} + +/* + * Remove a cookie from the hash table. + */ +static void fscache_unhash_cookie(struct fscache_cookie *cookie) +{ + struct hlist_bl_head *h; + unsigned int bucket; + + bucket = cookie->key_hash & (ARRAY_SIZE(fscache_cookie_hash) - 1); + h = &fscache_cookie_hash[bucket]; + + hlist_bl_lock(h); + hlist_bl_del(&cookie->hash_link); + clear_bit(FSCACHE_COOKIE_IS_HASHED, &cookie->flags); + hlist_bl_unlock(h); + fscache_stat(&fscache_n_relinquishes_dropped); +} + +static void fscache_drop_withdraw_cookie(struct fscache_cookie *cookie) +{ + fscache_cookie_drop_from_lru(cookie); + __fscache_withdraw_cookie(cookie); +} + +/** + * fscache_withdraw_cookie - Mark a cookie for withdrawal + * @cookie: The cookie to be withdrawn. + * + * Allow the cache backend to withdraw the backing for a cookie for its own + * reasons, even if that cookie is in active use. + */ +void fscache_withdraw_cookie(struct fscache_cookie *cookie) +{ + set_bit(FSCACHE_COOKIE_DO_WITHDRAW, &cookie->flags); + fscache_drop_withdraw_cookie(cookie); +} +EXPORT_SYMBOL(fscache_withdraw_cookie); + +/* + * Allow the netfs to release a cookie back to the cache. + * - the object will be marked as recyclable on disk if retire is true + */ +void __fscache_relinquish_cookie(struct fscache_cookie *cookie, bool retire) +{ + fscache_stat(&fscache_n_relinquishes); + if (retire) + fscache_stat(&fscache_n_relinquishes_retire); + + _enter("c=%08x{%d},%d", + cookie->debug_id, atomic_read(&cookie->n_active), retire); + + if (WARN(test_and_set_bit(FSCACHE_COOKIE_RELINQUISHED, &cookie->flags), + "Cookie c=%x already relinquished\n", cookie->debug_id)) + return; + + if (retire) + set_bit(FSCACHE_COOKIE_RETIRED, &cookie->flags); + trace_fscache_relinquish(cookie, retire); + + ASSERTCMP(atomic_read(&cookie->n_active), ==, 0); + ASSERTCMP(atomic_read(&cookie->volume->n_cookies), >, 0); + atomic_dec(&cookie->volume->n_cookies); + + if (test_bit(FSCACHE_COOKIE_HAS_BEEN_CACHED, &cookie->flags)) { + set_bit(FSCACHE_COOKIE_DO_RELINQUISH, &cookie->flags); + fscache_drop_withdraw_cookie(cookie); + } else { + fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_DROPPED); + fscache_unhash_cookie(cookie); + } + fscache_put_cookie(cookie, fscache_cookie_put_relinquish); +} +EXPORT_SYMBOL(__fscache_relinquish_cookie); + +/* + * Drop a reference to a cookie. + */ +void fscache_put_cookie(struct fscache_cookie *cookie, + enum fscache_cookie_trace where) +{ + struct fscache_volume *volume = cookie->volume; + unsigned int cookie_debug_id = cookie->debug_id; + bool zero; + int ref; + + zero = __refcount_dec_and_test(&cookie->ref, &ref); + trace_fscache_cookie(cookie_debug_id, ref - 1, where); + if (zero) { + fscache_free_cookie(cookie); + fscache_put_volume(volume, fscache_volume_put_cookie); + } +} +EXPORT_SYMBOL(fscache_put_cookie); + +/* + * Get a reference to a cookie. + */ +struct fscache_cookie *fscache_get_cookie(struct fscache_cookie *cookie, + enum fscache_cookie_trace where) +{ + int ref; + + __refcount_inc(&cookie->ref, &ref); + trace_fscache_cookie(cookie->debug_id, ref + 1, where); + return cookie; +} +EXPORT_SYMBOL(fscache_get_cookie); + +/* + * Ask the cache to effect invalidation of a cookie. + */ +static void fscache_perform_invalidation(struct fscache_cookie *cookie) +{ + if (!cookie->volume->cache->ops->invalidate_cookie(cookie)) + fscache_caching_failed(cookie); + fscache_end_cookie_access(cookie, fscache_access_invalidate_cookie_end); +} + +/* + * Invalidate an object. + */ +void __fscache_invalidate(struct fscache_cookie *cookie, + const void *aux_data, loff_t new_size, + unsigned int flags) +{ + bool is_caching; + + _enter("c=%x", cookie->debug_id); + + fscache_stat(&fscache_n_invalidates); + + if (WARN(test_bit(FSCACHE_COOKIE_RELINQUISHED, &cookie->flags), + "Trying to invalidate relinquished cookie\n")) + return; + + if ((flags & FSCACHE_INVAL_DIO_WRITE) && + test_and_set_bit(FSCACHE_COOKIE_DISABLED, &cookie->flags)) + return; + + spin_lock(&cookie->lock); + set_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags); + fscache_update_aux(cookie, aux_data, &new_size); + cookie->inval_counter++; + trace_fscache_invalidate(cookie, new_size); + + switch (cookie->state) { + case FSCACHE_COOKIE_STATE_INVALIDATING: /* is_still_valid will catch it */ + default: + spin_unlock(&cookie->lock); + _leave(" [no %u]", cookie->state); + return; + + case FSCACHE_COOKIE_STATE_LOOKING_UP: + if (!test_and_set_bit(FSCACHE_COOKIE_DO_INVALIDATE, &cookie->flags)) + __fscache_begin_cookie_access(cookie, fscache_access_invalidate_cookie); + fallthrough; + case FSCACHE_COOKIE_STATE_CREATING: + spin_unlock(&cookie->lock); + _leave(" [look %x]", cookie->inval_counter); + return; + + case FSCACHE_COOKIE_STATE_ACTIVE: + is_caching = fscache_begin_cookie_access( + cookie, fscache_access_invalidate_cookie); + if (is_caching) + __fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_INVALIDATING); + spin_unlock(&cookie->lock); + wake_up_cookie_state(cookie); + + if (is_caching) + fscache_queue_cookie(cookie, fscache_cookie_get_inval_work); + _leave(" [inv]"); + return; + } +} +EXPORT_SYMBOL(__fscache_invalidate); + +#ifdef CONFIG_PROC_FS +/* + * Generate a list of extant cookies in /proc/fs/fscache/cookies + */ +static int fscache_cookies_seq_show(struct seq_file *m, void *v) +{ + struct fscache_cookie *cookie; + unsigned int keylen = 0, auxlen = 0; + u8 *p; + + if (v == &fscache_cookies) { + seq_puts(m, + "COOKIE VOLUME REF ACT ACC S FL DEF \n" + "======== ======== === === === = == ================\n" + ); + return 0; + } + + cookie = list_entry(v, struct fscache_cookie, proc_link); + + seq_printf(m, + "%08x %08x %3d %3d %3d %c %02lx", + cookie->debug_id, + cookie->volume->debug_id, + refcount_read(&cookie->ref), + atomic_read(&cookie->n_active), + atomic_read(&cookie->n_accesses), + fscache_cookie_states[cookie->state], + cookie->flags); + + keylen = cookie->key_len; + auxlen = cookie->aux_len; + + if (keylen > 0 || auxlen > 0) { + seq_puts(m, " "); + p = keylen <= sizeof(cookie->inline_key) ? + cookie->inline_key : cookie->key; + for (; keylen > 0; keylen--) + seq_printf(m, "%02x", *p++); + if (auxlen > 0) { + seq_puts(m, ", "); + p = auxlen <= sizeof(cookie->inline_aux) ? + cookie->inline_aux : cookie->aux; + for (; auxlen > 0; auxlen--) + seq_printf(m, "%02x", *p++); + } + } + + seq_puts(m, "\n"); + return 0; +} + +static void *fscache_cookies_seq_start(struct seq_file *m, loff_t *_pos) + __acquires(fscache_cookies_lock) +{ + read_lock(&fscache_cookies_lock); + return seq_list_start_head(&fscache_cookies, *_pos); +} + +static void *fscache_cookies_seq_next(struct seq_file *m, void *v, loff_t *_pos) +{ + return seq_list_next(v, &fscache_cookies, _pos); +} + +static void fscache_cookies_seq_stop(struct seq_file *m, void *v) + __releases(rcu) +{ + read_unlock(&fscache_cookies_lock); +} + + +const struct seq_operations fscache_cookies_seq_ops = { + .start = fscache_cookies_seq_start, + .next = fscache_cookies_seq_next, + .stop = fscache_cookies_seq_stop, + .show = fscache_cookies_seq_show, +}; +#endif diff --git a/fs/netfs/fscache_internal.h b/fs/netfs/fscache_internal.h new file mode 100644 index 0000000000..a09b948fce --- /dev/null +++ b/fs/netfs/fscache_internal.h @@ -0,0 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* Internal definitions for FS-Cache + * + * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include "internal.h" + +#ifdef pr_fmt +#undef pr_fmt +#endif + +#define pr_fmt(fmt) "FS-Cache: " fmt diff --git a/fs/netfs/fscache_io.c b/fs/netfs/fscache_io.c new file mode 100644 index 0000000000..ad572f7ee8 --- /dev/null +++ b/fs/netfs/fscache_io.c @@ -0,0 +1,287 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Cache data I/O routines + * + * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ +#define FSCACHE_DEBUG_LEVEL OPERATION +#include <linux/fscache-cache.h> +#include <linux/uio.h> +#include <linux/bvec.h> +#include <linux/slab.h> +#include <linux/uio.h> +#include "internal.h" + +/** + * fscache_wait_for_operation - Wait for an object become accessible + * @cres: The cache resources for the operation being performed + * @want_state: The minimum state the object must be at + * + * See if the target cache object is at the specified minimum state of + * accessibility yet, and if not, wait for it. + */ +bool fscache_wait_for_operation(struct netfs_cache_resources *cres, + enum fscache_want_state want_state) +{ + struct fscache_cookie *cookie = fscache_cres_cookie(cres); + enum fscache_cookie_state state; + +again: + if (!fscache_cache_is_live(cookie->volume->cache)) { + _leave(" [broken]"); + return false; + } + + state = fscache_cookie_state(cookie); + _enter("c=%08x{%u},%x", cookie->debug_id, state, want_state); + + switch (state) { + case FSCACHE_COOKIE_STATE_CREATING: + case FSCACHE_COOKIE_STATE_INVALIDATING: + if (want_state == FSCACHE_WANT_PARAMS) + goto ready; /* There can be no content */ + fallthrough; + case FSCACHE_COOKIE_STATE_LOOKING_UP: + case FSCACHE_COOKIE_STATE_LRU_DISCARDING: + wait_var_event(&cookie->state, + fscache_cookie_state(cookie) != state); + goto again; + + case FSCACHE_COOKIE_STATE_ACTIVE: + goto ready; + case FSCACHE_COOKIE_STATE_DROPPED: + case FSCACHE_COOKIE_STATE_RELINQUISHING: + default: + _leave(" [not live]"); + return false; + } + +ready: + if (!cres->cache_priv2) + return cookie->volume->cache->ops->begin_operation(cres, want_state); + return true; +} +EXPORT_SYMBOL(fscache_wait_for_operation); + +/* + * Begin an I/O operation on the cache, waiting till we reach the right state. + * + * Attaches the resources required to the operation resources record. + */ +static int fscache_begin_operation(struct netfs_cache_resources *cres, + struct fscache_cookie *cookie, + enum fscache_want_state want_state, + enum fscache_access_trace why) +{ + enum fscache_cookie_state state; + long timeo; + bool once_only = false; + + cres->ops = NULL; + cres->cache_priv = cookie; + cres->cache_priv2 = NULL; + cres->debug_id = cookie->debug_id; + cres->inval_counter = cookie->inval_counter; + + if (!fscache_begin_cookie_access(cookie, why)) + return -ENOBUFS; + +again: + spin_lock(&cookie->lock); + + state = fscache_cookie_state(cookie); + _enter("c=%08x{%u},%x", cookie->debug_id, state, want_state); + + switch (state) { + case FSCACHE_COOKIE_STATE_LOOKING_UP: + case FSCACHE_COOKIE_STATE_LRU_DISCARDING: + case FSCACHE_COOKIE_STATE_INVALIDATING: + goto wait_for_file_wrangling; + case FSCACHE_COOKIE_STATE_CREATING: + if (want_state == FSCACHE_WANT_PARAMS) + goto ready; /* There can be no content */ + goto wait_for_file_wrangling; + case FSCACHE_COOKIE_STATE_ACTIVE: + goto ready; + case FSCACHE_COOKIE_STATE_DROPPED: + case FSCACHE_COOKIE_STATE_RELINQUISHING: + WARN(1, "Can't use cookie in state %u\n", cookie->state); + goto not_live; + default: + goto not_live; + } + +ready: + spin_unlock(&cookie->lock); + if (!cookie->volume->cache->ops->begin_operation(cres, want_state)) + goto failed; + return 0; + +wait_for_file_wrangling: + spin_unlock(&cookie->lock); + trace_fscache_access(cookie->debug_id, refcount_read(&cookie->ref), + atomic_read(&cookie->n_accesses), + fscache_access_io_wait); + timeo = wait_var_event_timeout(&cookie->state, + fscache_cookie_state(cookie) != state, 20 * HZ); + if (timeo <= 1 && !once_only) { + pr_warn("%s: cookie state change wait timed out: cookie->state=%u state=%u", + __func__, fscache_cookie_state(cookie), state); + fscache_print_cookie(cookie, 'O'); + once_only = true; + } + goto again; + +not_live: + spin_unlock(&cookie->lock); +failed: + cres->cache_priv = NULL; + cres->ops = NULL; + fscache_end_cookie_access(cookie, fscache_access_io_not_live); + _leave(" = -ENOBUFS"); + return -ENOBUFS; +} + +int __fscache_begin_read_operation(struct netfs_cache_resources *cres, + struct fscache_cookie *cookie) +{ + return fscache_begin_operation(cres, cookie, FSCACHE_WANT_PARAMS, + fscache_access_io_read); +} +EXPORT_SYMBOL(__fscache_begin_read_operation); + +int __fscache_begin_write_operation(struct netfs_cache_resources *cres, + struct fscache_cookie *cookie) +{ + return fscache_begin_operation(cres, cookie, FSCACHE_WANT_PARAMS, + fscache_access_io_write); +} +EXPORT_SYMBOL(__fscache_begin_write_operation); + +struct fscache_write_request { + struct netfs_cache_resources cache_resources; + struct address_space *mapping; + loff_t start; + size_t len; + bool set_bits; + netfs_io_terminated_t term_func; + void *term_func_priv; +}; + +void __fscache_clear_page_bits(struct address_space *mapping, + loff_t start, size_t len) +{ + pgoff_t first = start / PAGE_SIZE; + pgoff_t last = (start + len - 1) / PAGE_SIZE; + struct page *page; + + if (len) { + XA_STATE(xas, &mapping->i_pages, first); + + rcu_read_lock(); + xas_for_each(&xas, page, last) { + end_page_fscache(page); + } + rcu_read_unlock(); + } +} +EXPORT_SYMBOL(__fscache_clear_page_bits); + +/* + * Deal with the completion of writing the data to the cache. + */ +static void fscache_wreq_done(void *priv, ssize_t transferred_or_error, + bool was_async) +{ + struct fscache_write_request *wreq = priv; + + fscache_clear_page_bits(wreq->mapping, wreq->start, wreq->len, + wreq->set_bits); + + if (wreq->term_func) + wreq->term_func(wreq->term_func_priv, transferred_or_error, + was_async); + fscache_end_operation(&wreq->cache_resources); + kfree(wreq); +} + +void __fscache_write_to_cache(struct fscache_cookie *cookie, + struct address_space *mapping, + loff_t start, size_t len, loff_t i_size, + netfs_io_terminated_t term_func, + void *term_func_priv, + bool cond) +{ + struct fscache_write_request *wreq; + struct netfs_cache_resources *cres; + struct iov_iter iter; + int ret = -ENOBUFS; + + if (len == 0) + goto abandon; + + _enter("%llx,%zx", start, len); + + wreq = kzalloc(sizeof(struct fscache_write_request), GFP_NOFS); + if (!wreq) + goto abandon; + wreq->mapping = mapping; + wreq->start = start; + wreq->len = len; + wreq->set_bits = cond; + wreq->term_func = term_func; + wreq->term_func_priv = term_func_priv; + + cres = &wreq->cache_resources; + if (fscache_begin_operation(cres, cookie, FSCACHE_WANT_WRITE, + fscache_access_io_write) < 0) + goto abandon_free; + + ret = cres->ops->prepare_write(cres, &start, &len, len, i_size, false); + if (ret < 0) + goto abandon_end; + + /* TODO: Consider clearing page bits now for space the write isn't + * covering. This is more complicated than it appears when THPs are + * taken into account. + */ + + iov_iter_xarray(&iter, ITER_SOURCE, &mapping->i_pages, start, len); + fscache_write(cres, start, &iter, fscache_wreq_done, wreq); + return; + +abandon_end: + return fscache_wreq_done(wreq, ret, false); +abandon_free: + kfree(wreq); +abandon: + fscache_clear_page_bits(mapping, start, len, cond); + if (term_func) + term_func(term_func_priv, ret, false); +} +EXPORT_SYMBOL(__fscache_write_to_cache); + +/* + * Change the size of a backing object. + */ +void __fscache_resize_cookie(struct fscache_cookie *cookie, loff_t new_size) +{ + struct netfs_cache_resources cres; + + trace_fscache_resize(cookie, new_size); + if (fscache_begin_operation(&cres, cookie, FSCACHE_WANT_WRITE, + fscache_access_io_resize) == 0) { + fscache_stat(&fscache_n_resizes); + set_bit(FSCACHE_COOKIE_NEEDS_UPDATE, &cookie->flags); + + /* We cannot defer a resize as we need to do it inside the + * netfs's inode lock so that we're serialised with respect to + * writes. + */ + cookie->volume->cache->ops->resize_cookie(&cres, new_size); + fscache_end_operation(&cres); + } else { + fscache_stat(&fscache_n_resizes_null); + } +} +EXPORT_SYMBOL(__fscache_resize_cookie); diff --git a/fs/netfs/fscache_main.c b/fs/netfs/fscache_main.c new file mode 100644 index 0000000000..42e98bb523 --- /dev/null +++ b/fs/netfs/fscache_main.c @@ -0,0 +1,108 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* General filesystem local caching manager + * + * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#define FSCACHE_DEBUG_LEVEL CACHE +#include <linux/module.h> +#include <linux/init.h> +#include "internal.h" +#define CREATE_TRACE_POINTS +#include <trace/events/fscache.h> + +EXPORT_TRACEPOINT_SYMBOL(fscache_access_cache); +EXPORT_TRACEPOINT_SYMBOL(fscache_access_volume); +EXPORT_TRACEPOINT_SYMBOL(fscache_access); + +struct workqueue_struct *fscache_wq; +EXPORT_SYMBOL(fscache_wq); + +/* + * Mixing scores (in bits) for (7,20): + * Input delta: 1-bit 2-bit + * 1 round: 330.3 9201.6 + * 2 rounds: 1246.4 25475.4 + * 3 rounds: 1907.1 31295.1 + * 4 rounds: 2042.3 31718.6 + * Perfect: 2048 31744 + * (32*64) (32*31/2 * 64) + */ +#define HASH_MIX(x, y, a) \ + ( x ^= (a), \ + y ^= x, x = rol32(x, 7),\ + x += y, y = rol32(y,20),\ + y *= 9 ) + +static inline unsigned int fold_hash(unsigned long x, unsigned long y) +{ + /* Use arch-optimized multiply if one exists */ + return __hash_32(y ^ __hash_32(x)); +} + +/* + * Generate a hash. This is derived from full_name_hash(), but we want to be + * sure it is arch independent and that it doesn't change as bits of the + * computed hash value might appear on disk. The caller must guarantee that + * the source data is a multiple of four bytes in size. + */ +unsigned int fscache_hash(unsigned int salt, const void *data, size_t len) +{ + const __le32 *p = data; + unsigned int a, x = 0, y = salt, n = len / sizeof(__le32); + + for (; n; n--) { + a = le32_to_cpu(*p++); + HASH_MIX(x, y, a); + } + return fold_hash(x, y); +} + +/* + * initialise the fs caching module + */ +int __init fscache_init(void) +{ + int ret = -ENOMEM; + + fscache_wq = alloc_workqueue("fscache", WQ_UNBOUND | WQ_FREEZABLE, 0); + if (!fscache_wq) + goto error_wq; + + ret = fscache_proc_init(); + if (ret < 0) + goto error_proc; + + fscache_cookie_jar = kmem_cache_create("fscache_cookie_jar", + sizeof(struct fscache_cookie), + 0, 0, NULL); + if (!fscache_cookie_jar) { + pr_notice("Failed to allocate a cookie jar\n"); + ret = -ENOMEM; + goto error_cookie_jar; + } + + pr_notice("FS-Cache loaded\n"); + return 0; + +error_cookie_jar: + fscache_proc_cleanup(); +error_proc: + destroy_workqueue(fscache_wq); +error_wq: + return ret; +} + +/* + * clean up on module removal + */ +void __exit fscache_exit(void) +{ + _enter(""); + + kmem_cache_destroy(fscache_cookie_jar); + fscache_proc_cleanup(); + destroy_workqueue(fscache_wq); + pr_notice("FS-Cache unloaded\n"); +} diff --git a/fs/netfs/fscache_proc.c b/fs/netfs/fscache_proc.c new file mode 100644 index 0000000000..874d951bc3 --- /dev/null +++ b/fs/netfs/fscache_proc.c @@ -0,0 +1,47 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* FS-Cache statistics viewing interface + * + * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#define FSCACHE_DEBUG_LEVEL CACHE +#include <linux/module.h> +#include <linux/proc_fs.h> +#include <linux/seq_file.h> +#include "internal.h" + +/* + * Add files to /proc/fs/netfs/. + */ +int __init fscache_proc_init(void) +{ + if (!proc_symlink("fs/fscache", NULL, "netfs")) + goto error_sym; + + if (!proc_create_seq("fs/netfs/caches", S_IFREG | 0444, NULL, + &fscache_caches_seq_ops)) + goto error; + + if (!proc_create_seq("fs/netfs/volumes", S_IFREG | 0444, NULL, + &fscache_volumes_seq_ops)) + goto error; + + if (!proc_create_seq("fs/netfs/cookies", S_IFREG | 0444, NULL, + &fscache_cookies_seq_ops)) + goto error; + return 0; + +error: + remove_proc_entry("fs/fscache", NULL); +error_sym: + return -ENOMEM; +} + +/* + * Clean up the /proc/fs/fscache symlink. + */ +void fscache_proc_cleanup(void) +{ + remove_proc_subtree("fs/fscache", NULL); +} diff --git a/fs/netfs/fscache_stats.c b/fs/netfs/fscache_stats.c new file mode 100644 index 0000000000..add21abdf7 --- /dev/null +++ b/fs/netfs/fscache_stats.c @@ -0,0 +1,103 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* FS-Cache statistics + * + * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#define FSCACHE_DEBUG_LEVEL CACHE +#include <linux/proc_fs.h> +#include <linux/seq_file.h> +#include "internal.h" + +/* + * operation counters + */ +atomic_t fscache_n_volumes; +atomic_t fscache_n_volumes_collision; +atomic_t fscache_n_volumes_nomem; +atomic_t fscache_n_cookies; +atomic_t fscache_n_cookies_lru; +atomic_t fscache_n_cookies_lru_expired; +atomic_t fscache_n_cookies_lru_removed; +atomic_t fscache_n_cookies_lru_dropped; + +atomic_t fscache_n_acquires; +atomic_t fscache_n_acquires_ok; +atomic_t fscache_n_acquires_oom; + +atomic_t fscache_n_invalidates; + +atomic_t fscache_n_updates; +EXPORT_SYMBOL(fscache_n_updates); + +atomic_t fscache_n_relinquishes; +atomic_t fscache_n_relinquishes_retire; +atomic_t fscache_n_relinquishes_dropped; + +atomic_t fscache_n_resizes; +atomic_t fscache_n_resizes_null; + +atomic_t fscache_n_read; +EXPORT_SYMBOL(fscache_n_read); +atomic_t fscache_n_write; +EXPORT_SYMBOL(fscache_n_write); +atomic_t fscache_n_no_write_space; +EXPORT_SYMBOL(fscache_n_no_write_space); +atomic_t fscache_n_no_create_space; +EXPORT_SYMBOL(fscache_n_no_create_space); +atomic_t fscache_n_culled; +EXPORT_SYMBOL(fscache_n_culled); +atomic_t fscache_n_dio_misfit; +EXPORT_SYMBOL(fscache_n_dio_misfit); + +/* + * display the general statistics + */ +int fscache_stats_show(struct seq_file *m) +{ + seq_puts(m, "-- FS-Cache statistics --\n"); + seq_printf(m, "Cookies: n=%d v=%d vcol=%u voom=%u\n", + atomic_read(&fscache_n_cookies), + atomic_read(&fscache_n_volumes), + atomic_read(&fscache_n_volumes_collision), + atomic_read(&fscache_n_volumes_nomem) + ); + + seq_printf(m, "Acquire: n=%u ok=%u oom=%u\n", + atomic_read(&fscache_n_acquires), + atomic_read(&fscache_n_acquires_ok), + atomic_read(&fscache_n_acquires_oom)); + + seq_printf(m, "LRU : n=%u exp=%u rmv=%u drp=%u at=%ld\n", + atomic_read(&fscache_n_cookies_lru), + atomic_read(&fscache_n_cookies_lru_expired), + atomic_read(&fscache_n_cookies_lru_removed), + atomic_read(&fscache_n_cookies_lru_dropped), + timer_pending(&fscache_cookie_lru_timer) ? + fscache_cookie_lru_timer.expires - jiffies : 0); + + seq_printf(m, "Invals : n=%u\n", + atomic_read(&fscache_n_invalidates)); + + seq_printf(m, "Updates: n=%u rsz=%u rsn=%u\n", + atomic_read(&fscache_n_updates), + atomic_read(&fscache_n_resizes), + atomic_read(&fscache_n_resizes_null)); + + seq_printf(m, "Relinqs: n=%u rtr=%u drop=%u\n", + atomic_read(&fscache_n_relinquishes), + atomic_read(&fscache_n_relinquishes_retire), + atomic_read(&fscache_n_relinquishes_dropped)); + + seq_printf(m, "NoSpace: nwr=%u ncr=%u cull=%u\n", + atomic_read(&fscache_n_no_write_space), + atomic_read(&fscache_n_no_create_space), + atomic_read(&fscache_n_culled)); + + seq_printf(m, "IO : rd=%u wr=%u mis=%u\n", + atomic_read(&fscache_n_read), + atomic_read(&fscache_n_write), + atomic_read(&fscache_n_dio_misfit)); + return 0; +} diff --git a/fs/netfs/fscache_volume.c b/fs/netfs/fscache_volume.c new file mode 100644 index 0000000000..cdf991bdd9 --- /dev/null +++ b/fs/netfs/fscache_volume.c @@ -0,0 +1,520 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Volume-level cache cookie handling. + * + * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#define FSCACHE_DEBUG_LEVEL COOKIE +#include <linux/export.h> +#include <linux/slab.h> +#include "internal.h" + +#define fscache_volume_hash_shift 10 +static struct hlist_bl_head fscache_volume_hash[1 << fscache_volume_hash_shift]; +static atomic_t fscache_volume_debug_id; +static LIST_HEAD(fscache_volumes); + +static void fscache_create_volume_work(struct work_struct *work); + +struct fscache_volume *fscache_get_volume(struct fscache_volume *volume, + enum fscache_volume_trace where) +{ + int ref; + + __refcount_inc(&volume->ref, &ref); + trace_fscache_volume(volume->debug_id, ref + 1, where); + return volume; +} + +static void fscache_see_volume(struct fscache_volume *volume, + enum fscache_volume_trace where) +{ + int ref = refcount_read(&volume->ref); + + trace_fscache_volume(volume->debug_id, ref, where); +} + +/* + * Pin the cache behind a volume so that we can access it. + */ +static void __fscache_begin_volume_access(struct fscache_volume *volume, + struct fscache_cookie *cookie, + enum fscache_access_trace why) +{ + int n_accesses; + + n_accesses = atomic_inc_return(&volume->n_accesses); + smp_mb__after_atomic(); + trace_fscache_access_volume(volume->debug_id, cookie ? cookie->debug_id : 0, + refcount_read(&volume->ref), + n_accesses, why); +} + +/** + * fscache_begin_volume_access - Pin a cache so a volume can be accessed + * @volume: The volume cookie + * @cookie: A datafile cookie for a tracing reference (or NULL) + * @why: An indication of the circumstances of the access for tracing + * + * Attempt to pin the cache to prevent it from going away whilst we're + * accessing a volume and returns true if successful. This works as follows: + * + * (1) If the cache tests as not live (state is not FSCACHE_CACHE_IS_ACTIVE), + * then we return false to indicate access was not permitted. + * + * (2) If the cache tests as live, then we increment the volume's n_accesses + * count and then recheck the cache liveness, ending the access if it + * ceased to be live. + * + * (3) When we end the access, we decrement the volume's n_accesses and wake + * up the any waiters if it reaches 0. + * + * (4) Whilst the cache is caching, the volume's n_accesses is kept + * artificially incremented to prevent wakeups from happening. + * + * (5) When the cache is taken offline, the state is changed to prevent new + * accesses, the volume's n_accesses is decremented and we wait for it to + * become 0. + * + * The datafile @cookie and the @why indicator are merely provided for tracing + * purposes. + */ +bool fscache_begin_volume_access(struct fscache_volume *volume, + struct fscache_cookie *cookie, + enum fscache_access_trace why) +{ + if (!fscache_cache_is_live(volume->cache)) + return false; + __fscache_begin_volume_access(volume, cookie, why); + if (!fscache_cache_is_live(volume->cache)) { + fscache_end_volume_access(volume, cookie, fscache_access_unlive); + return false; + } + return true; +} + +/** + * fscache_end_volume_access - Unpin a cache at the end of an access. + * @volume: The volume cookie + * @cookie: A datafile cookie for a tracing reference (or NULL) + * @why: An indication of the circumstances of the access for tracing + * + * Unpin a cache volume after we've accessed it. The datafile @cookie and the + * @why indicator are merely provided for tracing purposes. + */ +void fscache_end_volume_access(struct fscache_volume *volume, + struct fscache_cookie *cookie, + enum fscache_access_trace why) +{ + int n_accesses; + + smp_mb__before_atomic(); + n_accesses = atomic_dec_return(&volume->n_accesses); + trace_fscache_access_volume(volume->debug_id, cookie ? cookie->debug_id : 0, + refcount_read(&volume->ref), + n_accesses, why); + if (n_accesses == 0) + wake_up_var(&volume->n_accesses); +} +EXPORT_SYMBOL(fscache_end_volume_access); + +static bool fscache_volume_same(const struct fscache_volume *a, + const struct fscache_volume *b) +{ + size_t klen; + + if (a->key_hash != b->key_hash || + a->cache != b->cache || + a->key[0] != b->key[0]) + return false; + + klen = round_up(a->key[0] + 1, sizeof(__le32)); + return memcmp(a->key, b->key, klen) == 0; +} + +static bool fscache_is_acquire_pending(struct fscache_volume *volume) +{ + return test_bit(FSCACHE_VOLUME_ACQUIRE_PENDING, &volume->flags); +} + +static void fscache_wait_on_volume_collision(struct fscache_volume *candidate, + unsigned int collidee_debug_id) +{ + wait_on_bit_timeout(&candidate->flags, FSCACHE_VOLUME_ACQUIRE_PENDING, + TASK_UNINTERRUPTIBLE, 20 * HZ); + if (fscache_is_acquire_pending(candidate)) { + pr_notice("Potential volume collision new=%08x old=%08x", + candidate->debug_id, collidee_debug_id); + fscache_stat(&fscache_n_volumes_collision); + wait_on_bit(&candidate->flags, FSCACHE_VOLUME_ACQUIRE_PENDING, + TASK_UNINTERRUPTIBLE); + } +} + +/* + * Attempt to insert the new volume into the hash. If there's a collision, we + * wait for the old volume to complete if it's being relinquished and an error + * otherwise. + */ +static bool fscache_hash_volume(struct fscache_volume *candidate) +{ + struct fscache_volume *cursor; + struct hlist_bl_head *h; + struct hlist_bl_node *p; + unsigned int bucket, collidee_debug_id = 0; + + bucket = candidate->key_hash & (ARRAY_SIZE(fscache_volume_hash) - 1); + h = &fscache_volume_hash[bucket]; + + hlist_bl_lock(h); + hlist_bl_for_each_entry(cursor, p, h, hash_link) { + if (fscache_volume_same(candidate, cursor)) { + if (!test_bit(FSCACHE_VOLUME_RELINQUISHED, &cursor->flags)) + goto collision; + fscache_see_volume(cursor, fscache_volume_get_hash_collision); + set_bit(FSCACHE_VOLUME_COLLIDED_WITH, &cursor->flags); + set_bit(FSCACHE_VOLUME_ACQUIRE_PENDING, &candidate->flags); + collidee_debug_id = cursor->debug_id; + break; + } + } + + hlist_bl_add_head(&candidate->hash_link, h); + hlist_bl_unlock(h); + + if (fscache_is_acquire_pending(candidate)) + fscache_wait_on_volume_collision(candidate, collidee_debug_id); + return true; + +collision: + fscache_see_volume(cursor, fscache_volume_collision); + hlist_bl_unlock(h); + return false; +} + +/* + * Allocate and initialise a volume representation cookie. + */ +static struct fscache_volume *fscache_alloc_volume(const char *volume_key, + const char *cache_name, + const void *coherency_data, + size_t coherency_len) +{ + struct fscache_volume *volume; + struct fscache_cache *cache; + size_t klen, hlen; + u8 *key; + + klen = strlen(volume_key); + if (klen > NAME_MAX) + return NULL; + + if (!coherency_data) + coherency_len = 0; + + cache = fscache_lookup_cache(cache_name, false); + if (IS_ERR(cache)) + return NULL; + + volume = kzalloc(struct_size(volume, coherency, coherency_len), + GFP_KERNEL); + if (!volume) + goto err_cache; + + volume->cache = cache; + volume->coherency_len = coherency_len; + if (coherency_data) + memcpy(volume->coherency, coherency_data, coherency_len); + INIT_LIST_HEAD(&volume->proc_link); + INIT_WORK(&volume->work, fscache_create_volume_work); + refcount_set(&volume->ref, 1); + spin_lock_init(&volume->lock); + + /* Stick the length on the front of the key and pad it out to make + * hashing easier. + */ + hlen = round_up(1 + klen + 1, sizeof(__le32)); + key = kzalloc(hlen, GFP_KERNEL); + if (!key) + goto err_vol; + key[0] = klen; + memcpy(key + 1, volume_key, klen); + + volume->key = key; + volume->key_hash = fscache_hash(0, key, hlen); + + volume->debug_id = atomic_inc_return(&fscache_volume_debug_id); + down_write(&fscache_addremove_sem); + atomic_inc(&cache->n_volumes); + list_add_tail(&volume->proc_link, &fscache_volumes); + fscache_see_volume(volume, fscache_volume_new_acquire); + fscache_stat(&fscache_n_volumes); + up_write(&fscache_addremove_sem); + _leave(" = v=%x", volume->debug_id); + return volume; + +err_vol: + kfree(volume); +err_cache: + fscache_put_cache(cache, fscache_cache_put_alloc_volume); + fscache_stat(&fscache_n_volumes_nomem); + return NULL; +} + +/* + * Create a volume's representation on disk. Have a volume ref and a cache + * access we have to release. + */ +static void fscache_create_volume_work(struct work_struct *work) +{ + const struct fscache_cache_ops *ops; + struct fscache_volume *volume = + container_of(work, struct fscache_volume, work); + + fscache_see_volume(volume, fscache_volume_see_create_work); + + ops = volume->cache->ops; + if (ops->acquire_volume) + ops->acquire_volume(volume); + fscache_end_cache_access(volume->cache, + fscache_access_acquire_volume_end); + + clear_and_wake_up_bit(FSCACHE_VOLUME_CREATING, &volume->flags); + fscache_put_volume(volume, fscache_volume_put_create_work); +} + +/* + * Dispatch a worker thread to create a volume's representation on disk. + */ +void fscache_create_volume(struct fscache_volume *volume, bool wait) +{ + if (test_and_set_bit(FSCACHE_VOLUME_CREATING, &volume->flags)) + goto maybe_wait; + if (volume->cache_priv) + goto no_wait; /* We raced */ + if (!fscache_begin_cache_access(volume->cache, + fscache_access_acquire_volume)) + goto no_wait; + + fscache_get_volume(volume, fscache_volume_get_create_work); + if (!schedule_work(&volume->work)) + fscache_put_volume(volume, fscache_volume_put_create_work); + +maybe_wait: + if (wait) { + fscache_see_volume(volume, fscache_volume_wait_create_work); + wait_on_bit(&volume->flags, FSCACHE_VOLUME_CREATING, + TASK_UNINTERRUPTIBLE); + } + return; +no_wait: + clear_bit_unlock(FSCACHE_VOLUME_CREATING, &volume->flags); + wake_up_bit(&volume->flags, FSCACHE_VOLUME_CREATING); +} + +/* + * Acquire a volume representation cookie and link it to a (proposed) cache. + */ +struct fscache_volume *__fscache_acquire_volume(const char *volume_key, + const char *cache_name, + const void *coherency_data, + size_t coherency_len) +{ + struct fscache_volume *volume; + + volume = fscache_alloc_volume(volume_key, cache_name, + coherency_data, coherency_len); + if (!volume) + return ERR_PTR(-ENOMEM); + + if (!fscache_hash_volume(volume)) { + fscache_put_volume(volume, fscache_volume_put_hash_collision); + return ERR_PTR(-EBUSY); + } + + fscache_create_volume(volume, false); + return volume; +} +EXPORT_SYMBOL(__fscache_acquire_volume); + +static void fscache_wake_pending_volume(struct fscache_volume *volume, + struct hlist_bl_head *h) +{ + struct fscache_volume *cursor; + struct hlist_bl_node *p; + + hlist_bl_for_each_entry(cursor, p, h, hash_link) { + if (fscache_volume_same(cursor, volume)) { + fscache_see_volume(cursor, fscache_volume_see_hash_wake); + clear_and_wake_up_bit(FSCACHE_VOLUME_ACQUIRE_PENDING, + &cursor->flags); + return; + } + } +} + +/* + * Remove a volume cookie from the hash table. + */ +static void fscache_unhash_volume(struct fscache_volume *volume) +{ + struct hlist_bl_head *h; + unsigned int bucket; + + bucket = volume->key_hash & (ARRAY_SIZE(fscache_volume_hash) - 1); + h = &fscache_volume_hash[bucket]; + + hlist_bl_lock(h); + hlist_bl_del(&volume->hash_link); + if (test_bit(FSCACHE_VOLUME_COLLIDED_WITH, &volume->flags)) + fscache_wake_pending_volume(volume, h); + hlist_bl_unlock(h); +} + +/* + * Drop a cache's volume attachments. + */ +static void fscache_free_volume(struct fscache_volume *volume) +{ + struct fscache_cache *cache = volume->cache; + + if (volume->cache_priv) { + __fscache_begin_volume_access(volume, NULL, + fscache_access_relinquish_volume); + if (volume->cache_priv) + cache->ops->free_volume(volume); + fscache_end_volume_access(volume, NULL, + fscache_access_relinquish_volume_end); + } + + down_write(&fscache_addremove_sem); + list_del_init(&volume->proc_link); + atomic_dec(&volume->cache->n_volumes); + up_write(&fscache_addremove_sem); + + if (!hlist_bl_unhashed(&volume->hash_link)) + fscache_unhash_volume(volume); + + trace_fscache_volume(volume->debug_id, 0, fscache_volume_free); + kfree(volume->key); + kfree(volume); + fscache_stat_d(&fscache_n_volumes); + fscache_put_cache(cache, fscache_cache_put_volume); +} + +/* + * Drop a reference to a volume cookie. + */ +void fscache_put_volume(struct fscache_volume *volume, + enum fscache_volume_trace where) +{ + if (volume) { + unsigned int debug_id = volume->debug_id; + bool zero; + int ref; + + zero = __refcount_dec_and_test(&volume->ref, &ref); + trace_fscache_volume(debug_id, ref - 1, where); + if (zero) + fscache_free_volume(volume); + } +} + +/* + * Relinquish a volume representation cookie. + */ +void __fscache_relinquish_volume(struct fscache_volume *volume, + const void *coherency_data, + bool invalidate) +{ + if (WARN_ON(test_and_set_bit(FSCACHE_VOLUME_RELINQUISHED, &volume->flags))) + return; + + if (invalidate) { + set_bit(FSCACHE_VOLUME_INVALIDATE, &volume->flags); + } else if (coherency_data) { + memcpy(volume->coherency, coherency_data, volume->coherency_len); + } + + fscache_put_volume(volume, fscache_volume_put_relinquish); +} +EXPORT_SYMBOL(__fscache_relinquish_volume); + +/** + * fscache_withdraw_volume - Withdraw a volume from being cached + * @volume: Volume cookie + * + * Withdraw a cache volume from service, waiting for all accesses to complete + * before returning. + */ +void fscache_withdraw_volume(struct fscache_volume *volume) +{ + int n_accesses; + + _debug("withdraw V=%x", volume->debug_id); + + /* Allow wakeups on dec-to-0 */ + n_accesses = atomic_dec_return(&volume->n_accesses); + trace_fscache_access_volume(volume->debug_id, 0, + refcount_read(&volume->ref), + n_accesses, fscache_access_cache_unpin); + + wait_var_event(&volume->n_accesses, + atomic_read(&volume->n_accesses) == 0); +} +EXPORT_SYMBOL(fscache_withdraw_volume); + +#ifdef CONFIG_PROC_FS +/* + * Generate a list of volumes in /proc/fs/fscache/volumes + */ +static int fscache_volumes_seq_show(struct seq_file *m, void *v) +{ + struct fscache_volume *volume; + + if (v == &fscache_volumes) { + seq_puts(m, + "VOLUME REF nCOOK ACC FL CACHE KEY\n" + "======== ===== ===== === == =============== ================\n"); + return 0; + } + + volume = list_entry(v, struct fscache_volume, proc_link); + seq_printf(m, + "%08x %5d %5d %3d %02lx %-15.15s %s\n", + volume->debug_id, + refcount_read(&volume->ref), + atomic_read(&volume->n_cookies), + atomic_read(&volume->n_accesses), + volume->flags, + volume->cache->name ?: "-", + volume->key + 1); + return 0; +} + +static void *fscache_volumes_seq_start(struct seq_file *m, loff_t *_pos) + __acquires(&fscache_addremove_sem) +{ + down_read(&fscache_addremove_sem); + return seq_list_start_head(&fscache_volumes, *_pos); +} + +static void *fscache_volumes_seq_next(struct seq_file *m, void *v, loff_t *_pos) +{ + return seq_list_next(v, &fscache_volumes, _pos); +} + +static void fscache_volumes_seq_stop(struct seq_file *m, void *v) + __releases(&fscache_addremove_sem) +{ + up_read(&fscache_addremove_sem); +} + +const struct seq_operations fscache_volumes_seq_ops = { + .start = fscache_volumes_seq_start, + .next = fscache_volumes_seq_next, + .stop = fscache_volumes_seq_stop, + .show = fscache_volumes_seq_show, +}; +#endif /* CONFIG_PROC_FS */ diff --git a/fs/netfs/internal.h b/fs/netfs/internal.h index 43fac1b14e..ec7045d244 100644 --- a/fs/netfs/internal.h +++ b/fs/netfs/internal.h @@ -5,9 +5,13 @@ * Written by David Howells (dhowells@redhat.com) */ +#include <linux/slab.h> +#include <linux/seq_file.h> #include <linux/netfs.h> #include <linux/fscache.h> +#include <linux/fscache-cache.h> #include <trace/events/netfs.h> +#include <trace/events/fscache.h> #ifdef pr_fmt #undef pr_fmt @@ -19,6 +23,8 @@ * buffered_read.c */ void netfs_rreq_unlock_folios(struct netfs_io_request *rreq); +int netfs_prefetch_for_write(struct file *file, struct folio *folio, + size_t offset, size_t len); /* * io.c @@ -29,6 +35,41 @@ int netfs_begin_read(struct netfs_io_request *rreq, bool sync); * main.c */ extern unsigned int netfs_debug; +extern struct list_head netfs_io_requests; +extern spinlock_t netfs_proc_lock; + +#ifdef CONFIG_PROC_FS +static inline void netfs_proc_add_rreq(struct netfs_io_request *rreq) +{ + spin_lock(&netfs_proc_lock); + list_add_tail_rcu(&rreq->proc_link, &netfs_io_requests); + spin_unlock(&netfs_proc_lock); +} +static inline void netfs_proc_del_rreq(struct netfs_io_request *rreq) +{ + if (!list_empty(&rreq->proc_link)) { + spin_lock(&netfs_proc_lock); + list_del_rcu(&rreq->proc_link); + spin_unlock(&netfs_proc_lock); + } +} +#else +static inline void netfs_proc_add_rreq(struct netfs_io_request *rreq) {} +static inline void netfs_proc_del_rreq(struct netfs_io_request *rreq) {} +#endif + +/* + * misc.c + */ +#define NETFS_FLAG_PUT_MARK BIT(0) +#define NETFS_FLAG_PAGECACHE_MARK BIT(1) +int netfs_xa_store_and_mark(struct xarray *xa, unsigned long index, + struct folio *folio, unsigned int flags, + gfp_t gfp_mask); +int netfs_add_folios_to_buffer(struct xarray *buffer, + struct address_space *mapping, + pgoff_t index, pgoff_t to, gfp_t gfp_mask); +void netfs_clear_buffer(struct xarray *buffer); /* * objects.c @@ -50,9 +91,20 @@ static inline void netfs_see_request(struct netfs_io_request *rreq, } /* + * output.c + */ +int netfs_begin_write(struct netfs_io_request *wreq, bool may_wait, + enum netfs_write_trace what); +struct netfs_io_request *netfs_begin_writethrough(struct kiocb *iocb, size_t len); +int netfs_advance_writethrough(struct netfs_io_request *wreq, size_t copied, bool to_page_end); +int netfs_end_writethrough(struct netfs_io_request *wreq, struct kiocb *iocb); + +/* * stats.c */ #ifdef CONFIG_NETFS_STATS +extern atomic_t netfs_n_rh_dio_read; +extern atomic_t netfs_n_rh_dio_write; extern atomic_t netfs_n_rh_readahead; extern atomic_t netfs_n_rh_readpage; extern atomic_t netfs_n_rh_rreq; @@ -71,7 +123,15 @@ extern atomic_t netfs_n_rh_write_begin; extern atomic_t netfs_n_rh_write_done; extern atomic_t netfs_n_rh_write_failed; extern atomic_t netfs_n_rh_write_zskip; +extern atomic_t netfs_n_wh_wstream_conflict; +extern atomic_t netfs_n_wh_upload; +extern atomic_t netfs_n_wh_upload_done; +extern atomic_t netfs_n_wh_upload_failed; +extern atomic_t netfs_n_wh_write; +extern atomic_t netfs_n_wh_write_done; +extern atomic_t netfs_n_wh_write_failed; +int netfs_stats_show(struct seq_file *m, void *v); static inline void netfs_stat(atomic_t *stat) { @@ -103,6 +163,176 @@ static inline bool netfs_is_cache_enabled(struct netfs_inode *ctx) #endif } +/* + * Get a ref on a netfs group attached to a dirty page (e.g. a ceph snap). + */ +static inline struct netfs_group *netfs_get_group(struct netfs_group *netfs_group) +{ + if (netfs_group) + refcount_inc(&netfs_group->ref); + return netfs_group; +} + +/* + * Dispose of a netfs group attached to a dirty page (e.g. a ceph snap). + */ +static inline void netfs_put_group(struct netfs_group *netfs_group) +{ + if (netfs_group && refcount_dec_and_test(&netfs_group->ref)) + netfs_group->free(netfs_group); +} + +/* + * Dispose of a netfs group attached to a dirty page (e.g. a ceph snap). + */ +static inline void netfs_put_group_many(struct netfs_group *netfs_group, int nr) +{ + if (netfs_group && refcount_sub_and_test(nr, &netfs_group->ref)) + netfs_group->free(netfs_group); +} + +/* + * fscache-cache.c + */ +#ifdef CONFIG_PROC_FS +extern const struct seq_operations fscache_caches_seq_ops; +#endif +bool fscache_begin_cache_access(struct fscache_cache *cache, enum fscache_access_trace why); +void fscache_end_cache_access(struct fscache_cache *cache, enum fscache_access_trace why); +struct fscache_cache *fscache_lookup_cache(const char *name, bool is_cache); +void fscache_put_cache(struct fscache_cache *cache, enum fscache_cache_trace where); + +static inline enum fscache_cache_state fscache_cache_state(const struct fscache_cache *cache) +{ + return smp_load_acquire(&cache->state); +} + +static inline bool fscache_cache_is_live(const struct fscache_cache *cache) +{ + return fscache_cache_state(cache) == FSCACHE_CACHE_IS_ACTIVE; +} + +static inline void fscache_set_cache_state(struct fscache_cache *cache, + enum fscache_cache_state new_state) +{ + smp_store_release(&cache->state, new_state); + +} + +static inline bool fscache_set_cache_state_maybe(struct fscache_cache *cache, + enum fscache_cache_state old_state, + enum fscache_cache_state new_state) +{ + return try_cmpxchg_release(&cache->state, &old_state, new_state); +} + +/* + * fscache-cookie.c + */ +extern struct kmem_cache *fscache_cookie_jar; +#ifdef CONFIG_PROC_FS +extern const struct seq_operations fscache_cookies_seq_ops; +#endif +extern struct timer_list fscache_cookie_lru_timer; + +extern void fscache_print_cookie(struct fscache_cookie *cookie, char prefix); +extern bool fscache_begin_cookie_access(struct fscache_cookie *cookie, + enum fscache_access_trace why); + +static inline void fscache_see_cookie(struct fscache_cookie *cookie, + enum fscache_cookie_trace where) +{ + trace_fscache_cookie(cookie->debug_id, refcount_read(&cookie->ref), + where); +} + +/* + * fscache-main.c + */ +extern unsigned int fscache_hash(unsigned int salt, const void *data, size_t len); +#ifdef CONFIG_FSCACHE +int __init fscache_init(void); +void __exit fscache_exit(void); +#else +static inline int fscache_init(void) { return 0; } +static inline void fscache_exit(void) {} +#endif + +/* + * fscache-proc.c + */ +#ifdef CONFIG_PROC_FS +extern int __init fscache_proc_init(void); +extern void fscache_proc_cleanup(void); +#else +#define fscache_proc_init() (0) +#define fscache_proc_cleanup() do {} while (0) +#endif + +/* + * fscache-stats.c + */ +#ifdef CONFIG_FSCACHE_STATS +extern atomic_t fscache_n_volumes; +extern atomic_t fscache_n_volumes_collision; +extern atomic_t fscache_n_volumes_nomem; +extern atomic_t fscache_n_cookies; +extern atomic_t fscache_n_cookies_lru; +extern atomic_t fscache_n_cookies_lru_expired; +extern atomic_t fscache_n_cookies_lru_removed; +extern atomic_t fscache_n_cookies_lru_dropped; + +extern atomic_t fscache_n_acquires; +extern atomic_t fscache_n_acquires_ok; +extern atomic_t fscache_n_acquires_oom; + +extern atomic_t fscache_n_invalidates; + +extern atomic_t fscache_n_relinquishes; +extern atomic_t fscache_n_relinquishes_retire; +extern atomic_t fscache_n_relinquishes_dropped; + +extern atomic_t fscache_n_resizes; +extern atomic_t fscache_n_resizes_null; + +static inline void fscache_stat(atomic_t *stat) +{ + atomic_inc(stat); +} + +static inline void fscache_stat_d(atomic_t *stat) +{ + atomic_dec(stat); +} + +#define __fscache_stat(stat) (stat) + +int fscache_stats_show(struct seq_file *m); +#else + +#define __fscache_stat(stat) (NULL) +#define fscache_stat(stat) do {} while (0) +#define fscache_stat_d(stat) do {} while (0) + +static inline int fscache_stats_show(struct seq_file *m) { return 0; } +#endif + +/* + * fscache-volume.c + */ +#ifdef CONFIG_PROC_FS +extern const struct seq_operations fscache_volumes_seq_ops; +#endif + +struct fscache_volume *fscache_get_volume(struct fscache_volume *volume, + enum fscache_volume_trace where); +void fscache_put_volume(struct fscache_volume *volume, + enum fscache_volume_trace where); +bool fscache_begin_volume_access(struct fscache_volume *volume, + struct fscache_cookie *cookie, + enum fscache_access_trace why); +void fscache_create_volume(struct fscache_volume *volume, bool wait); + /*****************************************************************************/ /* * debug tracing @@ -143,3 +373,57 @@ do { \ #define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__) #define _debug(FMT, ...) no_printk(FMT, ##__VA_ARGS__) #endif + +/* + * assertions + */ +#if 1 /* defined(__KDEBUGALL) */ + +#define ASSERT(X) \ +do { \ + if (unlikely(!(X))) { \ + pr_err("\n"); \ + pr_err("Assertion failed\n"); \ + BUG(); \ + } \ +} while (0) + +#define ASSERTCMP(X, OP, Y) \ +do { \ + if (unlikely(!((X) OP (Y)))) { \ + pr_err("\n"); \ + pr_err("Assertion failed\n"); \ + pr_err("%lx " #OP " %lx is false\n", \ + (unsigned long)(X), (unsigned long)(Y)); \ + BUG(); \ + } \ +} while (0) + +#define ASSERTIF(C, X) \ +do { \ + if (unlikely((C) && !(X))) { \ + pr_err("\n"); \ + pr_err("Assertion failed\n"); \ + BUG(); \ + } \ +} while (0) + +#define ASSERTIFCMP(C, X, OP, Y) \ +do { \ + if (unlikely((C) && !((X) OP (Y)))) { \ + pr_err("\n"); \ + pr_err("Assertion failed\n"); \ + pr_err("%lx " #OP " %lx is false\n", \ + (unsigned long)(X), (unsigned long)(Y)); \ + BUG(); \ + } \ +} while (0) + +#else + +#define ASSERT(X) do {} while (0) +#define ASSERTCMP(X, OP, Y) do {} while (0) +#define ASSERTIF(C, X) do {} while (0) +#define ASSERTIFCMP(C, X, OP, Y) do {} while (0) + +#endif /* assert or not */ diff --git a/fs/netfs/io.c b/fs/netfs/io.c index 7f753380e0..4261ad6c55 100644 --- a/fs/netfs/io.c +++ b/fs/netfs/io.c @@ -21,12 +21,7 @@ */ static void netfs_clear_unread(struct netfs_io_subrequest *subreq) { - struct iov_iter iter; - - iov_iter_xarray(&iter, ITER_DEST, &subreq->rreq->mapping->i_pages, - subreq->start + subreq->transferred, - subreq->len - subreq->transferred); - iov_iter_zero(iov_iter_count(&iter), &iter); + iov_iter_zero(iov_iter_count(&subreq->io_iter), &subreq->io_iter); } static void netfs_cache_read_terminated(void *priv, ssize_t transferred_or_error, @@ -46,14 +41,9 @@ static void netfs_read_from_cache(struct netfs_io_request *rreq, enum netfs_read_from_hole read_hole) { struct netfs_cache_resources *cres = &rreq->cache_resources; - struct iov_iter iter; netfs_stat(&netfs_n_rh_read); - iov_iter_xarray(&iter, ITER_DEST, &rreq->mapping->i_pages, - subreq->start + subreq->transferred, - subreq->len - subreq->transferred); - - cres->ops->read(cres, subreq->start, &iter, read_hole, + cres->ops->read(cres, subreq->start, &subreq->io_iter, read_hole, netfs_cache_read_terminated, subreq); } @@ -88,6 +78,13 @@ static void netfs_read_from_server(struct netfs_io_request *rreq, struct netfs_io_subrequest *subreq) { netfs_stat(&netfs_n_rh_download); + + if (rreq->origin != NETFS_DIO_READ && + iov_iter_count(&subreq->io_iter) != subreq->len - subreq->transferred) + pr_warn("R=%08x[%u] ITER PRE-MISMATCH %zx != %zx-%zx %lx\n", + rreq->debug_id, subreq->debug_index, + iov_iter_count(&subreq->io_iter), subreq->len, + subreq->transferred, subreq->flags); rreq->netfs_ops->issue_read(subreq); } @@ -127,9 +124,10 @@ static void netfs_rreq_unmark_after_write(struct netfs_io_request *rreq, /* We might have multiple writes from the same huge * folio, but we mustn't unlock a folio more than once. */ - if (have_unlocked && folio_index(folio) <= unlocked) + if (have_unlocked && folio->index <= unlocked) continue; - unlocked = folio_index(folio); + unlocked = folio_next_index(folio) - 1; + trace_netfs_folio(folio, netfs_folio_trace_end_copy); folio_end_fscache(folio); have_unlocked = true; } @@ -201,7 +199,7 @@ static void netfs_rreq_do_write_to_cache(struct netfs_io_request *rreq) } ret = cres->ops->prepare_write(cres, &subreq->start, &subreq->len, - rreq->i_size, true); + subreq->len, rreq->i_size, true); if (ret < 0) { trace_netfs_failure(rreq, subreq, ret, netfs_fail_prepare_write); trace_netfs_sreq(subreq, netfs_sreq_trace_write_skip); @@ -260,6 +258,30 @@ static void netfs_rreq_short_read(struct netfs_io_request *rreq, } /* + * Reset the subrequest iterator prior to resubmission. + */ +static void netfs_reset_subreq_iter(struct netfs_io_request *rreq, + struct netfs_io_subrequest *subreq) +{ + size_t remaining = subreq->len - subreq->transferred; + size_t count = iov_iter_count(&subreq->io_iter); + + if (count == remaining) + return; + + _debug("R=%08x[%u] ITER RESUB-MISMATCH %zx != %zx-%zx-%llx %x\n", + rreq->debug_id, subreq->debug_index, + iov_iter_count(&subreq->io_iter), subreq->transferred, + subreq->len, rreq->i_size, + subreq->io_iter.iter_type); + + if (count < remaining) + iov_iter_revert(&subreq->io_iter, remaining - count); + else + iov_iter_advance(&subreq->io_iter, count - remaining); +} + +/* * Resubmit any short or failed operations. Returns true if we got the rreq * ref back. */ @@ -287,6 +309,7 @@ static bool netfs_rreq_perform_resubmissions(struct netfs_io_request *rreq) trace_netfs_sreq(subreq, netfs_sreq_trace_download_instead); netfs_get_subrequest(subreq, netfs_sreq_trace_get_resubmit); atomic_inc(&rreq->nr_outstanding); + netfs_reset_subreq_iter(rreq, subreq); netfs_read_from_server(rreq, subreq); } else if (test_bit(NETFS_SREQ_SHORT_IO, &subreq->flags)) { netfs_rreq_short_read(rreq, subreq); @@ -321,6 +344,43 @@ static void netfs_rreq_is_still_valid(struct netfs_io_request *rreq) } /* + * Determine how much we can admit to having read from a DIO read. + */ +static void netfs_rreq_assess_dio(struct netfs_io_request *rreq) +{ + struct netfs_io_subrequest *subreq; + unsigned int i; + size_t transferred = 0; + + for (i = 0; i < rreq->direct_bv_count; i++) + flush_dcache_page(rreq->direct_bv[i].bv_page); + + list_for_each_entry(subreq, &rreq->subrequests, rreq_link) { + if (subreq->error || subreq->transferred == 0) + break; + transferred += subreq->transferred; + if (subreq->transferred < subreq->len) + break; + } + + for (i = 0; i < rreq->direct_bv_count; i++) + flush_dcache_page(rreq->direct_bv[i].bv_page); + + rreq->transferred = transferred; + task_io_account_read(transferred); + + if (rreq->iocb) { + rreq->iocb->ki_pos += transferred; + if (rreq->iocb->ki_complete) + rreq->iocb->ki_complete( + rreq->iocb, rreq->error ? rreq->error : transferred); + } + if (rreq->netfs_ops->done) + rreq->netfs_ops->done(rreq); + inode_dio_end(rreq->inode); +} + +/* * Assess the state of a read request and decide what to do next. * * Note that we could be in an ordinary kernel thread, on a workqueue or in @@ -340,8 +400,12 @@ again: return; } - netfs_rreq_unlock_folios(rreq); + if (rreq->origin != NETFS_DIO_READ) + netfs_rreq_unlock_folios(rreq); + else + netfs_rreq_assess_dio(rreq); + trace_netfs_rreq(rreq, netfs_rreq_trace_wake_ip); clear_bit_unlock(NETFS_RREQ_IN_PROGRESS, &rreq->flags); wake_up_bit(&rreq->flags, NETFS_RREQ_IN_PROGRESS); @@ -399,9 +463,9 @@ void netfs_subreq_terminated(struct netfs_io_subrequest *subreq, struct netfs_io_request *rreq = subreq->rreq; int u; - _enter("[%u]{%llx,%lx},%zd", - subreq->debug_index, subreq->start, subreq->flags, - transferred_or_error); + _enter("R=%x[%x]{%llx,%lx},%zd", + rreq->debug_id, subreq->debug_index, + subreq->start, subreq->flags, transferred_or_error); switch (subreq->source) { case NETFS_READ_FROM_CACHE: @@ -501,15 +565,20 @@ static enum netfs_io_source netfs_cache_prepare_read(struct netfs_io_subrequest */ static enum netfs_io_source netfs_rreq_prepare_read(struct netfs_io_request *rreq, - struct netfs_io_subrequest *subreq) + struct netfs_io_subrequest *subreq, + struct iov_iter *io_iter) { - enum netfs_io_source source; + enum netfs_io_source source = NETFS_DOWNLOAD_FROM_SERVER; + struct netfs_inode *ictx = netfs_inode(rreq->inode); + size_t lsize; _enter("%llx-%llx,%llx", subreq->start, subreq->start + subreq->len, rreq->i_size); - source = netfs_cache_prepare_read(subreq, rreq->i_size); - if (source == NETFS_INVALID_READ) - goto out; + if (rreq->origin != NETFS_DIO_READ) { + source = netfs_cache_prepare_read(subreq, rreq->i_size); + if (source == NETFS_INVALID_READ) + goto out; + } if (source == NETFS_DOWNLOAD_FROM_SERVER) { /* Call out to the netfs to let it shrink the request to fit @@ -518,19 +587,52 @@ netfs_rreq_prepare_read(struct netfs_io_request *rreq, * to make serial calls, it can indicate a short read and then * we will call it again. */ + if (rreq->origin != NETFS_DIO_READ) { + if (subreq->start >= ictx->zero_point) { + source = NETFS_FILL_WITH_ZEROES; + goto set; + } + if (subreq->len > ictx->zero_point - subreq->start) + subreq->len = ictx->zero_point - subreq->start; + } if (subreq->len > rreq->i_size - subreq->start) subreq->len = rreq->i_size - subreq->start; + if (rreq->rsize && subreq->len > rreq->rsize) + subreq->len = rreq->rsize; if (rreq->netfs_ops->clamp_length && !rreq->netfs_ops->clamp_length(subreq)) { source = NETFS_INVALID_READ; goto out; } + + if (subreq->max_nr_segs) { + lsize = netfs_limit_iter(io_iter, 0, subreq->len, + subreq->max_nr_segs); + if (subreq->len > lsize) { + subreq->len = lsize; + trace_netfs_sreq(subreq, netfs_sreq_trace_limited); + } + } } - if (WARN_ON(subreq->len == 0)) +set: + if (subreq->len > rreq->len) + pr_warn("R=%08x[%u] SREQ>RREQ %zx > %zx\n", + rreq->debug_id, subreq->debug_index, + subreq->len, rreq->len); + + if (WARN_ON(subreq->len == 0)) { source = NETFS_INVALID_READ; + goto out; + } + subreq->source = source; + trace_netfs_sreq(subreq, netfs_sreq_trace_prepare); + + subreq->io_iter = *io_iter; + iov_iter_truncate(&subreq->io_iter, subreq->len); + iov_iter_advance(io_iter, subreq->len); out: subreq->source = source; trace_netfs_sreq(subreq, netfs_sreq_trace_prepare); @@ -541,6 +643,7 @@ out: * Slice off a piece of a read request and submit an I/O request for it. */ static bool netfs_rreq_submit_slice(struct netfs_io_request *rreq, + struct iov_iter *io_iter, unsigned int *_debug_index) { struct netfs_io_subrequest *subreq; @@ -552,7 +655,7 @@ static bool netfs_rreq_submit_slice(struct netfs_io_request *rreq, subreq->debug_index = (*_debug_index)++; subreq->start = rreq->start + rreq->submitted; - subreq->len = rreq->len - rreq->submitted; + subreq->len = io_iter->count; _debug("slice %llx,%zx,%zx", subreq->start, subreq->len, rreq->submitted); list_add_tail(&subreq->rreq_link, &rreq->subrequests); @@ -565,7 +668,7 @@ static bool netfs_rreq_submit_slice(struct netfs_io_request *rreq, * (the starts must coincide), in which case, we go around the loop * again and ask it to download the next piece. */ - source = netfs_rreq_prepare_read(rreq, subreq); + source = netfs_rreq_prepare_read(rreq, subreq, io_iter); if (source == NETFS_INVALID_READ) goto subreq_failed; @@ -603,6 +706,7 @@ subreq_failed: */ int netfs_begin_read(struct netfs_io_request *rreq, bool sync) { + struct iov_iter io_iter; unsigned int debug_index = 0; int ret; @@ -611,50 +715,73 @@ int netfs_begin_read(struct netfs_io_request *rreq, bool sync) if (rreq->len == 0) { pr_err("Zero-sized read [R=%x]\n", rreq->debug_id); - netfs_put_request(rreq, false, netfs_rreq_trace_put_zero_len); return -EIO; } - INIT_WORK(&rreq->work, netfs_rreq_work); + if (rreq->origin == NETFS_DIO_READ) + inode_dio_begin(rreq->inode); - if (sync) - netfs_get_request(rreq, netfs_rreq_trace_get_hold); + // TODO: Use bounce buffer if requested + rreq->io_iter = rreq->iter; + + INIT_WORK(&rreq->work, netfs_rreq_work); /* Chop the read into slices according to what the cache and the netfs * want and submit each one. */ + netfs_get_request(rreq, netfs_rreq_trace_get_for_outstanding); atomic_set(&rreq->nr_outstanding, 1); + io_iter = rreq->io_iter; do { - if (!netfs_rreq_submit_slice(rreq, &debug_index)) + _debug("submit %llx + %zx >= %llx", + rreq->start, rreq->submitted, rreq->i_size); + if (rreq->origin == NETFS_DIO_READ && + rreq->start + rreq->submitted >= rreq->i_size) + break; + if (!netfs_rreq_submit_slice(rreq, &io_iter, &debug_index)) + break; + if (test_bit(NETFS_RREQ_BLOCKED, &rreq->flags) && + test_bit(NETFS_RREQ_NONBLOCK, &rreq->flags)) break; } while (rreq->submitted < rreq->len); + if (!rreq->submitted) { + netfs_put_request(rreq, false, netfs_rreq_trace_put_no_submit); + if (rreq->origin == NETFS_DIO_READ) + inode_dio_end(rreq->inode); + ret = 0; + goto out; + } + if (sync) { - /* Keep nr_outstanding incremented so that the ref always belongs to - * us, and the service code isn't punted off to a random thread pool to - * process. + /* Keep nr_outstanding incremented so that the ref always + * belongs to us, and the service code isn't punted off to a + * random thread pool to process. Note that this might start + * further work, such as writing to the cache. */ - for (;;) { - wait_var_event(&rreq->nr_outstanding, - atomic_read(&rreq->nr_outstanding) == 1); + wait_var_event(&rreq->nr_outstanding, + atomic_read(&rreq->nr_outstanding) == 1); + if (atomic_dec_and_test(&rreq->nr_outstanding)) netfs_rreq_assess(rreq, false); - if (!test_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags)) - break; - cond_resched(); - } + + trace_netfs_rreq(rreq, netfs_rreq_trace_wait_ip); + wait_on_bit(&rreq->flags, NETFS_RREQ_IN_PROGRESS, + TASK_UNINTERRUPTIBLE); ret = rreq->error; - if (ret == 0 && rreq->submitted < rreq->len) { + if (ret == 0 && rreq->submitted < rreq->len && + rreq->origin != NETFS_DIO_READ) { trace_netfs_failure(rreq, NULL, ret, netfs_fail_short_read); ret = -EIO; } - netfs_put_request(rreq, false, netfs_rreq_trace_put_hold); } else { /* If we decrement nr_outstanding to 0, the ref belongs to us. */ if (atomic_dec_and_test(&rreq->nr_outstanding)) netfs_rreq_assess(rreq, false); - ret = 0; + ret = -EIOCBQUEUED; } + +out: return ret; } diff --git a/fs/netfs/iterator.c b/fs/netfs/iterator.c index 2ff07ba655..b781bbbf1d 100644 --- a/fs/netfs/iterator.c +++ b/fs/netfs/iterator.c @@ -101,3 +101,100 @@ ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len, return npages; } EXPORT_SYMBOL_GPL(netfs_extract_user_iter); + +/* + * Select the span of a bvec iterator we're going to use. Limit it by both maximum + * size and maximum number of segments. Returns the size of the span in bytes. + */ +static size_t netfs_limit_bvec(const struct iov_iter *iter, size_t start_offset, + size_t max_size, size_t max_segs) +{ + const struct bio_vec *bvecs = iter->bvec; + unsigned int nbv = iter->nr_segs, ix = 0, nsegs = 0; + size_t len, span = 0, n = iter->count; + size_t skip = iter->iov_offset + start_offset; + + if (WARN_ON(!iov_iter_is_bvec(iter)) || + WARN_ON(start_offset > n) || + n == 0) + return 0; + + while (n && ix < nbv && skip) { + len = bvecs[ix].bv_len; + if (skip < len) + break; + skip -= len; + n -= len; + ix++; + } + + while (n && ix < nbv) { + len = min3(n, bvecs[ix].bv_len - skip, max_size); + span += len; + nsegs++; + ix++; + if (span >= max_size || nsegs >= max_segs) + break; + skip = 0; + n -= len; + } + + return min(span, max_size); +} + +/* + * Select the span of an xarray iterator we're going to use. Limit it by both + * maximum size and maximum number of segments. It is assumed that segments + * can be larger than a page in size, provided they're physically contiguous. + * Returns the size of the span in bytes. + */ +static size_t netfs_limit_xarray(const struct iov_iter *iter, size_t start_offset, + size_t max_size, size_t max_segs) +{ + struct folio *folio; + unsigned int nsegs = 0; + loff_t pos = iter->xarray_start + iter->iov_offset; + pgoff_t index = pos / PAGE_SIZE; + size_t span = 0, n = iter->count; + + XA_STATE(xas, iter->xarray, index); + + if (WARN_ON(!iov_iter_is_xarray(iter)) || + WARN_ON(start_offset > n) || + n == 0) + return 0; + max_size = min(max_size, n - start_offset); + + rcu_read_lock(); + xas_for_each(&xas, folio, ULONG_MAX) { + size_t offset, flen, len; + if (xas_retry(&xas, folio)) + continue; + if (WARN_ON(xa_is_value(folio))) + break; + if (WARN_ON(folio_test_hugetlb(folio))) + break; + + flen = folio_size(folio); + offset = offset_in_folio(folio, pos); + len = min(max_size, flen - offset); + span += len; + nsegs++; + if (span >= max_size || nsegs >= max_segs) + break; + } + + rcu_read_unlock(); + return min(span, max_size); +} + +size_t netfs_limit_iter(const struct iov_iter *iter, size_t start_offset, + size_t max_size, size_t max_segs) +{ + if (iov_iter_is_bvec(iter)) + return netfs_limit_bvec(iter, start_offset, max_size, max_segs); + if (iov_iter_is_xarray(iter)) + return netfs_limit_xarray(iter, start_offset, max_size, max_segs); + BUG(); +} +EXPORT_SYMBOL(netfs_limit_iter); diff --git a/fs/netfs/locking.c b/fs/netfs/locking.c new file mode 100644 index 0000000000..75dc52a49b --- /dev/null +++ b/fs/netfs/locking.c @@ -0,0 +1,216 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * I/O and data path helper functionality. + * + * Borrowed from NFS Copyright (c) 2016 Trond Myklebust + */ + +#include <linux/kernel.h> +#include <linux/netfs.h> +#include "internal.h" + +/* + * inode_dio_wait_interruptible - wait for outstanding DIO requests to finish + * @inode: inode to wait for + * + * Waits for all pending direct I/O requests to finish so that we can + * proceed with a truncate or equivalent operation. + * + * Must be called under a lock that serializes taking new references + * to i_dio_count, usually by inode->i_mutex. + */ +static int inode_dio_wait_interruptible(struct inode *inode) +{ + if (!atomic_read(&inode->i_dio_count)) + return 0; + + wait_queue_head_t *wq = bit_waitqueue(&inode->i_state, __I_DIO_WAKEUP); + DEFINE_WAIT_BIT(q, &inode->i_state, __I_DIO_WAKEUP); + + for (;;) { + prepare_to_wait(wq, &q.wq_entry, TASK_INTERRUPTIBLE); + if (!atomic_read(&inode->i_dio_count)) + break; + if (signal_pending(current)) + break; + schedule(); + } + finish_wait(wq, &q.wq_entry); + + return atomic_read(&inode->i_dio_count) ? -ERESTARTSYS : 0; +} + +/* Call with exclusively locked inode->i_rwsem */ +static int netfs_block_o_direct(struct netfs_inode *ictx) +{ + if (!test_bit(NETFS_ICTX_ODIRECT, &ictx->flags)) + return 0; + clear_bit(NETFS_ICTX_ODIRECT, &ictx->flags); + return inode_dio_wait_interruptible(&ictx->inode); +} + +/** + * netfs_start_io_read - declare the file is being used for buffered reads + * @inode: file inode + * + * Declare that a buffered read operation is about to start, and ensure + * that we block all direct I/O. + * On exit, the function ensures that the NETFS_ICTX_ODIRECT flag is unset, + * and holds a shared lock on inode->i_rwsem to ensure that the flag + * cannot be changed. + * In practice, this means that buffered read operations are allowed to + * execute in parallel, thanks to the shared lock, whereas direct I/O + * operations need to wait to grab an exclusive lock in order to set + * NETFS_ICTX_ODIRECT. + * Note that buffered writes and truncates both take a write lock on + * inode->i_rwsem, meaning that those are serialised w.r.t. the reads. + */ +int netfs_start_io_read(struct inode *inode) + __acquires(inode->i_rwsem) +{ + struct netfs_inode *ictx = netfs_inode(inode); + + /* Be an optimist! */ + if (down_read_interruptible(&inode->i_rwsem) < 0) + return -ERESTARTSYS; + if (test_bit(NETFS_ICTX_ODIRECT, &ictx->flags) == 0) + return 0; + up_read(&inode->i_rwsem); + + /* Slow path.... */ + if (down_write_killable(&inode->i_rwsem) < 0) + return -ERESTARTSYS; + if (netfs_block_o_direct(ictx) < 0) { + up_write(&inode->i_rwsem); + return -ERESTARTSYS; + } + downgrade_write(&inode->i_rwsem); + return 0; +} +EXPORT_SYMBOL(netfs_start_io_read); + +/** + * netfs_end_io_read - declare that the buffered read operation is done + * @inode: file inode + * + * Declare that a buffered read operation is done, and release the shared + * lock on inode->i_rwsem. + */ +void netfs_end_io_read(struct inode *inode) + __releases(inode->i_rwsem) +{ + up_read(&inode->i_rwsem); +} +EXPORT_SYMBOL(netfs_end_io_read); + +/** + * netfs_start_io_write - declare the file is being used for buffered writes + * @inode: file inode + * + * Declare that a buffered read operation is about to start, and ensure + * that we block all direct I/O. + */ +int netfs_start_io_write(struct inode *inode) + __acquires(inode->i_rwsem) +{ + struct netfs_inode *ictx = netfs_inode(inode); + + if (down_write_killable(&inode->i_rwsem) < 0) + return -ERESTARTSYS; + if (netfs_block_o_direct(ictx) < 0) { + up_write(&inode->i_rwsem); + return -ERESTARTSYS; + } + return 0; +} +EXPORT_SYMBOL(netfs_start_io_write); + +/** + * netfs_end_io_write - declare that the buffered write operation is done + * @inode: file inode + * + * Declare that a buffered write operation is done, and release the + * lock on inode->i_rwsem. + */ +void netfs_end_io_write(struct inode *inode) + __releases(inode->i_rwsem) +{ + up_write(&inode->i_rwsem); +} +EXPORT_SYMBOL(netfs_end_io_write); + +/* Call with exclusively locked inode->i_rwsem */ +static int netfs_block_buffered(struct inode *inode) +{ + struct netfs_inode *ictx = netfs_inode(inode); + int ret; + + if (!test_bit(NETFS_ICTX_ODIRECT, &ictx->flags)) { + set_bit(NETFS_ICTX_ODIRECT, &ictx->flags); + if (inode->i_mapping->nrpages != 0) { + unmap_mapping_range(inode->i_mapping, 0, 0, 0); + ret = filemap_fdatawait(inode->i_mapping); + if (ret < 0) { + clear_bit(NETFS_ICTX_ODIRECT, &ictx->flags); + return ret; + } + } + } + return 0; +} + +/** + * netfs_start_io_direct - declare the file is being used for direct i/o + * @inode: file inode + * + * Declare that a direct I/O operation is about to start, and ensure + * that we block all buffered I/O. + * On exit, the function ensures that the NETFS_ICTX_ODIRECT flag is set, + * and holds a shared lock on inode->i_rwsem to ensure that the flag + * cannot be changed. + * In practice, this means that direct I/O operations are allowed to + * execute in parallel, thanks to the shared lock, whereas buffered I/O + * operations need to wait to grab an exclusive lock in order to clear + * NETFS_ICTX_ODIRECT. + * Note that buffered writes and truncates both take a write lock on + * inode->i_rwsem, meaning that those are serialised w.r.t. O_DIRECT. + */ +int netfs_start_io_direct(struct inode *inode) + __acquires(inode->i_rwsem) +{ + struct netfs_inode *ictx = netfs_inode(inode); + int ret; + + /* Be an optimist! */ + if (down_read_interruptible(&inode->i_rwsem) < 0) + return -ERESTARTSYS; + if (test_bit(NETFS_ICTX_ODIRECT, &ictx->flags) != 0) + return 0; + up_read(&inode->i_rwsem); + + /* Slow path.... */ + if (down_write_killable(&inode->i_rwsem) < 0) + return -ERESTARTSYS; + ret = netfs_block_buffered(inode); + if (ret < 0) { + up_write(&inode->i_rwsem); + return ret; + } + downgrade_write(&inode->i_rwsem); + return 0; +} +EXPORT_SYMBOL(netfs_start_io_direct); + +/** + * netfs_end_io_direct - declare that the direct i/o operation is done + * @inode: file inode + * + * Declare that a direct I/O operation is done, and release the shared + * lock on inode->i_rwsem. + */ +void netfs_end_io_direct(struct inode *inode) + __releases(inode->i_rwsem) +{ + up_read(&inode->i_rwsem); +} +EXPORT_SYMBOL(netfs_end_io_direct); diff --git a/fs/netfs/main.c b/fs/netfs/main.c index 0685687029..5e77618a79 100644 --- a/fs/netfs/main.c +++ b/fs/netfs/main.c @@ -7,6 +7,8 @@ #include <linux/module.h> #include <linux/export.h> +#include <linux/proc_fs.h> +#include <linux/seq_file.h> #include "internal.h" #define CREATE_TRACE_POINTS #include <trace/events/netfs.h> @@ -15,6 +17,113 @@ MODULE_DESCRIPTION("Network fs support"); MODULE_AUTHOR("Red Hat, Inc."); MODULE_LICENSE("GPL"); +EXPORT_TRACEPOINT_SYMBOL(netfs_sreq); + unsigned netfs_debug; module_param_named(debug, netfs_debug, uint, S_IWUSR | S_IRUGO); MODULE_PARM_DESC(netfs_debug, "Netfs support debugging mask"); + +#ifdef CONFIG_PROC_FS +LIST_HEAD(netfs_io_requests); +DEFINE_SPINLOCK(netfs_proc_lock); + +static const char *netfs_origins[nr__netfs_io_origin] = { + [NETFS_READAHEAD] = "RA", + [NETFS_READPAGE] = "RP", + [NETFS_READ_FOR_WRITE] = "RW", + [NETFS_WRITEBACK] = "WB", + [NETFS_WRITETHROUGH] = "WT", + [NETFS_LAUNDER_WRITE] = "LW", + [NETFS_UNBUFFERED_WRITE] = "UW", + [NETFS_DIO_READ] = "DR", + [NETFS_DIO_WRITE] = "DW", +}; + +/* + * Generate a list of I/O requests in /proc/fs/netfs/requests + */ +static int netfs_requests_seq_show(struct seq_file *m, void *v) +{ + struct netfs_io_request *rreq; + + if (v == &netfs_io_requests) { + seq_puts(m, + "REQUEST OR REF FL ERR OPS COVERAGE\n" + "======== == === == ==== === =========\n" + ); + return 0; + } + + rreq = list_entry(v, struct netfs_io_request, proc_link); + seq_printf(m, + "%08x %s %3d %2lx %4d %3d @%04llx %zx/%zx", + rreq->debug_id, + netfs_origins[rreq->origin], + refcount_read(&rreq->ref), + rreq->flags, + rreq->error, + atomic_read(&rreq->nr_outstanding), + rreq->start, rreq->submitted, rreq->len); + seq_putc(m, '\n'); + return 0; +} + +static void *netfs_requests_seq_start(struct seq_file *m, loff_t *_pos) + __acquires(rcu) +{ + rcu_read_lock(); + return seq_list_start_head(&netfs_io_requests, *_pos); +} + +static void *netfs_requests_seq_next(struct seq_file *m, void *v, loff_t *_pos) +{ + return seq_list_next(v, &netfs_io_requests, _pos); +} + +static void netfs_requests_seq_stop(struct seq_file *m, void *v) + __releases(rcu) +{ + rcu_read_unlock(); +} + +static const struct seq_operations netfs_requests_seq_ops = { + .start = netfs_requests_seq_start, + .next = netfs_requests_seq_next, + .stop = netfs_requests_seq_stop, + .show = netfs_requests_seq_show, +}; +#endif /* CONFIG_PROC_FS */ + +static int __init netfs_init(void) +{ + int ret = -ENOMEM; + + if (!proc_mkdir("fs/netfs", NULL)) + goto error; + if (!proc_create_seq("fs/netfs/requests", S_IFREG | 0444, NULL, + &netfs_requests_seq_ops)) + goto error_proc; +#ifdef CONFIG_FSCACHE_STATS + if (!proc_create_single("fs/netfs/stats", S_IFREG | 0444, NULL, + netfs_stats_show)) + goto error_proc; +#endif + + ret = fscache_init(); + if (ret < 0) + goto error_proc; + return 0; + +error_proc: + remove_proc_entry("fs/netfs", NULL); +error: + return ret; +} +fs_initcall(netfs_init); + +static void __exit netfs_exit(void) +{ + fscache_exit(); + remove_proc_entry("fs/netfs", NULL); +} +module_exit(netfs_exit); diff --git a/fs/netfs/misc.c b/fs/netfs/misc.c new file mode 100644 index 0000000000..90051ced8e --- /dev/null +++ b/fs/netfs/misc.c @@ -0,0 +1,260 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Miscellaneous routines. + * + * Copyright (C) 2023 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include <linux/swap.h> +#include "internal.h" + +/* + * Attach a folio to the buffer and maybe set marks on it to say that we need + * to put the folio later and twiddle the pagecache flags. + */ +int netfs_xa_store_and_mark(struct xarray *xa, unsigned long index, + struct folio *folio, unsigned int flags, + gfp_t gfp_mask) +{ + XA_STATE_ORDER(xas, xa, index, folio_order(folio)); + +retry: + xas_lock(&xas); + for (;;) { + xas_store(&xas, folio); + if (!xas_error(&xas)) + break; + xas_unlock(&xas); + if (!xas_nomem(&xas, gfp_mask)) + return xas_error(&xas); + goto retry; + } + + if (flags & NETFS_FLAG_PUT_MARK) + xas_set_mark(&xas, NETFS_BUF_PUT_MARK); + if (flags & NETFS_FLAG_PAGECACHE_MARK) + xas_set_mark(&xas, NETFS_BUF_PAGECACHE_MARK); + xas_unlock(&xas); + return xas_error(&xas); +} + +/* + * Create the specified range of folios in the buffer attached to the read + * request. The folios are marked with NETFS_BUF_PUT_MARK so that we know that + * these need freeing later. + */ +int netfs_add_folios_to_buffer(struct xarray *buffer, + struct address_space *mapping, + pgoff_t index, pgoff_t to, gfp_t gfp_mask) +{ + struct folio *folio; + int ret; + + if (to + 1 == index) /* Page range is inclusive */ + return 0; + + do { + /* TODO: Figure out what order folio can be allocated here */ + folio = filemap_alloc_folio(readahead_gfp_mask(mapping), 0); + if (!folio) + return -ENOMEM; + folio->index = index; + ret = netfs_xa_store_and_mark(buffer, index, folio, + NETFS_FLAG_PUT_MARK, gfp_mask); + if (ret < 0) { + folio_put(folio); + return ret; + } + + index += folio_nr_pages(folio); + } while (index <= to && index != 0); + + return 0; +} + +/* + * Clear an xarray buffer, putting a ref on the folios that have + * NETFS_BUF_PUT_MARK set. + */ +void netfs_clear_buffer(struct xarray *buffer) +{ + struct folio *folio; + XA_STATE(xas, buffer, 0); + + rcu_read_lock(); + xas_for_each_marked(&xas, folio, ULONG_MAX, NETFS_BUF_PUT_MARK) { + folio_put(folio); + } + rcu_read_unlock(); + xa_destroy(buffer); +} + +/** + * netfs_dirty_folio - Mark folio dirty and pin a cache object for writeback + * @mapping: The mapping the folio belongs to. + * @folio: The folio being dirtied. + * + * Set the dirty flag on a folio and pin an in-use cache object in memory so + * that writeback can later write to it. This is intended to be called from + * the filesystem's ->dirty_folio() method. + * + * Return: true if the dirty flag was set on the folio, false otherwise. + */ +bool netfs_dirty_folio(struct address_space *mapping, struct folio *folio) +{ + struct inode *inode = mapping->host; + struct netfs_inode *ictx = netfs_inode(inode); + struct fscache_cookie *cookie = netfs_i_cookie(ictx); + bool need_use = false; + + _enter(""); + + if (!filemap_dirty_folio(mapping, folio)) + return false; + if (!fscache_cookie_valid(cookie)) + return true; + + if (!(inode->i_state & I_PINNING_NETFS_WB)) { + spin_lock(&inode->i_lock); + if (!(inode->i_state & I_PINNING_NETFS_WB)) { + inode->i_state |= I_PINNING_NETFS_WB; + need_use = true; + } + spin_unlock(&inode->i_lock); + + if (need_use) + fscache_use_cookie(cookie, true); + } + return true; +} +EXPORT_SYMBOL(netfs_dirty_folio); + +/** + * netfs_unpin_writeback - Unpin writeback resources + * @inode: The inode on which the cookie resides + * @wbc: The writeback control + * + * Unpin the writeback resources pinned by netfs_dirty_folio(). This is + * intended to be called as/by the netfs's ->write_inode() method. + */ +int netfs_unpin_writeback(struct inode *inode, struct writeback_control *wbc) +{ + struct fscache_cookie *cookie = netfs_i_cookie(netfs_inode(inode)); + + if (wbc->unpinned_netfs_wb) + fscache_unuse_cookie(cookie, NULL, NULL); + return 0; +} +EXPORT_SYMBOL(netfs_unpin_writeback); + +/** + * netfs_clear_inode_writeback - Clear writeback resources pinned by an inode + * @inode: The inode to clean up + * @aux: Auxiliary data to apply to the inode + * + * Clear any writeback resources held by an inode when the inode is evicted. + * This must be called before clear_inode() is called. + */ +void netfs_clear_inode_writeback(struct inode *inode, const void *aux) +{ + struct fscache_cookie *cookie = netfs_i_cookie(netfs_inode(inode)); + + if (inode->i_state & I_PINNING_NETFS_WB) { + loff_t i_size = i_size_read(inode); + fscache_unuse_cookie(cookie, aux, &i_size); + } +} +EXPORT_SYMBOL(netfs_clear_inode_writeback); + +/** + * netfs_invalidate_folio - Invalidate or partially invalidate a folio + * @folio: Folio proposed for release + * @offset: Offset of the invalidated region + * @length: Length of the invalidated region + * + * Invalidate part or all of a folio for a network filesystem. The folio will + * be removed afterwards if the invalidated region covers the entire folio. + */ +void netfs_invalidate_folio(struct folio *folio, size_t offset, size_t length) +{ + struct netfs_folio *finfo = NULL; + size_t flen = folio_size(folio); + + _enter("{%lx},%zx,%zx", folio->index, offset, length); + + folio_wait_fscache(folio); + + if (!folio_test_private(folio)) + return; + + finfo = netfs_folio_info(folio); + + if (offset == 0 && length >= flen) + goto erase_completely; + + if (finfo) { + /* We have a partially uptodate page from a streaming write. */ + unsigned int fstart = finfo->dirty_offset; + unsigned int fend = fstart + finfo->dirty_len; + unsigned int end = offset + length; + + if (offset >= fend) + return; + if (end <= fstart) + return; + if (offset <= fstart && end >= fend) + goto erase_completely; + if (offset <= fstart && end > fstart) + goto reduce_len; + if (offset > fstart && end >= fend) + goto move_start; + /* A partial write was split. The caller has already zeroed + * it, so just absorb the hole. + */ + } + return; + +erase_completely: + netfs_put_group(netfs_folio_group(folio)); + folio_detach_private(folio); + folio_clear_uptodate(folio); + kfree(finfo); + return; +reduce_len: + finfo->dirty_len = offset + length - finfo->dirty_offset; + return; +move_start: + finfo->dirty_len -= offset - finfo->dirty_offset; + finfo->dirty_offset = offset; +} +EXPORT_SYMBOL(netfs_invalidate_folio); + +/** + * netfs_release_folio - Try to release a folio + * @folio: Folio proposed for release + * @gfp: Flags qualifying the release + * + * Request release of a folio and clean up its private state if it's not busy. + * Returns true if the folio can now be released, false if not + */ +bool netfs_release_folio(struct folio *folio, gfp_t gfp) +{ + struct netfs_inode *ctx = netfs_inode(folio_inode(folio)); + unsigned long long end; + + end = folio_pos(folio) + folio_size(folio); + if (end > ctx->zero_point) + ctx->zero_point = end; + + if (folio_test_private(folio)) + return false; + if (folio_test_fscache(folio)) { + if (current_is_kswapd() || !(gfp & __GFP_FS)) + return false; + folio_wait_fscache(folio); + } + + fscache_note_page_release(netfs_i_cookie(ctx)); + return true; +} +EXPORT_SYMBOL(netfs_release_folio); diff --git a/fs/netfs/objects.c b/fs/netfs/objects.c index e17cdf53f6..610ceb5bd8 100644 --- a/fs/netfs/objects.c +++ b/fs/netfs/objects.c @@ -20,14 +20,20 @@ struct netfs_io_request *netfs_alloc_request(struct address_space *mapping, struct inode *inode = file ? file_inode(file) : mapping->host; struct netfs_inode *ctx = netfs_inode(inode); struct netfs_io_request *rreq; + bool is_unbuffered = (origin == NETFS_UNBUFFERED_WRITE || + origin == NETFS_DIO_READ || + origin == NETFS_DIO_WRITE); + bool cached = !is_unbuffered && netfs_is_cache_enabled(ctx); int ret; - rreq = kzalloc(sizeof(struct netfs_io_request), GFP_KERNEL); + rreq = kzalloc(ctx->ops->io_request_size ?: sizeof(struct netfs_io_request), + GFP_KERNEL); if (!rreq) return ERR_PTR(-ENOMEM); rreq->start = start; rreq->len = len; + rreq->upper_len = len; rreq->origin = origin; rreq->netfs_ops = ctx->ops; rreq->mapping = mapping; @@ -35,8 +41,14 @@ struct netfs_io_request *netfs_alloc_request(struct address_space *mapping, rreq->i_size = i_size_read(inode); rreq->debug_id = atomic_inc_return(&debug_ids); INIT_LIST_HEAD(&rreq->subrequests); + INIT_WORK(&rreq->work, NULL); refcount_set(&rreq->ref, 1); + __set_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags); + if (cached) + __set_bit(NETFS_RREQ_WRITE_TO_CACHE, &rreq->flags); + if (file && file->f_flags & O_NONBLOCK) + __set_bit(NETFS_RREQ_NONBLOCK, &rreq->flags); if (rreq->netfs_ops->init_request) { ret = rreq->netfs_ops->init_request(rreq, file); if (ret < 0) { @@ -45,6 +57,8 @@ struct netfs_io_request *netfs_alloc_request(struct address_space *mapping, } } + trace_netfs_rreq_ref(rreq->debug_id, 1, netfs_rreq_trace_new); + netfs_proc_add_rreq(rreq); netfs_stat(&netfs_n_rh_rreq); return rreq; } @@ -74,33 +88,47 @@ static void netfs_free_request(struct work_struct *work) { struct netfs_io_request *rreq = container_of(work, struct netfs_io_request, work); + unsigned int i; trace_netfs_rreq(rreq, netfs_rreq_trace_free); + netfs_proc_del_rreq(rreq); netfs_clear_subrequests(rreq, false); if (rreq->netfs_ops->free_request) rreq->netfs_ops->free_request(rreq); if (rreq->cache_resources.ops) rreq->cache_resources.ops->end_operation(&rreq->cache_resources); - kfree(rreq); + if (rreq->direct_bv) { + for (i = 0; i < rreq->direct_bv_count; i++) { + if (rreq->direct_bv[i].bv_page) { + if (rreq->direct_bv_unpin) + unpin_user_page(rreq->direct_bv[i].bv_page); + } + } + kvfree(rreq->direct_bv); + } + kfree_rcu(rreq, rcu); netfs_stat_d(&netfs_n_rh_rreq); } void netfs_put_request(struct netfs_io_request *rreq, bool was_async, enum netfs_rreq_ref_trace what) { - unsigned int debug_id = rreq->debug_id; + unsigned int debug_id; bool dead; int r; - dead = __refcount_dec_and_test(&rreq->ref, &r); - trace_netfs_rreq_ref(debug_id, r - 1, what); - if (dead) { - if (was_async) { - rreq->work.func = netfs_free_request; - if (!queue_work(system_unbound_wq, &rreq->work)) - BUG(); - } else { - netfs_free_request(&rreq->work); + if (rreq) { + debug_id = rreq->debug_id; + dead = __refcount_dec_and_test(&rreq->ref, &r); + trace_netfs_rreq_ref(debug_id, r - 1, what); + if (dead) { + if (was_async) { + rreq->work.func = netfs_free_request; + if (!queue_work(system_unbound_wq, &rreq->work)) + BUG(); + } else { + netfs_free_request(&rreq->work); + } } } } @@ -112,8 +140,11 @@ struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq { struct netfs_io_subrequest *subreq; - subreq = kzalloc(sizeof(struct netfs_io_subrequest), GFP_KERNEL); + subreq = kzalloc(rreq->netfs_ops->io_subrequest_size ?: + sizeof(struct netfs_io_subrequest), + GFP_KERNEL); if (subreq) { + INIT_WORK(&subreq->work, NULL); INIT_LIST_HEAD(&subreq->rreq_link); refcount_set(&subreq->ref, 2); subreq->rreq = rreq; @@ -140,6 +171,8 @@ static void netfs_free_subrequest(struct netfs_io_subrequest *subreq, struct netfs_io_request *rreq = subreq->rreq; trace_netfs_sreq(subreq, netfs_sreq_trace_free); + if (rreq->netfs_ops->free_subrequest) + rreq->netfs_ops->free_subrequest(subreq); kfree(subreq); netfs_stat_d(&netfs_n_rh_sreq); netfs_put_request(rreq, was_async, netfs_rreq_trace_put_subreq); diff --git a/fs/netfs/output.c b/fs/netfs/output.c new file mode 100644 index 0000000000..625eb68f3e --- /dev/null +++ b/fs/netfs/output.c @@ -0,0 +1,478 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Network filesystem high-level write support. + * + * Copyright (C) 2023 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/pagemap.h> +#include <linux/slab.h> +#include <linux/writeback.h> +#include <linux/pagevec.h> +#include "internal.h" + +/** + * netfs_create_write_request - Create a write operation. + * @wreq: The write request this is storing from. + * @dest: The destination type + * @start: Start of the region this write will modify + * @len: Length of the modification + * @worker: The worker function to handle the write(s) + * + * Allocate a write operation, set it up and add it to the list on a write + * request. + */ +struct netfs_io_subrequest *netfs_create_write_request(struct netfs_io_request *wreq, + enum netfs_io_source dest, + loff_t start, size_t len, + work_func_t worker) +{ + struct netfs_io_subrequest *subreq; + + subreq = netfs_alloc_subrequest(wreq); + if (subreq) { + INIT_WORK(&subreq->work, worker); + subreq->source = dest; + subreq->start = start; + subreq->len = len; + subreq->debug_index = wreq->subreq_counter++; + + switch (subreq->source) { + case NETFS_UPLOAD_TO_SERVER: + netfs_stat(&netfs_n_wh_upload); + break; + case NETFS_WRITE_TO_CACHE: + netfs_stat(&netfs_n_wh_write); + break; + default: + BUG(); + } + + subreq->io_iter = wreq->io_iter; + iov_iter_advance(&subreq->io_iter, subreq->start - wreq->start); + iov_iter_truncate(&subreq->io_iter, subreq->len); + + trace_netfs_sreq_ref(wreq->debug_id, subreq->debug_index, + refcount_read(&subreq->ref), + netfs_sreq_trace_new); + atomic_inc(&wreq->nr_outstanding); + list_add_tail(&subreq->rreq_link, &wreq->subrequests); + trace_netfs_sreq(subreq, netfs_sreq_trace_prepare); + } + + return subreq; +} +EXPORT_SYMBOL(netfs_create_write_request); + +/* + * Process a completed write request once all the component operations have + * been completed. + */ +static void netfs_write_terminated(struct netfs_io_request *wreq, bool was_async) +{ + struct netfs_io_subrequest *subreq; + struct netfs_inode *ctx = netfs_inode(wreq->inode); + size_t transferred = 0; + + _enter("R=%x[]", wreq->debug_id); + + trace_netfs_rreq(wreq, netfs_rreq_trace_write_done); + + list_for_each_entry(subreq, &wreq->subrequests, rreq_link) { + if (subreq->error || subreq->transferred == 0) + break; + transferred += subreq->transferred; + if (subreq->transferred < subreq->len) + break; + } + wreq->transferred = transferred; + + list_for_each_entry(subreq, &wreq->subrequests, rreq_link) { + if (!subreq->error) + continue; + switch (subreq->source) { + case NETFS_UPLOAD_TO_SERVER: + /* Depending on the type of failure, this may prevent + * writeback completion unless we're in disconnected + * mode. + */ + if (!wreq->error) + wreq->error = subreq->error; + break; + + case NETFS_WRITE_TO_CACHE: + /* Failure doesn't prevent writeback completion unless + * we're in disconnected mode. + */ + if (subreq->error != -ENOBUFS) + ctx->ops->invalidate_cache(wreq); + break; + + default: + WARN_ON_ONCE(1); + if (!wreq->error) + wreq->error = -EIO; + return; + } + } + + wreq->cleanup(wreq); + + if (wreq->origin == NETFS_DIO_WRITE && + wreq->mapping->nrpages) { + pgoff_t first = wreq->start >> PAGE_SHIFT; + pgoff_t last = (wreq->start + wreq->transferred - 1) >> PAGE_SHIFT; + invalidate_inode_pages2_range(wreq->mapping, first, last); + } + + if (wreq->origin == NETFS_DIO_WRITE) + inode_dio_end(wreq->inode); + + _debug("finished"); + trace_netfs_rreq(wreq, netfs_rreq_trace_wake_ip); + clear_bit_unlock(NETFS_RREQ_IN_PROGRESS, &wreq->flags); + wake_up_bit(&wreq->flags, NETFS_RREQ_IN_PROGRESS); + + if (wreq->iocb) { + wreq->iocb->ki_pos += transferred; + if (wreq->iocb->ki_complete) + wreq->iocb->ki_complete( + wreq->iocb, wreq->error ? wreq->error : transferred); + } + + netfs_clear_subrequests(wreq, was_async); + netfs_put_request(wreq, was_async, netfs_rreq_trace_put_complete); +} + +/* + * Deal with the completion of writing the data to the cache. + */ +void netfs_write_subrequest_terminated(void *_op, ssize_t transferred_or_error, + bool was_async) +{ + struct netfs_io_subrequest *subreq = _op; + struct netfs_io_request *wreq = subreq->rreq; + unsigned int u; + + _enter("%x[%x] %zd", wreq->debug_id, subreq->debug_index, transferred_or_error); + + switch (subreq->source) { + case NETFS_UPLOAD_TO_SERVER: + netfs_stat(&netfs_n_wh_upload_done); + break; + case NETFS_WRITE_TO_CACHE: + netfs_stat(&netfs_n_wh_write_done); + break; + case NETFS_INVALID_WRITE: + break; + default: + BUG(); + } + + if (IS_ERR_VALUE(transferred_or_error)) { + subreq->error = transferred_or_error; + trace_netfs_failure(wreq, subreq, transferred_or_error, + netfs_fail_write); + goto failed; + } + + if (WARN(transferred_or_error > subreq->len - subreq->transferred, + "Subreq excess write: R%x[%x] %zd > %zu - %zu", + wreq->debug_id, subreq->debug_index, + transferred_or_error, subreq->len, subreq->transferred)) + transferred_or_error = subreq->len - subreq->transferred; + + subreq->error = 0; + subreq->transferred += transferred_or_error; + + if (iov_iter_count(&subreq->io_iter) != subreq->len - subreq->transferred) + pr_warn("R=%08x[%u] ITER POST-MISMATCH %zx != %zx-%zx %x\n", + wreq->debug_id, subreq->debug_index, + iov_iter_count(&subreq->io_iter), subreq->len, + subreq->transferred, subreq->io_iter.iter_type); + + if (subreq->transferred < subreq->len) + goto incomplete; + + __clear_bit(NETFS_SREQ_NO_PROGRESS, &subreq->flags); +out: + trace_netfs_sreq(subreq, netfs_sreq_trace_terminated); + + /* If we decrement nr_outstanding to 0, the ref belongs to us. */ + u = atomic_dec_return(&wreq->nr_outstanding); + if (u == 0) + netfs_write_terminated(wreq, was_async); + else if (u == 1) + wake_up_var(&wreq->nr_outstanding); + + netfs_put_subrequest(subreq, was_async, netfs_sreq_trace_put_terminated); + return; + +incomplete: + if (transferred_or_error == 0) { + if (__test_and_set_bit(NETFS_SREQ_NO_PROGRESS, &subreq->flags)) { + subreq->error = -ENODATA; + goto failed; + } + } else { + __clear_bit(NETFS_SREQ_NO_PROGRESS, &subreq->flags); + } + + __set_bit(NETFS_SREQ_SHORT_IO, &subreq->flags); + set_bit(NETFS_RREQ_INCOMPLETE_IO, &wreq->flags); + goto out; + +failed: + switch (subreq->source) { + case NETFS_WRITE_TO_CACHE: + netfs_stat(&netfs_n_wh_write_failed); + set_bit(NETFS_RREQ_INCOMPLETE_IO, &wreq->flags); + break; + case NETFS_UPLOAD_TO_SERVER: + netfs_stat(&netfs_n_wh_upload_failed); + set_bit(NETFS_RREQ_FAILED, &wreq->flags); + wreq->error = subreq->error; + break; + default: + break; + } + goto out; +} +EXPORT_SYMBOL(netfs_write_subrequest_terminated); + +static void netfs_write_to_cache_op(struct netfs_io_subrequest *subreq) +{ + struct netfs_io_request *wreq = subreq->rreq; + struct netfs_cache_resources *cres = &wreq->cache_resources; + + trace_netfs_sreq(subreq, netfs_sreq_trace_submit); + + cres->ops->write(cres, subreq->start, &subreq->io_iter, + netfs_write_subrequest_terminated, subreq); +} + +static void netfs_write_to_cache_op_worker(struct work_struct *work) +{ + struct netfs_io_subrequest *subreq = + container_of(work, struct netfs_io_subrequest, work); + + netfs_write_to_cache_op(subreq); +} + +/** + * netfs_queue_write_request - Queue a write request for attention + * @subreq: The write request to be queued + * + * Queue the specified write request for processing by a worker thread. We + * pass the caller's ref on the request to the worker thread. + */ +void netfs_queue_write_request(struct netfs_io_subrequest *subreq) +{ + if (!queue_work(system_unbound_wq, &subreq->work)) + netfs_put_subrequest(subreq, false, netfs_sreq_trace_put_wip); +} +EXPORT_SYMBOL(netfs_queue_write_request); + +/* + * Set up a op for writing to the cache. + */ +static void netfs_set_up_write_to_cache(struct netfs_io_request *wreq) +{ + struct netfs_cache_resources *cres = &wreq->cache_resources; + struct netfs_io_subrequest *subreq; + struct netfs_inode *ctx = netfs_inode(wreq->inode); + struct fscache_cookie *cookie = netfs_i_cookie(ctx); + loff_t start = wreq->start; + size_t len = wreq->len; + int ret; + + if (!fscache_cookie_enabled(cookie)) { + clear_bit(NETFS_RREQ_WRITE_TO_CACHE, &wreq->flags); + return; + } + + _debug("write to cache"); + ret = fscache_begin_write_operation(cres, cookie); + if (ret < 0) + return; + + ret = cres->ops->prepare_write(cres, &start, &len, wreq->upper_len, + i_size_read(wreq->inode), true); + if (ret < 0) + return; + + subreq = netfs_create_write_request(wreq, NETFS_WRITE_TO_CACHE, start, len, + netfs_write_to_cache_op_worker); + if (!subreq) + return; + + netfs_write_to_cache_op(subreq); +} + +/* + * Begin the process of writing out a chunk of data. + * + * We are given a write request that holds a series of dirty regions and + * (partially) covers a sequence of folios, all of which are present. The + * pages must have been marked as writeback as appropriate. + * + * We need to perform the following steps: + * + * (1) If encrypting, create an output buffer and encrypt each block of the + * data into it, otherwise the output buffer will point to the original + * folios. + * + * (2) If the data is to be cached, set up a write op for the entire output + * buffer to the cache, if the cache wants to accept it. + * + * (3) If the data is to be uploaded (ie. not merely cached): + * + * (a) If the data is to be compressed, create a compression buffer and + * compress the data into it. + * + * (b) For each destination we want to upload to, set up write ops to write + * to that destination. We may need multiple writes if the data is not + * contiguous or the span exceeds wsize for a server. + */ +int netfs_begin_write(struct netfs_io_request *wreq, bool may_wait, + enum netfs_write_trace what) +{ + struct netfs_inode *ctx = netfs_inode(wreq->inode); + + _enter("R=%x %llx-%llx f=%lx", + wreq->debug_id, wreq->start, wreq->start + wreq->len - 1, + wreq->flags); + + trace_netfs_write(wreq, what); + if (wreq->len == 0 || wreq->iter.count == 0) { + pr_err("Zero-sized write [R=%x]\n", wreq->debug_id); + return -EIO; + } + + if (wreq->origin == NETFS_DIO_WRITE) + inode_dio_begin(wreq->inode); + + wreq->io_iter = wreq->iter; + + /* ->outstanding > 0 carries a ref */ + netfs_get_request(wreq, netfs_rreq_trace_get_for_outstanding); + atomic_set(&wreq->nr_outstanding, 1); + + /* Start the encryption/compression going. We can do that in the + * background whilst we generate a list of write ops that we want to + * perform. + */ + // TODO: Encrypt or compress the region as appropriate + + /* We need to write all of the region to the cache */ + if (test_bit(NETFS_RREQ_WRITE_TO_CACHE, &wreq->flags)) + netfs_set_up_write_to_cache(wreq); + + /* However, we don't necessarily write all of the region to the server. + * Caching of reads is being managed this way also. + */ + if (test_bit(NETFS_RREQ_UPLOAD_TO_SERVER, &wreq->flags)) + ctx->ops->create_write_requests(wreq, wreq->start, wreq->len); + + if (atomic_dec_and_test(&wreq->nr_outstanding)) + netfs_write_terminated(wreq, false); + + if (!may_wait) + return -EIOCBQUEUED; + + wait_on_bit(&wreq->flags, NETFS_RREQ_IN_PROGRESS, + TASK_UNINTERRUPTIBLE); + return wreq->error; +} + +/* + * Begin a write operation for writing through the pagecache. + */ +struct netfs_io_request *netfs_begin_writethrough(struct kiocb *iocb, size_t len) +{ + struct netfs_io_request *wreq; + struct file *file = iocb->ki_filp; + + wreq = netfs_alloc_request(file->f_mapping, file, iocb->ki_pos, len, + NETFS_WRITETHROUGH); + if (IS_ERR(wreq)) + return wreq; + + trace_netfs_write(wreq, netfs_write_trace_writethrough); + + __set_bit(NETFS_RREQ_UPLOAD_TO_SERVER, &wreq->flags); + iov_iter_xarray(&wreq->iter, ITER_SOURCE, &wreq->mapping->i_pages, wreq->start, 0); + wreq->io_iter = wreq->iter; + + /* ->outstanding > 0 carries a ref */ + netfs_get_request(wreq, netfs_rreq_trace_get_for_outstanding); + atomic_set(&wreq->nr_outstanding, 1); + return wreq; +} + +static void netfs_submit_writethrough(struct netfs_io_request *wreq, bool final) +{ + struct netfs_inode *ictx = netfs_inode(wreq->inode); + unsigned long long start; + size_t len; + + if (!test_bit(NETFS_RREQ_UPLOAD_TO_SERVER, &wreq->flags)) + return; + + start = wreq->start + wreq->submitted; + len = wreq->iter.count - wreq->submitted; + if (!final) { + len /= wreq->wsize; /* Round to number of maximum packets */ + len *= wreq->wsize; + } + + ictx->ops->create_write_requests(wreq, start, len); + wreq->submitted += len; +} + +/* + * Advance the state of the write operation used when writing through the + * pagecache. Data has been copied into the pagecache that we need to append + * to the request. If we've added more than wsize then we need to create a new + * subrequest. + */ +int netfs_advance_writethrough(struct netfs_io_request *wreq, size_t copied, bool to_page_end) +{ + _enter("ic=%zu sb=%zu ws=%u cp=%zu tp=%u", + wreq->iter.count, wreq->submitted, wreq->wsize, copied, to_page_end); + + wreq->iter.count += copied; + wreq->io_iter.count += copied; + if (to_page_end && wreq->io_iter.count - wreq->submitted >= wreq->wsize) + netfs_submit_writethrough(wreq, false); + + return wreq->error; +} + +/* + * End a write operation used when writing through the pagecache. + */ +int netfs_end_writethrough(struct netfs_io_request *wreq, struct kiocb *iocb) +{ + int ret = -EIOCBQUEUED; + + _enter("ic=%zu sb=%zu ws=%u", + wreq->iter.count, wreq->submitted, wreq->wsize); + + if (wreq->submitted < wreq->io_iter.count) + netfs_submit_writethrough(wreq, true); + + if (atomic_dec_and_test(&wreq->nr_outstanding)) + netfs_write_terminated(wreq, false); + + if (is_sync_kiocb(iocb)) { + wait_on_bit(&wreq->flags, NETFS_RREQ_IN_PROGRESS, + TASK_UNINTERRUPTIBLE); + ret = wreq->error; + } + + netfs_put_request(wreq, false, netfs_rreq_trace_put_return); + return ret; +} diff --git a/fs/netfs/stats.c b/fs/netfs/stats.c index 5510a7a14a..deeba9f9dc 100644 --- a/fs/netfs/stats.c +++ b/fs/netfs/stats.c @@ -9,6 +9,8 @@ #include <linux/seq_file.h> #include "internal.h" +atomic_t netfs_n_rh_dio_read; +atomic_t netfs_n_rh_dio_write; atomic_t netfs_n_rh_readahead; atomic_t netfs_n_rh_readpage; atomic_t netfs_n_rh_rreq; @@ -27,32 +29,48 @@ atomic_t netfs_n_rh_write_begin; atomic_t netfs_n_rh_write_done; atomic_t netfs_n_rh_write_failed; atomic_t netfs_n_rh_write_zskip; +atomic_t netfs_n_wh_wstream_conflict; +atomic_t netfs_n_wh_upload; +atomic_t netfs_n_wh_upload_done; +atomic_t netfs_n_wh_upload_failed; +atomic_t netfs_n_wh_write; +atomic_t netfs_n_wh_write_done; +atomic_t netfs_n_wh_write_failed; -void netfs_stats_show(struct seq_file *m) +int netfs_stats_show(struct seq_file *m, void *v) { - seq_printf(m, "RdHelp : RA=%u RP=%u WB=%u WBZ=%u rr=%u sr=%u\n", + seq_printf(m, "Netfs : DR=%u DW=%u RA=%u RP=%u WB=%u WBZ=%u\n", + atomic_read(&netfs_n_rh_dio_read), + atomic_read(&netfs_n_rh_dio_write), atomic_read(&netfs_n_rh_readahead), atomic_read(&netfs_n_rh_readpage), atomic_read(&netfs_n_rh_write_begin), - atomic_read(&netfs_n_rh_write_zskip), - atomic_read(&netfs_n_rh_rreq), - atomic_read(&netfs_n_rh_sreq)); - seq_printf(m, "RdHelp : ZR=%u sh=%u sk=%u\n", + atomic_read(&netfs_n_rh_write_zskip)); + seq_printf(m, "Netfs : ZR=%u sh=%u sk=%u\n", atomic_read(&netfs_n_rh_zero), atomic_read(&netfs_n_rh_short_read), atomic_read(&netfs_n_rh_write_zskip)); - seq_printf(m, "RdHelp : DL=%u ds=%u df=%u di=%u\n", + seq_printf(m, "Netfs : DL=%u ds=%u df=%u di=%u\n", atomic_read(&netfs_n_rh_download), atomic_read(&netfs_n_rh_download_done), atomic_read(&netfs_n_rh_download_failed), atomic_read(&netfs_n_rh_download_instead)); - seq_printf(m, "RdHelp : RD=%u rs=%u rf=%u\n", + seq_printf(m, "Netfs : RD=%u rs=%u rf=%u\n", atomic_read(&netfs_n_rh_read), atomic_read(&netfs_n_rh_read_done), atomic_read(&netfs_n_rh_read_failed)); - seq_printf(m, "RdHelp : WR=%u ws=%u wf=%u\n", - atomic_read(&netfs_n_rh_write), - atomic_read(&netfs_n_rh_write_done), - atomic_read(&netfs_n_rh_write_failed)); + seq_printf(m, "Netfs : UL=%u us=%u uf=%u\n", + atomic_read(&netfs_n_wh_upload), + atomic_read(&netfs_n_wh_upload_done), + atomic_read(&netfs_n_wh_upload_failed)); + seq_printf(m, "Netfs : WR=%u ws=%u wf=%u\n", + atomic_read(&netfs_n_wh_write), + atomic_read(&netfs_n_wh_write_done), + atomic_read(&netfs_n_wh_write_failed)); + seq_printf(m, "Netfs : rr=%u sr=%u wsc=%u\n", + atomic_read(&netfs_n_rh_rreq), + atomic_read(&netfs_n_rh_sreq), + atomic_read(&netfs_n_wh_wstream_conflict)); + return fscache_stats_show(m); } EXPORT_SYMBOL(netfs_stats_show); |