From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- fs/iomap/Makefile | 17 + fs/iomap/buffered-io.c | 1548 ++++++++++++++++++++++++++++++++++++++++++++++++ fs/iomap/direct-io.c | 696 ++++++++++++++++++++++ fs/iomap/fiemap.c | 124 ++++ fs/iomap/iter.c | 80 +++ fs/iomap/seek.c | 104 ++++ fs/iomap/swapfile.c | 195 ++++++ fs/iomap/trace.c | 12 + fs/iomap/trace.h | 191 ++++++ 9 files changed, 2967 insertions(+) create mode 100644 fs/iomap/Makefile create mode 100644 fs/iomap/buffered-io.c create mode 100644 fs/iomap/direct-io.c create mode 100644 fs/iomap/fiemap.c create mode 100644 fs/iomap/iter.c create mode 100644 fs/iomap/seek.c create mode 100644 fs/iomap/swapfile.c create mode 100644 fs/iomap/trace.c create mode 100644 fs/iomap/trace.h (limited to 'fs/iomap') diff --git a/fs/iomap/Makefile b/fs/iomap/Makefile new file mode 100644 index 000000000..fc070184b --- /dev/null +++ b/fs/iomap/Makefile @@ -0,0 +1,17 @@ +# SPDX-License-Identifier: GPL-2.0-or-later +# +# Copyright (c) 2019 Oracle. +# All Rights Reserved. +# + +ccflags-y += -I $(srctree)/$(src) # needed for trace events + +obj-$(CONFIG_FS_IOMAP) += iomap.o + +iomap-y += trace.o \ + iter.o +iomap-$(CONFIG_BLOCK) += buffered-io.o \ + direct-io.o \ + fiemap.o \ + seek.o +iomap-$(CONFIG_SWAP) += swapfile.o diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c new file mode 100644 index 000000000..a0a4d8de8 --- /dev/null +++ b/fs/iomap/buffered-io.c @@ -0,0 +1,1548 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2010 Red Hat, Inc. + * Copyright (C) 2016-2019 Christoph Hellwig. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "trace.h" + +#include "../internal.h" + +#define IOEND_BATCH_SIZE 4096 + +/* + * Structure allocated for each folio when block size < folio size + * to track sub-folio uptodate status and I/O completions. + */ +struct iomap_page { + atomic_t read_bytes_pending; + atomic_t write_bytes_pending; + spinlock_t uptodate_lock; + unsigned long uptodate[]; +}; + +static inline struct iomap_page *to_iomap_page(struct folio *folio) +{ + if (folio_test_private(folio)) + return folio_get_private(folio); + return NULL; +} + +static struct bio_set iomap_ioend_bioset; + +static struct iomap_page * +iomap_page_create(struct inode *inode, struct folio *folio, unsigned int flags) +{ + struct iomap_page *iop = to_iomap_page(folio); + unsigned int nr_blocks = i_blocks_per_folio(inode, folio); + gfp_t gfp; + + if (iop || nr_blocks <= 1) + return iop; + + if (flags & IOMAP_NOWAIT) + gfp = GFP_NOWAIT; + else + gfp = GFP_NOFS | __GFP_NOFAIL; + + iop = kzalloc(struct_size(iop, uptodate, BITS_TO_LONGS(nr_blocks)), + gfp); + if (iop) { + spin_lock_init(&iop->uptodate_lock); + if (folio_test_uptodate(folio)) + bitmap_fill(iop->uptodate, nr_blocks); + folio_attach_private(folio, iop); + } + return iop; +} + +static void iomap_page_release(struct folio *folio) +{ + struct iomap_page *iop = folio_detach_private(folio); + struct inode *inode = folio->mapping->host; + unsigned int nr_blocks = i_blocks_per_folio(inode, folio); + + if (!iop) + return; + WARN_ON_ONCE(atomic_read(&iop->read_bytes_pending)); + WARN_ON_ONCE(atomic_read(&iop->write_bytes_pending)); + WARN_ON_ONCE(bitmap_full(iop->uptodate, nr_blocks) != + folio_test_uptodate(folio)); + kfree(iop); +} + +/* + * Calculate the range inside the folio that we actually need to read. + */ +static void iomap_adjust_read_range(struct inode *inode, struct folio *folio, + loff_t *pos, loff_t length, size_t *offp, size_t *lenp) +{ + struct iomap_page *iop = to_iomap_page(folio); + loff_t orig_pos = *pos; + loff_t isize = i_size_read(inode); + unsigned block_bits = inode->i_blkbits; + unsigned block_size = (1 << block_bits); + size_t poff = offset_in_folio(folio, *pos); + size_t plen = min_t(loff_t, folio_size(folio) - poff, length); + unsigned first = poff >> block_bits; + unsigned last = (poff + plen - 1) >> block_bits; + + /* + * If the block size is smaller than the page size, we need to check the + * per-block uptodate status and adjust the offset and length if needed + * to avoid reading in already uptodate ranges. + */ + if (iop) { + unsigned int i; + + /* move forward for each leading block marked uptodate */ + for (i = first; i <= last; i++) { + if (!test_bit(i, iop->uptodate)) + break; + *pos += block_size; + poff += block_size; + plen -= block_size; + first++; + } + + /* truncate len if we find any trailing uptodate block(s) */ + for ( ; i <= last; i++) { + if (test_bit(i, iop->uptodate)) { + plen -= (last - i + 1) * block_size; + last = i - 1; + break; + } + } + } + + /* + * If the extent spans the block that contains the i_size, we need to + * handle both halves separately so that we properly zero data in the + * page cache for blocks that are entirely outside of i_size. + */ + if (orig_pos <= isize && orig_pos + length > isize) { + unsigned end = offset_in_folio(folio, isize - 1) >> block_bits; + + if (first <= end && last > end) + plen -= (last - end) * block_size; + } + + *offp = poff; + *lenp = plen; +} + +static void iomap_iop_set_range_uptodate(struct folio *folio, + struct iomap_page *iop, size_t off, size_t len) +{ + struct inode *inode = folio->mapping->host; + unsigned first = off >> inode->i_blkbits; + unsigned last = (off + len - 1) >> inode->i_blkbits; + unsigned long flags; + + spin_lock_irqsave(&iop->uptodate_lock, flags); + bitmap_set(iop->uptodate, first, last - first + 1); + if (bitmap_full(iop->uptodate, i_blocks_per_folio(inode, folio))) + folio_mark_uptodate(folio); + spin_unlock_irqrestore(&iop->uptodate_lock, flags); +} + +static void iomap_set_range_uptodate(struct folio *folio, + struct iomap_page *iop, size_t off, size_t len) +{ + if (iop) + iomap_iop_set_range_uptodate(folio, iop, off, len); + else + folio_mark_uptodate(folio); +} + +static void iomap_finish_folio_read(struct folio *folio, size_t offset, + size_t len, int error) +{ + struct iomap_page *iop = to_iomap_page(folio); + + if (unlikely(error)) { + folio_clear_uptodate(folio); + folio_set_error(folio); + } else { + iomap_set_range_uptodate(folio, iop, offset, len); + } + + if (!iop || atomic_sub_and_test(len, &iop->read_bytes_pending)) + folio_unlock(folio); +} + +static void iomap_read_end_io(struct bio *bio) +{ + int error = blk_status_to_errno(bio->bi_status); + struct folio_iter fi; + + bio_for_each_folio_all(fi, bio) + iomap_finish_folio_read(fi.folio, fi.offset, fi.length, error); + bio_put(bio); +} + +struct iomap_readpage_ctx { + struct folio *cur_folio; + bool cur_folio_in_bio; + struct bio *bio; + struct readahead_control *rac; +}; + +/** + * iomap_read_inline_data - copy inline data into the page cache + * @iter: iteration structure + * @folio: folio to copy to + * + * Copy the inline data in @iter into @folio and zero out the rest of the folio. + * Only a single IOMAP_INLINE extent is allowed at the end of each file. + * Returns zero for success to complete the read, or the usual negative errno. + */ +static int iomap_read_inline_data(const struct iomap_iter *iter, + struct folio *folio) +{ + struct iomap_page *iop; + const struct iomap *iomap = iomap_iter_srcmap(iter); + size_t size = i_size_read(iter->inode) - iomap->offset; + size_t poff = offset_in_page(iomap->offset); + size_t offset = offset_in_folio(folio, iomap->offset); + void *addr; + + if (folio_test_uptodate(folio)) + return 0; + + if (WARN_ON_ONCE(size > PAGE_SIZE - poff)) + return -EIO; + if (WARN_ON_ONCE(size > PAGE_SIZE - + offset_in_page(iomap->inline_data))) + return -EIO; + if (WARN_ON_ONCE(size > iomap->length)) + return -EIO; + if (offset > 0) + iop = iomap_page_create(iter->inode, folio, iter->flags); + else + iop = to_iomap_page(folio); + + addr = kmap_local_folio(folio, offset); + memcpy(addr, iomap->inline_data, size); + memset(addr + size, 0, PAGE_SIZE - poff - size); + kunmap_local(addr); + iomap_set_range_uptodate(folio, iop, offset, PAGE_SIZE - poff); + return 0; +} + +static inline bool iomap_block_needs_zeroing(const struct iomap_iter *iter, + loff_t pos) +{ + const struct iomap *srcmap = iomap_iter_srcmap(iter); + + return srcmap->type != IOMAP_MAPPED || + (srcmap->flags & IOMAP_F_NEW) || + pos >= i_size_read(iter->inode); +} + +static loff_t iomap_readpage_iter(const struct iomap_iter *iter, + struct iomap_readpage_ctx *ctx, loff_t offset) +{ + const struct iomap *iomap = &iter->iomap; + loff_t pos = iter->pos + offset; + loff_t length = iomap_length(iter) - offset; + struct folio *folio = ctx->cur_folio; + struct iomap_page *iop; + loff_t orig_pos = pos; + size_t poff, plen; + sector_t sector; + + if (iomap->type == IOMAP_INLINE) + return iomap_read_inline_data(iter, folio); + + /* zero post-eof blocks as the page may be mapped */ + iop = iomap_page_create(iter->inode, folio, iter->flags); + iomap_adjust_read_range(iter->inode, folio, &pos, length, &poff, &plen); + if (plen == 0) + goto done; + + if (iomap_block_needs_zeroing(iter, pos)) { + folio_zero_range(folio, poff, plen); + iomap_set_range_uptodate(folio, iop, poff, plen); + goto done; + } + + ctx->cur_folio_in_bio = true; + if (iop) + atomic_add(plen, &iop->read_bytes_pending); + + sector = iomap_sector(iomap, pos); + if (!ctx->bio || + bio_end_sector(ctx->bio) != sector || + !bio_add_folio(ctx->bio, folio, plen, poff)) { + gfp_t gfp = mapping_gfp_constraint(folio->mapping, GFP_KERNEL); + gfp_t orig_gfp = gfp; + unsigned int nr_vecs = DIV_ROUND_UP(length, PAGE_SIZE); + + if (ctx->bio) + submit_bio(ctx->bio); + + if (ctx->rac) /* same as readahead_gfp_mask */ + gfp |= __GFP_NORETRY | __GFP_NOWARN; + ctx->bio = bio_alloc(iomap->bdev, bio_max_segs(nr_vecs), + REQ_OP_READ, gfp); + /* + * If the bio_alloc fails, try it again for a single page to + * avoid having to deal with partial page reads. This emulates + * what do_mpage_read_folio does. + */ + if (!ctx->bio) { + ctx->bio = bio_alloc(iomap->bdev, 1, REQ_OP_READ, + orig_gfp); + } + if (ctx->rac) + ctx->bio->bi_opf |= REQ_RAHEAD; + ctx->bio->bi_iter.bi_sector = sector; + ctx->bio->bi_end_io = iomap_read_end_io; + bio_add_folio(ctx->bio, folio, plen, poff); + } + +done: + /* + * Move the caller beyond our range so that it keeps making progress. + * For that, we have to include any leading non-uptodate ranges, but + * we can skip trailing ones as they will be handled in the next + * iteration. + */ + return pos - orig_pos + plen; +} + +int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops) +{ + struct iomap_iter iter = { + .inode = folio->mapping->host, + .pos = folio_pos(folio), + .len = folio_size(folio), + }; + struct iomap_readpage_ctx ctx = { + .cur_folio = folio, + }; + int ret; + + trace_iomap_readpage(iter.inode, 1); + + while ((ret = iomap_iter(&iter, ops)) > 0) + iter.processed = iomap_readpage_iter(&iter, &ctx, 0); + + if (ret < 0) + folio_set_error(folio); + + if (ctx.bio) { + submit_bio(ctx.bio); + WARN_ON_ONCE(!ctx.cur_folio_in_bio); + } else { + WARN_ON_ONCE(ctx.cur_folio_in_bio); + folio_unlock(folio); + } + + /* + * Just like mpage_readahead and block_read_full_folio, we always + * return 0 and just set the folio error flag on errors. This + * should be cleaned up throughout the stack eventually. + */ + return 0; +} +EXPORT_SYMBOL_GPL(iomap_read_folio); + +static loff_t iomap_readahead_iter(const struct iomap_iter *iter, + struct iomap_readpage_ctx *ctx) +{ + loff_t length = iomap_length(iter); + loff_t done, ret; + + for (done = 0; done < length; done += ret) { + if (ctx->cur_folio && + offset_in_folio(ctx->cur_folio, iter->pos + done) == 0) { + if (!ctx->cur_folio_in_bio) + folio_unlock(ctx->cur_folio); + ctx->cur_folio = NULL; + } + if (!ctx->cur_folio) { + ctx->cur_folio = readahead_folio(ctx->rac); + ctx->cur_folio_in_bio = false; + } + ret = iomap_readpage_iter(iter, ctx, done); + if (ret <= 0) + return ret; + } + + return done; +} + +/** + * iomap_readahead - Attempt to read pages from a file. + * @rac: Describes the pages to be read. + * @ops: The operations vector for the filesystem. + * + * This function is for filesystems to call to implement their readahead + * address_space operation. + * + * Context: The @ops callbacks may submit I/O (eg to read the addresses of + * blocks from disc), and may wait for it. The caller may be trying to + * access a different page, and so sleeping excessively should be avoided. + * It may allocate memory, but should avoid costly allocations. This + * function is called with memalloc_nofs set, so allocations will not cause + * the filesystem to be reentered. + */ +void iomap_readahead(struct readahead_control *rac, const struct iomap_ops *ops) +{ + struct iomap_iter iter = { + .inode = rac->mapping->host, + .pos = readahead_pos(rac), + .len = readahead_length(rac), + }; + struct iomap_readpage_ctx ctx = { + .rac = rac, + }; + + trace_iomap_readahead(rac->mapping->host, readahead_count(rac)); + + while (iomap_iter(&iter, ops) > 0) + iter.processed = iomap_readahead_iter(&iter, &ctx); + + if (ctx.bio) + submit_bio(ctx.bio); + if (ctx.cur_folio) { + if (!ctx.cur_folio_in_bio) + folio_unlock(ctx.cur_folio); + } +} +EXPORT_SYMBOL_GPL(iomap_readahead); + +/* + * iomap_is_partially_uptodate checks whether blocks within a folio are + * uptodate or not. + * + * Returns true if all blocks which correspond to the specified part + * of the folio are uptodate. + */ +bool iomap_is_partially_uptodate(struct folio *folio, size_t from, size_t count) +{ + struct iomap_page *iop = to_iomap_page(folio); + struct inode *inode = folio->mapping->host; + unsigned first, last, i; + + if (!iop) + return false; + + /* Caller's range may extend past the end of this folio */ + count = min(folio_size(folio) - from, count); + + /* First and last blocks in range within folio */ + first = from >> inode->i_blkbits; + last = (from + count - 1) >> inode->i_blkbits; + + for (i = first; i <= last; i++) + if (!test_bit(i, iop->uptodate)) + return false; + return true; +} +EXPORT_SYMBOL_GPL(iomap_is_partially_uptodate); + +bool iomap_release_folio(struct folio *folio, gfp_t gfp_flags) +{ + trace_iomap_release_folio(folio->mapping->host, folio_pos(folio), + folio_size(folio)); + + /* + * mm accommodates an old ext3 case where clean folios might + * not have had the dirty bit cleared. Thus, it can send actual + * dirty folios to ->release_folio() via shrink_active_list(); + * skip those here. + */ + if (folio_test_dirty(folio) || folio_test_writeback(folio)) + return false; + iomap_page_release(folio); + return true; +} +EXPORT_SYMBOL_GPL(iomap_release_folio); + +void iomap_invalidate_folio(struct folio *folio, size_t offset, size_t len) +{ + trace_iomap_invalidate_folio(folio->mapping->host, + folio_pos(folio) + offset, len); + + /* + * If we're invalidating the entire folio, clear the dirty state + * from it and release it to avoid unnecessary buildup of the LRU. + */ + if (offset == 0 && len == folio_size(folio)) { + WARN_ON_ONCE(folio_test_writeback(folio)); + folio_cancel_dirty(folio); + iomap_page_release(folio); + } +} +EXPORT_SYMBOL_GPL(iomap_invalidate_folio); + +static void +iomap_write_failed(struct inode *inode, loff_t pos, unsigned len) +{ + loff_t i_size = i_size_read(inode); + + /* + * Only truncate newly allocated pages beyoned EOF, even if the + * write started inside the existing inode size. + */ + if (pos + len > i_size) + truncate_pagecache_range(inode, max(pos, i_size), + pos + len - 1); +} + +static int iomap_read_folio_sync(loff_t block_start, struct folio *folio, + size_t poff, size_t plen, const struct iomap *iomap) +{ + struct bio_vec bvec; + struct bio bio; + + bio_init(&bio, iomap->bdev, &bvec, 1, REQ_OP_READ); + bio.bi_iter.bi_sector = iomap_sector(iomap, block_start); + bio_add_folio(&bio, folio, plen, poff); + return submit_bio_wait(&bio); +} + +static int __iomap_write_begin(const struct iomap_iter *iter, loff_t pos, + size_t len, struct folio *folio) +{ + const struct iomap *srcmap = iomap_iter_srcmap(iter); + struct iomap_page *iop; + loff_t block_size = i_blocksize(iter->inode); + loff_t block_start = round_down(pos, block_size); + loff_t block_end = round_up(pos + len, block_size); + unsigned int nr_blocks = i_blocks_per_folio(iter->inode, folio); + size_t from = offset_in_folio(folio, pos), to = from + len; + size_t poff, plen; + + if (folio_test_uptodate(folio)) + return 0; + folio_clear_error(folio); + + iop = iomap_page_create(iter->inode, folio, iter->flags); + if ((iter->flags & IOMAP_NOWAIT) && !iop && nr_blocks > 1) + return -EAGAIN; + + do { + iomap_adjust_read_range(iter->inode, folio, &block_start, + block_end - block_start, &poff, &plen); + if (plen == 0) + break; + + if (!(iter->flags & IOMAP_UNSHARE) && + (from <= poff || from >= poff + plen) && + (to <= poff || to >= poff + plen)) + continue; + + if (iomap_block_needs_zeroing(iter, block_start)) { + if (WARN_ON_ONCE(iter->flags & IOMAP_UNSHARE)) + return -EIO; + folio_zero_segments(folio, poff, from, to, poff + plen); + } else { + int status; + + if (iter->flags & IOMAP_NOWAIT) + return -EAGAIN; + + status = iomap_read_folio_sync(block_start, folio, + poff, plen, srcmap); + if (status) + return status; + } + iomap_set_range_uptodate(folio, iop, poff, plen); + } while ((block_start += plen) < block_end); + + return 0; +} + +static int iomap_write_begin_inline(const struct iomap_iter *iter, + struct folio *folio) +{ + /* needs more work for the tailpacking case; disable for now */ + if (WARN_ON_ONCE(iomap_iter_srcmap(iter)->offset != 0)) + return -EIO; + return iomap_read_inline_data(iter, folio); +} + +static int iomap_write_begin(const struct iomap_iter *iter, loff_t pos, + size_t len, struct folio **foliop) +{ + const struct iomap_page_ops *page_ops = iter->iomap.page_ops; + const struct iomap *srcmap = iomap_iter_srcmap(iter); + struct folio *folio; + unsigned fgp = FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE | FGP_NOFS; + int status = 0; + + if (iter->flags & IOMAP_NOWAIT) + fgp |= FGP_NOWAIT; + + BUG_ON(pos + len > iter->iomap.offset + iter->iomap.length); + if (srcmap != &iter->iomap) + BUG_ON(pos + len > srcmap->offset + srcmap->length); + + if (fatal_signal_pending(current)) + return -EINTR; + + if (!mapping_large_folio_support(iter->inode->i_mapping)) + len = min_t(size_t, len, PAGE_SIZE - offset_in_page(pos)); + + if (page_ops && page_ops->page_prepare) { + status = page_ops->page_prepare(iter->inode, pos, len); + if (status) + return status; + } + + folio = __filemap_get_folio(iter->inode->i_mapping, pos >> PAGE_SHIFT, + fgp, mapping_gfp_mask(iter->inode->i_mapping)); + if (!folio) { + status = (iter->flags & IOMAP_NOWAIT) ? -EAGAIN : -ENOMEM; + goto out_no_page; + } + if (pos + len > folio_pos(folio) + folio_size(folio)) + len = folio_pos(folio) + folio_size(folio) - pos; + + if (srcmap->type == IOMAP_INLINE) + status = iomap_write_begin_inline(iter, folio); + else if (srcmap->flags & IOMAP_F_BUFFER_HEAD) + status = __block_write_begin_int(folio, pos, len, NULL, srcmap); + else + status = __iomap_write_begin(iter, pos, len, folio); + + if (unlikely(status)) + goto out_unlock; + + *foliop = folio; + return 0; + +out_unlock: + folio_unlock(folio); + folio_put(folio); + iomap_write_failed(iter->inode, pos, len); + +out_no_page: + if (page_ops && page_ops->page_done) + page_ops->page_done(iter->inode, pos, 0, NULL); + return status; +} + +static size_t __iomap_write_end(struct inode *inode, loff_t pos, size_t len, + size_t copied, struct folio *folio) +{ + struct iomap_page *iop = to_iomap_page(folio); + flush_dcache_folio(folio); + + /* + * The blocks that were entirely written will now be uptodate, so we + * don't have to worry about a read_folio reading them and overwriting a + * partial write. However, if we've encountered a short write and only + * partially written into a block, it will not be marked uptodate, so a + * read_folio might come in and destroy our partial write. + * + * Do the simplest thing and just treat any short write to a + * non-uptodate page as a zero-length write, and force the caller to + * redo the whole thing. + */ + if (unlikely(copied < len && !folio_test_uptodate(folio))) + return 0; + iomap_set_range_uptodate(folio, iop, offset_in_folio(folio, pos), len); + filemap_dirty_folio(inode->i_mapping, folio); + return copied; +} + +static size_t iomap_write_end_inline(const struct iomap_iter *iter, + struct folio *folio, loff_t pos, size_t copied) +{ + const struct iomap *iomap = &iter->iomap; + void *addr; + + WARN_ON_ONCE(!folio_test_uptodate(folio)); + BUG_ON(!iomap_inline_data_valid(iomap)); + + flush_dcache_folio(folio); + addr = kmap_local_folio(folio, pos); + memcpy(iomap_inline_data(iomap, pos), addr, copied); + kunmap_local(addr); + + mark_inode_dirty(iter->inode); + return copied; +} + +/* Returns the number of bytes copied. May be 0. Cannot be an errno. */ +static size_t iomap_write_end(struct iomap_iter *iter, loff_t pos, size_t len, + size_t copied, struct folio *folio) +{ + const struct iomap_page_ops *page_ops = iter->iomap.page_ops; + const struct iomap *srcmap = iomap_iter_srcmap(iter); + loff_t old_size = iter->inode->i_size; + size_t ret; + + if (srcmap->type == IOMAP_INLINE) { + ret = iomap_write_end_inline(iter, folio, pos, copied); + } else if (srcmap->flags & IOMAP_F_BUFFER_HEAD) { + ret = block_write_end(NULL, iter->inode->i_mapping, pos, len, + copied, &folio->page, NULL); + } else { + ret = __iomap_write_end(iter->inode, pos, len, copied, folio); + } + + /* + * Update the in-memory inode size after copying the data into the page + * cache. It's up to the file system to write the updated size to disk, + * preferably after I/O completion so that no stale data is exposed. + */ + if (pos + ret > old_size) { + i_size_write(iter->inode, pos + ret); + iter->iomap.flags |= IOMAP_F_SIZE_CHANGED; + } + folio_unlock(folio); + + if (old_size < pos) + pagecache_isize_extended(iter->inode, old_size, pos); + if (page_ops && page_ops->page_done) + page_ops->page_done(iter->inode, pos, ret, &folio->page); + folio_put(folio); + + if (ret < len) + iomap_write_failed(iter->inode, pos + ret, len - ret); + return ret; +} + +static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i) +{ + loff_t length = iomap_length(iter); + loff_t pos = iter->pos; + ssize_t written = 0; + long status = 0; + struct address_space *mapping = iter->inode->i_mapping; + unsigned int bdp_flags = (iter->flags & IOMAP_NOWAIT) ? BDP_ASYNC : 0; + + do { + struct folio *folio; + struct page *page; + unsigned long offset; /* Offset into pagecache page */ + unsigned long bytes; /* Bytes to write to page */ + size_t copied; /* Bytes copied from user */ + + offset = offset_in_page(pos); + bytes = min_t(unsigned long, PAGE_SIZE - offset, + iov_iter_count(i)); +again: + status = balance_dirty_pages_ratelimited_flags(mapping, + bdp_flags); + if (unlikely(status)) + break; + + if (bytes > length) + bytes = length; + + /* + * Bring in the user page that we'll copy from _first_. + * Otherwise there's a nasty deadlock on copying from the + * same page as we're writing to, without it being marked + * up-to-date. + * + * For async buffered writes the assumption is that the user + * page has already been faulted in. This can be optimized by + * faulting the user page. + */ + if (unlikely(fault_in_iov_iter_readable(i, bytes) == bytes)) { + status = -EFAULT; + break; + } + + status = iomap_write_begin(iter, pos, bytes, &folio); + if (unlikely(status)) + break; + + page = folio_file_page(folio, pos >> PAGE_SHIFT); + if (mapping_writably_mapped(mapping)) + flush_dcache_page(page); + + copied = copy_page_from_iter_atomic(page, offset, bytes, i); + + status = iomap_write_end(iter, pos, bytes, copied, folio); + + if (unlikely(copied != status)) + iov_iter_revert(i, copied - status); + + cond_resched(); + if (unlikely(status == 0)) { + /* + * A short copy made iomap_write_end() reject the + * thing entirely. Might be memory poisoning + * halfway through, might be a race with munmap, + * might be severe memory pressure. + */ + if (copied) + bytes = copied; + goto again; + } + pos += status; + written += status; + length -= status; + } while (iov_iter_count(i) && length); + + if (status == -EAGAIN) { + iov_iter_revert(i, written); + return -EAGAIN; + } + return written ? written : status; +} + +ssize_t +iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i, + const struct iomap_ops *ops) +{ + struct iomap_iter iter = { + .inode = iocb->ki_filp->f_mapping->host, + .pos = iocb->ki_pos, + .len = iov_iter_count(i), + .flags = IOMAP_WRITE, + }; + int ret; + + if (iocb->ki_flags & IOCB_NOWAIT) + iter.flags |= IOMAP_NOWAIT; + + while ((ret = iomap_iter(&iter, ops)) > 0) + iter.processed = iomap_write_iter(&iter, i); + if (iter.pos == iocb->ki_pos) + return ret; + return iter.pos - iocb->ki_pos; +} +EXPORT_SYMBOL_GPL(iomap_file_buffered_write); + +static loff_t iomap_unshare_iter(struct iomap_iter *iter) +{ + struct iomap *iomap = &iter->iomap; + const struct iomap *srcmap = iomap_iter_srcmap(iter); + loff_t pos = iter->pos; + loff_t length = iomap_length(iter); + long status = 0; + loff_t written = 0; + + /* don't bother with blocks that are not shared to start with */ + if (!(iomap->flags & IOMAP_F_SHARED)) + return length; + /* don't bother with holes or unwritten extents */ + if (srcmap->type == IOMAP_HOLE || srcmap->type == IOMAP_UNWRITTEN) + return length; + + do { + unsigned long offset = offset_in_page(pos); + unsigned long bytes = min_t(loff_t, PAGE_SIZE - offset, length); + struct folio *folio; + + status = iomap_write_begin(iter, pos, bytes, &folio); + if (unlikely(status)) + return status; + + status = iomap_write_end(iter, pos, bytes, bytes, folio); + if (WARN_ON_ONCE(status == 0)) + return -EIO; + + cond_resched(); + + pos += status; + written += status; + length -= status; + + balance_dirty_pages_ratelimited(iter->inode->i_mapping); + } while (length); + + return written; +} + +int +iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len, + const struct iomap_ops *ops) +{ + struct iomap_iter iter = { + .inode = inode, + .pos = pos, + .len = len, + .flags = IOMAP_WRITE | IOMAP_UNSHARE, + }; + int ret; + + while ((ret = iomap_iter(&iter, ops)) > 0) + iter.processed = iomap_unshare_iter(&iter); + return ret; +} +EXPORT_SYMBOL_GPL(iomap_file_unshare); + +static loff_t iomap_zero_iter(struct iomap_iter *iter, bool *did_zero) +{ + const struct iomap *srcmap = iomap_iter_srcmap(iter); + loff_t pos = iter->pos; + loff_t length = iomap_length(iter); + loff_t written = 0; + + /* already zeroed? we're done. */ + if (srcmap->type == IOMAP_HOLE || srcmap->type == IOMAP_UNWRITTEN) + return length; + + do { + struct folio *folio; + int status; + size_t offset; + size_t bytes = min_t(u64, SIZE_MAX, length); + + status = iomap_write_begin(iter, pos, bytes, &folio); + if (status) + return status; + + offset = offset_in_folio(folio, pos); + if (bytes > folio_size(folio) - offset) + bytes = folio_size(folio) - offset; + + folio_zero_range(folio, offset, bytes); + folio_mark_accessed(folio); + + bytes = iomap_write_end(iter, pos, bytes, bytes, folio); + if (WARN_ON_ONCE(bytes == 0)) + return -EIO; + + pos += bytes; + length -= bytes; + written += bytes; + } while (length > 0); + + if (did_zero) + *did_zero = true; + return written; +} + +int +iomap_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero, + const struct iomap_ops *ops) +{ + struct iomap_iter iter = { + .inode = inode, + .pos = pos, + .len = len, + .flags = IOMAP_ZERO, + }; + int ret; + + while ((ret = iomap_iter(&iter, ops)) > 0) + iter.processed = iomap_zero_iter(&iter, did_zero); + return ret; +} +EXPORT_SYMBOL_GPL(iomap_zero_range); + +int +iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero, + const struct iomap_ops *ops) +{ + unsigned int blocksize = i_blocksize(inode); + unsigned int off = pos & (blocksize - 1); + + /* Block boundary? Nothing to do */ + if (!off) + return 0; + return iomap_zero_range(inode, pos, blocksize - off, did_zero, ops); +} +EXPORT_SYMBOL_GPL(iomap_truncate_page); + +static loff_t iomap_folio_mkwrite_iter(struct iomap_iter *iter, + struct folio *folio) +{ + loff_t length = iomap_length(iter); + int ret; + + if (iter->iomap.flags & IOMAP_F_BUFFER_HEAD) { + ret = __block_write_begin_int(folio, iter->pos, length, NULL, + &iter->iomap); + if (ret) + return ret; + block_commit_write(&folio->page, 0, length); + } else { + WARN_ON_ONCE(!folio_test_uptodate(folio)); + folio_mark_dirty(folio); + } + + return length; +} + +vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops) +{ + struct iomap_iter iter = { + .inode = file_inode(vmf->vma->vm_file), + .flags = IOMAP_WRITE | IOMAP_FAULT, + }; + struct folio *folio = page_folio(vmf->page); + ssize_t ret; + + folio_lock(folio); + ret = folio_mkwrite_check_truncate(folio, iter.inode); + if (ret < 0) + goto out_unlock; + iter.pos = folio_pos(folio); + iter.len = ret; + while ((ret = iomap_iter(&iter, ops)) > 0) + iter.processed = iomap_folio_mkwrite_iter(&iter, folio); + + if (ret < 0) + goto out_unlock; + folio_wait_stable(folio); + return VM_FAULT_LOCKED; +out_unlock: + folio_unlock(folio); + return block_page_mkwrite_return(ret); +} +EXPORT_SYMBOL_GPL(iomap_page_mkwrite); + +static void iomap_finish_folio_write(struct inode *inode, struct folio *folio, + size_t len, int error) +{ + struct iomap_page *iop = to_iomap_page(folio); + + if (error) { + folio_set_error(folio); + mapping_set_error(inode->i_mapping, error); + } + + WARN_ON_ONCE(i_blocks_per_folio(inode, folio) > 1 && !iop); + WARN_ON_ONCE(iop && atomic_read(&iop->write_bytes_pending) <= 0); + + if (!iop || atomic_sub_and_test(len, &iop->write_bytes_pending)) + folio_end_writeback(folio); +} + +/* + * We're now finished for good with this ioend structure. Update the page + * state, release holds on bios, and finally free up memory. Do not use the + * ioend after this. + */ +static u32 +iomap_finish_ioend(struct iomap_ioend *ioend, int error) +{ + struct inode *inode = ioend->io_inode; + struct bio *bio = &ioend->io_inline_bio; + struct bio *last = ioend->io_bio, *next; + u64 start = bio->bi_iter.bi_sector; + loff_t offset = ioend->io_offset; + bool quiet = bio_flagged(bio, BIO_QUIET); + u32 folio_count = 0; + + for (bio = &ioend->io_inline_bio; bio; bio = next) { + struct folio_iter fi; + + /* + * For the last bio, bi_private points to the ioend, so we + * need to explicitly end the iteration here. + */ + if (bio == last) + next = NULL; + else + next = bio->bi_private; + + /* walk all folios in bio, ending page IO on them */ + bio_for_each_folio_all(fi, bio) { + iomap_finish_folio_write(inode, fi.folio, fi.length, + error); + folio_count++; + } + bio_put(bio); + } + /* The ioend has been freed by bio_put() */ + + if (unlikely(error && !quiet)) { + printk_ratelimited(KERN_ERR +"%s: writeback error on inode %lu, offset %lld, sector %llu", + inode->i_sb->s_id, inode->i_ino, offset, start); + } + return folio_count; +} + +/* + * Ioend completion routine for merged bios. This can only be called from task + * contexts as merged ioends can be of unbound length. Hence we have to break up + * the writeback completions into manageable chunks to avoid long scheduler + * holdoffs. We aim to keep scheduler holdoffs down below 10ms so that we get + * good batch processing throughput without creating adverse scheduler latency + * conditions. + */ +void +iomap_finish_ioends(struct iomap_ioend *ioend, int error) +{ + struct list_head tmp; + u32 completions; + + might_sleep(); + + list_replace_init(&ioend->io_list, &tmp); + completions = iomap_finish_ioend(ioend, error); + + while (!list_empty(&tmp)) { + if (completions > IOEND_BATCH_SIZE * 8) { + cond_resched(); + completions = 0; + } + ioend = list_first_entry(&tmp, struct iomap_ioend, io_list); + list_del_init(&ioend->io_list); + completions += iomap_finish_ioend(ioend, error); + } +} +EXPORT_SYMBOL_GPL(iomap_finish_ioends); + +/* + * We can merge two adjacent ioends if they have the same set of work to do. + */ +static bool +iomap_ioend_can_merge(struct iomap_ioend *ioend, struct iomap_ioend *next) +{ + if (ioend->io_bio->bi_status != next->io_bio->bi_status) + return false; + if ((ioend->io_flags & IOMAP_F_SHARED) ^ + (next->io_flags & IOMAP_F_SHARED)) + return false; + if ((ioend->io_type == IOMAP_UNWRITTEN) ^ + (next->io_type == IOMAP_UNWRITTEN)) + return false; + if (ioend->io_offset + ioend->io_size != next->io_offset) + return false; + /* + * Do not merge physically discontiguous ioends. The filesystem + * completion functions will have to iterate the physical + * discontiguities even if we merge the ioends at a logical level, so + * we don't gain anything by merging physical discontiguities here. + * + * We cannot use bio->bi_iter.bi_sector here as it is modified during + * submission so does not point to the start sector of the bio at + * completion. + */ + if (ioend->io_sector + (ioend->io_size >> 9) != next->io_sector) + return false; + return true; +} + +void +iomap_ioend_try_merge(struct iomap_ioend *ioend, struct list_head *more_ioends) +{ + struct iomap_ioend *next; + + INIT_LIST_HEAD(&ioend->io_list); + + while ((next = list_first_entry_or_null(more_ioends, struct iomap_ioend, + io_list))) { + if (!iomap_ioend_can_merge(ioend, next)) + break; + list_move_tail(&next->io_list, &ioend->io_list); + ioend->io_size += next->io_size; + } +} +EXPORT_SYMBOL_GPL(iomap_ioend_try_merge); + +static int +iomap_ioend_compare(void *priv, const struct list_head *a, + const struct list_head *b) +{ + struct iomap_ioend *ia = container_of(a, struct iomap_ioend, io_list); + struct iomap_ioend *ib = container_of(b, struct iomap_ioend, io_list); + + if (ia->io_offset < ib->io_offset) + return -1; + if (ia->io_offset > ib->io_offset) + return 1; + return 0; +} + +void +iomap_sort_ioends(struct list_head *ioend_list) +{ + list_sort(NULL, ioend_list, iomap_ioend_compare); +} +EXPORT_SYMBOL_GPL(iomap_sort_ioends); + +static void iomap_writepage_end_bio(struct bio *bio) +{ + struct iomap_ioend *ioend = bio->bi_private; + + iomap_finish_ioend(ioend, blk_status_to_errno(bio->bi_status)); +} + +/* + * Submit the final bio for an ioend. + * + * If @error is non-zero, it means that we have a situation where some part of + * the submission process has failed after we've marked pages for writeback + * and unlocked them. In this situation, we need to fail the bio instead of + * submitting it. This typically only happens on a filesystem shutdown. + */ +static int +iomap_submit_ioend(struct iomap_writepage_ctx *wpc, struct iomap_ioend *ioend, + int error) +{ + ioend->io_bio->bi_private = ioend; + ioend->io_bio->bi_end_io = iomap_writepage_end_bio; + + if (wpc->ops->prepare_ioend) + error = wpc->ops->prepare_ioend(ioend, error); + if (error) { + /* + * If we're failing the IO now, just mark the ioend with an + * error and finish it. This will run IO completion immediately + * as there is only one reference to the ioend at this point in + * time. + */ + ioend->io_bio->bi_status = errno_to_blk_status(error); + bio_endio(ioend->io_bio); + return error; + } + + submit_bio(ioend->io_bio); + return 0; +} + +static struct iomap_ioend * +iomap_alloc_ioend(struct inode *inode, struct iomap_writepage_ctx *wpc, + loff_t offset, sector_t sector, struct writeback_control *wbc) +{ + struct iomap_ioend *ioend; + struct bio *bio; + + bio = bio_alloc_bioset(wpc->iomap.bdev, BIO_MAX_VECS, + REQ_OP_WRITE | wbc_to_write_flags(wbc), + GFP_NOFS, &iomap_ioend_bioset); + bio->bi_iter.bi_sector = sector; + wbc_init_bio(wbc, bio); + + ioend = container_of(bio, struct iomap_ioend, io_inline_bio); + INIT_LIST_HEAD(&ioend->io_list); + ioend->io_type = wpc->iomap.type; + ioend->io_flags = wpc->iomap.flags; + ioend->io_inode = inode; + ioend->io_size = 0; + ioend->io_folios = 0; + ioend->io_offset = offset; + ioend->io_bio = bio; + ioend->io_sector = sector; + return ioend; +} + +/* + * Allocate a new bio, and chain the old bio to the new one. + * + * Note that we have to perform the chaining in this unintuitive order + * so that the bi_private linkage is set up in the right direction for the + * traversal in iomap_finish_ioend(). + */ +static struct bio * +iomap_chain_bio(struct bio *prev) +{ + struct bio *new; + + new = bio_alloc(prev->bi_bdev, BIO_MAX_VECS, prev->bi_opf, GFP_NOFS); + bio_clone_blkg_association(new, prev); + new->bi_iter.bi_sector = bio_end_sector(prev); + + bio_chain(prev, new); + bio_get(prev); /* for iomap_finish_ioend */ + submit_bio(prev); + return new; +} + +static bool +iomap_can_add_to_ioend(struct iomap_writepage_ctx *wpc, loff_t offset, + sector_t sector) +{ + if ((wpc->iomap.flags & IOMAP_F_SHARED) != + (wpc->ioend->io_flags & IOMAP_F_SHARED)) + return false; + if (wpc->iomap.type != wpc->ioend->io_type) + return false; + if (offset != wpc->ioend->io_offset + wpc->ioend->io_size) + return false; + if (sector != bio_end_sector(wpc->ioend->io_bio)) + return false; + /* + * Limit ioend bio chain lengths to minimise IO completion latency. This + * also prevents long tight loops ending page writeback on all the + * folios in the ioend. + */ + if (wpc->ioend->io_folios >= IOEND_BATCH_SIZE) + return false; + return true; +} + +/* + * Test to see if we have an existing ioend structure that we could append to + * first; otherwise finish off the current ioend and start another. + */ +static void +iomap_add_to_ioend(struct inode *inode, loff_t pos, struct folio *folio, + struct iomap_page *iop, struct iomap_writepage_ctx *wpc, + struct writeback_control *wbc, struct list_head *iolist) +{ + sector_t sector = iomap_sector(&wpc->iomap, pos); + unsigned len = i_blocksize(inode); + size_t poff = offset_in_folio(folio, pos); + + if (!wpc->ioend || !iomap_can_add_to_ioend(wpc, pos, sector)) { + if (wpc->ioend) + list_add(&wpc->ioend->io_list, iolist); + wpc->ioend = iomap_alloc_ioend(inode, wpc, pos, sector, wbc); + } + + if (!bio_add_folio(wpc->ioend->io_bio, folio, len, poff)) { + wpc->ioend->io_bio = iomap_chain_bio(wpc->ioend->io_bio); + bio_add_folio(wpc->ioend->io_bio, folio, len, poff); + } + + if (iop) + atomic_add(len, &iop->write_bytes_pending); + wpc->ioend->io_size += len; + wbc_account_cgroup_owner(wbc, &folio->page, len); +} + +/* + * We implement an immediate ioend submission policy here to avoid needing to + * chain multiple ioends and hence nest mempool allocations which can violate + * the forward progress guarantees we need to provide. The current ioend we're + * adding blocks to is cached in the writepage context, and if the new block + * doesn't append to the cached ioend, it will create a new ioend and cache that + * instead. + * + * If a new ioend is created and cached, the old ioend is returned and queued + * locally for submission once the entire page is processed or an error has been + * detected. While ioends are submitted immediately after they are completed, + * batching optimisations are provided by higher level block plugging. + * + * At the end of a writeback pass, there will be a cached ioend remaining on the + * writepage context that the caller will need to submit. + */ +static int +iomap_writepage_map(struct iomap_writepage_ctx *wpc, + struct writeback_control *wbc, struct inode *inode, + struct folio *folio, u64 end_pos) +{ + struct iomap_page *iop = iomap_page_create(inode, folio, 0); + struct iomap_ioend *ioend, *next; + unsigned len = i_blocksize(inode); + unsigned nblocks = i_blocks_per_folio(inode, folio); + u64 pos = folio_pos(folio); + int error = 0, count = 0, i; + LIST_HEAD(submit_list); + + WARN_ON_ONCE(iop && atomic_read(&iop->write_bytes_pending) != 0); + + /* + * Walk through the folio to find areas to write back. If we + * run off the end of the current map or find the current map + * invalid, grab a new one. + */ + for (i = 0; i < nblocks && pos < end_pos; i++, pos += len) { + if (iop && !test_bit(i, iop->uptodate)) + continue; + + error = wpc->ops->map_blocks(wpc, inode, pos); + if (error) + break; + trace_iomap_writepage_map(inode, &wpc->iomap); + if (WARN_ON_ONCE(wpc->iomap.type == IOMAP_INLINE)) + continue; + if (wpc->iomap.type == IOMAP_HOLE) + continue; + iomap_add_to_ioend(inode, pos, folio, iop, wpc, wbc, + &submit_list); + count++; + } + if (count) + wpc->ioend->io_folios++; + + WARN_ON_ONCE(!wpc->ioend && !list_empty(&submit_list)); + WARN_ON_ONCE(!folio_test_locked(folio)); + WARN_ON_ONCE(folio_test_writeback(folio)); + WARN_ON_ONCE(folio_test_dirty(folio)); + + /* + * We cannot cancel the ioend directly here on error. We may have + * already set other pages under writeback and hence we have to run I/O + * completion to mark the error state of the pages under writeback + * appropriately. + */ + if (unlikely(error)) { + /* + * Let the filesystem know what portion of the current page + * failed to map. If the page hasn't been added to ioend, it + * won't be affected by I/O completion and we must unlock it + * now. + */ + if (wpc->ops->discard_folio) + wpc->ops->discard_folio(folio, pos); + if (!count) { + folio_unlock(folio); + goto done; + } + } + + folio_start_writeback(folio); + folio_unlock(folio); + + /* + * Preserve the original error if there was one; catch + * submission errors here and propagate into subsequent ioend + * submissions. + */ + list_for_each_entry_safe(ioend, next, &submit_list, io_list) { + int error2; + + list_del_init(&ioend->io_list); + error2 = iomap_submit_ioend(wpc, ioend, error); + if (error2 && !error) + error = error2; + } + + /* + * We can end up here with no error and nothing to write only if we race + * with a partial page truncate on a sub-page block sized filesystem. + */ + if (!count) + folio_end_writeback(folio); +done: + mapping_set_error(inode->i_mapping, error); + return error; +} + +/* + * Write out a dirty page. + * + * For delalloc space on the page, we need to allocate space and flush it. + * For unwritten space on the page, we need to start the conversion to + * regular allocated space. + */ +static int +iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data) +{ + struct folio *folio = page_folio(page); + struct iomap_writepage_ctx *wpc = data; + struct inode *inode = folio->mapping->host; + u64 end_pos, isize; + + trace_iomap_writepage(inode, folio_pos(folio), folio_size(folio)); + + /* + * Refuse to write the folio out if we're called from reclaim context. + * + * This avoids stack overflows when called from deeply used stacks in + * random callers for direct reclaim or memcg reclaim. We explicitly + * allow reclaim from kswapd as the stack usage there is relatively low. + * + * This should never happen except in the case of a VM regression so + * warn about it. + */ + if (WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == + PF_MEMALLOC)) + goto redirty; + + /* + * Is this folio beyond the end of the file? + * + * The folio index is less than the end_index, adjust the end_pos + * to the highest offset that this folio should represent. + * ----------------------------------------------------- + * | file mapping | | + * ----------------------------------------------------- + * | Page ... | Page N-2 | Page N-1 | Page N | | + * ^--------------------------------^----------|-------- + * | desired writeback range | see else | + * ---------------------------------^------------------| + */ + isize = i_size_read(inode); + end_pos = folio_pos(folio) + folio_size(folio); + if (end_pos > isize) { + /* + * Check whether the page to write out is beyond or straddles + * i_size or not. + * ------------------------------------------------------- + * | file mapping | | + * ------------------------------------------------------- + * | Page ... | Page N-2 | Page N-1 | Page N | Beyond | + * ^--------------------------------^-----------|--------- + * | | Straddles | + * ---------------------------------^-----------|--------| + */ + size_t poff = offset_in_folio(folio, isize); + pgoff_t end_index = isize >> PAGE_SHIFT; + + /* + * Skip the page if it's fully outside i_size, e.g. + * due to a truncate operation that's in progress. We've + * cleaned this page and truncate will finish things off for + * us. + * + * Note that the end_index is unsigned long. If the given + * offset is greater than 16TB on a 32-bit system then if we + * checked if the page is fully outside i_size with + * "if (page->index >= end_index + 1)", "end_index + 1" would + * overflow and evaluate to 0. Hence this page would be + * redirtied and written out repeatedly, which would result in + * an infinite loop; the user program performing this operation + * would hang. Instead, we can detect this situation by + * checking if the page is totally beyond i_size or if its + * offset is just equal to the EOF. + */ + if (folio->index > end_index || + (folio->index == end_index && poff == 0)) + goto unlock; + + /* + * The page straddles i_size. It must be zeroed out on each + * and every writepage invocation because it may be mmapped. + * "A file is mapped in multiples of the page size. For a file + * that is not a multiple of the page size, the remaining + * memory is zeroed when mapped, and writes to that region are + * not written out to the file." + */ + folio_zero_segment(folio, poff, folio_size(folio)); + end_pos = isize; + } + + return iomap_writepage_map(wpc, wbc, inode, folio, end_pos); + +redirty: + folio_redirty_for_writepage(wbc, folio); +unlock: + folio_unlock(folio); + return 0; +} + +int +iomap_writepages(struct address_space *mapping, struct writeback_control *wbc, + struct iomap_writepage_ctx *wpc, + const struct iomap_writeback_ops *ops) +{ + int ret; + + wpc->ops = ops; + ret = write_cache_pages(mapping, wbc, iomap_do_writepage, wpc); + if (!wpc->ioend) + return ret; + return iomap_submit_ioend(wpc, wpc->ioend, ret); +} +EXPORT_SYMBOL_GPL(iomap_writepages); + +static int __init iomap_init(void) +{ + return bioset_init(&iomap_ioend_bioset, 4 * (PAGE_SIZE / SECTOR_SIZE), + offsetof(struct iomap_ioend, io_inline_bio), + BIOSET_NEED_BVECS); +} +fs_initcall(iomap_init); diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c new file mode 100644 index 000000000..105c4a1d2 --- /dev/null +++ b/fs/iomap/direct-io.c @@ -0,0 +1,696 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2010 Red Hat, Inc. + * Copyright (c) 2016-2021 Christoph Hellwig. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "trace.h" + +#include "../internal.h" + +/* + * Private flags for iomap_dio, must not overlap with the public ones in + * iomap.h: + */ +#define IOMAP_DIO_WRITE_FUA (1 << 28) +#define IOMAP_DIO_NEED_SYNC (1 << 29) +#define IOMAP_DIO_WRITE (1 << 30) +#define IOMAP_DIO_DIRTY (1 << 31) + +struct iomap_dio { + struct kiocb *iocb; + const struct iomap_dio_ops *dops; + loff_t i_size; + loff_t size; + atomic_t ref; + unsigned flags; + int error; + size_t done_before; + bool wait_for_completion; + + union { + /* used during submission and for synchronous completion: */ + struct { + struct iov_iter *iter; + struct task_struct *waiter; + struct bio *poll_bio; + } submit; + + /* used for aio completion: */ + struct { + struct work_struct work; + } aio; + }; +}; + +static struct bio *iomap_dio_alloc_bio(const struct iomap_iter *iter, + struct iomap_dio *dio, unsigned short nr_vecs, blk_opf_t opf) +{ + if (dio->dops && dio->dops->bio_set) + return bio_alloc_bioset(iter->iomap.bdev, nr_vecs, opf, + GFP_KERNEL, dio->dops->bio_set); + return bio_alloc(iter->iomap.bdev, nr_vecs, opf, GFP_KERNEL); +} + +static void iomap_dio_submit_bio(const struct iomap_iter *iter, + struct iomap_dio *dio, struct bio *bio, loff_t pos) +{ + atomic_inc(&dio->ref); + + /* Sync dio can't be polled reliably */ + if ((dio->iocb->ki_flags & IOCB_HIPRI) && !is_sync_kiocb(dio->iocb)) { + bio_set_polled(bio, dio->iocb); + dio->submit.poll_bio = bio; + } + + if (dio->dops && dio->dops->submit_io) + dio->dops->submit_io(iter, bio, pos); + else + submit_bio(bio); +} + +ssize_t iomap_dio_complete(struct iomap_dio *dio) +{ + const struct iomap_dio_ops *dops = dio->dops; + struct kiocb *iocb = dio->iocb; + struct inode *inode = file_inode(iocb->ki_filp); + loff_t offset = iocb->ki_pos; + ssize_t ret = dio->error; + + if (dops && dops->end_io) + ret = dops->end_io(iocb, dio->size, ret, dio->flags); + + if (likely(!ret)) { + ret = dio->size; + /* check for short read */ + if (offset + ret > dio->i_size && + !(dio->flags & IOMAP_DIO_WRITE)) + ret = dio->i_size - offset; + } + + /* + * Try again to invalidate clean pages which might have been cached by + * non-direct readahead, or faulted in by get_user_pages() if the source + * of the write was an mmap'ed region of the file we're writing. Either + * one is a pretty crazy thing to do, so we don't support it 100%. If + * this invalidation fails, tough, the write still worked... + * + * And this page cache invalidation has to be after ->end_io(), as some + * filesystems convert unwritten extents to real allocations in + * ->end_io() when necessary, otherwise a racing buffer read would cache + * zeros from unwritten extents. + */ + if (!dio->error && dio->size && + (dio->flags & IOMAP_DIO_WRITE) && inode->i_mapping->nrpages) { + int err; + err = invalidate_inode_pages2_range(inode->i_mapping, + offset >> PAGE_SHIFT, + (offset + dio->size - 1) >> PAGE_SHIFT); + if (err) + dio_warn_stale_pagecache(iocb->ki_filp); + } + + inode_dio_end(file_inode(iocb->ki_filp)); + if (ret > 0) { + iocb->ki_pos += ret; + + /* + * If this is a DSYNC write, make sure we push it to stable + * storage now that we've written data. + */ + if (dio->flags & IOMAP_DIO_NEED_SYNC) + ret = generic_write_sync(iocb, ret); + if (ret > 0) + ret += dio->done_before; + } + kfree(dio); + return ret; +} +EXPORT_SYMBOL_GPL(iomap_dio_complete); + +static void iomap_dio_complete_work(struct work_struct *work) +{ + struct iomap_dio *dio = container_of(work, struct iomap_dio, aio.work); + struct kiocb *iocb = dio->iocb; + + iocb->ki_complete(iocb, iomap_dio_complete(dio)); +} + +/* + * Set an error in the dio if none is set yet. We have to use cmpxchg + * as the submission context and the completion context(s) can race to + * update the error. + */ +static inline void iomap_dio_set_error(struct iomap_dio *dio, int ret) +{ + cmpxchg(&dio->error, 0, ret); +} + +void iomap_dio_bio_end_io(struct bio *bio) +{ + struct iomap_dio *dio = bio->bi_private; + bool should_dirty = (dio->flags & IOMAP_DIO_DIRTY); + + if (bio->bi_status) + iomap_dio_set_error(dio, blk_status_to_errno(bio->bi_status)); + + if (atomic_dec_and_test(&dio->ref)) { + if (dio->wait_for_completion) { + struct task_struct *waiter = dio->submit.waiter; + WRITE_ONCE(dio->submit.waiter, NULL); + blk_wake_io_task(waiter); + } else if (dio->flags & IOMAP_DIO_WRITE) { + struct inode *inode = file_inode(dio->iocb->ki_filp); + + WRITE_ONCE(dio->iocb->private, NULL); + INIT_WORK(&dio->aio.work, iomap_dio_complete_work); + queue_work(inode->i_sb->s_dio_done_wq, &dio->aio.work); + } else { + WRITE_ONCE(dio->iocb->private, NULL); + iomap_dio_complete_work(&dio->aio.work); + } + } + + if (should_dirty) { + bio_check_pages_dirty(bio); + } else { + bio_release_pages(bio, false); + bio_put(bio); + } +} +EXPORT_SYMBOL_GPL(iomap_dio_bio_end_io); + +static void iomap_dio_zero(const struct iomap_iter *iter, struct iomap_dio *dio, + loff_t pos, unsigned len) +{ + struct inode *inode = file_inode(dio->iocb->ki_filp); + struct page *page = ZERO_PAGE(0); + struct bio *bio; + + bio = iomap_dio_alloc_bio(iter, dio, 1, REQ_OP_WRITE | REQ_SYNC | REQ_IDLE); + fscrypt_set_bio_crypt_ctx(bio, inode, pos >> inode->i_blkbits, + GFP_KERNEL); + bio->bi_iter.bi_sector = iomap_sector(&iter->iomap, pos); + bio->bi_private = dio; + bio->bi_end_io = iomap_dio_bio_end_io; + + get_page(page); + __bio_add_page(bio, page, len, 0); + iomap_dio_submit_bio(iter, dio, bio, pos); +} + +/* + * Figure out the bio's operation flags from the dio request, the + * mapping, and whether or not we want FUA. Note that we can end up + * clearing the WRITE_FUA flag in the dio request. + */ +static inline blk_opf_t iomap_dio_bio_opflags(struct iomap_dio *dio, + const struct iomap *iomap, bool use_fua) +{ + blk_opf_t opflags = REQ_SYNC | REQ_IDLE; + + if (!(dio->flags & IOMAP_DIO_WRITE)) { + WARN_ON_ONCE(iomap->flags & IOMAP_F_ZONE_APPEND); + return REQ_OP_READ; + } + + if (iomap->flags & IOMAP_F_ZONE_APPEND) + opflags |= REQ_OP_ZONE_APPEND; + else + opflags |= REQ_OP_WRITE; + + if (use_fua) + opflags |= REQ_FUA; + else + dio->flags &= ~IOMAP_DIO_WRITE_FUA; + + return opflags; +} + +static loff_t iomap_dio_bio_iter(const struct iomap_iter *iter, + struct iomap_dio *dio) +{ + const struct iomap *iomap = &iter->iomap; + struct inode *inode = iter->inode; + unsigned int blkbits = blksize_bits(bdev_logical_block_size(iomap->bdev)); + unsigned int fs_block_size = i_blocksize(inode), pad; + loff_t length = iomap_length(iter); + loff_t pos = iter->pos; + blk_opf_t bio_opf; + struct bio *bio; + bool need_zeroout = false; + bool use_fua = false; + int nr_pages, ret = 0; + size_t copied = 0; + size_t orig_count; + + if ((pos | length) & ((1 << blkbits) - 1) || + !bdev_iter_is_aligned(iomap->bdev, dio->submit.iter)) + return -EINVAL; + + if (iomap->type == IOMAP_UNWRITTEN) { + dio->flags |= IOMAP_DIO_UNWRITTEN; + need_zeroout = true; + } + + if (iomap->flags & IOMAP_F_SHARED) + dio->flags |= IOMAP_DIO_COW; + + if (iomap->flags & IOMAP_F_NEW) { + need_zeroout = true; + } else if (iomap->type == IOMAP_MAPPED) { + /* + * Use a FUA write if we need datasync semantics, this is a pure + * data IO that doesn't require any metadata updates (including + * after IO completion such as unwritten extent conversion) and + * the underlying device supports FUA. This allows us to avoid + * cache flushes on IO completion. + */ + if (!(iomap->flags & (IOMAP_F_SHARED|IOMAP_F_DIRTY)) && + (dio->flags & IOMAP_DIO_WRITE_FUA) && bdev_fua(iomap->bdev)) + use_fua = true; + } + + /* + * Save the original count and trim the iter to just the extent we + * are operating on right now. The iter will be re-expanded once + * we are done. + */ + orig_count = iov_iter_count(dio->submit.iter); + iov_iter_truncate(dio->submit.iter, length); + + if (!iov_iter_count(dio->submit.iter)) + goto out; + + /* + * We can only poll for single bio I/Os. + */ + if (need_zeroout || + ((dio->flags & IOMAP_DIO_WRITE) && pos >= i_size_read(inode))) + dio->iocb->ki_flags &= ~IOCB_HIPRI; + + if (need_zeroout) { + /* zero out from the start of the block to the write offset */ + pad = pos & (fs_block_size - 1); + if (pad) + iomap_dio_zero(iter, dio, pos - pad, pad); + } + + /* + * Set the operation flags early so that bio_iov_iter_get_pages + * can set up the page vector appropriately for a ZONE_APPEND + * operation. + */ + bio_opf = iomap_dio_bio_opflags(dio, iomap, use_fua); + + nr_pages = bio_iov_vecs_to_alloc(dio->submit.iter, BIO_MAX_VECS); + do { + size_t n; + if (dio->error) { + iov_iter_revert(dio->submit.iter, copied); + copied = ret = 0; + goto out; + } + + bio = iomap_dio_alloc_bio(iter, dio, nr_pages, bio_opf); + fscrypt_set_bio_crypt_ctx(bio, inode, pos >> inode->i_blkbits, + GFP_KERNEL); + bio->bi_iter.bi_sector = iomap_sector(iomap, pos); + bio->bi_ioprio = dio->iocb->ki_ioprio; + bio->bi_private = dio; + bio->bi_end_io = iomap_dio_bio_end_io; + + ret = bio_iov_iter_get_pages(bio, dio->submit.iter); + if (unlikely(ret)) { + /* + * We have to stop part way through an IO. We must fall + * through to the sub-block tail zeroing here, otherwise + * this short IO may expose stale data in the tail of + * the block we haven't written data to. + */ + bio_put(bio); + goto zero_tail; + } + + n = bio->bi_iter.bi_size; + if (dio->flags & IOMAP_DIO_WRITE) { + task_io_account_write(n); + } else { + if (dio->flags & IOMAP_DIO_DIRTY) + bio_set_pages_dirty(bio); + } + + dio->size += n; + copied += n; + + nr_pages = bio_iov_vecs_to_alloc(dio->submit.iter, + BIO_MAX_VECS); + /* + * We can only poll for single bio I/Os. + */ + if (nr_pages) + dio->iocb->ki_flags &= ~IOCB_HIPRI; + iomap_dio_submit_bio(iter, dio, bio, pos); + pos += n; + } while (nr_pages); + + /* + * We need to zeroout the tail of a sub-block write if the extent type + * requires zeroing or the write extends beyond EOF. If we don't zero + * the block tail in the latter case, we can expose stale data via mmap + * reads of the EOF block. + */ +zero_tail: + if (need_zeroout || + ((dio->flags & IOMAP_DIO_WRITE) && pos >= i_size_read(inode))) { + /* zero out from the end of the write to the end of the block */ + pad = pos & (fs_block_size - 1); + if (pad) + iomap_dio_zero(iter, dio, pos, fs_block_size - pad); + } +out: + /* Undo iter limitation to current extent */ + iov_iter_reexpand(dio->submit.iter, orig_count - copied); + if (copied) + return copied; + return ret; +} + +static loff_t iomap_dio_hole_iter(const struct iomap_iter *iter, + struct iomap_dio *dio) +{ + loff_t length = iov_iter_zero(iomap_length(iter), dio->submit.iter); + + dio->size += length; + if (!length) + return -EFAULT; + return length; +} + +static loff_t iomap_dio_inline_iter(const struct iomap_iter *iomi, + struct iomap_dio *dio) +{ + const struct iomap *iomap = &iomi->iomap; + struct iov_iter *iter = dio->submit.iter; + void *inline_data = iomap_inline_data(iomap, iomi->pos); + loff_t length = iomap_length(iomi); + loff_t pos = iomi->pos; + size_t copied; + + if (WARN_ON_ONCE(!iomap_inline_data_valid(iomap))) + return -EIO; + + if (dio->flags & IOMAP_DIO_WRITE) { + loff_t size = iomi->inode->i_size; + + if (pos > size) + memset(iomap_inline_data(iomap, size), 0, pos - size); + copied = copy_from_iter(inline_data, length, iter); + if (copied) { + if (pos + copied > size) + i_size_write(iomi->inode, pos + copied); + mark_inode_dirty(iomi->inode); + } + } else { + copied = copy_to_iter(inline_data, length, iter); + } + dio->size += copied; + if (!copied) + return -EFAULT; + return copied; +} + +static loff_t iomap_dio_iter(const struct iomap_iter *iter, + struct iomap_dio *dio) +{ + switch (iter->iomap.type) { + case IOMAP_HOLE: + if (WARN_ON_ONCE(dio->flags & IOMAP_DIO_WRITE)) + return -EIO; + return iomap_dio_hole_iter(iter, dio); + case IOMAP_UNWRITTEN: + if (!(dio->flags & IOMAP_DIO_WRITE)) + return iomap_dio_hole_iter(iter, dio); + return iomap_dio_bio_iter(iter, dio); + case IOMAP_MAPPED: + return iomap_dio_bio_iter(iter, dio); + case IOMAP_INLINE: + return iomap_dio_inline_iter(iter, dio); + case IOMAP_DELALLOC: + /* + * DIO is not serialised against mmap() access at all, and so + * if the page_mkwrite occurs between the writeback and the + * iomap_iter() call in the DIO path, then it will see the + * DELALLOC block that the page-mkwrite allocated. + */ + pr_warn_ratelimited("Direct I/O collision with buffered writes! File: %pD4 Comm: %.20s\n", + dio->iocb->ki_filp, current->comm); + return -EIO; + default: + WARN_ON_ONCE(1); + return -EIO; + } +} + +/* + * iomap_dio_rw() always completes O_[D]SYNC writes regardless of whether the IO + * is being issued as AIO or not. This allows us to optimise pure data writes + * to use REQ_FUA rather than requiring generic_write_sync() to issue a + * REQ_FLUSH post write. This is slightly tricky because a single request here + * can be mapped into multiple disjoint IOs and only a subset of the IOs issued + * may be pure data writes. In that case, we still need to do a full data sync + * completion. + * + * When page faults are disabled and @dio_flags includes IOMAP_DIO_PARTIAL, + * __iomap_dio_rw can return a partial result if it encounters a non-resident + * page in @iter after preparing a transfer. In that case, the non-resident + * pages can be faulted in and the request resumed with @done_before set to the + * number of bytes previously transferred. The request will then complete with + * the correct total number of bytes transferred; this is essential for + * completing partial requests asynchronously. + * + * Returns -ENOTBLK In case of a page invalidation invalidation failure for + * writes. The callers needs to fall back to buffered I/O in this case. + */ +struct iomap_dio * +__iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, + const struct iomap_ops *ops, const struct iomap_dio_ops *dops, + unsigned int dio_flags, void *private, size_t done_before) +{ + struct address_space *mapping = iocb->ki_filp->f_mapping; + struct inode *inode = file_inode(iocb->ki_filp); + struct iomap_iter iomi = { + .inode = inode, + .pos = iocb->ki_pos, + .len = iov_iter_count(iter), + .flags = IOMAP_DIRECT, + .private = private, + }; + loff_t end = iomi.pos + iomi.len - 1, ret = 0; + bool wait_for_completion = + is_sync_kiocb(iocb) || (dio_flags & IOMAP_DIO_FORCE_WAIT); + struct blk_plug plug; + struct iomap_dio *dio; + + if (!iomi.len) + return NULL; + + dio = kmalloc(sizeof(*dio), GFP_KERNEL); + if (!dio) + return ERR_PTR(-ENOMEM); + + dio->iocb = iocb; + atomic_set(&dio->ref, 1); + dio->size = 0; + dio->i_size = i_size_read(inode); + dio->dops = dops; + dio->error = 0; + dio->flags = 0; + dio->done_before = done_before; + + dio->submit.iter = iter; + dio->submit.waiter = current; + dio->submit.poll_bio = NULL; + + if (iov_iter_rw(iter) == READ) { + if (iomi.pos >= dio->i_size) + goto out_free_dio; + + if (iocb->ki_flags & IOCB_NOWAIT) { + if (filemap_range_needs_writeback(mapping, iomi.pos, + end)) { + ret = -EAGAIN; + goto out_free_dio; + } + iomi.flags |= IOMAP_NOWAIT; + } + + if (user_backed_iter(iter)) + dio->flags |= IOMAP_DIO_DIRTY; + } else { + iomi.flags |= IOMAP_WRITE; + dio->flags |= IOMAP_DIO_WRITE; + + if (iocb->ki_flags & IOCB_NOWAIT) { + if (filemap_range_has_page(mapping, iomi.pos, end)) { + ret = -EAGAIN; + goto out_free_dio; + } + iomi.flags |= IOMAP_NOWAIT; + } + + /* for data sync or sync, we need sync completion processing */ + if (iocb_is_dsync(iocb) && !(dio_flags & IOMAP_DIO_NOSYNC)) { + dio->flags |= IOMAP_DIO_NEED_SYNC; + + /* + * For datasync only writes, we optimistically try + * using FUA for this IO. Any non-FUA write that + * occurs will clear this flag, hence we know before + * completion whether a cache flush is necessary. + */ + if (!(iocb->ki_flags & IOCB_SYNC)) + dio->flags |= IOMAP_DIO_WRITE_FUA; + } + } + + if (dio_flags & IOMAP_DIO_OVERWRITE_ONLY) { + ret = -EAGAIN; + if (iomi.pos >= dio->i_size || + iomi.pos + iomi.len > dio->i_size) + goto out_free_dio; + iomi.flags |= IOMAP_OVERWRITE_ONLY; + } + + ret = filemap_write_and_wait_range(mapping, iomi.pos, end); + if (ret) + goto out_free_dio; + + if (iov_iter_rw(iter) == WRITE) { + /* + * Try to invalidate cache pages for the range we are writing. + * If this invalidation fails, let the caller fall back to + * buffered I/O. + */ + if (invalidate_inode_pages2_range(mapping, + iomi.pos >> PAGE_SHIFT, end >> PAGE_SHIFT)) { + trace_iomap_dio_invalidate_fail(inode, iomi.pos, + iomi.len); + ret = -ENOTBLK; + goto out_free_dio; + } + + if (!wait_for_completion && !inode->i_sb->s_dio_done_wq) { + ret = sb_init_dio_done_wq(inode->i_sb); + if (ret < 0) + goto out_free_dio; + } + } + + inode_dio_begin(inode); + + blk_start_plug(&plug); + while ((ret = iomap_iter(&iomi, ops)) > 0) { + iomi.processed = iomap_dio_iter(&iomi, dio); + + /* + * We can only poll for single bio I/Os. + */ + iocb->ki_flags &= ~IOCB_HIPRI; + } + + blk_finish_plug(&plug); + + /* + * We only report that we've read data up to i_size. + * Revert iter to a state corresponding to that as some callers (such + * as the splice code) rely on it. + */ + if (iov_iter_rw(iter) == READ && iomi.pos >= dio->i_size) + iov_iter_revert(iter, iomi.pos - dio->i_size); + + if (ret == -EFAULT && dio->size && (dio_flags & IOMAP_DIO_PARTIAL)) { + if (!(iocb->ki_flags & IOCB_NOWAIT)) + wait_for_completion = true; + ret = 0; + } + + /* magic error code to fall back to buffered I/O */ + if (ret == -ENOTBLK) { + wait_for_completion = true; + ret = 0; + } + if (ret < 0) + iomap_dio_set_error(dio, ret); + + /* + * If all the writes we issued were FUA, we don't need to flush the + * cache on IO completion. Clear the sync flag for this case. + */ + if (dio->flags & IOMAP_DIO_WRITE_FUA) + dio->flags &= ~IOMAP_DIO_NEED_SYNC; + + WRITE_ONCE(iocb->private, dio->submit.poll_bio); + + /* + * We are about to drop our additional submission reference, which + * might be the last reference to the dio. There are three different + * ways we can progress here: + * + * (a) If this is the last reference we will always complete and free + * the dio ourselves. + * (b) If this is not the last reference, and we serve an asynchronous + * iocb, we must never touch the dio after the decrement, the + * I/O completion handler will complete and free it. + * (c) If this is not the last reference, but we serve a synchronous + * iocb, the I/O completion handler will wake us up on the drop + * of the final reference, and we will complete and free it here + * after we got woken by the I/O completion handler. + */ + dio->wait_for_completion = wait_for_completion; + if (!atomic_dec_and_test(&dio->ref)) { + if (!wait_for_completion) + return ERR_PTR(-EIOCBQUEUED); + + for (;;) { + set_current_state(TASK_UNINTERRUPTIBLE); + if (!READ_ONCE(dio->submit.waiter)) + break; + + blk_io_schedule(); + } + __set_current_state(TASK_RUNNING); + } + + return dio; + +out_free_dio: + kfree(dio); + if (ret) + return ERR_PTR(ret); + return NULL; +} +EXPORT_SYMBOL_GPL(__iomap_dio_rw); + +ssize_t +iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, + const struct iomap_ops *ops, const struct iomap_dio_ops *dops, + unsigned int dio_flags, void *private, size_t done_before) +{ + struct iomap_dio *dio; + + dio = __iomap_dio_rw(iocb, iter, ops, dops, dio_flags, private, + done_before); + if (IS_ERR_OR_NULL(dio)) + return PTR_ERR_OR_ZERO(dio); + return iomap_dio_complete(dio); +} +EXPORT_SYMBOL_GPL(iomap_dio_rw); diff --git a/fs/iomap/fiemap.c b/fs/iomap/fiemap.c new file mode 100644 index 000000000..610ca6f1e --- /dev/null +++ b/fs/iomap/fiemap.c @@ -0,0 +1,124 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2016-2021 Christoph Hellwig. + */ +#include +#include +#include +#include +#include +#include + +static int iomap_to_fiemap(struct fiemap_extent_info *fi, + const struct iomap *iomap, u32 flags) +{ + switch (iomap->type) { + case IOMAP_HOLE: + /* skip holes */ + return 0; + case IOMAP_DELALLOC: + flags |= FIEMAP_EXTENT_DELALLOC | FIEMAP_EXTENT_UNKNOWN; + break; + case IOMAP_MAPPED: + break; + case IOMAP_UNWRITTEN: + flags |= FIEMAP_EXTENT_UNWRITTEN; + break; + case IOMAP_INLINE: + flags |= FIEMAP_EXTENT_DATA_INLINE; + break; + } + + if (iomap->flags & IOMAP_F_MERGED) + flags |= FIEMAP_EXTENT_MERGED; + if (iomap->flags & IOMAP_F_SHARED) + flags |= FIEMAP_EXTENT_SHARED; + + return fiemap_fill_next_extent(fi, iomap->offset, + iomap->addr != IOMAP_NULL_ADDR ? iomap->addr : 0, + iomap->length, flags); +} + +static loff_t iomap_fiemap_iter(const struct iomap_iter *iter, + struct fiemap_extent_info *fi, struct iomap *prev) +{ + int ret; + + if (iter->iomap.type == IOMAP_HOLE) + return iomap_length(iter); + + ret = iomap_to_fiemap(fi, prev, 0); + *prev = iter->iomap; + switch (ret) { + case 0: /* success */ + return iomap_length(iter); + case 1: /* extent array full */ + return 0; + default: /* error */ + return ret; + } +} + +int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fi, + u64 start, u64 len, const struct iomap_ops *ops) +{ + struct iomap_iter iter = { + .inode = inode, + .pos = start, + .len = len, + .flags = IOMAP_REPORT, + }; + struct iomap prev = { + .type = IOMAP_HOLE, + }; + int ret; + + ret = fiemap_prep(inode, fi, start, &iter.len, 0); + if (ret) + return ret; + + while ((ret = iomap_iter(&iter, ops)) > 0) + iter.processed = iomap_fiemap_iter(&iter, fi, &prev); + + if (prev.type != IOMAP_HOLE) { + ret = iomap_to_fiemap(fi, &prev, FIEMAP_EXTENT_LAST); + if (ret < 0) + return ret; + } + + /* inode with no (attribute) mapping will give ENOENT */ + if (ret < 0 && ret != -ENOENT) + return ret; + return 0; +} +EXPORT_SYMBOL_GPL(iomap_fiemap); + +/* legacy ->bmap interface. 0 is the error return (!) */ +sector_t +iomap_bmap(struct address_space *mapping, sector_t bno, + const struct iomap_ops *ops) +{ + struct iomap_iter iter = { + .inode = mapping->host, + .pos = (loff_t)bno << mapping->host->i_blkbits, + .len = i_blocksize(mapping->host), + .flags = IOMAP_REPORT, + }; + const unsigned int blkshift = mapping->host->i_blkbits - SECTOR_SHIFT; + int ret; + + if (filemap_write_and_wait(mapping)) + return 0; + + bno = 0; + while ((ret = iomap_iter(&iter, ops)) > 0) { + if (iter.iomap.type == IOMAP_MAPPED) + bno = iomap_sector(&iter.iomap, iter.pos) >> blkshift; + /* leave iter.processed unset to abort loop */ + } + if (ret) + return 0; + + return bno; +} +EXPORT_SYMBOL_GPL(iomap_bmap); diff --git a/fs/iomap/iter.c b/fs/iomap/iter.c new file mode 100644 index 000000000..a1c7592d2 --- /dev/null +++ b/fs/iomap/iter.c @@ -0,0 +1,80 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2010 Red Hat, Inc. + * Copyright (c) 2016-2021 Christoph Hellwig. + */ +#include +#include +#include "trace.h" + +static inline int iomap_iter_advance(struct iomap_iter *iter) +{ + /* handle the previous iteration (if any) */ + if (iter->iomap.length) { + if (iter->processed <= 0) + return iter->processed; + if (WARN_ON_ONCE(iter->processed > iomap_length(iter))) + return -EIO; + iter->pos += iter->processed; + iter->len -= iter->processed; + if (!iter->len) + return 0; + } + + /* clear the state for the next iteration */ + iter->processed = 0; + memset(&iter->iomap, 0, sizeof(iter->iomap)); + memset(&iter->srcmap, 0, sizeof(iter->srcmap)); + return 1; +} + +static inline void iomap_iter_done(struct iomap_iter *iter) +{ + WARN_ON_ONCE(iter->iomap.offset > iter->pos); + WARN_ON_ONCE(iter->iomap.length == 0); + WARN_ON_ONCE(iter->iomap.offset + iter->iomap.length <= iter->pos); + + trace_iomap_iter_dstmap(iter->inode, &iter->iomap); + if (iter->srcmap.type != IOMAP_HOLE) + trace_iomap_iter_srcmap(iter->inode, &iter->srcmap); +} + +/** + * iomap_iter - iterate over a ranges in a file + * @iter: iteration structue + * @ops: iomap ops provided by the file system + * + * Iterate over filesystem-provided space mappings for the provided file range. + * + * This function handles cleanup of resources acquired for iteration when the + * filesystem indicates there are no more space mappings, which means that this + * function must be called in a loop that continues as long it returns a + * positive value. If 0 or a negative value is returned, the caller must not + * return to the loop body. Within a loop body, there are two ways to break out + * of the loop body: leave @iter.processed unchanged, or set it to a negative + * errno. + */ +int iomap_iter(struct iomap_iter *iter, const struct iomap_ops *ops) +{ + int ret; + + if (iter->iomap.length && ops->iomap_end) { + ret = ops->iomap_end(iter->inode, iter->pos, iomap_length(iter), + iter->processed > 0 ? iter->processed : 0, + iter->flags, &iter->iomap); + if (ret < 0 && !iter->processed) + return ret; + } + + trace_iomap_iter(iter, ops, _RET_IP_); + ret = iomap_iter_advance(iter); + if (ret <= 0) + return ret; + + ret = ops->iomap_begin(iter->inode, iter->pos, iter->len, iter->flags, + &iter->iomap, &iter->srcmap); + if (ret < 0) + return ret; + iomap_iter_done(iter); + return 1; +} diff --git a/fs/iomap/seek.c b/fs/iomap/seek.c new file mode 100644 index 000000000..a845c012b --- /dev/null +++ b/fs/iomap/seek.c @@ -0,0 +1,104 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2017 Red Hat, Inc. + * Copyright (c) 2018-2021 Christoph Hellwig. + */ +#include +#include +#include +#include +#include +#include + +static loff_t iomap_seek_hole_iter(const struct iomap_iter *iter, + loff_t *hole_pos) +{ + loff_t length = iomap_length(iter); + + switch (iter->iomap.type) { + case IOMAP_UNWRITTEN: + *hole_pos = mapping_seek_hole_data(iter->inode->i_mapping, + iter->pos, iter->pos + length, SEEK_HOLE); + if (*hole_pos == iter->pos + length) + return length; + return 0; + case IOMAP_HOLE: + *hole_pos = iter->pos; + return 0; + default: + return length; + } +} + +loff_t +iomap_seek_hole(struct inode *inode, loff_t pos, const struct iomap_ops *ops) +{ + loff_t size = i_size_read(inode); + struct iomap_iter iter = { + .inode = inode, + .pos = pos, + .flags = IOMAP_REPORT, + }; + int ret; + + /* Nothing to be found before or beyond the end of the file. */ + if (pos < 0 || pos >= size) + return -ENXIO; + + iter.len = size - pos; + while ((ret = iomap_iter(&iter, ops)) > 0) + iter.processed = iomap_seek_hole_iter(&iter, &pos); + if (ret < 0) + return ret; + if (iter.len) /* found hole before EOF */ + return pos; + return size; +} +EXPORT_SYMBOL_GPL(iomap_seek_hole); + +static loff_t iomap_seek_data_iter(const struct iomap_iter *iter, + loff_t *hole_pos) +{ + loff_t length = iomap_length(iter); + + switch (iter->iomap.type) { + case IOMAP_HOLE: + return length; + case IOMAP_UNWRITTEN: + *hole_pos = mapping_seek_hole_data(iter->inode->i_mapping, + iter->pos, iter->pos + length, SEEK_DATA); + if (*hole_pos < 0) + return length; + return 0; + default: + *hole_pos = iter->pos; + return 0; + } +} + +loff_t +iomap_seek_data(struct inode *inode, loff_t pos, const struct iomap_ops *ops) +{ + loff_t size = i_size_read(inode); + struct iomap_iter iter = { + .inode = inode, + .pos = pos, + .flags = IOMAP_REPORT, + }; + int ret; + + /* Nothing to be found before or beyond the end of the file. */ + if (pos < 0 || pos >= size) + return -ENXIO; + + iter.len = size - pos; + while ((ret = iomap_iter(&iter, ops)) > 0) + iter.processed = iomap_seek_data_iter(&iter, &pos); + if (ret < 0) + return ret; + if (iter.len) /* found data before EOF */ + return pos; + /* We've reached the end of the file without finding data */ + return -ENXIO; +} +EXPORT_SYMBOL_GPL(iomap_seek_data); diff --git a/fs/iomap/swapfile.c b/fs/iomap/swapfile.c new file mode 100644 index 000000000..5fc0ac36d --- /dev/null +++ b/fs/iomap/swapfile.c @@ -0,0 +1,195 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2018 Oracle. All Rights Reserved. + * Author: Darrick J. Wong + */ +#include +#include +#include +#include +#include + +/* Swapfile activation */ + +struct iomap_swapfile_info { + struct iomap iomap; /* accumulated iomap */ + struct swap_info_struct *sis; + uint64_t lowest_ppage; /* lowest physical addr seen (pages) */ + uint64_t highest_ppage; /* highest physical addr seen (pages) */ + unsigned long nr_pages; /* number of pages collected */ + int nr_extents; /* extent count */ + struct file *file; +}; + +/* + * Collect physical extents for this swap file. Physical extents reported to + * the swap code must be trimmed to align to a page boundary. The logical + * offset within the file is irrelevant since the swapfile code maps logical + * page numbers of the swap device to the physical page-aligned extents. + */ +static int iomap_swapfile_add_extent(struct iomap_swapfile_info *isi) +{ + struct iomap *iomap = &isi->iomap; + unsigned long nr_pages; + unsigned long max_pages; + uint64_t first_ppage; + uint64_t first_ppage_reported; + uint64_t next_ppage; + int error; + + if (unlikely(isi->nr_pages >= isi->sis->max)) + return 0; + max_pages = isi->sis->max - isi->nr_pages; + + /* + * Round the start up and the end down so that the physical + * extent aligns to a page boundary. + */ + first_ppage = ALIGN(iomap->addr, PAGE_SIZE) >> PAGE_SHIFT; + next_ppage = ALIGN_DOWN(iomap->addr + iomap->length, PAGE_SIZE) >> + PAGE_SHIFT; + + /* Skip too-short physical extents. */ + if (first_ppage >= next_ppage) + return 0; + nr_pages = next_ppage - first_ppage; + nr_pages = min(nr_pages, max_pages); + + /* + * Calculate how much swap space we're adding; the first page contains + * the swap header and doesn't count. The mm still wants that first + * page fed to add_swap_extent, however. + */ + first_ppage_reported = first_ppage; + if (iomap->offset == 0) + first_ppage_reported++; + if (isi->lowest_ppage > first_ppage_reported) + isi->lowest_ppage = first_ppage_reported; + if (isi->highest_ppage < (next_ppage - 1)) + isi->highest_ppage = next_ppage - 1; + + /* Add extent, set up for the next call. */ + error = add_swap_extent(isi->sis, isi->nr_pages, nr_pages, first_ppage); + if (error < 0) + return error; + isi->nr_extents += error; + isi->nr_pages += nr_pages; + return 0; +} + +static int iomap_swapfile_fail(struct iomap_swapfile_info *isi, const char *str) +{ + char *buf, *p = ERR_PTR(-ENOMEM); + + buf = kmalloc(PATH_MAX, GFP_KERNEL); + if (buf) + p = file_path(isi->file, buf, PATH_MAX); + pr_err("swapon: file %s %s\n", IS_ERR(p) ? "" : p, str); + kfree(buf); + return -EINVAL; +} + +/* + * Accumulate iomaps for this swap file. We have to accumulate iomaps because + * swap only cares about contiguous page-aligned physical extents and makes no + * distinction between written and unwritten extents. + */ +static loff_t iomap_swapfile_iter(const struct iomap_iter *iter, + struct iomap *iomap, struct iomap_swapfile_info *isi) +{ + switch (iomap->type) { + case IOMAP_MAPPED: + case IOMAP_UNWRITTEN: + /* Only real or unwritten extents. */ + break; + case IOMAP_INLINE: + /* No inline data. */ + return iomap_swapfile_fail(isi, "is inline"); + default: + return iomap_swapfile_fail(isi, "has unallocated extents"); + } + + /* No uncommitted metadata or shared blocks. */ + if (iomap->flags & IOMAP_F_DIRTY) + return iomap_swapfile_fail(isi, "is not committed"); + if (iomap->flags & IOMAP_F_SHARED) + return iomap_swapfile_fail(isi, "has shared extents"); + + /* Only one bdev per swap file. */ + if (iomap->bdev != isi->sis->bdev) + return iomap_swapfile_fail(isi, "outside the main device"); + + if (isi->iomap.length == 0) { + /* No accumulated extent, so just store it. */ + memcpy(&isi->iomap, iomap, sizeof(isi->iomap)); + } else if (isi->iomap.addr + isi->iomap.length == iomap->addr) { + /* Append this to the accumulated extent. */ + isi->iomap.length += iomap->length; + } else { + /* Otherwise, add the retained iomap and store this one. */ + int error = iomap_swapfile_add_extent(isi); + if (error) + return error; + memcpy(&isi->iomap, iomap, sizeof(isi->iomap)); + } + return iomap_length(iter); +} + +/* + * Iterate a swap file's iomaps to construct physical extents that can be + * passed to the swapfile subsystem. + */ +int iomap_swapfile_activate(struct swap_info_struct *sis, + struct file *swap_file, sector_t *pagespan, + const struct iomap_ops *ops) +{ + struct inode *inode = swap_file->f_mapping->host; + struct iomap_iter iter = { + .inode = inode, + .pos = 0, + .len = ALIGN_DOWN(i_size_read(inode), PAGE_SIZE), + .flags = IOMAP_REPORT, + }; + struct iomap_swapfile_info isi = { + .sis = sis, + .lowest_ppage = (sector_t)-1ULL, + .file = swap_file, + }; + int ret; + + /* + * Persist all file mapping metadata so that we won't have any + * IOMAP_F_DIRTY iomaps. + */ + ret = vfs_fsync(swap_file, 1); + if (ret) + return ret; + + while ((ret = iomap_iter(&iter, ops)) > 0) + iter.processed = iomap_swapfile_iter(&iter, &iter.iomap, &isi); + if (ret < 0) + return ret; + + if (isi.iomap.length) { + ret = iomap_swapfile_add_extent(&isi); + if (ret) + return ret; + } + + /* + * If this swapfile doesn't contain even a single page-aligned + * contiguous range of blocks, reject this useless swapfile to + * prevent confusion later on. + */ + if (isi.nr_pages == 0) { + pr_warn("swapon: Cannot find a single usable page in file.\n"); + return -EINVAL; + } + + *pagespan = 1 + isi.highest_ppage - isi.lowest_ppage; + sis->max = isi.nr_pages; + sis->pages = isi.nr_pages - 1; + sis->highest_bit = isi.nr_pages - 1; + return isi.nr_extents; +} +EXPORT_SYMBOL_GPL(iomap_swapfile_activate); diff --git a/fs/iomap/trace.c b/fs/iomap/trace.c new file mode 100644 index 000000000..da217246b --- /dev/null +++ b/fs/iomap/trace.c @@ -0,0 +1,12 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2019 Christoph Hellwig + */ +#include + +/* + * We include this last to have the helpers above available for the trace + * event implementations. + */ +#define CREATE_TRACE_POINTS +#include "trace.h" diff --git a/fs/iomap/trace.h b/fs/iomap/trace.h new file mode 100644 index 000000000..f6ea9540d --- /dev/null +++ b/fs/iomap/trace.h @@ -0,0 +1,191 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (c) 2009-2021 Christoph Hellwig + * + * NOTE: none of these tracepoints shall be considered a stable kernel ABI + * as they can change at any time. + * + * Current conventions for printing numbers measuring specific units: + * + * offset: byte offset into a subcomponent of a file operation + * pos: file offset, in bytes + * length: length of a file operation, in bytes + * ino: inode number + * + * Numbers describing space allocations should be formatted in hexadecimal. + */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM iomap + +#if !defined(_IOMAP_TRACE_H) || defined(TRACE_HEADER_MULTI_READ) +#define _IOMAP_TRACE_H + +#include + +struct inode; + +DECLARE_EVENT_CLASS(iomap_readpage_class, + TP_PROTO(struct inode *inode, int nr_pages), + TP_ARGS(inode, nr_pages), + TP_STRUCT__entry( + __field(dev_t, dev) + __field(u64, ino) + __field(int, nr_pages) + ), + TP_fast_assign( + __entry->dev = inode->i_sb->s_dev; + __entry->ino = inode->i_ino; + __entry->nr_pages = nr_pages; + ), + TP_printk("dev %d:%d ino 0x%llx nr_pages %d", + MAJOR(__entry->dev), MINOR(__entry->dev), + __entry->ino, + __entry->nr_pages) +) + +#define DEFINE_READPAGE_EVENT(name) \ +DEFINE_EVENT(iomap_readpage_class, name, \ + TP_PROTO(struct inode *inode, int nr_pages), \ + TP_ARGS(inode, nr_pages)) +DEFINE_READPAGE_EVENT(iomap_readpage); +DEFINE_READPAGE_EVENT(iomap_readahead); + +DECLARE_EVENT_CLASS(iomap_range_class, + TP_PROTO(struct inode *inode, loff_t off, u64 len), + TP_ARGS(inode, off, len), + TP_STRUCT__entry( + __field(dev_t, dev) + __field(u64, ino) + __field(loff_t, size) + __field(loff_t, offset) + __field(u64, length) + ), + TP_fast_assign( + __entry->dev = inode->i_sb->s_dev; + __entry->ino = inode->i_ino; + __entry->size = i_size_read(inode); + __entry->offset = off; + __entry->length = len; + ), + TP_printk("dev %d:%d ino 0x%llx size 0x%llx offset 0x%llx length 0x%llx", + MAJOR(__entry->dev), MINOR(__entry->dev), + __entry->ino, + __entry->size, + __entry->offset, + __entry->length) +) + +#define DEFINE_RANGE_EVENT(name) \ +DEFINE_EVENT(iomap_range_class, name, \ + TP_PROTO(struct inode *inode, loff_t off, u64 len),\ + TP_ARGS(inode, off, len)) +DEFINE_RANGE_EVENT(iomap_writepage); +DEFINE_RANGE_EVENT(iomap_release_folio); +DEFINE_RANGE_EVENT(iomap_invalidate_folio); +DEFINE_RANGE_EVENT(iomap_dio_invalidate_fail); + +#define IOMAP_TYPE_STRINGS \ + { IOMAP_HOLE, "HOLE" }, \ + { IOMAP_DELALLOC, "DELALLOC" }, \ + { IOMAP_MAPPED, "MAPPED" }, \ + { IOMAP_UNWRITTEN, "UNWRITTEN" }, \ + { IOMAP_INLINE, "INLINE" } + +#define IOMAP_FLAGS_STRINGS \ + { IOMAP_WRITE, "WRITE" }, \ + { IOMAP_ZERO, "ZERO" }, \ + { IOMAP_REPORT, "REPORT" }, \ + { IOMAP_FAULT, "FAULT" }, \ + { IOMAP_DIRECT, "DIRECT" }, \ + { IOMAP_NOWAIT, "NOWAIT" } + +#define IOMAP_F_FLAGS_STRINGS \ + { IOMAP_F_NEW, "NEW" }, \ + { IOMAP_F_DIRTY, "DIRTY" }, \ + { IOMAP_F_SHARED, "SHARED" }, \ + { IOMAP_F_MERGED, "MERGED" }, \ + { IOMAP_F_BUFFER_HEAD, "BH" }, \ + { IOMAP_F_SIZE_CHANGED, "SIZE_CHANGED" } + +DECLARE_EVENT_CLASS(iomap_class, + TP_PROTO(struct inode *inode, struct iomap *iomap), + TP_ARGS(inode, iomap), + TP_STRUCT__entry( + __field(dev_t, dev) + __field(u64, ino) + __field(u64, addr) + __field(loff_t, offset) + __field(u64, length) + __field(u16, type) + __field(u16, flags) + __field(dev_t, bdev) + ), + TP_fast_assign( + __entry->dev = inode->i_sb->s_dev; + __entry->ino = inode->i_ino; + __entry->addr = iomap->addr; + __entry->offset = iomap->offset; + __entry->length = iomap->length; + __entry->type = iomap->type; + __entry->flags = iomap->flags; + __entry->bdev = iomap->bdev ? iomap->bdev->bd_dev : 0; + ), + TP_printk("dev %d:%d ino 0x%llx bdev %d:%d addr 0x%llx offset 0x%llx " + "length 0x%llx type %s flags %s", + MAJOR(__entry->dev), MINOR(__entry->dev), + __entry->ino, + MAJOR(__entry->bdev), MINOR(__entry->bdev), + __entry->addr, + __entry->offset, + __entry->length, + __print_symbolic(__entry->type, IOMAP_TYPE_STRINGS), + __print_flags(__entry->flags, "|", IOMAP_F_FLAGS_STRINGS)) +) + +#define DEFINE_IOMAP_EVENT(name) \ +DEFINE_EVENT(iomap_class, name, \ + TP_PROTO(struct inode *inode, struct iomap *iomap), \ + TP_ARGS(inode, iomap)) +DEFINE_IOMAP_EVENT(iomap_iter_dstmap); +DEFINE_IOMAP_EVENT(iomap_iter_srcmap); +DEFINE_IOMAP_EVENT(iomap_writepage_map); + +TRACE_EVENT(iomap_iter, + TP_PROTO(struct iomap_iter *iter, const void *ops, + unsigned long caller), + TP_ARGS(iter, ops, caller), + TP_STRUCT__entry( + __field(dev_t, dev) + __field(u64, ino) + __field(loff_t, pos) + __field(u64, length) + __field(unsigned int, flags) + __field(const void *, ops) + __field(unsigned long, caller) + ), + TP_fast_assign( + __entry->dev = iter->inode->i_sb->s_dev; + __entry->ino = iter->inode->i_ino; + __entry->pos = iter->pos; + __entry->length = iomap_length(iter); + __entry->flags = iter->flags; + __entry->ops = ops; + __entry->caller = caller; + ), + TP_printk("dev %d:%d ino 0x%llx pos 0x%llx length 0x%llx flags %s (0x%x) ops %ps caller %pS", + MAJOR(__entry->dev), MINOR(__entry->dev), + __entry->ino, + __entry->pos, + __entry->length, + __print_flags(__entry->flags, "|", IOMAP_FLAGS_STRINGS), + __entry->flags, + __entry->ops, + (void *)__entry->caller) +); + +#endif /* _IOMAP_TRACE_H */ + +#undef TRACE_INCLUDE_PATH +#define TRACE_INCLUDE_PATH . +#define TRACE_INCLUDE_FILE trace +#include -- cgit v1.2.3