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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /fs/9p/vfs_addr.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'fs/9p/vfs_addr.c')
-rw-r--r-- | fs/9p/vfs_addr.c | 360 |
1 files changed, 360 insertions, 0 deletions
diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c new file mode 100644 index 000000000..a19891015 --- /dev/null +++ b/fs/9p/vfs_addr.c @@ -0,0 +1,360 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * This file contians vfs address (mmap) ops for 9P2000. + * + * Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com> + * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov> + */ + +#include <linux/module.h> +#include <linux/errno.h> +#include <linux/fs.h> +#include <linux/file.h> +#include <linux/stat.h> +#include <linux/string.h> +#include <linux/inet.h> +#include <linux/pagemap.h> +#include <linux/idr.h> +#include <linux/sched.h> +#include <linux/swap.h> +#include <linux/uio.h> +#include <linux/netfs.h> +#include <net/9p/9p.h> +#include <net/9p/client.h> + +#include "v9fs.h" +#include "v9fs_vfs.h" +#include "cache.h" +#include "fid.h" + +/** + * v9fs_issue_read - Issue a read from 9P + * @subreq: The read to make + */ +static void v9fs_issue_read(struct netfs_io_subrequest *subreq) +{ + struct netfs_io_request *rreq = subreq->rreq; + struct p9_fid *fid = rreq->netfs_priv; + struct iov_iter to; + loff_t pos = subreq->start + subreq->transferred; + size_t len = subreq->len - subreq->transferred; + int total, err; + + iov_iter_xarray(&to, ITER_DEST, &rreq->mapping->i_pages, pos, len); + + total = p9_client_read(fid, pos, &to, &err); + + /* if we just extended the file size, any portion not in + * cache won't be on server and is zeroes */ + __set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags); + + netfs_subreq_terminated(subreq, err ?: total, false); +} + +/** + * v9fs_init_request - Initialise a read request + * @rreq: The read request + * @file: The file being read from + */ +static int v9fs_init_request(struct netfs_io_request *rreq, struct file *file) +{ + struct inode *inode = file_inode(file); + struct v9fs_inode *v9inode = V9FS_I(inode); + struct p9_fid *fid = file->private_data; + + BUG_ON(!fid); + + /* we might need to read from a fid that was opened write-only + * for read-modify-write of page cache, use the writeback fid + * for that */ + if (rreq->origin == NETFS_READ_FOR_WRITE && + (fid->mode & O_ACCMODE) == O_WRONLY) { + fid = v9inode->writeback_fid; + BUG_ON(!fid); + } + + p9_fid_get(fid); + rreq->netfs_priv = fid; + return 0; +} + +/** + * v9fs_free_request - Cleanup request initialized by v9fs_init_rreq + * @rreq: The I/O request to clean up + */ +static void v9fs_free_request(struct netfs_io_request *rreq) +{ + struct p9_fid *fid = rreq->netfs_priv; + + p9_fid_put(fid); +} + +/** + * v9fs_begin_cache_operation - Begin a cache operation for a read + * @rreq: The read request + */ +static int v9fs_begin_cache_operation(struct netfs_io_request *rreq) +{ +#ifdef CONFIG_9P_FSCACHE + struct fscache_cookie *cookie = v9fs_inode_cookie(V9FS_I(rreq->inode)); + + return fscache_begin_read_operation(&rreq->cache_resources, cookie); +#else + return -ENOBUFS; +#endif +} + +const struct netfs_request_ops v9fs_req_ops = { + .init_request = v9fs_init_request, + .free_request = v9fs_free_request, + .begin_cache_operation = v9fs_begin_cache_operation, + .issue_read = v9fs_issue_read, +}; + +/** + * v9fs_release_folio - release the private state associated with a folio + * @folio: The folio to be released + * @gfp: The caller's allocation restrictions + * + * Returns true if the page can be released, false otherwise. + */ + +static bool v9fs_release_folio(struct folio *folio, gfp_t gfp) +{ + struct inode *inode = folio_inode(folio); + + if (folio_test_private(folio)) + return false; +#ifdef CONFIG_9P_FSCACHE + if (folio_test_fscache(folio)) { + if (current_is_kswapd() || !(gfp & __GFP_FS)) + return false; + folio_wait_fscache(folio); + } +#endif + fscache_note_page_release(v9fs_inode_cookie(V9FS_I(inode))); + return true; +} + +static void v9fs_invalidate_folio(struct folio *folio, size_t offset, + size_t length) +{ + folio_wait_fscache(folio); +} + +static void v9fs_write_to_cache_done(void *priv, ssize_t transferred_or_error, + bool was_async) +{ + struct v9fs_inode *v9inode = priv; + __le32 version; + + if (IS_ERR_VALUE(transferred_or_error) && + transferred_or_error != -ENOBUFS) { + version = cpu_to_le32(v9inode->qid.version); + fscache_invalidate(v9fs_inode_cookie(v9inode), &version, + i_size_read(&v9inode->netfs.inode), 0); + } +} + +static int v9fs_vfs_write_folio_locked(struct folio *folio) +{ + struct inode *inode = folio_inode(folio); + struct v9fs_inode *v9inode = V9FS_I(inode); + struct fscache_cookie *cookie = v9fs_inode_cookie(v9inode); + loff_t start = folio_pos(folio); + loff_t i_size = i_size_read(inode); + struct iov_iter from; + size_t len = folio_size(folio); + int err; + + if (start >= i_size) + return 0; /* Simultaneous truncation occurred */ + + len = min_t(loff_t, i_size - start, len); + + iov_iter_xarray(&from, ITER_SOURCE, &folio_mapping(folio)->i_pages, start, len); + + /* We should have writeback_fid always set */ + BUG_ON(!v9inode->writeback_fid); + + folio_wait_fscache(folio); + folio_start_writeback(folio); + + p9_client_write(v9inode->writeback_fid, start, &from, &err); + + if (err == 0 && + fscache_cookie_enabled(cookie) && + test_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags)) { + folio_start_fscache(folio); + fscache_write_to_cache(v9fs_inode_cookie(v9inode), + folio_mapping(folio), start, len, i_size, + v9fs_write_to_cache_done, v9inode, + true); + } + + folio_end_writeback(folio); + return err; +} + +static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc) +{ + struct folio *folio = page_folio(page); + int retval; + + p9_debug(P9_DEBUG_VFS, "folio %p\n", folio); + + retval = v9fs_vfs_write_folio_locked(folio); + if (retval < 0) { + if (retval == -EAGAIN) { + folio_redirty_for_writepage(wbc, folio); + retval = 0; + } else { + mapping_set_error(folio_mapping(folio), retval); + } + } else + retval = 0; + + folio_unlock(folio); + return retval; +} + +static int v9fs_launder_folio(struct folio *folio) +{ + int retval; + + if (folio_clear_dirty_for_io(folio)) { + retval = v9fs_vfs_write_folio_locked(folio); + if (retval) + return retval; + } + folio_wait_fscache(folio); + return 0; +} + +/** + * v9fs_direct_IO - 9P address space operation for direct I/O + * @iocb: target I/O control block + * @iter: The data/buffer to use + * + * The presence of v9fs_direct_IO() in the address space ops vector + * allowes open() O_DIRECT flags which would have failed otherwise. + * + * In the non-cached mode, we shunt off direct read and write requests before + * the VFS gets them, so this method should never be called. + * + * Direct IO is not 'yet' supported in the cached mode. Hence when + * this routine is called through generic_file_aio_read(), the read/write fails + * with an error. + * + */ +static ssize_t +v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter) +{ + struct file *file = iocb->ki_filp; + loff_t pos = iocb->ki_pos; + ssize_t n; + int err = 0; + + if (iov_iter_rw(iter) == WRITE) { + n = p9_client_write(file->private_data, pos, iter, &err); + if (n) { + struct inode *inode = file_inode(file); + loff_t i_size = i_size_read(inode); + + if (pos + n > i_size) + inode_add_bytes(inode, pos + n - i_size); + } + } else { + n = p9_client_read(file->private_data, pos, iter, &err); + } + return n ? n : err; +} + +static int v9fs_write_begin(struct file *filp, struct address_space *mapping, + loff_t pos, unsigned int len, + struct page **subpagep, void **fsdata) +{ + int retval; + struct folio *folio; + struct v9fs_inode *v9inode = V9FS_I(mapping->host); + + p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping); + + BUG_ON(!v9inode->writeback_fid); + + /* Prefetch area to be written into the cache if we're caching this + * file. We need to do this before we get a lock on the page in case + * there's more than one writer competing for the same cache block. + */ + retval = netfs_write_begin(&v9inode->netfs, filp, mapping, pos, len, &folio, fsdata); + if (retval < 0) + return retval; + + *subpagep = &folio->page; + return retval; +} + +static int v9fs_write_end(struct file *filp, struct address_space *mapping, + loff_t pos, unsigned int len, unsigned int copied, + struct page *subpage, void *fsdata) +{ + loff_t last_pos = pos + copied; + struct folio *folio = page_folio(subpage); + struct inode *inode = mapping->host; + struct v9fs_inode *v9inode = V9FS_I(inode); + + p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping); + + if (!folio_test_uptodate(folio)) { + if (unlikely(copied < len)) { + copied = 0; + goto out; + } + + folio_mark_uptodate(folio); + } + + /* + * No need to use i_size_read() here, the i_size + * cannot change under us because we hold the i_mutex. + */ + if (last_pos > inode->i_size) { + inode_add_bytes(inode, last_pos - inode->i_size); + i_size_write(inode, last_pos); + fscache_update_cookie(v9fs_inode_cookie(v9inode), NULL, &last_pos); + } + folio_mark_dirty(folio); +out: + folio_unlock(folio); + folio_put(folio); + + return copied; +} + +#ifdef CONFIG_9P_FSCACHE +/* + * Mark a page as having been made dirty and thus needing writeback. We also + * need to pin the cache object to write back to. + */ +static bool v9fs_dirty_folio(struct address_space *mapping, struct folio *folio) +{ + struct v9fs_inode *v9inode = V9FS_I(mapping->host); + + return fscache_dirty_folio(mapping, folio, v9fs_inode_cookie(v9inode)); +} +#else +#define v9fs_dirty_folio filemap_dirty_folio +#endif + +const struct address_space_operations v9fs_addr_operations = { + .read_folio = netfs_read_folio, + .readahead = netfs_readahead, + .dirty_folio = v9fs_dirty_folio, + .writepage = v9fs_vfs_writepage, + .write_begin = v9fs_write_begin, + .write_end = v9fs_write_end, + .release_folio = v9fs_release_folio, + .invalidate_folio = v9fs_invalidate_folio, + .launder_folio = v9fs_launder_folio, + .direct_IO = v9fs_direct_IO, +}; |