github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-26 08:02:27 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

netfs, afs: Fix write skipping in dir/link writepages

Browse Source 
Fix netfs_write_single() and afs_single_writepages() to better handle a
write that would be skipped due to lock contention and WB_SYNC_NONE by
returning 1 from netfs_write_single() if it skipped and making
afs_single_writepages() skip also.  If a skip occurs, the inode must be
re-marked as the VFS may have cleared the mark.

This is really only theoretical for directories in netfs_write_single() as
the only path to that is through afs_single_writepages() that takes the
->validate_lock around it, thereby serialising it.

Fixes: 6dd8093661 ("afs: Use netfslib for directories")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-24-dhowells@redhat.com
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
David Howells 2026-05-12 13:34:00 +01:00 committed by Christian Brauner
parent ded0c6f160
commit 9871938f99
No known key found for this signature in database
GPG Key ID: 91C61BC06578DCA2
2 changed files with 16 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
fs/afs/dir.c
View File

@ -2206,7 +2206,14 @@ int afs_single_writepages(struct address_space *mapping,
/* Need to lock to prevent the folio queue and folios from being thrown
* away.
*/
down_read(&dvnode->validate_lock);
if (!down_read_trylock(&dvnode->validate_lock)) {
if (wbc->sync_mode == WB_SYNC_NONE) {
/* The VFS will have undirtied the inode. */
netfs_single_mark_inode_dirty(&dvnode->netfs.inode);
return 0;
}
down_read(&dvnode->validate_lock);
}
if (is_dir ?
test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags) :
@ -2214,6 +2221,8 @@ int afs_single_writepages(struct address_space *mapping,
iov_iter_folio_queue(&iter, ITER_SOURCE, dvnode->directory, 0, 0,
i_size_read(&dvnode->netfs.inode));
ret = netfs_writeback_single(mapping, wbc, &iter);
if (ret == 1)
ret = 0; /* Skipped write due to lock conflict. */
}
up_read(&dvnode->validate_lock);

7
fs/netfs/write_issue.c
View File

@ -830,6 +830,9 @@ static int netfs_write_folio_single(struct netfs_io_request *wreq,
*
* Write a monolithic, non-pagecache object back to the server and/or
* the cache.
*
* Return: 0 if successful; 1 if skipped due to lock conflict and WB_SYNC_NONE;
* or a negative error code.
*/
int netfs_writeback_single(struct address_space *mapping,
struct writeback_control *wbc,
@ -846,8 +849,10 @@ int netfs_writeback_single(struct address_space *mapping,
if (!mutex_trylock(&ictx->wb_lock)) {
if (wbc->sync_mode == WB_SYNC_NONE) {
/* The VFS will have undirtied the inode. */
netfs_single_mark_inode_dirty(&ictx->inode);
netfs_stat(&netfs_n_wb_lock_skip);
return 0;
return 1;
}
netfs_stat(&netfs_n_wb_lock_wait);
mutex_lock(&ictx->wb_lock);