2024-04-17 08:47:54

by David Howells

[permalink] [raw]
Subject: [PATCH] netfs: Fix writethrough-mode error handling

Fix the error return in netfs_perform_write() acting in writethrough-mode
to return any cached error in the case that netfs_end_writethrough()
returns 0.

This can affect the use of O_SYNC/O_DSYNC/RWF_SYNC/RWF_DSYNC in 9p and afs.

Fixes: 41d8e7673a77 ("netfs: Implement a write-through caching option")
Signed-off-by: David Howells <[email protected]>
Reviewed-by: Jeff Layton <[email protected]>
cc: Eric Van Hensbergen <[email protected]>
cc: Latchesar Ionkov <[email protected]>
cc: Dominique Martinet <[email protected]>
cc: Christian Schoenebeck <[email protected]>
cc: Marc Dionne <[email protected]>
cc: [email protected]
cc: [email protected]
cc: [email protected]
cc: [email protected]
---
fs/netfs/buffered_write.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c
index 9a0d32e4b422..8f13ca8fbc74 100644
--- a/fs/netfs/buffered_write.c
+++ b/fs/netfs/buffered_write.c
@@ -164,7 +164,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
enum netfs_how_to_modify howto;
enum netfs_folio_trace trace;
unsigned int bdp_flags = (iocb->ki_flags & IOCB_SYNC) ? 0: BDP_ASYNC;
- ssize_t written = 0, ret;
+ ssize_t written = 0, ret, ret2;
loff_t i_size, pos = iocb->ki_pos, from, to;
size_t max_chunk = PAGE_SIZE << MAX_PAGECACHE_ORDER;
bool maybe_trouble = false;
@@ -395,10 +395,12 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,

out:
if (unlikely(wreq)) {
- ret = netfs_end_writethrough(wreq, iocb);
+ ret2 = netfs_end_writethrough(wreq, iocb);
wbc_detach_inode(&wbc);
- if (ret == -EIOCBQUEUED)
- return ret;
+ if (ret2 == -EIOCBQUEUED)
+ return ret2;
+ if (ret == 0)
+ ret = ret2;
}

iocb->ki_pos += written;



2024-04-17 11:27:22

by Christian Brauner

[permalink] [raw]
Subject: Re: [PATCH] netfs: Fix writethrough-mode error handling

On Wed, 17 Apr 2024 09:47:19 +0100, David Howells wrote:
> Fix the error return in netfs_perform_write() acting in writethrough-mode
> to return any cached error in the case that netfs_end_writethrough()
> returns 0.
>
> This can affect the use of O_SYNC/O_DSYNC/RWF_SYNC/RWF_DSYNC in 9p and afs.
>
>
> [...]

Applied to the vfs.fixes branch of the vfs/vfs.git tree.
Patches in the vfs.fixes branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree: https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs.fixes

[1/1] netfs: Fix writethrough-mode error handling
https://git.kernel.org/vfs/vfs/c/c70fd201bd29