This is a note to let you know that I've just added the patch titled
xfs: return errors from partial I/O failures to files
to the 4.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xfs-return-errors-from-partial-i-o-failures-to-files.patch
and it can be found in the queue-4.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c9eb256eda4420c06bb10f5e8fbdbe1a34bc98e0 Mon Sep 17 00:00:00 2001
From: David Jeffery <djeffery@xxxxxxxxxx>
Date: Fri, 28 Aug 2015 14:50:45 +1000
Subject: xfs: return errors from partial I/O failures to files
From: David Jeffery <djeffery@xxxxxxxxxx>
commit c9eb256eda4420c06bb10f5e8fbdbe1a34bc98e0 upstream.
There is an issue with xfs's error reporting in some cases of I/O partially
failing and partially succeeding. Calls like fsync() can report success even
though not all I/O was successful in partial-failure cases such as one disk of
a RAID0 array being offline.
The issue can occur when there are more than one bio per xfs_ioend struct.
Each call to xfs_end_bio() for a bio completing will write a value to
ioend->io_error. If a successful bio completes after any failed bio, no
error is reported do to it writing 0 over the error code set by any failed bio.
The I/O error information is now lost and when the ioend is completed
only success is reported back up the filesystem stack.
xfs_end_bio() should only set ioend->io_error in the case of BIO_UPTODATE
being clear. ioend->io_error is initialized to 0 at allocation so only needs
to be updated by a failed bio. Also check that ioend->io_error is 0 so that
the first error reported will be the error code returned.
Signed-off-by: David Jeffery <djeffery@xxxxxxxxxx>
Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx>
Signed-off-by: Dave Chinner <david@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/xfs/xfs_aops.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -356,7 +356,8 @@ xfs_end_bio(
{
xfs_ioend_t *ioend = bio->bi_private;
- ioend->io_error = test_bit(BIO_UPTODATE, &bio->bi_flags) ? 0 : error;
+ if (!ioend->io_error && !test_bit(BIO_UPTODATE, &bio->bi_flags))
+ ioend->io_error = error;
/* Toss bio and pass work off to an xfsdatad thread */
bio->bi_private = NULL;
Patches currently in stable-queue which might be from djeffery@xxxxxxxxxx are
queue-4.2/xfs-return-errors-from-partial-i-o-failures-to-files.patch
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