| From | Luis Henriques <> | Subject | [PATCH 3.16.y-ckt 061/133] xfs: return errors from partial I/O failures to files | Date | Wed, 30 Sep 2015 10:50:09 +0100 |
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3.16.7-ckt18 -stable review patch. If anyone has any objections, please let me know.
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From: David Jeffery <djeffery@redhat.com>
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@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com> [ luis: backported to 3.16: adjusted context ] Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- fs/xfs/xfs_aops.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index 4ff074bc2a7d..3fc699ea7ba0 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -377,7 +377,8 @@ xfs_end_bio( xfs_ioend_t *ioend = bio->bi_private; ASSERT(atomic_read(&bio->bi_cnt) >= 1); - 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;
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