[PATCH 04/25] xfs: uncached buffer reads need to return an error

Dave Chinner
2012-10-25T06:32:36Z

From: Dave Chinner <dchinner@redhat.com>

With verification being done as an IO completion callback, different
errors can be returned from a read. Uncached reads only return a
buffer or NULL on failure, which means the verification error cannot
be returned to the caller.

Split the error handling for these reads into two - a failure to get
a buffer will still return NULL, but a read error will return a
referenced buffer with b_error set rather than NULL. The caller is
responsible for checking the error state of the buffer returned.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/xfs/xfs_buf.c | 9 ++-------
fs/xfs/xfs_fsops.c | 5 +++++
fs/xfs/xfs_mount.c | 6 ++++++
fs/xfs/xfs_rtalloc.c | 9 ++++++++-
4 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 7cab1b3..62b7e89 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -715,8 +715,7 @@ xfs_buf_read_uncached(
int flags,
xfs_buf_iodone_t verify)
{
- xfs_buf_t *bp;
- int error;
+ struct xfs_buf *bp;

bp = xfs_buf_get_uncached(target, numblks, flags);
if (!bp)
@@ -730,11 +729,7 @@ xfs_buf_read_uncached(
bp->b_iodone = verify;

xfsbdstrat(target->bt_mount, bp);
- error = xfs_buf_iowait(bp);
- if (error) {
- xfs_buf_relse(bp);
- return NULL;
- }
+ xfs_buf_iowait(bp);
return bp;
}

diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index 917e121..dee14eb 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -149,6 +149,11 @@ xfs_growfs_data_private(
XFS_FSS_TO_BB(mp, 1), 0, NULL);
if (!bp)
return EIO;
+ if (bp->b_error) {
+ int error = bp->b_error;
+ xfs_buf_relse(bp);
+ return error;
+ }
xfs_buf_relse(bp);

new = nb; /* use new as a temporary here */
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index d39ad72..dc51e32 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -658,6 +658,12 @@ reread:
xfs_warn(mp, "SB buffer read failed");
return EIO;
}
+ if (bp->b_error) {
+ error = bp->b_error;
+ if (loud)
+ xfs_warn(mp, "SB validate failed");
+ goto release_buf;
+ }

/*
* Initialize the mount structure from the superblock.
diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
index b271ed9..98dc670 100644
--- a/fs/xfs/xfs_rtalloc.c
+++ b/fs/xfs/xfs_rtalloc.c
@@ -1876,6 +1876,11 @@ xfs_growfs_rt(
XFS_FSB_TO_BB(mp, 1), 0, NULL);
if (!bp)
return EIO;
+ if (bp->b_error) {
+ error = bp->b_error;
+ xfs_buf_relse(bp);
+ return error;
+ }
xfs_buf_relse(bp);

/*
@@ -2221,8 +2226,10 @@ xfs_rtmount_init(
bp = xfs_buf_read_uncached(mp->m_rtdev_targp,
d - XFS_FSB_TO_BB(mp, 1),
XFS_FSB_TO_BB(mp, 1), 0, NULL);
- if (!bp) {
+ if (!bp || bp->b_error) {
xfs_warn(mp, "realtime device size check failed");
+ if (bp)
+ xfs_buf_relse(bp);
return EIO;
}
xfs_buf_relse(bp);
--
1.7.10