[PATCH 9/9] xfs: check xfs_buf_read_uncached returns correctly

Dave Chinner
2014-08-15T06:39:18Z

From: Dave Chinner <dchinner@redhat.com>

xfs_buf_read_uncached() has two failure modes. If can either return
NULL or bp->b_error != 0 depending on the type of failure, and not
all callers check for both. Fix it up.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/xfs/xfs_mount.c | 55 ++++++++++++++++++++++++++++++------------------------
1 file changed, 31 insertions(+), 24 deletions(-)

diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index d0ef01e..10a365a 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -304,13 +304,8 @@ xfs_readsb(
reread:
bp = xfs_buf_read_uncached(mp->m_ddev_targp, XFS_SB_DADDR,
BTOBB(sector_size), 0, buf_ops);
- if (!bp) {
- if (loud)
- xfs_warn(mp, "SB buffer read failed");
- return -EIO;
- }
- if (bp->b_error) {
- error = bp->b_error;
+ if (!bp || bp->b_error) {
+ error = bp ? bp->b_error : -ENOMEM;
if (loud)
xfs_warn(mp, "SB validate failed with error %d.", error);
/* bad CRC means corrupted metadata */
@@ -368,7 +363,8 @@ reread:
return 0;

release_buf:
- xfs_buf_relse(bp);
+ if (bp)
+ xfs_buf_relse(bp);
return error;
}

@@ -546,10 +542,12 @@ xfs_set_inoalignment(xfs_mount_t *mp)
* Check that the data (and log if separate) is an ok size.
*/
STATIC int
-xfs_check_sizes(xfs_mount_t *mp)
+xfs_check_sizes(
+ struct xfs_mount *mp)
{
- xfs_buf_t *bp;
+ struct xfs_buf *bp;
xfs_daddr_t d;
+ int error;

d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_dblocks) {
@@ -559,28 +557,37 @@ xfs_check_sizes(xfs_mount_t *mp)
bp = xfs_buf_read_uncached(mp->m_ddev_targp,
d - XFS_FSS_TO_BB(mp, 1),
XFS_FSS_TO_BB(mp, 1), 0, NULL);
- if (!bp) {
+ if (!bp || bp->b_error) {
xfs_warn(mp, "last sector read failed");
- return -EIO;
+ goto out_fail;
}
xfs_buf_relse(bp);

- if (mp->m_logdev_targp != mp->m_ddev_targp) {
- d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
- if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_logblocks) {
- xfs_warn(mp, "log size mismatch detected");
- return -EFBIG;
- }
- bp = xfs_buf_read_uncached(mp->m_logdev_targp,
+ if (mp->m_logdev_targp == mp->m_ddev_targp)
+ return 0;
+
+ d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
+ if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_logblocks) {
+ xfs_warn(mp, "log size mismatch detected");
+ return -EFBIG;
+ }
+ bp = xfs_buf_read_uncached(mp->m_logdev_targp,
d - XFS_FSB_TO_BB(mp, 1),
XFS_FSB_TO_BB(mp, 1), 0, NULL);
- if (!bp) {
- xfs_warn(mp, "log device read failed");
- return -EIO;
- }
- xfs_buf_relse(bp);
+ if (!bp || bp->b_error) {
+ xfs_warn(mp, "log device read failed");
+ goto out_fail;
}
+ xfs_buf_relse(bp);
return 0;
+
+out_fail:
+ if (!bp)
+ return -EIO;
+ error = bp->b_error;
+ xfs_buf_relse(bp);
+ return error;
+
}

/*
--
2.0.0