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authorDarrick J. Wong <darrick.wong@oracle.com>2016-01-04 16:13:21 +1100
committerDave Chinner <david@fromorbit.com>2016-01-04 16:13:21 +1100
commit96f859d52bcb1c6ea6f3388d39862bf7143e2f30 (patch)
tree0f70d2c8cd62cd3a2d947a4ee002aa4cac9414fe
parent6d3eb1eca0e35cc1c0c80eacb7e7fe23c0dbfb07 (diff)
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libxfs: pack the agfl header structure so XFS_AGFL_SIZE is correct
Because struct xfs_agfl is 36 bytes long and has a 64-bit integer inside it, gcc will quietly round the structure size up to the nearest 64 bits -- in this case, 40 bytes. This results in the XFS_AGFL_SIZE macro returning incorrect results for v5 filesystems on 64-bit machines (118 items instead of 119). As a result, a 32-bit xfs_repair will see garbage in AGFL item 119 and complain. Therefore, tell gcc not to pad the structure so that the AGFL size calculation is correct. cc: <stable@vger.kernel.org> # 3.10 - 4.4 Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
-rw-r--r--fs/xfs/libxfs/xfs_format.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index 8774498ce0ff..e2536bb1c760 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -786,7 +786,7 @@ typedef struct xfs_agfl {
__be64 agfl_lsn;
__be32 agfl_crc;
__be32 agfl_bno[]; /* actually XFS_AGFL_SIZE(mp) */
-} xfs_agfl_t;
+} __attribute__((packed)) xfs_agfl_t;
#define XFS_AGFL_CRC_OFF offsetof(struct xfs_agfl, agfl_crc)