Commit 96f859d5 authored by Darrick J. Wong's avatar Darrick J. Wong Committed by Dave Chinner

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: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
parent 6d3eb1ec
...@@ -786,7 +786,7 @@ typedef struct xfs_agfl { ...@@ -786,7 +786,7 @@ typedef struct xfs_agfl {
__be64 agfl_lsn; __be64 agfl_lsn;
__be32 agfl_crc; __be32 agfl_crc;
__be32 agfl_bno[]; /* actually XFS_AGFL_SIZE(mp) */ __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) #define XFS_AGFL_CRC_OFF offsetof(struct xfs_agfl, agfl_crc)
......
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