[XFS] factor out xfs_read_agi helper

Add a helper to read the AGI header and perform basic verification.
Based on hunks from a larger patch from Dave Chinner.

(First sent on Juli 23rd)

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Niv Sardi <xaiki@sgi.com>
This commit is contained in:
Christoph Hellwig
2008-11-28 14:23:37 +11:00
committed by Niv Sardi
parent 26c5295135
commit 5e1be0fb1a
4 changed files with 98 additions and 135 deletions

View File

@@ -1462,70 +1462,95 @@ xfs_ialloc_log_agi(
xfs_trans_log_buf(tp, bp, first, last);
}
#ifdef DEBUG
STATIC void
xfs_check_agi_unlinked(
struct xfs_agi *agi)
{
int i;
for (i = 0; i < XFS_AGI_UNLINKED_BUCKETS; i++)
ASSERT(agi->agi_unlinked[i]);
}
#else
#define xfs_check_agi_unlinked(agi)
#endif
/*
* Read in the allocation group header (inode allocation section)
*/
int
xfs_ialloc_read_agi(
xfs_mount_t *mp, /* file system mount structure */
xfs_trans_t *tp, /* transaction pointer */
xfs_agnumber_t agno, /* allocation group number */
xfs_buf_t **bpp) /* allocation group hdr buf */
xfs_read_agi(
struct xfs_mount *mp, /* file system mount structure */
struct xfs_trans *tp, /* transaction pointer */
xfs_agnumber_t agno, /* allocation group number */
struct xfs_buf **bpp) /* allocation group hdr buf */
{
xfs_agi_t *agi; /* allocation group header */
int agi_ok; /* agi is consistent */
xfs_buf_t *bp; /* allocation group hdr buf */
xfs_perag_t *pag; /* per allocation group data */
int error;
struct xfs_agi *agi; /* allocation group header */
int agi_ok; /* agi is consistent */
int error;
ASSERT(agno != NULLAGNUMBER);
error = xfs_trans_read_buf(
mp, tp, mp->m_ddev_targp,
error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
XFS_AG_DADDR(mp, agno, XFS_AGI_DADDR(mp)),
XFS_FSS_TO_BB(mp, 1), 0, &bp);
XFS_FSS_TO_BB(mp, 1), 0, bpp);
if (error)
return error;
ASSERT(bp && !XFS_BUF_GETERROR(bp));
ASSERT(*bpp && !XFS_BUF_GETERROR(*bpp));
agi = XFS_BUF_TO_AGI(*bpp);
/*
* Validate the magic number of the agi block.
*/
agi = XFS_BUF_TO_AGI(bp);
agi_ok =
be32_to_cpu(agi->agi_magicnum) == XFS_AGI_MAGIC &&
XFS_AGI_GOOD_VERSION(be32_to_cpu(agi->agi_versionnum));
agi_ok = be32_to_cpu(agi->agi_magicnum) == XFS_AGI_MAGIC &&
XFS_AGI_GOOD_VERSION(be32_to_cpu(agi->agi_versionnum)) &&
be32_to_cpu(agi->agi_seqno) == agno;
if (unlikely(XFS_TEST_ERROR(!agi_ok, mp, XFS_ERRTAG_IALLOC_READ_AGI,
XFS_RANDOM_IALLOC_READ_AGI))) {
XFS_CORRUPTION_ERROR("xfs_ialloc_read_agi", XFS_ERRLEVEL_LOW,
XFS_CORRUPTION_ERROR("xfs_read_agi", XFS_ERRLEVEL_LOW,
mp, agi);
xfs_trans_brelse(tp, bp);
xfs_trans_brelse(tp, *bpp);
return XFS_ERROR(EFSCORRUPTED);
}
XFS_BUF_SET_VTYPE_REF(*bpp, B_FS_AGI, XFS_AGI_REF);
xfs_check_agi_unlinked(agi);
return 0;
}
int
xfs_ialloc_read_agi(
struct xfs_mount *mp, /* file system mount structure */
struct xfs_trans *tp, /* transaction pointer */
xfs_agnumber_t agno, /* allocation group number */
struct xfs_buf **bpp) /* allocation group hdr buf */
{
struct xfs_agi *agi; /* allocation group header */
struct xfs_perag *pag; /* per allocation group data */
int error;
error = xfs_read_agi(mp, tp, agno, bpp);
if (error)
return error;
agi = XFS_BUF_TO_AGI(*bpp);
pag = &mp->m_perag[agno];
if (!pag->pagi_init) {
pag->pagi_freecount = be32_to_cpu(agi->agi_freecount);
pag->pagi_count = be32_to_cpu(agi->agi_count);
pag->pagi_init = 1;
} else {
/*
* It's possible for these to be out of sync if
* we are in the middle of a forced shutdown.
*/
ASSERT(pag->pagi_freecount == be32_to_cpu(agi->agi_freecount) ||
XFS_FORCED_SHUTDOWN(mp));
}
#ifdef DEBUG
{
int i;
for (i = 0; i < XFS_AGI_UNLINKED_BUCKETS; i++)
ASSERT(agi->agi_unlinked[i]);
}
#endif
XFS_BUF_SET_VTYPE_REF(bp, B_FS_AGI, XFS_AGI_REF);
*bpp = bp;
/*
* It's possible for these to be out of sync if
* we are in the middle of a forced shutdown.
*/
ASSERT(pag->pagi_freecount == be32_to_cpu(agi->agi_freecount) ||
XFS_FORCED_SHUTDOWN(mp));
return 0;
}