[XFS] factor out xfs_read_agf helper
Add a helper to read the AGF 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>
diff --git a/fs/xfs/xfs_alloc.c b/fs/xfs/xfs_alloc.c
index c47ce90..028e44e 100644
--- a/fs/xfs/xfs_alloc.c
+++ b/fs/xfs/xfs_alloc.c
@@ -2233,44 +2233,41 @@
* Read in the allocation group header (free/alloc section).
*/
int /* error */
-xfs_alloc_read_agf(
- xfs_mount_t *mp, /* mount point structure */
- xfs_trans_t *tp, /* transaction pointer */
- xfs_agnumber_t agno, /* allocation group number */
- int flags, /* XFS_ALLOC_FLAG_... */
- xfs_buf_t **bpp) /* buffer for the ag freelist header */
+xfs_read_agf(
+ struct xfs_mount *mp, /* mount point structure */
+ struct xfs_trans *tp, /* transaction pointer */
+ xfs_agnumber_t agno, /* allocation group number */
+ int flags, /* XFS_BUF_ */
+ struct xfs_buf **bpp) /* buffer for the ag freelist header */
{
- xfs_agf_t *agf; /* ag freelist header */
+ struct xfs_agf *agf; /* ag freelist header */
int agf_ok; /* set if agf is consistent */
- xfs_buf_t *bp; /* return value */
- xfs_perag_t *pag; /* per allocation group data */
int error;
ASSERT(agno != NULLAGNUMBER);
error = xfs_trans_read_buf(
mp, tp, mp->m_ddev_targp,
XFS_AG_DADDR(mp, agno, XFS_AGF_DADDR(mp)),
- XFS_FSS_TO_BB(mp, 1),
- (flags & XFS_ALLOC_FLAG_TRYLOCK) ? XFS_BUF_TRYLOCK : 0U,
- &bp);
+ XFS_FSS_TO_BB(mp, 1), flags, bpp);
if (error)
return error;
- ASSERT(!bp || !XFS_BUF_GETERROR(bp));
- if (!bp) {
- *bpp = NULL;
+ if (!*bpp)
return 0;
- }
+
+ ASSERT(!XFS_BUF_GETERROR(*bpp));
+ agf = XFS_BUF_TO_AGF(*bpp);
+
/*
* Validate the magic number of the agf block.
*/
- agf = XFS_BUF_TO_AGF(bp);
agf_ok =
be32_to_cpu(agf->agf_magicnum) == XFS_AGF_MAGIC &&
XFS_AGF_GOOD_VERSION(be32_to_cpu(agf->agf_versionnum)) &&
be32_to_cpu(agf->agf_freeblks) <= be32_to_cpu(agf->agf_length) &&
be32_to_cpu(agf->agf_flfirst) < XFS_AGFL_SIZE(mp) &&
be32_to_cpu(agf->agf_fllast) < XFS_AGFL_SIZE(mp) &&
- be32_to_cpu(agf->agf_flcount) <= XFS_AGFL_SIZE(mp);
+ be32_to_cpu(agf->agf_flcount) <= XFS_AGFL_SIZE(mp) &&
+ be32_to_cpu(agf->agf_seqno) == agno;
if (xfs_sb_version_haslazysbcount(&mp->m_sb))
agf_ok = agf_ok && be32_to_cpu(agf->agf_btreeblks) <=
be32_to_cpu(agf->agf_length);
@@ -2278,9 +2275,41 @@
XFS_RANDOM_ALLOC_READ_AGF))) {
XFS_CORRUPTION_ERROR("xfs_alloc_read_agf",
XFS_ERRLEVEL_LOW, mp, agf);
- xfs_trans_brelse(tp, bp);
+ xfs_trans_brelse(tp, *bpp);
return XFS_ERROR(EFSCORRUPTED);
}
+
+ XFS_BUF_SET_VTYPE_REF(*bpp, B_FS_AGF, XFS_AGF_REF);
+ return 0;
+}
+
+/*
+ * Read in the allocation group header (free/alloc section).
+ */
+int /* error */
+xfs_alloc_read_agf(
+ struct xfs_mount *mp, /* mount point structure */
+ struct xfs_trans *tp, /* transaction pointer */
+ xfs_agnumber_t agno, /* allocation group number */
+ int flags, /* XFS_ALLOC_FLAG_... */
+ struct xfs_buf **bpp) /* buffer for the ag freelist header */
+{
+ struct xfs_agf *agf; /* ag freelist header */
+ struct xfs_perag *pag; /* per allocation group data */
+ int error;
+
+ ASSERT(agno != NULLAGNUMBER);
+
+ error = xfs_read_agf(mp, tp, agno,
+ (flags & XFS_ALLOC_FLAG_TRYLOCK) ? XFS_BUF_TRYLOCK : 0,
+ bpp);
+ if (error)
+ return error;
+ if (!*bpp)
+ return 0;
+ ASSERT(!XFS_BUF_GETERROR(*bpp));
+
+ agf = XFS_BUF_TO_AGF(*bpp);
pag = &mp->m_perag[agno];
if (!pag->pagf_init) {
pag->pagf_freeblks = be32_to_cpu(agf->agf_freeblks);
@@ -2308,8 +2337,6 @@
be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNTi]));
}
#endif
- XFS_BUF_SET_VTYPE_REF(bp, B_FS_AGF, XFS_AGF_REF);
- *bpp = bp;
return 0;
}