[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>
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Niv Sardi

parent
26c5295135
commit
5e1be0fb1a
@@ -1462,70 +1462,95 @@ xfs_ialloc_log_agi(
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xfs_trans_log_buf(tp, bp, first, last);
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}
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#ifdef DEBUG
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STATIC void
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xfs_check_agi_unlinked(
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struct xfs_agi *agi)
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{
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int i;
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for (i = 0; i < XFS_AGI_UNLINKED_BUCKETS; i++)
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ASSERT(agi->agi_unlinked[i]);
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}
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#else
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#define xfs_check_agi_unlinked(agi)
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#endif
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/*
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* Read in the allocation group header (inode allocation section)
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*/
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int
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xfs_ialloc_read_agi(
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xfs_mount_t *mp, /* file system mount structure */
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xfs_trans_t *tp, /* transaction pointer */
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xfs_agnumber_t agno, /* allocation group number */
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xfs_buf_t **bpp) /* allocation group hdr buf */
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xfs_read_agi(
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struct xfs_mount *mp, /* file system mount structure */
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struct xfs_trans *tp, /* transaction pointer */
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xfs_agnumber_t agno, /* allocation group number */
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struct xfs_buf **bpp) /* allocation group hdr buf */
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{
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xfs_agi_t *agi; /* allocation group header */
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int agi_ok; /* agi is consistent */
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xfs_buf_t *bp; /* allocation group hdr buf */
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xfs_perag_t *pag; /* per allocation group data */
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int error;
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struct xfs_agi *agi; /* allocation group header */
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int agi_ok; /* agi is consistent */
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int error;
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ASSERT(agno != NULLAGNUMBER);
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error = xfs_trans_read_buf(
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mp, tp, mp->m_ddev_targp,
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error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
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XFS_AG_DADDR(mp, agno, XFS_AGI_DADDR(mp)),
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XFS_FSS_TO_BB(mp, 1), 0, &bp);
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XFS_FSS_TO_BB(mp, 1), 0, bpp);
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if (error)
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return error;
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ASSERT(bp && !XFS_BUF_GETERROR(bp));
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ASSERT(*bpp && !XFS_BUF_GETERROR(*bpp));
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agi = XFS_BUF_TO_AGI(*bpp);
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/*
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* Validate the magic number of the agi block.
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*/
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agi = XFS_BUF_TO_AGI(bp);
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agi_ok =
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be32_to_cpu(agi->agi_magicnum) == XFS_AGI_MAGIC &&
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XFS_AGI_GOOD_VERSION(be32_to_cpu(agi->agi_versionnum));
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agi_ok = be32_to_cpu(agi->agi_magicnum) == XFS_AGI_MAGIC &&
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XFS_AGI_GOOD_VERSION(be32_to_cpu(agi->agi_versionnum)) &&
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be32_to_cpu(agi->agi_seqno) == agno;
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if (unlikely(XFS_TEST_ERROR(!agi_ok, mp, XFS_ERRTAG_IALLOC_READ_AGI,
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XFS_RANDOM_IALLOC_READ_AGI))) {
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XFS_CORRUPTION_ERROR("xfs_ialloc_read_agi", XFS_ERRLEVEL_LOW,
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XFS_CORRUPTION_ERROR("xfs_read_agi", XFS_ERRLEVEL_LOW,
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mp, agi);
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xfs_trans_brelse(tp, bp);
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xfs_trans_brelse(tp, *bpp);
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return XFS_ERROR(EFSCORRUPTED);
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}
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XFS_BUF_SET_VTYPE_REF(*bpp, B_FS_AGI, XFS_AGI_REF);
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xfs_check_agi_unlinked(agi);
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return 0;
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}
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int
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xfs_ialloc_read_agi(
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struct xfs_mount *mp, /* file system mount structure */
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struct xfs_trans *tp, /* transaction pointer */
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xfs_agnumber_t agno, /* allocation group number */
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struct xfs_buf **bpp) /* allocation group hdr buf */
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{
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struct xfs_agi *agi; /* allocation group header */
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struct xfs_perag *pag; /* per allocation group data */
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int error;
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error = xfs_read_agi(mp, tp, agno, bpp);
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if (error)
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return error;
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agi = XFS_BUF_TO_AGI(*bpp);
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pag = &mp->m_perag[agno];
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if (!pag->pagi_init) {
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pag->pagi_freecount = be32_to_cpu(agi->agi_freecount);
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pag->pagi_count = be32_to_cpu(agi->agi_count);
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pag->pagi_init = 1;
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} else {
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/*
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* It's possible for these to be out of sync if
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* we are in the middle of a forced shutdown.
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*/
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ASSERT(pag->pagi_freecount == be32_to_cpu(agi->agi_freecount) ||
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XFS_FORCED_SHUTDOWN(mp));
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}
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#ifdef DEBUG
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{
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int i;
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for (i = 0; i < XFS_AGI_UNLINKED_BUCKETS; i++)
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ASSERT(agi->agi_unlinked[i]);
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}
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#endif
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XFS_BUF_SET_VTYPE_REF(bp, B_FS_AGI, XFS_AGI_REF);
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*bpp = bp;
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/*
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* It's possible for these to be out of sync if
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* we are in the middle of a forced shutdown.
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*/
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ASSERT(pag->pagi_freecount == be32_to_cpu(agi->agi_freecount) ||
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XFS_FORCED_SHUTDOWN(mp));
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return 0;
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}
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