1 files changed, 35 insertions, 21 deletions

diff --git a/fs/xfs/xfs_ialloc.c b/fs/xfs/xfs_ialloc.c
index 12e3dead439d..5bd255e5f7b8 100644
--- a/fs/xfs/xfs_ialloc.c
+++ b/fs/xfs/xfs_ialloc.c
@@ -1472,6 +1472,40 @@ xfs_check_agi_unlinked(
 #define xfs_check_agi_unlinked(agi)
 #endif
 
+static void
+xfs_agi_read_verify(
+        struct xfs_buf  *bp)
+{
+        struct xfs_mount *mp = bp->b_target->bt_mount;
+        struct xfs_agi  *agi = XFS_BUF_TO_AGI(bp);
+        int             agi_ok;
+
+        /*
+         * Validate the magic number of the agi block.
+         */
+        agi_ok = agi->agi_magicnum == cpu_to_be32(XFS_AGI_MAGIC) &&
+                XFS_AGI_GOOD_VERSION(be32_to_cpu(agi->agi_versionnum));
+
+        /*
+         * during growfs operations, the perag is not fully initialised,
+         * so we can't use it for any useful checking. growfs ensures we can't
+         * use it by using uncached buffers that don't have the perag attached
+         * so we can detect and avoid this problem.
+         */
+        if (bp->b_pag)
+                agi_ok = agi_ok && be32_to_cpu(agi->agi_seqno) ==
+                                                bp->b_pag->pag_agno;
+
+        if (unlikely(XFS_TEST_ERROR(!agi_ok, mp, XFS_ERRTAG_IALLOC_READ_AGI,
+                        XFS_RANDOM_IALLOC_READ_AGI))) {
+                XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, agi);
+                xfs_buf_ioerror(bp, EFSCORRUPTED);
+        }
+        xfs_check_agi_unlinked(agi);
+        bp->b_iodone = NULL;
+        xfs_buf_ioend(bp, 0);
+}
+
 /*
  * Read in the allocation group header (inode allocation section)
  */
@@ -1482,38 +1516,18 @@ xfs_read_agi(
         xfs_agnumber_t          agno,   /* allocation group number */
         struct xfs_buf          **bpp)  /* allocation group hdr buf */
 {
-        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,
                         XFS_AG_DADDR(mp, agno, XFS_AGI_DADDR(mp)),
-                        XFS_FSS_TO_BB(mp, 1), 0, bpp, NULL);
+                        XFS_FSS_TO_BB(mp, 1), 0, bpp, xfs_agi_read_verify);
         if (error)
                 return error;
 
         ASSERT(!xfs_buf_geterror(*bpp));
-        agi = XFS_BUF_TO_AGI(*bpp);
-
-        /*
-         * Validate the magic number of the agi block.
-         */
-        agi_ok = agi->agi_magicnum == cpu_to_be32(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_read_agi", XFS_ERRLEVEL_LOW,
-                                     mp, agi);
-                xfs_trans_brelse(tp, *bpp);
-                return XFS_ERROR(EFSCORRUPTED);
-        }
-
         xfs_buf_set_ref(*bpp, XFS_AGI_REF);
-
-        xfs_check_agi_unlinked(agi);
         return 0;
 }