[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>

1 files changed, 11 insertions, 15 deletions

diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index b552676ca5c4..d94987915d5e 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -3970,7 +3970,6 @@ xlog_recover_check_summary(
         xfs_agf_t       *agfp;
         xfs_buf_t       *agfbp;
         xfs_buf_t       *agibp;
-        xfs_daddr_t     agfdaddr;
         xfs_buf_t       *sbbp;
 #ifdef XFS_LOUD_RECOVERY
         xfs_sb_t        *sbp;
@@ -3987,21 +3986,18 @@ xlog_recover_check_summary(
         itotal = 0LL;
         ifree = 0LL;
         for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
-                agfdaddr = XFS_AG_DADDR(mp, agno, XFS_AGF_DADDR(mp));
-                agfbp = xfs_buf_read(mp->m_ddev_targp, agfdaddr,
-                                XFS_FSS_TO_BB(mp, 1), 0);
-                if (XFS_BUF_ISERROR(agfbp)) {
-                        xfs_ioerror_alert("xlog_recover_check_summary(agf)",
-                                                mp, agfbp, agfdaddr);
+                error = xfs_read_agf(mp, NULL, agno, 0, &agfbp);
+                if (error) {
+                        xfs_fs_cmn_err(CE_ALERT, mp,
+                                        "xlog_recover_check_summary(agf)"
+                                        "agf read failed agno %d error %d",
+                                                        agno, error);
+                } else {
+                        agfp = XFS_BUF_TO_AGF(agfbp);
+                        freeblks += be32_to_cpu(agfp->agf_freeblks) +
+                                    be32_to_cpu(agfp->agf_flcount);
+                        xfs_buf_relse(agfbp);
                 }
-                agfp = XFS_BUF_TO_AGF(agfbp);
-                ASSERT(XFS_AGF_MAGIC == be32_to_cpu(agfp->agf_magicnum));
-                ASSERT(XFS_AGF_GOOD_VERSION(be32_to_cpu(agfp->agf_versionnum)));
-                ASSERT(be32_to_cpu(agfp->agf_seqno) == agno);
-
-                freeblks += be32_to_cpu(agfp->agf_freeblks) +
-                            be32_to_cpu(agfp->agf_flcount);
-                xfs_buf_relse(agfbp);
 
                 error = xfs_read_agi(mp, NULL, agno, &agibp);
                 if (!error) {