xfs_repair: rebuild the bmap btree for realtime files

Use the realtime rmap btree information to rebuild an inode's data fork
when appropriate.

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

diff --git a/repair/bmap_repair.c b/repair/bmap_repair.c
index 7e7c2a39f5724b6775b9032407982e8c4c38221b..5d1f639be81ff4471801579c1b8b22a86c48e4fb 100644 (file)
--- a/repair/bmap_repair.c
+++ b/repair/bmap_repair.c
@@ -209,6 +209,101 @@ xrep_bmap_scan_ag(
        return error;
 }
 
+/* Check for any obvious errors or conflicts in the file mapping. */
+STATIC int
+xrep_bmap_check_rtfork_rmap(
+       struct repair_ctx               *sc,
+       struct xfs_btree_cur            *cur,
+       const struct xfs_rmap_irec      *rec)
+{
+       /* xattr extents are never stored on realtime devices */
+       if (rec->rm_flags & XFS_RMAP_ATTR_FORK)
+               return EFSCORRUPTED;
+
+       /* bmbt blocks are never stored on realtime devices */
+       if (rec->rm_flags & XFS_RMAP_BMBT_BLOCK)
+               return EFSCORRUPTED;
+
+       /* Data extents for non-rt files are never stored on the rt device. */
+       if (!XFS_IS_REALTIME_INODE(sc->ip))
+               return EFSCORRUPTED;
+
+       /* Check the file offsets and physical extents. */
+       if (!xfs_verify_fileext(sc->mp, rec->rm_offset, rec->rm_blockcount))
+               return EFSCORRUPTED;
+
+       /* Check that this fits in the rt volume. */
+       if (!xfs_verify_rgbext(to_rtg(cur->bc_group), rec->rm_startblock,
+                               rec->rm_blockcount))
+               return EFSCORRUPTED;
+
+       return 0;
+}
+
+/* Record realtime extents that belong to this inode's fork. */
+STATIC int
+xrep_bmap_walk_rtrmap(
+       struct xfs_btree_cur            *cur,
+       const struct xfs_rmap_irec      *rec,
+       void                            *priv)
+{
+       struct xrep_bmap                *rb = priv;
+       int                             error = 0;
+
+       /* Skip extents which are not owned by this inode and fork. */
+       if (rec->rm_owner != rb->sc->ip->i_ino)
+               return 0;
+
+       error = xrep_bmap_check_rtfork_rmap(rb->sc, cur, rec);
+       if (error)
+               return error;
+
+       /*
+        * Record all blocks allocated to this file even if the extent isn't
+        * for the fork we're rebuilding so that we can reset di_nblocks later.
+        */
+       rb->nblocks += rec->rm_blockcount;
+
+       /* If this rmap isn't for the fork we want, we're done. */
+       if (rb->whichfork == XFS_DATA_FORK &&
+           (rec->rm_flags & XFS_RMAP_ATTR_FORK))
+               return 0;
+       if (rb->whichfork == XFS_ATTR_FORK &&
+           !(rec->rm_flags & XFS_RMAP_ATTR_FORK))
+               return 0;
+
+       return xrep_bmap_from_rmap(rb, rec->rm_offset, rec->rm_startblock,
+                       rec->rm_blockcount,
+                       rec->rm_flags & XFS_RMAP_UNWRITTEN);
+}
+
+/*
+ * Scan the realtime reverse mappings to build the new extent map.  The rt rmap
+ * inodes must be loaded from disk explicitly here, since we have not yet
+ * validated the metadata directory tree but do not wish to throw away user
+ * data unnecessarily.
+ */
+STATIC int
+xrep_bmap_scan_rt(
+       struct xrep_bmap        *rb,
+       struct xfs_rtgroup      *rtg)
+{
+       struct repair_ctx       *sc = rb->sc;
+       struct xfs_mount        *mp = sc->mp;
+       struct xfs_inode        *ip = rtg_rmap(rtg);
+       struct xfs_btree_cur    *cur;
+       int                     error;
+
+       /* failed to load the rtdir inode? */
+       if (!xfs_has_rtrmapbt(mp) || !ip)
+               return ENOENT;
+
+       cur = libxfs_rtrmapbt_init_cursor(sc->tp, rtg);
+       error = -libxfs_rmap_query_all(cur, xrep_bmap_walk_rtrmap, rb);
+       libxfs_btree_del_cursor(cur, error);
+       return error;
+}
+
 /*
  * Collect block mappings for this fork of this inode and decide if we have
  * enough space to rebuild.  Caller is responsible for cleaning up the list if
@@ -219,8 +314,18 @@ xrep_bmap_find_mappings(
        struct xrep_bmap        *rb)
 {
        struct xfs_perag        *pag = NULL;
+       struct xfs_rtgroup      *rtg = NULL;
        int                     error;
 
+       /* Iterate the rtrmaps for extents. */
+       while ((rtg = xfs_rtgroup_next(rb->sc->mp, rtg))) {
+               error = xrep_bmap_scan_rt(rb, rtg);
+               if (error) {
+                       libxfs_rtgroup_put(rtg);
+                       return error;
+               }
+       }
+
        /* Iterate the rmaps for extents. */
        while ((pag = xfs_perag_next(rb->sc->mp, pag))) {
                error = xrep_bmap_scan_ag(rb, pag);
@@ -570,10 +675,6 @@ xrep_bmap_check_inputs(
                return EINVAL;
        }
 
-       /* Don't know how to rebuild realtime data forks. */
-       if (XFS_IS_REALTIME_INODE(sc->ip))
-               return EOPNOTSUPP;
-
        return 0;
 }