repair: handle directory block corruption in phase 6

This should only occur in no-modify mode, but when we fail to find
the last extent in a directory btree due to corruption we need to
trash the directory if it's the first data block we find the error
on. That is because there is nothing to recover from the directory,
and if we try to scan it xfs_reapir segv's because nothing has been
read from disk.

Also catch a memory allocation failure in this code, too.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/repair/phase6.c b/repair/phase6.c
index 9b10f1669a11d16114e0f3231b4cedada73e8dd2..f13069f4cd7167aa6d9f7f5a8ca4de40415fea42 100644 (file)
--- a/repair/phase6.c
+++ b/repair/phase6.c
@@ -1529,9 +1529,8 @@ longform_dir2_entry_check_data(
 
                *freetabp = freetab = realloc(freetab, FREETAB_SIZE(db + 1));
                if (!freetab) {
-                       do_error(
-       _("realloc failed in longform_dir2_entry_check_data (%zu bytes)\n"),
-                               FREETAB_SIZE(db + 1));
+                       do_error(_("realloc failed in %s (%zu bytes)\n"),
+                               __func__, FREETAB_SIZE(db + 1));
                }
                e.v = NULLDATAOFF;
                e.s = 0;
@@ -2178,8 +2177,8 @@ longform_dir2_entry_check(xfs_mount_t     *mp,
        *need_dot = 1;
        freetab = malloc(FREETAB_SIZE(ip->i_d.di_size / mp->m_dirblksize));
        if (!freetab) {
-               do_error(
-               _("malloc failed in longform_dir2_entry_check (%" PRId64 " bytes)\n"),
+               do_error(_("malloc failed in %s (%" PRId64 " bytes)\n"),
+                       __func__,
                        FREETAB_SIZE(ip->i_d.di_size / mp->m_dirblksize));
                exit(1);
        }
@@ -2191,6 +2190,10 @@ longform_dir2_entry_check(xfs_mount_t    *mp,
        }
        num_bps = freetab->naents;
        bplist = calloc(num_bps, sizeof(struct xfs_buf*));
+       if (!bplist)
+               do_error(_("calloc failed in %s (%zu bytes)\n"),
+                       __func__, num_bps * sizeof(struct xfs_buf*));
+
        /* is this a block, leaf, or node directory? */
        libxfs_dir2_isblock(NULL, ip, &isblock);
        libxfs_dir2_isleaf(NULL, ip, &isleaf);
@@ -2203,16 +2206,26 @@ longform_dir2_entry_check(xfs_mount_t   *mp,
                int                      error;
 
                next_da_bno = da_bno + mp->m_dirblkfsbs - 1;
-               if (bmap_next_offset(NULL, ip, &next_da_bno, XFS_DATA_FORK))
+               if (bmap_next_offset(NULL, ip, &next_da_bno, XFS_DATA_FORK)) {
+                       /*
+                        * if this is the first block, there isn't anything we
+                        * can recover so we just trash it.
+                        */
+                        if (da_bno == 0) {
+                               fixit++;
+                               goto out_fix;
+                       }
                        break;
+               }
+
                db = xfs_dir2_da_to_db(mp, da_bno);
                if (db >= num_bps) {
                        /* more data blocks than expected */
                        num_bps = db + 1;
                        bplist = realloc(bplist, num_bps * sizeof(struct xfs_buf*));
                        if (!bplist)
-                               do_error(
-               _("realloc failed in longform_dir2_entry_check (%zu bytes)\n"),
+                               do_error(_("realloc failed in %s (%zu bytes)\n"),
+                                       __func__,
                                        num_bps * sizeof(struct xfs_buf*));
                }