xfs: don't allow overly small or large realtime volumes

Source kernel commit: e14293803f4e84eb23a417b462b56251033b5a66

Don't allow realtime volumes that are less than one rt extent long.
This has been broken across 4 LTS kernels with nobody noticing, so let's
just disable it.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bill O'Donnell <bodonnel@redhat.com>

diff --git a/libxfs/xfs_rtbitmap.h b/libxfs/xfs_rtbitmap.h
index 6e5bae324cc3763f55ff21569f30cade29e7da3a..1c84b52de3d42455ca2f56d7e848a14ca144073d 100644 (file)
--- a/libxfs/xfs_rtbitmap.h
+++ b/libxfs/xfs_rtbitmap.h
@@ -353,6 +353,18 @@ int xfs_rtfree_blocks(struct xfs_trans *tp, xfs_fsblock_t rtbno,
 
 uint8_t xfs_compute_rextslog(xfs_rtbxlen_t rtextents);
 
+/* Do we support an rt volume having this number of rtextents? */
+static inline bool
+xfs_validate_rtextents(
+       xfs_rtbxlen_t           rtextents)
+{
+       /* No runt rt volumes */
+       if (rtextents == 0)
+               return false;
+
+       return true;
+}
+
 xfs_filblks_t xfs_rtbitmap_blockcount(struct xfs_mount *mp, xfs_rtbxlen_t
                rtextents);
 unsigned long long xfs_rtbitmap_wordcount(struct xfs_mount *mp,
@@ -372,6 +384,7 @@ unsigned long long xfs_rtsummary_wordcount(struct xfs_mount *mp,
 # define xfs_rtbuf_cache_relse(a)                      (0)
 # define xfs_rtalloc_extent_is_free(m,t,s,l,i)         (-ENOSYS)
 # define xfs_compute_rextslog(rtx)                     (0)
+# define xfs_validate_rtextents(rtx)                   (false)
 static inline xfs_filblks_t
 xfs_rtbitmap_blockcount(struct xfs_mount *mp, xfs_rtbxlen_t rtextents)
 {

diff --git a/libxfs/xfs_sb.c b/libxfs/xfs_sb.c
index 95a29bf1ffcfc80cc1d5c45e9056a55ab33212e9..7a72d5a17910b1f0c8f1beff6d1d86a1eaae33f3 100644 (file)
--- a/libxfs/xfs_sb.c
+++ b/libxfs/xfs_sb.c
@@ -507,7 +507,8 @@ xfs_validate_sb_common(
                rbmblocks = howmany_64(sbp->sb_rextents,
                                       NBBY * sbp->sb_blocksize);
 
-               if (sbp->sb_rextents != rexts ||
+               if (!xfs_validate_rtextents(rexts) ||
+                   sbp->sb_rextents != rexts ||
                    sbp->sb_rextslog != xfs_compute_rextslog(rexts) ||
                    sbp->sb_rbmblocks != rbmblocks) {
                        xfs_notice(mp,

diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
index abea619436522bed85c3e548b3ed289c26861c3f..1a0a71dbec781524d12c252624fea93311c69213 100644 (file)
--- a/mkfs/xfs_mkfs.c
+++ b/mkfs/xfs_mkfs.c
@@ -3025,6 +3025,11 @@ reported by the device (%u).\n"),
        }
 
        cfg->rtextents = cfg->rtblocks / cfg->rtextblocks;
+       if (cfg->rtextents == 0) {
+               fprintf(stderr,
+_("cannot have an rt subvolume with zero extents\n"));
+               usage();
+       }
        cfg->rtbmblocks = (xfs_extlen_t)howmany(cfg->rtextents,
                                                NBBY * cfg->blocksize);
 }

diff --git a/repair/sb.c b/repair/sb.c
index 384840db1cec8f8869d834d345fb59946c1cd3f3..faf79d9d08350fbf57c463b4e6c042c98b0c7790 100644 (file)
--- a/repair/sb.c
+++ b/repair/sb.c
@@ -475,6 +475,9 @@ verify_sb(char *sb_buf, xfs_sb_t *sb, int is_primary_sb)
                if (sb->sb_rblocks / sb->sb_rextsize != sb->sb_rextents)
                        return(XR_BAD_RT_GEO_DATA);
 
+               if (sb->sb_rextents == 0)
+                       return XR_BAD_RT_GEO_DATA;
+
                if (sb->sb_rextslog != libxfs_compute_rextslog(sb->sb_rextents))
                        return(XR_BAD_RT_GEO_DATA);