[XFS] Don't grow filesystems past the size they can index.

When growing a filesystem we don't check to see if the new size overflows
the page cache index range, so we can do silly things like grow a
filesystem page 16TB on a 32bit. Check new filesystem sizes against the
limits the kernel can support.

SGI-PV: 957886
SGI-Modid: xfs-linux-melb:xfs-kern:28563a

Signed-Off-By: Nathan Scott <nscott@aconex.com>
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>

4 files changed, 29 insertions, 13 deletions

diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index b599e6be9ec1..25e5eae8a976 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -140,6 +140,8 @@ xfs_growfs_data_private(
         pct = in->imaxpct;
         if (nb < mp->m_sb.sb_dblocks || pct < 0 || pct > 100)
                 return XFS_ERROR(EINVAL);
+        if ((error = xfs_sb_validate_fsb_count(&mp->m_sb, nb)))
+                return error;
         dpct = pct - mp->m_sb.sb_imax_pct;
         error = xfs_read_buf(mp, mp->m_ddev_targp,
                         XFS_FSB_TO_BB(mp, nb) - XFS_FSS_TO_BB(mp, 1),
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index a96bde6df96d..5de1f392e632 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -202,6 +202,27 @@ xfs_mount_free(
         kmem_free(mp, sizeof(xfs_mount_t));
 }
 
+/*
+ * Check size of device based on the (data/realtime) block count.
+ * Note: this check is used by the growfs code as well as mount.
+ */
+int
+xfs_sb_validate_fsb_count(
+        xfs_sb_t        *sbp,
+        __uint64_t      nblocks)
+{
+        ASSERT(PAGE_SHIFT >= sbp->sb_blocklog);
+        ASSERT(sbp->sb_blocklog >= BBSHIFT);
+
+#if XFS_BIG_BLKNOS     /* Limited by ULONG_MAX of page cache index */
+        if (nblocks >> (PAGE_CACHE_SHIFT - sbp->sb_blocklog) > ULONG_MAX)
+                return E2BIG;
+#else                  /* Limited by UINT_MAX of sectors */
+        if (nblocks << (sbp->sb_blocklog - BBSHIFT) > UINT_MAX)
+                return E2BIG;
+#endif
+        return 0;
+}
 
 /*
  * Check the validity of the SB found.
@@ -284,18 +305,8 @@ xfs_mount_validate_sb(
                 return XFS_ERROR(EFSCORRUPTED);
         }
 
-        ASSERT(PAGE_SHIFT >= sbp->sb_blocklog);
-        ASSERT(sbp->sb_blocklog >= BBSHIFT);
-
-#if XFS_BIG_BLKNOS     /* Limited by ULONG_MAX of page cache index */
-        if (unlikely(
-            (sbp->sb_dblocks >> (PAGE_SHIFT - sbp->sb_blocklog)) > ULONG_MAX ||
-            (sbp->sb_rblocks >> (PAGE_SHIFT - sbp->sb_blocklog)) > ULONG_MAX)) {
-#else                  /* Limited by UINT_MAX of sectors */
-        if (unlikely(
-            (sbp->sb_dblocks << (sbp->sb_blocklog - BBSHIFT)) > UINT_MAX ||
-            (sbp->sb_rblocks << (sbp->sb_blocklog - BBSHIFT)) > UINT_MAX)) {
-#endif
+        if (xfs_sb_validate_fsb_count(sbp, sbp->sb_dblocks) ||
+            xfs_sb_validate_fsb_count(sbp, sbp->sb_rblocks)) {
                 xfs_fs_mount_cmn_err(flags,
                         "file system too large to be mounted on this system.");
                 return XFS_ERROR(E2BIG);
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 82304b94646d..871a5bfd8617 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -624,6 +624,7 @@ extern int	xfs_sync_inodes(xfs_mount_t *, int, int *);
 extern xfs_agnumber_t   xfs_initialize_perag(struct bhv_vfs *, xfs_mount_t *,
                                                 xfs_agnumber_t);
 extern void     xfs_xlatesb(void *, struct xfs_sb *, int, __int64_t);
+extern int      xfs_sb_validate_fsb_count(struct xfs_sb *, __uint64_t);
 
 extern struct xfs_dmops xfs_dmcore_stub;
 extern struct xfs_qmops xfs_qmcore_stub;
diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
index b3a5f07bd073..47082c01872d 100644
--- a/fs/xfs/xfs_rtalloc.c
+++ b/fs/xfs/xfs_rtalloc.c
@@ -1882,11 +1882,13 @@ xfs_growfs_rt(
             (nrblocks = in->newblocks) <= sbp->sb_rblocks ||
             (sbp->sb_rblocks && (in->extsize != sbp->sb_rextsize)))
                 return XFS_ERROR(EINVAL);
+        if ((error = xfs_sb_validate_fsb_count(sbp, nrblocks)))
+                return error;
         /*
          * Read in the last block of the device, make sure it exists.
          */
         error = xfs_read_buf(mp, mp->m_rtdev_targp,
-                        XFS_FSB_TO_BB(mp, in->newblocks - 1),
+                        XFS_FSB_TO_BB(mp, nrblocks - 1),
                         XFS_FSB_TO_BB(mp, 1), 0, &bp);
         if (error)
                 return error;