[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>

1 files changed, 23 insertions, 12 deletions

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);