xfs: factor out a xfs_rt_check_size helper

Add a helper to check that the last block of a RT device is readable
to share the code between mount and growfs.  This also adds the mount
time overflow check to growfs and improves the error messages.

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

diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
index 15cc9c88a9f8a825f314d36e312524b4700b75f5..98717117bbaa8f8685b61f7890ea9ecdc3b6fb0d 100644 (file)
--- a/fs/xfs/xfs_rtalloc.c
+++ b/fs/xfs/xfs_rtalloc.c
@@ -1248,6 +1248,34 @@ xfs_grow_last_rtg(
                        mp->m_sb.sb_rgextents;
 }
 
+/*
+ * Read in the last block of the RT device to make sure it is accessible.
+ */
+static int
+xfs_rt_check_size(
+       struct xfs_mount        *mp,
+       xfs_rfsblock_t          last_block)
+{
+       xfs_daddr_t             daddr = XFS_FSB_TO_BB(mp, last_block);
+       struct xfs_buf          *bp;
+       int                     error;
+
+       if (XFS_BB_TO_FSB(mp, daddr) != last_block) {
+               xfs_warn(mp, "RT device size overflow: %llu != %llu",
+                       XFS_BB_TO_FSB(mp, daddr), last_block);
+               return -EFBIG;
+       }
+
+       error = xfs_buf_read_uncached(mp->m_rtdev_targp, daddr,
+                       XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
+       if (error)
+               xfs_warn(mp, "cannot read last RT device sector (%lld)",
+                               last_block);
+       else
+               xfs_buf_relse(bp);
+       return error;
+}
+
 /*
  * Grow the realtime area of the filesystem.
  */
@@ -1259,7 +1287,6 @@ xfs_growfs_rt(
        xfs_rgnumber_t          old_rgcount = mp->m_sb.sb_rgcount;
        xfs_rgnumber_t          new_rgcount = 1;
        xfs_rgnumber_t          rgno;
-       struct xfs_buf          *bp;
        xfs_agblock_t           old_rextsize = mp->m_sb.sb_rextsize;
        int                     error;
 
@@ -1302,15 +1329,10 @@ xfs_growfs_rt(
        error = xfs_sb_validate_fsb_count(&mp->m_sb, in->newblocks);
        if (error)
                goto out_unlock;
-       /*
-        * Read in the last block of the device, make sure it exists.
-        */
-       error = xfs_buf_read_uncached(mp->m_rtdev_targp,
-                               XFS_FSB_TO_BB(mp, in->newblocks - 1),
-                               XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
+
+       error = xfs_rt_check_size(mp, in->newblocks - 1);
        if (error)
                goto out_unlock;
-       xfs_buf_relse(bp);
 
        /*
         * Calculate new parameters.  These are the final values to be reached.
@@ -1443,10 +1465,6 @@ int                              /* error */
 xfs_rtmount_init(
        struct xfs_mount        *mp)    /* file system mount structure */
 {
-       struct xfs_buf          *bp;    /* buffer for last block of subvolume */
-       xfs_daddr_t             d;      /* address of last block of subvolume */
-       int                     error;
-
        if (mp->m_sb.sb_rblocks == 0)
                return 0;
        if (mp->m_rtdev_targp == NULL) {
@@ -1457,25 +1475,7 @@ xfs_rtmount_init(
 
        mp->m_rsumblocks = xfs_rtsummary_blockcount(mp, &mp->m_rsumlevels);
 
-       /*
-        * Check that the realtime section is an ok size.
-        */
-       d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_rblocks);
-       if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_rblocks) {
-               xfs_warn(mp, "realtime mount -- %llu != %llu",
-                       (unsigned long long) XFS_BB_TO_FSB(mp, d),
-                       (unsigned long long) mp->m_sb.sb_rblocks);
-               return -EFBIG;
-       }
-       error = xfs_buf_read_uncached(mp->m_rtdev_targp,
-                                       d - XFS_FSB_TO_BB(mp, 1),
-                                       XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
-       if (error) {
-               xfs_warn(mp, "realtime device size check failed");
-               return error;
-       }
-       xfs_buf_relse(bp);
-       return 0;
+       return xfs_rt_check_size(mp, mp->m_sb.sb_rblocks - 1);
 }
 
 static int