[GFS2] Fix bmap to map extents properly

This fix means that bmap will map extents of the length requested
by the VFS rather than guessing at it, or just mapping one block
at a time. The other callers of gfs2_block_map are audited to ensure
they send the correct max extent lengths (i.e. set bh->b_size correctly).

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 7 insertions, 6 deletions

diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index cc57f2ecd219..06e9a8cb45e9 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -434,8 +434,7 @@ static int lookup_block(struct gfs2_inode *ip, struct buffer_head *bh,
  */
 
 static int gfs2_block_pointers(struct inode *inode, u64 lblock, int create,
-                               struct buffer_head *bh_map, struct metapath *mp,
-                               unsigned int maxlen)
+                               struct buffer_head *bh_map, struct metapath *mp)
 {
         struct gfs2_inode *ip = GFS2_I(inode);
         struct gfs2_sbd *sdp = GFS2_SB(inode);
@@ -448,6 +447,7 @@ static int gfs2_block_pointers(struct inode *inode, u64 lblock, int create,
         int new = 0;
         u64 dblock = 0;
         int boundary;
+        unsigned int maxlen = bh_map->b_size >> inode->i_blkbits;
 
         BUG_ON(maxlen == 0);
 
@@ -541,13 +541,13 @@ static inline void bmap_unlock(struct inode *inode, int create)
 }
 
 int gfs2_block_map(struct inode *inode, u64 lblock, int create,
-                   struct buffer_head *bh, unsigned int maxlen)
+                   struct buffer_head *bh)
 {
         struct metapath mp;
         int ret;
 
         bmap_lock(inode, create);
-        ret = gfs2_block_pointers(inode, lblock, create, bh, &mp, maxlen);
+        ret = gfs2_block_pointers(inode, lblock, create, bh, &mp);
         bmap_unlock(inode, create);
         return ret;
 }
@@ -555,7 +555,7 @@ int gfs2_block_map(struct inode *inode, u64 lblock, int create,
 int gfs2_extent_map(struct inode *inode, u64 lblock, int *new, u64 *dblock, unsigned *extlen)
 {
         struct metapath mp;
-        struct buffer_head bh = { .b_state = 0, .b_blocknr = 0, .b_size = 0 };
+        struct buffer_head bh = { .b_state = 0, .b_blocknr = 0 };
         int ret;
         int create = *new;
 
@@ -563,8 +563,9 @@ int gfs2_extent_map(struct inode *inode, u64 lblock, int *new, u64 *dblock, unsi
         BUG_ON(!dblock);
         BUG_ON(!new);
 
+        bh.b_size = 1 << (inode->i_blkbits + 5);
         bmap_lock(inode, create);
-        ret = gfs2_block_pointers(inode, lblock, create, &bh, &mp, 32);
+        ret = gfs2_block_pointers(inode, lblock, create, &bh, &mp);
         bmap_unlock(inode, create);
         *extlen = bh.b_size >> inode->i_blkbits;
         *dblock = bh.b_blocknr;