[GFS2] Speed up gfs2_write_alloc_required, deprecate gfs2_extent_map

This patch removes the call to gfs2_extent_map from gfs2_write_alloc_required,
instead we call gfs2_block_map directly. This results in fewer overall calls
to gfs2_block_map in the multi-block case.

Also, gfs2_extent_map is marked as deprecated so that people know that its
going away as soon as all the callers have been converted.

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

1 files changed, 19 insertions, 17 deletions

diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index e9456ebd3bb6..a25444ac648b 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -548,6 +548,9 @@ out_fail:
         return error;
 }
 
+/*
+ * Deprecated: do not use in new code
+ */
 int gfs2_extent_map(struct inode *inode, u64 lblock, int *new, u64 *dblock, unsigned *extlen)
 {
         struct buffer_head bh = { .b_state = 0, .b_blocknr = 0 };
@@ -1197,10 +1200,9 @@ int gfs2_write_alloc_required(struct gfs2_inode *ip, u64 offset,
                               unsigned int len, int *alloc_required)
 {
         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
-        u64 lblock, lblock_stop, dblock;
-        u32 extlen;
-        int new = 0;
-        int error = 0;
+        struct buffer_head bh;
+        unsigned int shift;
+        u64 lblock, lblock_stop, size;
 
         *alloc_required = 0;
 
@@ -1214,6 +1216,8 @@ int gfs2_write_alloc_required(struct gfs2_inode *ip, u64 offset,
                 return 0;
         }
 
+        *alloc_required = 1;
+        shift = sdp->sd_sb.sb_bsize_shift;
         if (gfs2_is_dir(ip)) {
                 unsigned int bsize = sdp->sd_jbsize;
                 lblock = offset;
@@ -1221,27 +1225,25 @@ int gfs2_write_alloc_required(struct gfs2_inode *ip, u64 offset,
                 lblock_stop = offset + len + bsize - 1;
                 do_div(lblock_stop, bsize);
         } else {
-                unsigned int shift = sdp->sd_sb.sb_bsize_shift;
                 u64 end_of_file = (ip->i_di.di_size + sdp->sd_sb.sb_bsize - 1) >> shift;
                 lblock = offset >> shift;
                 lblock_stop = (offset + len + sdp->sd_sb.sb_bsize - 1) >> shift;
-                if (lblock_stop > end_of_file) {
-                        *alloc_required = 1;
+                if (lblock_stop > end_of_file)
                         return 0;
-                }
         }
 
-        for (; lblock < lblock_stop; lblock += extlen) {
-                error = gfs2_extent_map(&ip->i_inode, lblock, &new, &dblock, &extlen);
-                if (error)
-                        return error;
-
-                if (!dblock) {
-                        *alloc_required = 1;
+        size = (lblock_stop - lblock) << shift;
+        do {
+                bh.b_state = 0;
+                bh.b_size = size;
+                gfs2_block_map(&ip->i_inode, lblock, &bh, 0);
+                if (!buffer_mapped(&bh))
                         return 0;
-                }
-        }
+                size -= bh.b_size;
+                lblock += (bh.b_size >> ip->i_inode.i_blkbits);
+        } while(size > 0);
 
+        *alloc_required = 0;
         return 0;
 }