[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>

diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index e9456eb..a25444a 100644 (file)
--- 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;
 }