f2fs: optimize the flow of f2fs_map_blocks

check map->m_len right after it changes to avoid excess call
to update dnode_of_data.

Signed-off-by: Fan li <fanofcode.li@samsung.com>
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 292a06cbea072a7504774e5e354c90347043cfbd..e34b1bdfc9955de2f6f9bdae18c14886a760390a 100644 (file)
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -573,6 +573,7 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
        int err = 0, ofs = 1;
        struct extent_info ei;
        bool allocated = false;
+       block_t blkaddr;
 
        map->m_len = 0;
        map->m_flags = 0;
@@ -636,6 +637,9 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
        pgofs++;
 
 get_next:
+       if (map->m_len >= maxblocks)
+               goto sync_out;
+
        if (dn.ofs_in_node >= end_offset) {
                if (allocated)
                        sync_inode_page(&dn);
@@ -653,44 +657,43 @@ get_next:
                end_offset = ADDRS_PER_PAGE(dn.node_page, F2FS_I(inode));
        }
 
-       if (maxblocks > map->m_len) {
-               block_t blkaddr = datablock_addr(dn.node_page, dn.ofs_in_node);
+       blkaddr = datablock_addr(dn.node_page, dn.ofs_in_node);
 
-               if (blkaddr == NEW_ADDR || blkaddr == NULL_ADDR) {
-                       if (create) {
-                               if (unlikely(f2fs_cp_error(sbi))) {
-                                       err = -EIO;
-                                       goto sync_out;
-                               }
-                               err = __allocate_data_block(&dn);
-                               if (err)
-                                       goto sync_out;
-                               allocated = true;
-                               map->m_flags |= F2FS_MAP_NEW;
-                               blkaddr = dn.data_blkaddr;
-                       } else {
-                               /*
-                                * we only merge preallocated unwritten blocks
-                                * for fiemap.
-                                */
-                               if (flag != F2FS_GET_BLOCK_FIEMAP ||
-                                               blkaddr != NEW_ADDR)
-                                       goto sync_out;
+       if (blkaddr == NEW_ADDR || blkaddr == NULL_ADDR) {
+               if (create) {
+                       if (unlikely(f2fs_cp_error(sbi))) {
+                               err = -EIO;
+                               goto sync_out;
                        }
+                       err = __allocate_data_block(&dn);
+                       if (err)
+                               goto sync_out;
+                       allocated = true;
+                       map->m_flags |= F2FS_MAP_NEW;
+                       blkaddr = dn.data_blkaddr;
+               } else {
+                       /*
+                        * we only merge preallocated unwritten blocks
+                        * for fiemap.
+                        */
+                       if (flag != F2FS_GET_BLOCK_FIEMAP ||
+                                       blkaddr != NEW_ADDR)
+                               goto sync_out;
                }
+       }
 
-               /* Give more consecutive addresses for the readahead */
-               if ((map->m_pblk != NEW_ADDR &&
-                               blkaddr == (map->m_pblk + ofs)) ||
-                               (map->m_pblk == NEW_ADDR &&
-                               blkaddr == NEW_ADDR)) {
-                       ofs++;
-                       dn.ofs_in_node++;
-                       pgofs++;
-                       map->m_len++;
-                       goto get_next;
-               }
+       /* Give more consecutive addresses for the readahead */
+       if ((map->m_pblk != NEW_ADDR &&
+                       blkaddr == (map->m_pblk + ofs)) ||
+                       (map->m_pblk == NEW_ADDR &&
+                       blkaddr == NEW_ADDR)) {
+               ofs++;
+               dn.ofs_in_node++;
+               pgofs++;
+               map->m_len++;
+               goto get_next;
        }
+
 sync_out:
        if (allocated)
                sync_inode_page(&dn);