There are two advantages to update b_size in this way:
1. get_data_block tends to round down b_size to align with
block size, if b_size isn't aligned already, it would take
an extra loop to go through the range. So we round it up first.
2. unlike extent-based file, get_data_block could be time-consuming
for indirect-based file, update b_size may avoid looking up blocks
outside the range.
Signed-off-by: Fan li <fanofcode...@samsung.com>
---
fs/f2fs/data.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index f89cf07..29fec76 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -798,15 +798,15 @@ int f2fs_fiemap(struct inode *inode, struct
fiemap_extent_info *fieinfo,
isize = i_size_read(inode);
mutex_lock(&inode->i_mutex);
- if (logical_to_blk(inode, len) == 0)
- len = blk_to_logical(inode, 1);
start_blk = logical_to_blk(inode, start);
last_blk = logical_to_blk(inode, start + len - 1);
-
next:
memset(&map_bh, 0, sizeof(struct buffer_head));
- map_bh.b_size = len;
+ if (last_blk >= start_blk)
+ map_bh.b_size = blk_to_logical(inode, last_blk - start_blk + 1);
+ else
+ map_bh.b_size = blk_to_logical(inode, 1);
ret = get_data_block(inode, start_blk, &map_bh, 0,
F2FS_GET_BLOCK_FIEMAP);
--
1.7.9.5
------------------------------------------------------------------------------
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