On 2024/11/5 15:28, Zhiguo Niu wrote:
Chao Yu <c...@kernel.org> 于2024年11月5日周二 15:04写道：
On 2024/11/4 9:56, Zhiguo Niu wrote:
If user give a file size as "length" parameter for fiemap
operations, but if this size is non-block size aligned,
it will show 2 segments fiemap results even this whole file
is contiguous on disk, such as the following results:
./f2fs_io fiemap 0 19034 ylog/analyzer.py
Fiemap: offset = 0 len = 19034
logical addr. physical addr. length flags
0 0000000000000000 0000000020baa000 0000000000004000 00001000
1 0000000000004000 0000000020bae000 0000000000001000 00001001
after this patch:
./f2fs_io fiemap 0 19034 ylog/analyzer.py
Fiemap: offset = 0 len = 19034
logical addr. physical addr. length flags
0 0000000000000000 00000000315f3000 0000000000005000 00001001
Signed-off-by: Zhiguo Niu <zhiguo....@unisoc.com>
---
V2: correct commit msg according to Chao's questions
f2fs_io has been modified for testing, the length for fiemap is
real file size, not block number
---
fs/f2fs/data.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 306b86b0..9fc229d 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1966,8 +1966,8 @@ int f2fs_fiemap(struct inode *inode, struct
fiemap_extent_info *fieinfo,
goto out;
}
- if (bytes_to_blks(inode, len) == 0)
- len = blks_to_bytes(inode, 1);
+ if (len & (blks_to_bytes(inode, 1) - 1))
+ len = round_up(len, blks_to_bytes(inode, 1));
How do you think of getting rid of above alignment for len?
start_blk = bytes_to_blks(inode, start);
last_blk = bytes_to_blks(inode, start + len - 1);
And round up end position w/:
last_blk = bytes_to_blks(inode, round_up(start + len - 1, F2FS_BLKSIZE));
Hi Chao,
I think this will change the current code logic
-------------
if (start_blk > last_blk)
goto out;
-------------
for example, a file with size 19006, but the length from the user is 16384.
before this modification, last_blk = bytes_to_blks(inode, start +
len - 1) = (inode, 16383) = 3
after the first f2fs_map_blocks(). start_blk change to be 4,
after the second f2fs_map_blocks(), fiemap_fill_nex_exten will be
called to fill user parameter and then
will goto out because start_blk > last_blk, then fiemap flow finishes.
but after this modification, last_blk will be 4
will do f2fs_map_blocks() until reach the max_file_blocks(inode)
Yes, you're right, however, w/ this patch, it may change last_blk, e.g.
xfs_io file -c "fiemap -v 0 19006" vs xfs_io file -c "fiemap -v 2 19006"
start_blk and last_blk will be: 0, 4 and 0, 5.
Should we round_up len after start_blk & last_blk calculation?
Thanks,
thanks！
Thanks,
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