[PATCH 3/4] f2fs: fix to adjust appropriate length for fiemap

From: Chao Yu
Date: Thu Nov 07 2024 - 20:26:27 EST


From: Zhiguo Niu <zhiguo.niu@xxxxxxxxxx>

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.niu@xxxxxxxxxx>
---
fs/f2fs/data.c | 6 +++---
include/linux/f2fs_fs.h | 1 +
2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 0e8390cbdb5b..69f1cb0490ee 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1938,12 +1938,12 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
goto out;
}

- if (F2FS_BYTES_TO_BLK(len) == 0)
- len = F2FS_BLKSIZE;
-
start_blk = F2FS_BYTES_TO_BLK(start);
last_blk = F2FS_BYTES_TO_BLK(start + len - 1);

+ if (len & F2FS_BLKSIZE_MASK)
+ len = round_up(len, F2FS_BLKSIZE);
+
next:
memset(&map, 0, sizeof(map));
map.m_lblk = start_blk;
diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
index 3b2ad444c002..c24f8bc01045 100644
--- a/include/linux/f2fs_fs.h
+++ b/include/linux/f2fs_fs.h
@@ -24,6 +24,7 @@
#define NEW_ADDR ((block_t)-1) /* used as block_t addresses */
#define COMPRESS_ADDR ((block_t)-2) /* used as compressed data flag */

+#define F2FS_BLKSIZE_MASK (F2FS_BLKSIZE - 1)
#define F2FS_BYTES_TO_BLK(bytes) ((unsigned long long)(bytes) >> F2FS_BLKSIZE_BITS)
#define F2FS_BLK_TO_BYTES(blk) ((unsigned long long)(blk) << F2FS_BLKSIZE_BITS)
#define F2FS_BLK_END_BYTES(blk) (F2FS_BLK_TO_BYTES(blk + 1) - 1)
--
2.40.1