f2fs: fix incorrect mapping for bmap

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The test step is like below:
1. touch file
2. truncate -s $((1024*1024)) file
3. fallocate -o 0 -l $((1024*1024)) file
4. fibmap.f2fs file

Our result of fibmap.f2fs showed below is not correct:

file_pos   start_blk     end_blk        blks
       0    -937166132    -937166132           1
    4096    -937166132    -937166132           1
    8192    -937166132    -937166132           1
   12288    -937166132    -937166132           1
   16384    -937166132    -937166132           1
   20480    -937166132    -937166132           1
...
 1040384    -937166132    -937166132           1
 1044480    -937166132    -937166132           1

This is because f2fs_map_blocks will return with no error when meeting
a hole or preallocated block, the caller __get_data_block will map the
uninitialized variable value to bh->b_blocknr.

Unfortunately generic_block_bmap will neither check the return value of
get_data() nor check mapping info of buffer_head, result in returning
the random block address.

After fixing the issue, our result shows correctly:

file_pos   start_blk     end_blk        blks
       0           0           0         256

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

...

This commit is contained in:

Chao Yu 2015-08-19 19:11:19 +08:00 • committed by Jaegeuk Kim

parent c031f6a904

commit e2b4e2bc88

2 changed files with 42 additions and 12 deletions

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50

fs/f2fs/data.c

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6

fs/f2fs/f2fs.h

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