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| author | Chao Yu <chao2.yu@samsung.com> | 2014-05-28 04:56:09 +0400 |
|---|---|---|
| committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2014-06-04 08:34:30 +0400 |
| commit | bfec07d0f8ed78b10df3ca3bc23e27de1166ea45 (patch) | |
| tree | c6134dfc647176474944cbb244bd15de4d4607ac /Documentation/filesystems/f2fs.txt | |
| parent | d631abdac9d541d282a1461b5aeae70aa3866e9f (diff) | |
| download | linux-bfec07d0f8ed78b10df3ca3bc23e27de1166ea45.tar.xz | |
f2fs: avoid overflow when large directory feathure is enabled
When large directory feathure is enable, We have one case which could cause
overflow in dir_buckets() as following:
special case: level + dir_level >= 32 and level < MAX_DIR_HASH_DEPTH / 2.
Here we define MAX_DIR_BUCKETS to limit the return value when the condition
could trigger potential overflow.
Changes from V1
o modify description of calculation in f2fs.txt suggested by Changman Lee.
Suggested-by: Changman Lee <cm224.lee@samsung.com>
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'Documentation/filesystems/f2fs.txt')
| -rw-r--r-- | Documentation/filesystems/f2fs.txt | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt index 25311e113e75..51afba17bbae 100644 --- a/Documentation/filesystems/f2fs.txt +++ b/Documentation/filesystems/f2fs.txt @@ -461,11 +461,11 @@ The number of blocks and buckets are determined by, # of blocks in level #n = | `- 4, Otherwise - ,- 2^ (n + dir_level), - | if n < MAX_DIR_HASH_DEPTH / 2, + ,- 2^(n + dir_level), + | if n + dir_level < MAX_DIR_HASH_DEPTH / 2, # of buckets in level #n = | - `- 2^((MAX_DIR_HASH_DEPTH / 2 + dir_level) - 1), - Otherwise + `- 2^((MAX_DIR_HASH_DEPTH / 2) - 1), + Otherwise When F2FS finds a file name in a directory, at first a hash value of the file name is calculated. Then, F2FS scans the hash table in level #0 to find the |