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| author | Theodore Ts'o <tytso@mit.edu> | 2014-09-01 22:32:09 +0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2014-09-01 22:32:09 +0400 |
| commit | 713e8dde3e71e92db2d8cc8459d236ce1fb576ce (patch) | |
| tree | 775c6493db0b4a15cd9e33d86f8981b3e27332df | |
| parent | 19008f6dfa16d23afcd09dceaa598bb6da8de4b1 (diff) | |
| download | linux-713e8dde3e71e92db2d8cc8459d236ce1fb576ce.tar.xz | |
ext4: fix ZERO_RANGE bug hidden by flag aliasing
We accidently aliased EXT4_EX_NOCACHE and EXT4_GET_CONVERT_UNWRITTEN
falgs, which apparently was hiding a bug that was unmasked when this
flag aliasing issue was addressed (see the subsequent commit). The
reproduction case was:
fsx -N 10000 -l 500000 -r 4096 -t 4096 -w 4096 -Z -R -W /vdb/junk
... which would cause fsx to report corruption in the data file.
The fix we have is a bit of an overkill, but I'd much rather be
conservative for now, and we can optimize ZERO_RANGE_FL handling
later. The fact that we need to zap the extent_status cache for the
inode is unfortunate, but correctness is far more important than
performance.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: Namjae Jeon <namjae.jeon@samsung.com>
| -rw-r--r-- | fs/ext4/extents.c | 21 |
1 files changed, 14 insertions, 7 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index d00937336f19..bf205f72be35 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -4802,7 +4802,8 @@ static long ext4_zero_range(struct file *file, loff_t offset, max_blocks -= lblk; flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT | - EXT4_GET_BLOCKS_CONVERT_UNWRITTEN; + EXT4_GET_BLOCKS_CONVERT_UNWRITTEN | + EXT4_EX_NOCACHE; if (mode & FALLOC_FL_KEEP_SIZE) flags |= EXT4_GET_BLOCKS_KEEP_SIZE; @@ -4840,15 +4841,21 @@ static long ext4_zero_range(struct file *file, loff_t offset, ext4_inode_block_unlocked_dio(inode); inode_dio_wait(inode); + ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size, + flags, mode); + if (ret) + goto out_dio; /* * Remove entire range from the extent status tree. + * + * ext4_es_remove_extent(inode, lblk, max_blocks) is + * NOT sufficient. I'm not sure why this is the case, + * but let's be conservative and remove the extent + * status tree for the entire inode. There should be + * no outstanding delalloc extents thanks to the + * filemap_write_and_wait_range() call above. */ - ret = ext4_es_remove_extent(inode, lblk, max_blocks); - if (ret) - goto out_dio; - - ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size, - flags, mode); + ret = ext4_es_remove_extent(inode, 0, EXT_MAX_BLOCKS); if (ret) goto out_dio; } |