diff options
| author | Dmitry Monakhov <dmonakhov@openvz.org> | 2012-10-05 11:32:02 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2012-10-05 11:32:02 -0400 |
| commit | 60d4616f3dc63371b3dc367e5e88fd4b4f037f65 (patch) | |
| tree | 1365c73827aa4efd95d805e314f13182366d1251 | |
| parent | c278531d39f3158bfee93dc67da0b77e09776de2 (diff) | |
ext4: serialize fallocate with ext4_convert_unwritten_extents
Fallocate should wait for pended ext4_convert_unwritten_extents()
otherwise following race may happen:
ftruncate( ,12288);
fallocate( ,0, 4096)
io_sibmit( ,0, 4096); /* Write to fallocated area, split extent if needed */
fallocate( ,0, 8192); /* Grow extent and broke assumption about extent */
Later kwork completion will do:
->ext4_convert_unwritten_extents (0, 4096)
->ext4_map_blocks(handle, inode, &map, EXT4_GET_BLOCKS_IO_CONVERT_EXT);
->ext4_ext_map_blocks() /* Will find new extent: ex = [0,2] !!!!!! */
->ext4_ext_handle_uninitialized_extents()
->ext4_convert_unwritten_extents_endio()
/* convert [0,2] extent to initialized, but only[0,1] was written */
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
| -rw-r--r-- | fs/ext4/extents.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 1c94cca35ed1..c2789271e7b4 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -4428,6 +4428,9 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) */ if (len <= EXT_UNINIT_MAX_LEN << blkbits) flags |= EXT4_GET_BLOCKS_NO_NORMALIZE; + + /* Prevent race condition between unwritten */ + ext4_flush_unwritten_io(inode); retry: while (ret >= 0 && ret < max_blocks) { map.m_lblk = map.m_lblk + ret; |