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| author | Chao Yu <yuchao0@huawei.com> | 2016-07-13 01:18:29 (GMT) |
|---|---|---|
| committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2016-07-15 22:21:22 (GMT) |
| commit | 82e0a5aa5ddf794b3e1b21fcd091228736871882 (patch) | |
| tree | 4cc2beb40b6756219c2da15a5546ec9772f0ec0e /fs/f2fs/data.c | |
| parent | 44a83499dda714d9262a9bf4fdac8c077893c9e6 (diff) | |
| download | linux-82e0a5aa5ddf794b3e1b21fcd091228736871882.tar.xz | |
f2fs: fix to avoid data update racing between GC and DIO
Datas in file can be operated by GC and DIO simultaneously, so we will
face race case as below:
For write case:
Thread A Thread B
- generic_file_direct_write
- invalidate_inode_pages2_range
- f2fs_direct_IO
- do_blockdev_direct_IO
- do_direct_IO
- get_more_blocks
- f2fs_gc
- do_garbage_collect
- gc_data_segment
- move_data_page
- do_write_data_page
migrate data block to new block address
- dio_bio_submit
update user data to old block address
For read case:
Thread A Thread B
- generic_file_direct_write
- invalidate_inode_pages2_range
- f2fs_direct_IO
- do_blockdev_direct_IO
- do_direct_IO
- get_more_blocks
- f2fs_balance_fs
- f2fs_gc
- do_garbage_collect
- gc_data_segment
- move_data_page
- do_write_data_page
migrate data block to new block address
- write_checkpoint
- do_checkpoint
- clear_prefree_segments
- f2fs_issue_discard
discard old block adress
- dio_bio_submit
update user buffer from obsolete block address
In order to fix this, for one file, we should let DIO and GC getting exclusion
against with each other.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs/f2fs/data.c')
| -rw-r--r-- | fs/f2fs/data.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 6500995..adfe47b 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -1716,6 +1716,7 @@ static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter) struct inode *inode = mapping->host; size_t count = iov_iter_count(iter); loff_t offset = iocb->ki_pos; + int rw = iov_iter_rw(iter); int err; err = check_direct_IO(inode, iter, offset); @@ -1729,8 +1730,11 @@ static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter) trace_f2fs_direct_IO_enter(inode, offset, count, iov_iter_rw(iter)); + down_read(&F2FS_I(inode)->dio_rwsem[rw]); err = blockdev_direct_IO(iocb, inode, iter, get_data_block_dio); - if (iov_iter_rw(iter) == WRITE) { + up_read(&F2FS_I(inode)->dio_rwsem[rw]); + + if (rw == WRITE) { if (err > 0) set_inode_flag(inode, FI_UPDATE_WRITE); else if (err < 0) |