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| author | Chao Yu <yuchao0@huawei.com> | 2016-07-13 04:18:29 +0300 |
|---|---|---|
| committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2016-07-16 01:21:22 +0300 |
| commit | 82e0a5aa5ddf794b3e1b21fcd091228736871882 (patch) | |
| tree | 4cc2beb40b6756219c2da15a5546ec9772f0ec0e /fs/f2fs/gc.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/gc.c')
| -rw-r--r-- | fs/f2fs/gc.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c index c61213785914..5c8acf754513 100644 --- a/fs/f2fs/gc.c +++ b/fs/f2fs/gc.c @@ -755,12 +755,32 @@ next_step: /* phase 3 */ inode = find_gc_inode(gc_list, dni.ino); if (inode) { + struct f2fs_inode_info *fi = F2FS_I(inode); + bool locked = false; + + if (S_ISREG(inode->i_mode)) { + if (!down_write_trylock(&fi->dio_rwsem[READ])) + continue; + if (!down_write_trylock( + &fi->dio_rwsem[WRITE])) { + up_write(&fi->dio_rwsem[READ]); + continue; + } + locked = true; + } + start_bidx = start_bidx_of_node(nofs, inode) + ofs_in_node; if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode)) move_encrypted_block(inode, start_bidx); else move_data_page(inode, start_bidx, gc_type); + + if (locked) { + up_write(&fi->dio_rwsem[WRITE]); + up_write(&fi->dio_rwsem[READ]); + } + stat_inc_data_blk_count(sbi, 1, gc_type); } } |