diff options
author | Chao Yu <yuchao0@huawei.com> | 2017-11-23 23:26:52 +0800 |
---|---|---|
committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2018-01-02 19:27:28 -0800 |
commit | 21020812c9e1ab593367fad9ce579f842a0b406d (patch) | |
tree | 753b5e94c5b00ca74dc64d370b259f88070e2e05 | |
parent | e17d488bce9ef4fe3b18d1548ea79b65f836b497 (diff) | |
download | linux-21020812c9e1ab593367fad9ce579f842a0b406d.tar.bz2 |
f2fs: fix lock dependency in between dio_rwsem & i_mmap_sem
test/generic/208 reports a potential deadlock as below:
Chain exists of:
&mm->mmap_sem --> &fi->i_mmap_sem --> &fi->dio_rwsem[WRITE]
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&fi->dio_rwsem[WRITE]);
lock(&fi->i_mmap_sem);
lock(&fi->dio_rwsem[WRITE]);
lock(&mm->mmap_sem);
This patch changes the lock dependency as below in fallocate() to
fix this issue:
- dio_rwsem
- i_mmap_sem
Fixes: bb06664a534b ("f2fs: avoid race in between GC and block exchange")
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
-rw-r--r-- | fs/f2fs/file.c | 20 |
1 files changed, 9 insertions, 11 deletions
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index 7874bbd7311d..84a011a522a1 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -1186,14 +1186,14 @@ static int f2fs_collapse_range(struct inode *inode, loff_t offset, loff_t len) pg_start = offset >> PAGE_SHIFT; pg_end = (offset + len) >> PAGE_SHIFT; + /* avoid gc operation during block exchange */ + down_write(&F2FS_I(inode)->dio_rwsem[WRITE]); + down_write(&F2FS_I(inode)->i_mmap_sem); /* write out all dirty pages from offset */ ret = filemap_write_and_wait_range(inode->i_mapping, offset, LLONG_MAX); if (ret) - goto out; - - /* avoid gc operation during block exchange */ - down_write(&F2FS_I(inode)->dio_rwsem[WRITE]); + goto out_unlock; truncate_pagecache(inode, offset); @@ -1212,9 +1212,8 @@ static int f2fs_collapse_range(struct inode *inode, loff_t offset, loff_t len) if (!ret) f2fs_i_size_write(inode, new_size); out_unlock: - up_write(&F2FS_I(inode)->dio_rwsem[WRITE]); -out: up_write(&F2FS_I(inode)->i_mmap_sem); + up_write(&F2FS_I(inode)->dio_rwsem[WRITE]); return ret; } @@ -1385,6 +1384,9 @@ static int f2fs_insert_range(struct inode *inode, loff_t offset, loff_t len) f2fs_balance_fs(sbi, true); + /* avoid gc operation during block exchange */ + down_write(&F2FS_I(inode)->dio_rwsem[WRITE]); + down_write(&F2FS_I(inode)->i_mmap_sem); ret = truncate_blocks(inode, i_size_read(inode), true); if (ret) @@ -1395,9 +1397,6 @@ static int f2fs_insert_range(struct inode *inode, loff_t offset, loff_t len) if (ret) goto out; - /* avoid gc operation during block exchange */ - down_write(&F2FS_I(inode)->dio_rwsem[WRITE]); - truncate_pagecache(inode, offset); pg_start = offset >> PAGE_SHIFT; @@ -1425,10 +1424,9 @@ static int f2fs_insert_range(struct inode *inode, loff_t offset, loff_t len) if (!ret) f2fs_i_size_write(inode, new_size); - - up_write(&F2FS_I(inode)->dio_rwsem[WRITE]); out: up_write(&F2FS_I(inode)->i_mmap_sem); + up_write(&F2FS_I(inode)->dio_rwsem[WRITE]); return ret; } |