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authorChao Yu <yuchao0@huawei.com>2017-11-23 18:26:52 +0300
committerJaegeuk Kim <jaegeuk@kernel.org>2018-01-03 06:27:28 +0300
commit21020812c9e1ab593367fad9ce579f842a0b406d (patch)
tree753b5e94c5b00ca74dc64d370b259f88070e2e05 /fs/f2fs/file.c
parente17d488bce9ef4fe3b18d1548ea79b65f836b497 (diff)
downloadlinux-21020812c9e1ab593367fad9ce579f842a0b406d.tar.xz
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>
Diffstat (limited to 'fs/f2fs/file.c')
-rw-r--r--fs/f2fs/file.c20
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;
}