projects / thirdparty / kernel / stable-queue.git / blame
| Commit | Line | Data |
|---|---|---|
| 72fc6108 GKH |
1 | From foo@baz Mon Apr 9 10:16:32 CEST 2018 |
| 2 | From: Chao Yu <yuchao0@huawei.com> | |
| 3 | Date: Thu, 23 Nov 2017 23:26:52 +0800 | |
| 4 | Subject: f2fs: fix lock dependency in between dio_rwsem & i_mmap_sem | |
| 5 | ||
| 6 | From: Chao Yu <yuchao0@huawei.com> | |
| 7 | ||
| 8 | ||
| 9 | [ Upstream commit 21020812c9e1ab593367fad9ce579f842a0b406d ] | |
| 10 | ||
| 11 | test/generic/208 reports a potential deadlock as below: | |
| 12 | ||
| 13 | Chain exists of: | |
| 14 | &mm->mmap_sem --> &fi->i_mmap_sem --> &fi->dio_rwsem[WRITE] | |
| 15 | ||
| 16 | Possible unsafe locking scenario: | |
| 17 | ||
| 18 | CPU0 CPU1 | |
| 19 | ---- ---- | |
| 20 | lock(&fi->dio_rwsem[WRITE]); | |
| 21 | lock(&fi->i_mmap_sem); | |
| 22 | lock(&fi->dio_rwsem[WRITE]); | |
| 23 | lock(&mm->mmap_sem); | |
| 24 | ||
| 25 | This patch changes the lock dependency as below in fallocate() to | |
| 26 | fix this issue: | |
| 27 | - dio_rwsem | |
| 28 | - i_mmap_sem | |
| 29 | ||
| 30 | Fixes: bb06664a534b ("f2fs: avoid race in between GC and block exchange") | |
| 31 | Signed-off-by: Chao Yu <yuchao0@huawei.com> | |
| 32 | Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> | |
| 33 | Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> | |
| 34 | Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
| 35 | --- | |
| 36 | fs/f2fs/file.c | 20 +++++++++----------- | |
| 37 | 1 file changed, 9 insertions(+), 11 deletions(-) | |
| 38 | ||
| 39 | --- a/fs/f2fs/file.c | |
| 40 | +++ b/fs/f2fs/file.c | |
| 41 | @@ -1186,14 +1186,14 @@ static int f2fs_collapse_range(struct in | |
| 42 | pg_start = offset >> PAGE_SHIFT; | |
| 43 | pg_end = (offset + len) >> PAGE_SHIFT; | |
| 44 | ||
| 45 | + /* avoid gc operation during block exchange */ | |
| 46 | + down_write(&F2FS_I(inode)->dio_rwsem[WRITE]); | |
| 47 | + | |
| 48 | down_write(&F2FS_I(inode)->i_mmap_sem); | |
| 49 | /* write out all dirty pages from offset */ | |
| 50 | ret = filemap_write_and_wait_range(inode->i_mapping, offset, LLONG_MAX); | |
| 51 | if (ret) | |
| 52 | - goto out; | |
| 53 | - | |
| 54 | - /* avoid gc operation during block exchange */ | |
| 55 | - down_write(&F2FS_I(inode)->dio_rwsem[WRITE]); | |
| 56 | + goto out_unlock; | |
| 57 | ||
| 58 | truncate_pagecache(inode, offset); | |
| 59 | ||
| 60 | @@ -1212,9 +1212,8 @@ static int f2fs_collapse_range(struct in | |
| 61 | if (!ret) | |
| 62 | f2fs_i_size_write(inode, new_size); | |
| 63 | out_unlock: | |
| 64 | - up_write(&F2FS_I(inode)->dio_rwsem[WRITE]); | |
| 65 | -out: | |
| 66 | up_write(&F2FS_I(inode)->i_mmap_sem); | |
| 67 | + up_write(&F2FS_I(inode)->dio_rwsem[WRITE]); | |
| 68 | return ret; | |
| 69 | } | |
| 70 | ||
| 71 | @@ -1385,6 +1384,9 @@ static int f2fs_insert_range(struct inod | |
| 72 | ||
| 73 | f2fs_balance_fs(sbi, true); | |
| 74 | ||
| 75 | + /* avoid gc operation during block exchange */ | |
| 76 | + down_write(&F2FS_I(inode)->dio_rwsem[WRITE]); | |
| 77 | + | |
| 78 | down_write(&F2FS_I(inode)->i_mmap_sem); | |
| 79 | ret = truncate_blocks(inode, i_size_read(inode), true); | |
| 80 | if (ret) | |
| 81 | @@ -1395,9 +1397,6 @@ static int f2fs_insert_range(struct inod | |
| 82 | if (ret) | |
| 83 | goto out; | |
| 84 | ||
| 85 | - /* avoid gc operation during block exchange */ | |
| 86 | - down_write(&F2FS_I(inode)->dio_rwsem[WRITE]); | |
| 87 | - | |
| 88 | truncate_pagecache(inode, offset); | |
| 89 | ||
| 90 | pg_start = offset >> PAGE_SHIFT; | |
| 91 | @@ -1425,10 +1424,9 @@ static int f2fs_insert_range(struct inod | |
| 92 | ||
| 93 | if (!ret) | |
| 94 | f2fs_i_size_write(inode, new_size); | |
| 95 | - | |
| 96 | - up_write(&F2FS_I(inode)->dio_rwsem[WRITE]); | |
| 97 | out: | |
| 98 | up_write(&F2FS_I(inode)->i_mmap_sem); | |
| 99 | + up_write(&F2FS_I(inode)->dio_rwsem[WRITE]); | |
| 100 | return ret; | |
| 101 | } | |
| 102 |