Hi,
在 2018/12/18 下午7:57，“zhangyi (F)”<yi.zhang@xxxxxxxxxx> 写入:
Commit 9af0b3d12577 "ext4: fix race when setting the bitmap corrupted
flag" want to fix race between setting inode/block bitmap corrupted
flag and reducing free group inodes/clusters counter to prevent
multiple frees. But ext4_test_and_set_bit() will invoke
__test_and_set_bit() which is non-atomic, so the race is still there.
Fix this by invoke test_and_set_bit() instead.
Fixes: 9af0b3d12577 ("ext4: fix race when setting the bitmap corrupted flag")
Signed-off-by: zhangyi (F) <yi.zhang@xxxxxxxxxx>
Thanks for fixing this!, I was not aware of __test_and_set_bit() is not non-atomic operation before.
Reviewed-by: Wang Shilong <wshilong@xxxxxxx>
Btw for a stable process question, commit 9af0b3d12577 had CC tag to Stable kernel, should we
add it again here or with 'Fixes' tag, it will be included automatically?
Thanks,
Shilong
---
fs/ext4/ext4.h | 6 ++++++
fs/ext4/super.c | 6 ++----
2 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 3f89d0a..755ba14 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2888,6 +2888,12 @@ struct ext4_group_info {
(test_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &((grp)->bb_state)))
#define EXT4_MB_GRP_IBITMAP_CORRUPT(grp) \
(test_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &((grp)->bb_state)))
+#define EXT4_MB_GRP_TEST_AND_SET_BBITMAP_CORRUPT(grp) \
+ (test_and_set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, \
+ &((grp)->bb_state)))
+#define EXT4_MB_GRP_TEST_AND_SET_IBITMAP_CORRUPT(grp) \
+ (test_and_set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, \
+ &((grp)->bb_state)))
#define EXT4_MB_GRP_WAS_TRIMMED(grp) \
(test_bit(EXT4_GROUP_INFO_WAS_TRIMMED_BIT, &((grp)->bb_state)))
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 53ff6c2..5b83765 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -798,16 +798,14 @@ void ext4_mark_group_bitmap_corrupted(struct super_block *sb,
int ret;
if (flags & EXT4_GROUP_INFO_BBITMAP_CORRUPT) {
- ret = ext4_test_and_set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT,
- &grp->bb_state);
+ ret = EXT4_MB_GRP_TEST_AND_SET_BBITMAP_CORRUPT(grp);
if (!ret)
percpu_counter_sub(&sbi->s_freeclusters_counter,
grp->bb_free);
}
if (flags & EXT4_GROUP_INFO_IBITMAP_CORRUPT) {
- ret = ext4_test_and_set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT,
- &grp->bb_state);
+ ret = EXT4_MB_GRP_TEST_AND_SET_IBITMAP_CORRUPT(grp);
if (!ret && gdp) {
int count;
--
2.7.4
