[PATCH] f2fs: fix to keep consistent i_gc_rwsem lock order

Chao Yu
2023-04-10T02:11:53Z

i_gc_rwsem[WRITE] and i_gc_rwsem[READ] lock order is reversed
in gc_data_segment() and f2fs_dio_write_iter(), fix to keep
consistent lock order as below:
1. lock i_gc_rwsem[WRITE]
2. lock i_gc_rwsem[READ]

Signed-off-by: Chao Yu <chao@kernel.org>
---
fs/f2fs/gc.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 6dc2bc710ba8..91841b0057ba 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -1616,14 +1616,14 @@ static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
int err;

if (S_ISREG(inode->i_mode)) {
- if (!f2fs_down_write_trylock(&fi->i_gc_rwsem[READ])) {
+ if (!f2fs_down_write_trylock(&fi->i_gc_rwsem[WRITE])) {
sbi->skipped_gc_rwsem++;
continue;
}
if (!f2fs_down_write_trylock(
- &fi->i_gc_rwsem[WRITE])) {
+ &fi->i_gc_rwsem[READ])) {
sbi->skipped_gc_rwsem++;
- f2fs_up_write(&fi->i_gc_rwsem[READ]);
+ f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
continue;
}
locked = true;
@@ -1646,8 +1646,8 @@ static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
submitted++;

if (locked) {
- f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
f2fs_up_write(&fi->i_gc_rwsem[READ]);
+ f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
}

stat_inc_data_blk_count(sbi, 1, gc_type);
--
2.25.1