[PATCH 5.16 0793/1017] f2fs: dont get FREEZE lock in f2fs_evict_inode in frozen fs

Greg Kroah-Hartman
2022-04-05T10:27:42Z

From: Jaegeuk Kim <jaegeuk@kernel.org>

[ Upstream commit ba900534f807f0b327c92d5141c85d2313e2d55c ]

Let's purge inode cache in order to avoid the below deadlock.

[freeze test] shrinkder
freeze_super
- pwercpu_down_write(SB_FREEZE_FS)
- super_cache_scan
- down_read(&sb->s_umount)
- prune_icache_sb
- dispose_list
- evict
- f2fs_evict_inode
thaw_super
- down_write(&sb->s_umount);
- __percpu_down_read(SB_FREEZE_FS)

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
Documentation/ABI/testing/sysfs-fs-f2fs | 1 +
fs/f2fs/debug.c | 1 +
fs/f2fs/f2fs.h | 1 +
fs/f2fs/inode.c | 6 ++++--
fs/f2fs/super.c | 4 ++++
5 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index b268e3e18b4a..91e2b549f817 100644
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -425,6 +425,7 @@ Description: Show status of f2fs superblock in real time.
0x800 SBI_QUOTA_SKIP_FLUSH skip flushing quota in current CP
0x1000 SBI_QUOTA_NEED_REPAIR quota file may be corrupted
0x2000 SBI_IS_RESIZEFS resizefs is in process
+ 0x4000 SBI_IS_FREEZING freefs is in process
====== ===================== =================================

What: /sys/fs/f2fs/<disk>/ckpt_thread_ioprio
diff --git a/fs/f2fs/debug.c b/fs/f2fs/debug.c
index 8c50518475a9..07ad0d81f0c5 100644
--- a/fs/f2fs/debug.c
+++ b/fs/f2fs/debug.c
@@ -338,6 +338,7 @@ static char *s_flag[] = {
[SBI_QUOTA_SKIP_FLUSH] = " quota_skip_flush",
[SBI_QUOTA_NEED_REPAIR] = " quota_need_repair",
[SBI_IS_RESIZEFS] = " resizefs",
+ [SBI_IS_FREEZING] = " freezefs",
};

static int stat_show(struct seq_file *s, void *v)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index d753094a4919..980c0c2b6350 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1259,6 +1259,7 @@ enum {
SBI_QUOTA_SKIP_FLUSH, /* skip flushing quota in current CP */
SBI_QUOTA_NEED_REPAIR, /* quota file may be corrupted */
SBI_IS_RESIZEFS, /* resizefs is in process */
+ SBI_IS_FREEZING, /* freezefs is in process */
};

enum {
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index 5a10f98dbbc3..a40e52ba5ec8 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -769,7 +769,8 @@ void f2fs_evict_inode(struct inode *inode)
f2fs_remove_ino_entry(sbi, inode->i_ino, UPDATE_INO);
f2fs_remove_ino_entry(sbi, inode->i_ino, FLUSH_INO);

- sb_start_intwrite(inode->i_sb);
+ if (!is_sbi_flag_set(sbi, SBI_IS_FREEZING))
+ sb_start_intwrite(inode->i_sb);
set_inode_flag(inode, FI_NO_ALLOC);
i_size_write(inode, 0);
retry:
@@ -800,7 +801,8 @@ void f2fs_evict_inode(struct inode *inode)
if (dquot_initialize_needed(inode))
set_sbi_flag(sbi, SBI_QUOTA_NEED_REPAIR);
}
- sb_end_intwrite(inode->i_sb);
+ if (!is_sbi_flag_set(sbi, SBI_IS_FREEZING))
+ sb_end_intwrite(inode->i_sb);
no_delete:
dquot_drop(inode);

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 45106b426e8d..9402d5b2c7fd 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1668,11 +1668,15 @@ static int f2fs_freeze(struct super_block *sb)
/* ensure no checkpoint required */
if (!llist_empty(&F2FS_SB(sb)->cprc_info.issue_list))
return -EINVAL;
+
+ /* to avoid deadlock on f2fs_evict_inode->SB_FREEZE_FS */
+ set_sbi_flag(F2FS_SB(sb), SBI_IS_FREEZING);
return 0;
}

static int f2fs_unfreeze(struct super_block *sb)
{
+ clear_sbi_flag(F2FS_SB(sb), SBI_IS_FREEZING);
return 0;
}

--
2.34.1