[PATCH 5.14 150/432] f2fs: fix unexpected ENOENT comes from f2fs_map_blocks()

Greg Kroah-Hartman
2021-09-16T17:25:20Z

From: Chao Yu <chao@kernel.org>

[ Upstream commit adf9ea89c719c1d23794e363f631e376b3ff8cbc ]

In below path, it will return ENOENT if filesystem is shutdown:

- f2fs_map_blocks
- f2fs_get_dnode_of_data
- f2fs_get_node_page
- __get_node_page
- read_node_page
- is_sbi_flag_set(sbi, SBI_IS_SHUTDOWN)
return -ENOENT
- force return value from ENOENT to 0

It should be fine for read case, since it indicates a hole condition,
and caller could use .m_next_pgofs to skip the hole and continue the
lookup.

However it may cause confusing for write case, since leaving a hole
there, and said nothing was wrong doesn't help.

There is at least one case from dax_iomap_actor() will complain that,
so fix this in prior to supporting dax in f2fs.

xfstest generic/388 reports below warning:

ubuntu godown: xfstests-induced forced shutdown of /mnt/scratch_f2fs:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 485833 at fs/dax.c:1127 dax_iomap_actor+0x339/0x370
Call Trace:
iomap_apply+0x1c4/0x7b0
? dax_iomap_rw+0x1c0/0x1c0
dax_iomap_rw+0xad/0x1c0
? dax_iomap_rw+0x1c0/0x1c0
f2fs_file_write_iter+0x5ab/0x970 [f2fs]
do_iter_readv_writev+0x273/0x2e0
do_iter_write+0xab/0x1f0
vfs_iter_write+0x21/0x40
iter_file_splice_write+0x287/0x540
do_splice+0x37c/0xa60
__x64_sys_splice+0x15f/0x3a0
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae

ubuntu godown: xfstests-induced forced shutdown of /mnt/scratch_f2fs:
------------[ cut here ]------------
RIP: 0010:dax_iomap_pte_fault.isra.0+0x72e/0x14a0
Call Trace:
dax_iomap_fault+0x44/0x70
f2fs_dax_huge_fault+0x155/0x400 [f2fs]
f2fs_dax_fault+0x18/0x30 [f2fs]
__do_fault+0x4e/0x120
do_fault+0x3cf/0x7a0
__handle_mm_fault+0xa8c/0xf20
? find_held_lock+0x39/0xd0
handle_mm_fault+0x1b6/0x480
do_user_addr_fault+0x320/0xcd0
? rcu_read_lock_sched_held+0x67/0xc0
exc_page_fault+0x77/0x3f0
? asm_exc_page_fault+0x8/0x30
asm_exc_page_fault+0x1e/0x30

Fixes: 83a3bfdb5a8a ("f2fs: indicate shutdown f2fs to allow unmount successfully")
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/f2fs/data.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 6eda24768d4b..f2498e4ad89d 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1492,7 +1492,21 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
if (err) {
if (flag == F2FS_GET_BLOCK_BMAP)
map->m_pblk = 0;
+
if (err == -ENOENT) {
+ /*
+ * There is one exceptional case that read_node_page()
+ * may return -ENOENT due to filesystem has been
+ * shutdown or cp_error, so force to convert error
+ * number to EIO for such case.
+ */
+ if (map->m_may_create &&
+ (is_sbi_flag_set(sbi, SBI_IS_SHUTDOWN) ||
+ f2fs_cp_error(sbi))) {
+ err = -EIO;
+ goto unlock_out;
+ }
+
err = 0;
if (map->m_next_pgofs)
*map->m_next_pgofs =
--
2.30.2