If one read IO is always failing, we can fall into an infinite loop in
f2fs_sync_dirty_inodes. This happens during xfstests/generic/475.
[ 142.803335] Buffer I/O error on dev dm-1, logical block 8388592, async page read
...
[ 382.887210] submit_bio_noacct+0xdd/0x2a0
[ 382.887213] submit_bio+0x80/0x110
[ 382.887223] __submit_bio+0x4d/0x300 [f2fs]
[ 382.887282] f2fs_submit_page_bio+0x125/0x200 [f2fs]
[ 382.887299] __get_meta_page+0xc9/0x280 [f2fs]
[ 382.887315] f2fs_get_meta_page+0x13/0x20 [f2fs]
[ 382.887331] f2fs_get_node_info+0x317/0x3c0 [f2fs]
[ 382.887350] f2fs_do_write_data_page+0x327/0x6f0 [f2fs]
[ 382.887367] f2fs_write_single_data_page+0x5b7/0x960 [f2fs]
[ 382.887386] f2fs_write_cache_pages+0x302/0x890 [f2fs]
[ 382.887405] ? preempt_count_add+0x7a/0xc0
[ 382.887408] f2fs_write_data_pages+0xfd/0x320 [f2fs]
[ 382.887425] ? _raw_spin_unlock+0x1a/0x30
[ 382.887428] do_writepages+0xd3/0x1d0
[ 382.887432] filemap_fdatawrite_wbc+0x69/0x90
[ 382.887434] filemap_fdatawrite+0x50/0x70
[ 382.887437] f2fs_sync_dirty_inodes+0xa4/0x270 [f2fs]
[ 382.887453] f2fs_write_checkpoint+0x189/0x1640 [f2fs]
[ 382.887469] ? schedule_timeout+0x114/0x150
[ 382.887471] ? ttwu_do_activate+0x6d/0xb0
[ 382.887473] ? preempt_count_add+0x7a/0xc0
[ 382.887476] kill_f2fs_super+0xca/0x100 [f2fs]
[ 382.887491] deactivate_locked_super+0x35/0xa0
[ 382.887494] deactivate_super+0x40/0x50
[ 382.887497] cleanup_mnt+0x139/0x190
[ 382.887499] __cleanup_mnt+0x12/0x20
[ 382.887501] task_work_run+0x64/0xa0
[ 382.887505] exit_to_user_mode_prepare+0x1b7/0x1c0
[ 382.887508] syscall_exit_to_user_mode+0x27/0x50
[ 382.887510] do_syscall_64+0x48/0xc0
[ 382.887513] entry_SYSCALL_64_after_hwframe+0x44/0xae
Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>