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f2fs: Set GF_NOFS in read_cache_page_gfp while doing f2fs_quota_read 

Quota code itself is serializing the operations by taking mutex_lock.
It seems a below deadlock can happen if GF_NOFS is not used in
f2fs_quota_read

__switch_to+0x88
__schedule+0x5b0
schedule+0x78
schedule_preempt_disabled+0x20
__mutex_lock_slowpath+0xdc   		//mutex owner is itself
mutex_lock+0x2c
dquot_commit+0x30			//mutex_lock(&dqopt->dqio_mutex);
dqput+0xe0
__dquot_drop+0x80
dquot_drop+0x48
f2fs_evict_inode+0x218
evict+0xa8
dispose_list+0x3c
prune_icache_sb+0x58
super_cache_scan+0xf4
do_shrink_slab+0x208
shrink_slab.part.40+0xac
shrink_zone+0x1b0
do_try_to_free_pages+0x25c
try_to_free_pages+0x164
__alloc_pages_nodemask+0x534
do_read_cache_page+0x6c
read_cache_page+0x14
f2fs_quota_read+0xa4
read_blk+0x54
find_tree_dqentry+0xe4
find_tree_dqentry+0xb8
find_tree_dqentry+0xb8
find_tree_dqentry+0xb8
qtree_read_dquot+0x68
v2_read_dquot+0x24
dquot_acquire+0x5c			// mutex_lock(&dqopt->dqio_mutex);
dqget+0x238
__dquot_initialize+0xd4
dquot_initialize+0x10
dquot_file_open+0x34
f2fs_file_open+0x6c
do_dentry_open+0x1e4
vfs_open+0x6c
path_openat+0xa20
do_filp_open+0x4c
do_sys_open+0x178

Signed-off-by: Ritesh Harjani <riteshh@codeaurora.org>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This commit is contained in:
Ritesh Harjani 2018-03-16 18:53:53 +05:30 committed by Jaegeuk Kim
parent ff62af200b
commit 02117b8ae9
1 changed files with 1 additions and 1 deletions
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2
fs/f2fs/super.c
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@ -1572,7 +1572,7 @@ static ssize_t f2fs_quota_read(struct super_block *sb, int type, char *data,
while (toread > 0) {
tocopy = min_t(unsigned long, sb->s_blocksize - offset, toread);
repeat:
page = read_mapping_page(mapping, blkidx, NULL);
page = read_cache_page_gfp(mapping, blkidx, GFP_NOFS);
if (IS_ERR(page)) {
if (PTR_ERR(page) == -ENOMEM) {
congestion_wait(BLK_RW_ASYNC, HZ/50);