From: Dmitry Monakhov <dmtrmonakhov@xxxxxxxxxxxxxx> commit 6ff33d99fc5c96797103b48b7b0902c296f09c05 upstream. Write only quotas which are dirty at entry. XFSTEST: https://github.com/dmonakhov/xfstests/commit/b10ad23566a5bf75832a6f500e1236084083cddc Link: https://lore.kernel.org/r/20191031103920.3919-1-dmonakhov@xxxxxxxxxx CC: stable@xxxxxxxxxxxxxxx Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx> Signed-off-by: Dmitry Monakhov <dmtrmonakhov@xxxxxxxxxxxxxx> Signed-off-by: Jan Kara <jack@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/quota/dquot.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) --- a/fs/quota/dquot.c +++ b/fs/quota/dquot.c @@ -623,7 +623,7 @@ EXPORT_SYMBOL(dquot_scan_active); /* Write all dquot structures to quota files */ int dquot_writeback_dquots(struct super_block *sb, int type) { - struct list_head *dirty; + struct list_head dirty; struct dquot *dquot; struct quota_info *dqopt = sb_dqopt(sb); int cnt; @@ -637,9 +637,10 @@ int dquot_writeback_dquots(struct super_ if (!sb_has_quota_active(sb, cnt)) continue; spin_lock(&dq_list_lock); - dirty = &dqopt->info[cnt].dqi_dirty_list; - while (!list_empty(dirty)) { - dquot = list_first_entry(dirty, struct dquot, + /* Move list away to avoid livelock. */ + list_replace_init(&dqopt->info[cnt].dqi_dirty_list, &dirty); + while (!list_empty(&dirty)) { + dquot = list_first_entry(&dirty, struct dquot, dq_dirty); WARN_ON(!test_bit(DQ_ACTIVE_B, &dquot->dq_flags));
