maillist inclusion category: bugfix bugzilla: 188812,https://gitee.com/openeuler/kernel/issues/I7E0YR
Reference: https://www.spinics.net/lists/kernel/msg4844759.html
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As Honza said, remove_inode_dquot_ref() currently does not release the last dquot reference but instead adds the dquot to tofree_head list. This is because dqput() can sleep while dropping of the last dquot reference (writing back the dquot and calling ->release_dquot()) and that must not happen under dq_list_lock. Now that dqput() queues the final dquot cleanup into a workqueue, remove_inode_dquot_ref() can call dqput() unconditionally and we can significantly simplify it.
Here we open code the simplified code of remove_inode_dquot_ref() into remove_dquot_ref() and remove the function put_dquot_list() which is no longer used.
Signed-off-by: Baokun Li libaokun1@huawei.com --- fs/quota/dquot.c | 70 +++++++----------------------------------------- 1 file changed, 9 insertions(+), 61 deletions(-)
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c index 6697de231735..47aaf8328c97 100644 --- a/fs/quota/dquot.c +++ b/fs/quota/dquot.c @@ -1074,59 +1074,7 @@ static int add_dquot_ref(struct super_block *sb, int type) return err; }
-/* - * Remove references to dquots from inode and add dquot to list for freeing - * if we have the last reference to dquot - */ -static void remove_inode_dquot_ref(struct inode *inode, int type, - struct list_head *tofree_head) -{ - struct dquot **dquots = i_dquot(inode); - struct dquot *dquot = dquots[type]; - - if (!dquot) - return; - - dquots[type] = NULL; - if (list_empty(&dquot->dq_free)) { - /* - * The inode still has reference to dquot so it can't be in the - * free list - */ - spin_lock(&dq_list_lock); - list_add(&dquot->dq_free, tofree_head); - spin_unlock(&dq_list_lock); - } else { - /* - * Dquot is already in a list to put so we won't drop the last - * reference here. - */ - dqput(dquot); - } -} - -/* - * Free list of dquots - * Dquots are removed from inodes and no new references can be got so we are - * the only ones holding reference - */ -static void put_dquot_list(struct list_head *tofree_head) -{ - struct list_head *act_head; - struct dquot *dquot; - - act_head = tofree_head->next; - while (act_head != tofree_head) { - dquot = list_entry(act_head, struct dquot, dq_free); - act_head = act_head->next; - /* Remove dquot from the list so we won't have problems... */ - list_del_init(&dquot->dq_free); - dqput(dquot); - } -} - -static void remove_dquot_ref(struct super_block *sb, int type, - struct list_head *tofree_head) +static void remove_dquot_ref(struct super_block *sb, int type) { struct inode *inode; #ifdef CONFIG_QUOTA_DEBUG @@ -1143,11 +1091,16 @@ static void remove_dquot_ref(struct super_block *sb, int type, */ spin_lock(&dq_data_lock); if (!IS_NOQUOTA(inode)) { + struct dquot **dquots = i_dquot(inode); + struct dquot *dquot = dquots[type]; + #ifdef CONFIG_QUOTA_DEBUG if (unlikely(inode_get_rsv_space(inode) > 0)) reserved = 1; #endif - remove_inode_dquot_ref(inode, type, tofree_head); + dquots[type] = NULL; + if (dquot) + dqput(dquot); } spin_unlock(&dq_data_lock); } @@ -1164,13 +1117,8 @@ static void remove_dquot_ref(struct super_block *sb, int type, /* Gather all references from inodes and drop them */ static void drop_dquot_ref(struct super_block *sb, int type) { - LIST_HEAD(tofree_head); - - if (sb->dq_op) { - remove_dquot_ref(sb, type, &tofree_head); - synchronize_srcu(&dquot_srcu); - put_dquot_list(&tofree_head); - } + if (sb->dq_op) + remove_dquot_ref(sb, type); }
static inline