Merging upstream version 5.10.216.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 101 insertions, 125 deletions

diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 4bb4b4b79..6a7b7d447 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -401,15 +401,17 @@ int dquot_mark_dquot_dirty(struct dquot *dquot)
 EXPORT_SYMBOL(dquot_mark_dquot_dirty);
 
 /* Dirtify all the dquots - this can block when journalling */
-static inline int mark_all_dquot_dirty(struct dquot * const *dquot)
+static inline int mark_all_dquot_dirty(struct dquot __rcu * const *dquots)
 {
 	int ret, err, cnt;
+	struct dquot *dquot;
 
 	ret = err = 0;
 	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
-		if (dquot[cnt])
+		dquot = srcu_dereference(dquots[cnt], &dquot_srcu);
+		if (dquot)
 			/* Even in case of error we have to continue */
-			ret = mark_dquot_dirty(dquot[cnt]);
+			ret = mark_dquot_dirty(dquot);
 		if (!err)
 			err = ret;
 	}
@@ -1006,14 +1008,15 @@ out:
 }
 EXPORT_SYMBOL(dqget);
 
-static inline struct dquot **i_dquot(struct inode *inode)
+static inline struct dquot __rcu **i_dquot(struct inode *inode)
 {
-	return inode->i_sb->s_op->get_dquots(inode);
+	/* Force __rcu for now until filesystems are fixed */
+	return (struct dquot __rcu **)inode->i_sb->s_op->get_dquots(inode);
 }
 
 static int dqinit_needed(struct inode *inode, int type)
 {
-	struct dquot * const *dquots;
+	struct dquot __rcu * const *dquots;
 	int cnt;
 
 	if (IS_NOQUOTA(inode))
@@ -1086,59 +1089,7 @@ out:
 	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
@@ -1155,11 +1106,18 @@ static void remove_dquot_ref(struct super_block *sb, int type,
 		 */
 		spin_lock(&dq_data_lock);
 		if (!IS_NOQUOTA(inode)) {
+			struct dquot __rcu **dquots = i_dquot(inode);
+			struct dquot *dquot = srcu_dereference_check(
+				dquots[type], &dquot_srcu,
+				lockdep_is_held(&dq_data_lock));
+
 #ifdef CONFIG_QUOTA_DEBUG
 			if (unlikely(inode_get_rsv_space(inode) > 0))
 				reserved = 1;
 #endif
-			remove_inode_dquot_ref(inode, type, tofree_head);
+			rcu_assign_pointer(dquots[type], NULL);
+			if (dquot)
+				dqput(dquot);
 		}
 		spin_unlock(&dq_data_lock);
 	}
@@ -1176,13 +1134,8 @@ 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
@@ -1515,7 +1468,8 @@ static int inode_quota_active(const struct inode *inode)
 static int __dquot_initialize(struct inode *inode, int type)
 {
 	int cnt, init_needed = 0;
-	struct dquot **dquots, *got[MAXQUOTAS] = {};
+	struct dquot __rcu **dquots;
+	struct dquot *got[MAXQUOTAS] = {};
 	struct super_block *sb = inode->i_sb;
 	qsize_t rsv;
 	int ret = 0;
@@ -1590,7 +1544,7 @@ static int __dquot_initialize(struct inode *inode, int type)
 		if (!got[cnt])
 			continue;
 		if (!dquots[cnt]) {
-			dquots[cnt] = got[cnt];
+			rcu_assign_pointer(dquots[cnt], got[cnt]);
 			got[cnt] = NULL;
 			/*
 			 * Make quota reservation system happy if someone
@@ -1598,12 +1552,16 @@ static int __dquot_initialize(struct inode *inode, int type)
 			 */
 			rsv = inode_get_rsv_space(inode);
 			if (unlikely(rsv)) {
+				struct dquot *dquot = srcu_dereference_check(
+					dquots[cnt], &dquot_srcu,
+					lockdep_is_held(&dq_data_lock));
+
 				spin_lock(&inode->i_lock);
 				/* Get reservation again under proper lock */
 				rsv = __inode_get_rsv_space(inode);
-				spin_lock(&dquots[cnt]->dq_dqb_lock);
-				dquots[cnt]->dq_dqb.dqb_rsvspace += rsv;
-				spin_unlock(&dquots[cnt]->dq_dqb_lock);
+				spin_lock(&dquot->dq_dqb_lock);
+				dquot->dq_dqb.dqb_rsvspace += rsv;
+				spin_unlock(&dquot->dq_dqb_lock);
 				spin_unlock(&inode->i_lock);
 			}
 		}
@@ -1625,7 +1583,7 @@ EXPORT_SYMBOL(dquot_initialize);
 
 bool dquot_initialize_needed(struct inode *inode)
 {
-	struct dquot **dquots;
+	struct dquot __rcu **dquots;
 	int i;
 
 	if (!inode_quota_active(inode))
@@ -1650,13 +1608,14 @@ EXPORT_SYMBOL(dquot_initialize_needed);
 static void __dquot_drop(struct inode *inode)
 {
 	int cnt;
-	struct dquot **dquots = i_dquot(inode);
+	struct dquot __rcu **dquots = i_dquot(inode);
 	struct dquot *put[MAXQUOTAS];
 
 	spin_lock(&dq_data_lock);
 	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
-		put[cnt] = dquots[cnt];
-		dquots[cnt] = NULL;
+		put[cnt] = srcu_dereference_check(dquots[cnt], &dquot_srcu,
+					lockdep_is_held(&dq_data_lock));
+		rcu_assign_pointer(dquots[cnt], NULL);
 	}
 	spin_unlock(&dq_data_lock);
 	dqput_all(put);
@@ -1664,7 +1623,7 @@ static void __dquot_drop(struct inode *inode)
 
 void dquot_drop(struct inode *inode)
 {
-	struct dquot * const *dquots;
+	struct dquot __rcu * const *dquots;
 	int cnt;
 
 	if (IS_NOQUOTA(inode))
@@ -1737,7 +1696,8 @@ int __dquot_alloc_space(struct inode *inode, qsize_t number, int flags)
 	int cnt, ret = 0, index;
 	struct dquot_warn warn[MAXQUOTAS];
 	int reserve = flags & DQUOT_SPACE_RESERVE;
-	struct dquot **dquots;
+	struct dquot __rcu **dquots;
+	struct dquot *dquot;
 
 	if (!inode_quota_active(inode)) {
 		if (reserve) {
@@ -1757,27 +1717,26 @@ int __dquot_alloc_space(struct inode *inode, qsize_t number, int flags)
 	index = srcu_read_lock(&dquot_srcu);
 	spin_lock(&inode->i_lock);
 	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
-		if (!dquots[cnt])
+		dquot = srcu_dereference(dquots[cnt], &dquot_srcu);
+		if (!dquot)
 			continue;
 		if (reserve) {
-			ret = dquot_add_space(dquots[cnt], 0, number, flags,
-					      &warn[cnt]);
+			ret = dquot_add_space(dquot, 0, number, flags, &warn[cnt]);
 		} else {
-			ret = dquot_add_space(dquots[cnt], number, 0, flags,
-					      &warn[cnt]);
+			ret = dquot_add_space(dquot, number, 0, flags, &warn[cnt]);
 		}
 		if (ret) {
 			/* Back out changes we already did */
 			for (cnt--; cnt >= 0; cnt--) {
-				if (!dquots[cnt])
+				dquot = srcu_dereference(dquots[cnt], &dquot_srcu);
+				if (!dquot)
 					continue;
-				spin_lock(&dquots[cnt]->dq_dqb_lock);
+				spin_lock(&dquot->dq_dqb_lock);
 				if (reserve)
-					dquot_free_reserved_space(dquots[cnt],
-								  number);
+					dquot_free_reserved_space(dquot, number);
 				else
-					dquot_decr_space(dquots[cnt], number);
-				spin_unlock(&dquots[cnt]->dq_dqb_lock);
+					dquot_decr_space(dquot, number);
+				spin_unlock(&dquot->dq_dqb_lock);
 			}
 			spin_unlock(&inode->i_lock);
 			goto out_flush_warn;
@@ -1807,7 +1766,8 @@ int dquot_alloc_inode(struct inode *inode)
 {
 	int cnt, ret = 0, index;
 	struct dquot_warn warn[MAXQUOTAS];
-	struct dquot * const *dquots;
+	struct dquot __rcu * const *dquots;
+	struct dquot *dquot;
 
 	if (!inode_quota_active(inode))
 		return 0;
@@ -1818,17 +1778,19 @@ int dquot_alloc_inode(struct inode *inode)
 	index = srcu_read_lock(&dquot_srcu);
 	spin_lock(&inode->i_lock);
 	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
-		if (!dquots[cnt])
+		dquot = srcu_dereference(dquots[cnt], &dquot_srcu);
+		if (!dquot)
 			continue;
-		ret = dquot_add_inodes(dquots[cnt], 1, &warn[cnt]);
+		ret = dquot_add_inodes(dquot, 1, &warn[cnt]);
 		if (ret) {
 			for (cnt--; cnt >= 0; cnt--) {
-				if (!dquots[cnt])
+				dquot = srcu_dereference(dquots[cnt], &dquot_srcu);
+				if (!dquot)
 					continue;
 				/* Back out changes we already did */
-				spin_lock(&dquots[cnt]->dq_dqb_lock);
-				dquot_decr_inodes(dquots[cnt], 1);
-				spin_unlock(&dquots[cnt]->dq_dqb_lock);
+				spin_lock(&dquot->dq_dqb_lock);
+				dquot_decr_inodes(dquot, 1);
+				spin_unlock(&dquot->dq_dqb_lock);
 			}
 			goto warn_put_all;
 		}
@@ -1849,7 +1811,8 @@ EXPORT_SYMBOL(dquot_alloc_inode);
  */
 int dquot_claim_space_nodirty(struct inode *inode, qsize_t number)
 {
-	struct dquot **dquots;
+	struct dquot __rcu **dquots;
+	struct dquot *dquot;
 	int cnt, index;
 
 	if (!inode_quota_active(inode)) {
@@ -1865,9 +1828,8 @@ int dquot_claim_space_nodirty(struct inode *inode, qsize_t number)
 	spin_lock(&inode->i_lock);
 	/* Claim reserved quotas to allocated quotas */
 	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
-		if (dquots[cnt]) {
-			struct dquot *dquot = dquots[cnt];
-
+		dquot = srcu_dereference(dquots[cnt], &dquot_srcu);
+		if (dquot) {
 			spin_lock(&dquot->dq_dqb_lock);
 			if (WARN_ON_ONCE(dquot->dq_dqb.dqb_rsvspace < number))
 				number = dquot->dq_dqb.dqb_rsvspace;
@@ -1891,7 +1853,8 @@ EXPORT_SYMBOL(dquot_claim_space_nodirty);
  */
 void dquot_reclaim_space_nodirty(struct inode *inode, qsize_t number)
 {
-	struct dquot **dquots;
+	struct dquot __rcu **dquots;
+	struct dquot *dquot;
 	int cnt, index;
 
 	if (!inode_quota_active(inode)) {
@@ -1907,9 +1870,8 @@ void dquot_reclaim_space_nodirty(struct inode *inode, qsize_t number)
 	spin_lock(&inode->i_lock);
 	/* Claim reserved quotas to allocated quotas */
 	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
-		if (dquots[cnt]) {
-			struct dquot *dquot = dquots[cnt];
-
+		dquot = srcu_dereference(dquots[cnt], &dquot_srcu);
+		if (dquot) {
 			spin_lock(&dquot->dq_dqb_lock);
 			if (WARN_ON_ONCE(dquot->dq_dqb.dqb_curspace < number))
 				number = dquot->dq_dqb.dqb_curspace;
@@ -1935,7 +1897,8 @@ void __dquot_free_space(struct inode *inode, qsize_t number, int flags)
 {
 	unsigned int cnt;
 	struct dquot_warn warn[MAXQUOTAS];
-	struct dquot **dquots;
+	struct dquot __rcu **dquots;
+	struct dquot *dquot;
 	int reserve = flags & DQUOT_SPACE_RESERVE, index;
 
 	if (!inode_quota_active(inode)) {
@@ -1956,17 +1919,18 @@ void __dquot_free_space(struct inode *inode, qsize_t number, int flags)
 		int wtype;
 
 		warn[cnt].w_type = QUOTA_NL_NOWARN;
-		if (!dquots[cnt])
+		dquot = srcu_dereference(dquots[cnt], &dquot_srcu);
+		if (!dquot)
 			continue;
-		spin_lock(&dquots[cnt]->dq_dqb_lock);
-		wtype = info_bdq_free(dquots[cnt], number);
+		spin_lock(&dquot->dq_dqb_lock);
+		wtype = info_bdq_free(dquot, number);
 		if (wtype != QUOTA_NL_NOWARN)
-			prepare_warning(&warn[cnt], dquots[cnt], wtype);
+			prepare_warning(&warn[cnt], dquot, wtype);
 		if (reserve)
-			dquot_free_reserved_space(dquots[cnt], number);
+			dquot_free_reserved_space(dquot, number);
 		else
-			dquot_decr_space(dquots[cnt], number);
-		spin_unlock(&dquots[cnt]->dq_dqb_lock);
+			dquot_decr_space(dquot, number);
+		spin_unlock(&dquot->dq_dqb_lock);
 	}
 	if (reserve)
 		*inode_reserved_space(inode) -= number;
@@ -1990,7 +1954,8 @@ void dquot_free_inode(struct inode *inode)
 {
 	unsigned int cnt;
 	struct dquot_warn warn[MAXQUOTAS];
-	struct dquot * const *dquots;
+	struct dquot __rcu * const *dquots;
+	struct dquot *dquot;
 	int index;
 
 	if (!inode_quota_active(inode))
@@ -2001,16 +1966,16 @@ void dquot_free_inode(struct inode *inode)
 	spin_lock(&inode->i_lock);
 	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
 		int wtype;
-
 		warn[cnt].w_type = QUOTA_NL_NOWARN;
-		if (!dquots[cnt])
+		dquot = srcu_dereference(dquots[cnt], &dquot_srcu);
+		if (!dquot)
 			continue;
-		spin_lock(&dquots[cnt]->dq_dqb_lock);
-		wtype = info_idq_free(dquots[cnt], 1);
+		spin_lock(&dquot->dq_dqb_lock);
+		wtype = info_idq_free(dquot, 1);
 		if (wtype != QUOTA_NL_NOWARN)
-			prepare_warning(&warn[cnt], dquots[cnt], wtype);
-		dquot_decr_inodes(dquots[cnt], 1);
-		spin_unlock(&dquots[cnt]->dq_dqb_lock);
+			prepare_warning(&warn[cnt], dquot, wtype);
+		dquot_decr_inodes(dquot, 1);
+		spin_unlock(&dquot->dq_dqb_lock);
 	}
 	spin_unlock(&inode->i_lock);
 	mark_all_dquot_dirty(dquots);
@@ -2036,8 +2001,9 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
 	qsize_t cur_space;
 	qsize_t rsv_space = 0;
 	qsize_t inode_usage = 1;
+	struct dquot __rcu **dquots;
 	struct dquot *transfer_from[MAXQUOTAS] = {};
-	int cnt, ret = 0;
+	int cnt, index, ret = 0;
 	char is_valid[MAXQUOTAS] = {};
 	struct dquot_warn warn_to[MAXQUOTAS];
 	struct dquot_warn warn_from_inodes[MAXQUOTAS];
@@ -2068,6 +2034,7 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
 	}
 	cur_space = __inode_get_bytes(inode);
 	rsv_space = __inode_get_rsv_space(inode);
+	dquots = i_dquot(inode);
 	/*
 	 * Build the transfer_from list, check limits, and update usage in
 	 * the target structures.
@@ -2082,7 +2049,8 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
 		if (!sb_has_quota_active(inode->i_sb, cnt))
 			continue;
 		is_valid[cnt] = 1;
-		transfer_from[cnt] = i_dquot(inode)[cnt];
+		transfer_from[cnt] = srcu_dereference_check(dquots[cnt],
+				&dquot_srcu, lockdep_is_held(&dq_data_lock));
 		ret = dquot_add_inodes(transfer_to[cnt], inode_usage,
 				       &warn_to[cnt]);
 		if (ret)
@@ -2121,13 +2089,21 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
 						  rsv_space);
 			spin_unlock(&transfer_from[cnt]->dq_dqb_lock);
 		}
-		i_dquot(inode)[cnt] = transfer_to[cnt];
+		rcu_assign_pointer(dquots[cnt], transfer_to[cnt]);
 	}
 	spin_unlock(&inode->i_lock);
 	spin_unlock(&dq_data_lock);
 
-	mark_all_dquot_dirty(transfer_from);
-	mark_all_dquot_dirty(transfer_to);
+	/*
+	 * These arrays are local and we hold dquot references so we don't need
+	 * the srcu protection but still take dquot_srcu to avoid warning in
+	 * mark_all_dquot_dirty().
+	 */
+	index = srcu_read_lock(&dquot_srcu);
+	mark_all_dquot_dirty((struct dquot __rcu **)transfer_from);
+	mark_all_dquot_dirty((struct dquot __rcu **)transfer_to);
+	srcu_read_unlock(&dquot_srcu, index);
+
 	flush_warnings(warn_to);
 	flush_warnings(warn_from_inodes);
 	flush_warnings(warn_from_space);