diff --git a/fs/inode.c b/fs/inode.c
index 3a41f83a4ba5598536d57b8a5230f34da66621aa..8c57cea7bbbb6b3ed5a83e7a7b09df326b4b55ea 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -886,36 +886,45 @@ long prune_icache_sb(struct super_block *sb, struct shrink_control *sc)
return freed;
}
-static void __wait_on_freeing_inode(struct inode *inode);
+static void __wait_on_freeing_inode(struct inode *inode, bool locked);
/*
* Called with the inode lock held.
*/
static struct inode *find_inode(struct super_block *sb,
struct hlist_head *head,
int (*test)(struct inode *, void *),
- void *data)
+ void *data, bool locked)
{
struct inode *inode = NULL;
+ if (locked)
+ lockdep_assert_held(&inode_hash_lock);
+ else
+ lockdep_assert_not_held(&inode_hash_lock);
+
+ rcu_read_lock();
repeat:
- hlist_for_each_entry(inode, head, i_hash) {
+ hlist_for_each_entry_rcu(inode, head, i_hash) {
if (inode->i_sb != sb)
continue;
if (!test(inode, data))
continue;
spin_lock(&inode->i_lock);
if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
- __wait_on_freeing_inode(inode);
+ __wait_on_freeing_inode(inode, locked);
goto repeat;
}
if (unlikely(inode->i_state & I_CREATING)) {
spin_unlock(&inode->i_lock);
+ rcu_read_unlock();
return ERR_PTR(-ESTALE);
}
__iget(inode);
spin_unlock(&inode->i_lock);
+ rcu_read_unlock();
return inode;
}
+ rcu_read_unlock();
return NULL;
}
@@ -924,29 +933,39 @@ static struct inode *find_inode(struct super_block *sb,
* iget_locked for details.
*/
static struct inode *find_inode_fast(struct super_block *sb,
- struct hlist_head *head, unsigned long ino)
+ struct hlist_head *head, unsigned long ino,
+ bool locked)
{
struct inode *inode = NULL;
+ if (locked)
+ lockdep_assert_held(&inode_hash_lock);
+ else
+ lockdep_assert_not_held(&inode_hash_lock);
+
+ rcu_read_lock();
repeat:
- hlist_for_each_entry(inode, head, i_hash) {
+ hlist_for_each_entry_rcu(inode, head, i_hash) {
if (inode->i_ino != ino)
continue;
if (inode->i_sb != sb)
continue;
spin_lock(&inode->i_lock);
if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
- __wait_on_freeing_inode(inode);
+ __wait_on_freeing_inode(inode, locked);
goto repeat;
}
if (unlikely(inode->i_state & I_CREATING)) {
spin_unlock(&inode->i_lock);
+ rcu_read_unlock();
return ERR_PTR(-ESTALE);
}
__iget(inode);
spin_unlock(&inode->i_lock);
+ rcu_read_unlock();
return inode;
}
+ rcu_read_unlock();
return NULL;
}
@@ -1161,7 +1180,7 @@ struct inode *inode_insert5(struct inode *inode, unsigned long hashval,
again:
spin_lock(&inode_hash_lock);
- old = find_inode(inode->i_sb, head, test, data);
+ old = find_inode(inode->i_sb, head, test, data, true);
if (unlikely(old)) {
/*
* Uhhuh, somebody else created the same inode under us.
@@ -1245,6 +1264,48 @@ struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
}
EXPORT_SYMBOL(iget5_locked);
+/**
+ * iget5_locked_rcu - obtain an inode from a mounted file system
+ * @sb: super block of file system
+ * @hashval: hash value (usually inode number) to get
+ * @test: callback used for comparisons between inodes
+ * @set: callback used to initialize a new struct inode
+ * @data: opaque data pointer to pass to @test and @set
+ *
+ * This is equivalent to iget5_locked, except the @test callback must
+ * tolerate the inode not being stable, including being mid-teardown.
+ */
+struct inode *iget5_locked_rcu(struct super_block *sb, unsigned long hashval,
+ int (*test)(struct inode *, void *),
+ int (*set)(struct inode *, void *), void *data)
+{
+ struct hlist_head *head = inode_hashtable + hash(sb, hashval);
+ struct inode *inode, *new;
+
+again:
+ inode = find_inode(sb, head, test, data, false);
+ if (inode) {
+ if (IS_ERR(inode))
+ return NULL;
+ wait_on_inode(inode);
+ if (unlikely(inode_unhashed(inode))) {
+ iput(inode);
+ goto again;
+ }
+ return inode;
+ }
+
+ new = alloc_inode(sb);
+ if (new) {
+ new->i_state = 0;
+ inode = inode_insert5(new, hashval, test, set, data);
+ if (unlikely(inode != new))
+ destroy_inode(new);
+ }
+ return inode;
+}
+EXPORT_SYMBOL_GPL(iget5_locked_rcu);
+
/**
* iget_locked - obtain an inode from a mounted file system
* @sb: super block of file system
@@ -1263,9 +1324,7 @@ struct inode *iget_locked(struct super_block *sb, unsigned long ino)
struct hlist_head *head = inode_hashtable + hash(sb, ino);
struct inode *inode;
again:
- spin_lock(&inode_hash_lock);
- inode = find_inode_fast(sb, head, ino);
- spin_unlock(&inode_hash_lock);
+ inode = find_inode_fast(sb, head, ino, false);
if (inode) {
if (IS_ERR(inode))
return NULL;
@@ -1283,7 +1342,7 @@ struct inode *iget_locked(struct super_block *sb, unsigned long ino)
spin_lock(&inode_hash_lock);
/* We released the lock, so.. */
- old = find_inode_fast(sb, head, ino);
+ old = find_inode_fast(sb, head, ino, true);
if (!old) {
inode->i_ino = ino;
spin_lock(&inode->i_lock);
@@ -1419,7 +1478,7 @@ struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
struct inode *inode;
spin_lock(&inode_hash_lock);
- inode = find_inode(sb, head, test, data);
+ inode = find_inode(sb, head, test, data, true);
spin_unlock(&inode_hash_lock);
return IS_ERR(inode) ? NULL : inode;
@@ -1474,7 +1533,7 @@ struct inode *ilookup(struct super_block *sb, unsigned long ino)
struct inode *inode;
again:
spin_lock(&inode_hash_lock);
- inode = find_inode_fast(sb, head, ino);
+ inode = find_inode_fast(sb, head, ino, true);
spin_unlock(&inode_hash_lock);
if (inode) {
@@ -2235,17 +2294,21 @@ EXPORT_SYMBOL(inode_needs_sync);
* wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list
* will DTRT.
*/
-static void __wait_on_freeing_inode(struct inode *inode)
+static void __wait_on_freeing_inode(struct inode *inode, bool locked)
{
wait_queue_head_t *wq;
DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW);
wq = bit_waitqueue(&inode->i_state, __I_NEW);
prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE);
spin_unlock(&inode->i_lock);
- spin_unlock(&inode_hash_lock);
+ rcu_read_unlock();
+ if (locked)
+ spin_unlock(&inode_hash_lock);
schedule();
finish_wait(wq, &wait.wq_entry);
- spin_lock(&inode_hash_lock);
+ if (locked)
+ spin_lock(&inode_hash_lock);
+ rcu_read_lock();
}
static __initdata unsigned long ihash_entries;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 0283cf366c2a93fd0799e7acf14973b93fb64301..aac51da4f90cc5918b950b76a9a1c68d566fb0d6 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3029,7 +3029,12 @@ extern struct inode *inode_insert5(struct inode *inode, unsigned long hashval,
int (*test)(struct inode *, void *),
int (*set)(struct inode *, void *),
void *data);
-extern struct inode * iget5_locked(struct super_block *, unsigned long, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *);
+struct inode *iget5_locked(struct super_block *, unsigned long,
+ int (*test)(struct inode *, void *),
+ int (*set)(struct inode *, void *), void *);
+struct inode *iget5_locked_rcu(struct super_block *, unsigned long,
+ int (*test)(struct inode *, void *),
+ int (*set)(struct inode *, void *), void *);
extern struct inode * iget_locked(struct super_block *, unsigned long);
extern struct inode *find_inode_nowait(struct super_block *,
unsigned long,