diff options
Diffstat (limited to 'fs/inode.c')
| -rw-r--r-- | fs/inode.c | 40 |
1 files changed, 30 insertions, 10 deletions
diff --git a/fs/inode.c b/fs/inode.c index f356fe2ec2b6..470b57ef1cf5 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -676,6 +676,16 @@ static void evict(struct inode *inode) remove_inode_hash(inode); + /* + * Wake up waiters in __wait_on_freeing_inode(). + * + * Lockless hash lookup may end up finding the inode before we removed + * it above, but only lock it *after* we are done with the wakeup below. + * In this case the potential waiter cannot safely block. + * + * The inode being unhashed after the call to remove_inode_hash() is + * used as an indicator whether blocking on it is safe. + */ spin_lock(&inode->i_lock); wake_up_bit(&inode->i_state, __I_NEW); BUG_ON(inode->i_state != (I_FREEING | I_CLEAR)); @@ -888,18 +898,18 @@ long prune_icache_sb(struct super_block *sb, struct shrink_control *sc) return freed; } -static void __wait_on_freeing_inode(struct inode *inode, bool locked); +static void __wait_on_freeing_inode(struct inode *inode, bool is_inode_hash_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, bool locked) + void *data, bool is_inode_hash_locked) { struct inode *inode = NULL; - if (locked) + if (is_inode_hash_locked) lockdep_assert_held(&inode_hash_lock); else lockdep_assert_not_held(&inode_hash_lock); @@ -913,7 +923,7 @@ repeat: continue; spin_lock(&inode->i_lock); if (inode->i_state & (I_FREEING|I_WILL_FREE)) { - __wait_on_freeing_inode(inode, locked); + __wait_on_freeing_inode(inode, is_inode_hash_locked); goto repeat; } if (unlikely(inode->i_state & I_CREATING)) { @@ -936,11 +946,11 @@ repeat: */ static struct inode *find_inode_fast(struct super_block *sb, struct hlist_head *head, unsigned long ino, - bool locked) + bool is_inode_hash_locked) { struct inode *inode = NULL; - if (locked) + if (is_inode_hash_locked) lockdep_assert_held(&inode_hash_lock); else lockdep_assert_not_held(&inode_hash_lock); @@ -954,7 +964,7 @@ repeat: continue; spin_lock(&inode->i_lock); if (inode->i_state & (I_FREEING|I_WILL_FREE)) { - __wait_on_freeing_inode(inode, locked); + __wait_on_freeing_inode(inode, is_inode_hash_locked); goto repeat; } if (unlikely(inode->i_state & I_CREATING)) { @@ -2287,19 +2297,29 @@ 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, bool locked) +static void __wait_on_freeing_inode(struct inode *inode, bool is_inode_hash_locked) { wait_queue_head_t *wq; DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW); + + /* + * Handle racing against evict(), see that routine for more details. + */ + if (unlikely(inode_unhashed(inode))) { + WARN_ON(is_inode_hash_locked); + spin_unlock(&inode->i_lock); + return; + } + wq = bit_waitqueue(&inode->i_state, __I_NEW); prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE); spin_unlock(&inode->i_lock); rcu_read_unlock(); - if (locked) + if (is_inode_hash_locked) spin_unlock(&inode_hash_lock); schedule(); finish_wait(wq, &wait.wq_entry); - if (locked) + if (is_inode_hash_locked) spin_lock(&inode_hash_lock); rcu_read_lock(); } |