From 261bca86ed4f7f391d1938167624e78da61dcc6b Mon Sep 17 00:00:00 2001 From: Al Viro Date: Tue, 30 Dec 2008 01:48:21 -0500 Subject: nfsd/create race fixes, infrastructure new helpers - insert_inode_locked() and insert_inode_locked4(). Hash new inode, making sure that there's no such inode in icache already. If there is and it does not end up unhashed (as would happen if we have nfsd trying to resolve a bogus fhandle), fail. Otherwise insert our inode into hash and succeed. In either case have i_state set to new+locked; cleanup ends up being simpler with such calling conventions. Signed-off-by: Al Viro --- fs/inode.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/fs.h | 2 ++ 2 files changed, 61 insertions(+) diff --git a/fs/inode.c b/fs/inode.c index 098a2443196..7de1cda9248 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -1032,6 +1032,65 @@ struct inode *iget_locked(struct super_block *sb, unsigned long ino) EXPORT_SYMBOL(iget_locked); +int insert_inode_locked(struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + ino_t ino = inode->i_ino; + struct hlist_head *head = inode_hashtable + hash(sb, ino); + struct inode *old; + + inode->i_state |= I_LOCK|I_NEW; + while (1) { + spin_lock(&inode_lock); + old = find_inode_fast(sb, head, ino); + if (likely(!old)) { + hlist_add_head(&inode->i_hash, head); + spin_unlock(&inode_lock); + return 0; + } + __iget(old); + spin_unlock(&inode_lock); + wait_on_inode(old); + if (unlikely(!hlist_unhashed(&old->i_hash))) { + iput(old); + return -EBUSY; + } + iput(old); + } +} + +EXPORT_SYMBOL(insert_inode_locked); + +int insert_inode_locked4(struct inode *inode, unsigned long hashval, + int (*test)(struct inode *, void *), void *data) +{ + struct super_block *sb = inode->i_sb; + struct hlist_head *head = inode_hashtable + hash(sb, hashval); + struct inode *old; + + inode->i_state |= I_LOCK|I_NEW; + + while (1) { + spin_lock(&inode_lock); + old = find_inode(sb, head, test, data); + if (likely(!old)) { + hlist_add_head(&inode->i_hash, head); + spin_unlock(&inode_lock); + return 0; + } + __iget(old); + spin_unlock(&inode_lock); + wait_on_inode(old); + if (unlikely(!hlist_unhashed(&old->i_hash))) { + iput(old); + return -EBUSY; + } + iput(old); + } +} + +EXPORT_SYMBOL(insert_inode_locked4); + /** * __insert_inode_hash - hash an inode * @inode: unhashed inode diff --git a/include/linux/fs.h b/include/linux/fs.h index be16ce01fb1..e2170ee21e1 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1902,6 +1902,8 @@ extern struct inode *ilookup(struct super_block *sb, unsigned long ino); extern struct inode * iget5_locked(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 int insert_inode_locked4(struct inode *, unsigned long, int (*test)(struct inode *, void *), void *); +extern int insert_inode_locked(struct inode *); extern void unlock_new_inode(struct inode *); extern void __iget(struct inode * inode); -- cgit v1.2.3-70-g09d2