From ad5e195ac9fdf4e2b28b8cf14937e5b9384dac2e Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Sat, 23 Oct 2010 07:00:16 -0400 Subject: [PATCH] fs: Stop abusing find_inode_fast in iunique Stop abusing find_inode_fast for iunique and opencode the inode hash walk. Introduce a new iunique_lock to protect the iunique counters once inode_lock is removed. Based on a patch originally from Nick Piggin. Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro --- fs/inode.c | 30 +++++++++++++++++++++++++----- 1 file changed, 25 insertions(+), 5 deletions(-) diff --git a/fs/inode.c b/fs/inode.c index 5e5bafe70ceb..a8035e8576df 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -884,6 +884,27 @@ static struct inode *get_new_inode_fast(struct super_block *sb, return inode; } +/* + * search the inode cache for a matching inode number. + * If we find one, then the inode number we are trying to + * allocate is not unique and so we should not use it. + * + * Returns 1 if the inode number is unique, 0 if it is not. + */ +static int test_inode_iunique(struct super_block *sb, unsigned long ino) +{ + struct hlist_head *b = inode_hashtable + hash(sb, ino); + struct hlist_node *node; + struct inode *inode; + + hlist_for_each_entry(inode, node, b, i_hash) { + if (inode->i_ino == ino && inode->i_sb == sb) + return 0; + } + + return 1; +} + /** * iunique - get a unique inode number * @sb: superblock @@ -905,19 +926,18 @@ ino_t iunique(struct super_block *sb, ino_t max_reserved) * error if st_ino won't fit in target struct field. Use 32bit counter * here to attempt to avoid that. */ + static DEFINE_SPINLOCK(iunique_lock); static unsigned int counter; - struct inode *inode; - struct hlist_head *head; ino_t res; spin_lock(&inode_lock); + spin_lock(&iunique_lock); do { if (counter <= max_reserved) counter = max_reserved + 1; res = counter++; - head = inode_hashtable + hash(sb, res); - inode = find_inode_fast(sb, head, res); - } while (inode != NULL); + } while (!test_inode_iunique(sb, res)); + spin_unlock(&iunique_lock); spin_unlock(&inode_lock); return res;