From 8290c35f87304a6b73d4fd17b03580b4f7425de8 Mon Sep 17 00:00:00 2001 From: David Chinner Date: Thu, 30 Oct 2008 17:35:24 +1100 Subject: [PATCH] Inode: Allow external list initialisation To allow XFS to combine the XFS and linux inodes into a single structure, we need to drive inode lookup from the XFS inode cache, not the generic inode cache. This means that we need initialise a struct inode from a context outside alloc_inode() as it is no longer used by XFS. After inode allocation and initialisation, we need to add the inode to the superblock list, the in-use list, hash it and do some accounting. This all needs to be done with the inode_lock held and there are already several places in fs/inode.c that do this list manipulation. Factor out the common code, add a locking wrapper and export the function so ti can be called from XFS. Signed-off-by: Dave Chinner Signed-off-by: Christoph Hellwig Signed-off-by: Lachlan McIlroy --- fs/inode.c | 67 +++++++++++++++++++++++++++++++--------------- include/linux/fs.h | 1 + 2 files changed, 47 insertions(+), 21 deletions(-) diff --git a/fs/inode.c b/fs/inode.c index e7ee99907d6..fbcf6c5e760 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -550,6 +550,49 @@ repeat: return node ? inode : NULL; } +static unsigned long hash(struct super_block *sb, unsigned long hashval) +{ + unsigned long tmp; + + tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) / + L1_CACHE_BYTES; + tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS); + return tmp & I_HASHMASK; +} + +static inline void +__inode_add_to_lists(struct super_block *sb, struct hlist_head *head, + struct inode *inode) +{ + inodes_stat.nr_inodes++; + list_add(&inode->i_list, &inode_in_use); + list_add(&inode->i_sb_list, &sb->s_inodes); + if (head) + hlist_add_head(&inode->i_hash, head); +} + +/** + * inode_add_to_lists - add a new inode to relevant lists + * @sb - superblock inode belongs to. + * @inode - inode to mark in use + * + * When an inode is allocated it needs to be accounted for, added to the in use + * list, the owning superblock and the inode hash. This needs to be done under + * the inode_lock, so export a function to do this rather than the inode lock + * itself. We calculate the hash list to add to here so it is all internal + * which requires the caller to have already set up the inode number in the + * inode to add. + */ +void inode_add_to_lists(struct super_block *sb, struct inode *inode) +{ + struct hlist_head *head = inode_hashtable + hash(sb, inode->i_ino); + + spin_lock(&inode_lock); + __inode_add_to_lists(sb, head, inode); + spin_unlock(&inode_lock); +} +EXPORT_SYMBOL_GPL(inode_add_to_lists); + /** * new_inode - obtain an inode * @sb: superblock @@ -577,9 +620,7 @@ struct inode *new_inode(struct super_block *sb) inode = alloc_inode(sb); if (inode) { spin_lock(&inode_lock); - inodes_stat.nr_inodes++; - list_add(&inode->i_list, &inode_in_use); - list_add(&inode->i_sb_list, &sb->s_inodes); + __inode_add_to_lists(sb, NULL, inode); inode->i_ino = ++last_ino; inode->i_state = 0; spin_unlock(&inode_lock); @@ -638,10 +679,7 @@ static struct inode * get_new_inode(struct super_block *sb, struct hlist_head *h if (set(inode, data)) goto set_failed; - inodes_stat.nr_inodes++; - list_add(&inode->i_list, &inode_in_use); - list_add(&inode->i_sb_list, &sb->s_inodes); - hlist_add_head(&inode->i_hash, head); + __inode_add_to_lists(sb, head, inode); inode->i_state = I_LOCK|I_NEW; spin_unlock(&inode_lock); @@ -687,10 +725,7 @@ static struct inode * get_new_inode_fast(struct super_block *sb, struct hlist_he old = find_inode_fast(sb, head, ino); if (!old) { inode->i_ino = ino; - inodes_stat.nr_inodes++; - list_add(&inode->i_list, &inode_in_use); - list_add(&inode->i_sb_list, &sb->s_inodes); - hlist_add_head(&inode->i_hash, head); + __inode_add_to_lists(sb, head, inode); inode->i_state = I_LOCK|I_NEW; spin_unlock(&inode_lock); @@ -714,16 +749,6 @@ static struct inode * get_new_inode_fast(struct super_block *sb, struct hlist_he return inode; } -static unsigned long hash(struct super_block *sb, unsigned long hashval) -{ - unsigned long tmp; - - tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) / - L1_CACHE_BYTES; - tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS); - return tmp & I_HASHMASK; -} - /** * iunique - get a unique inode number * @sb: superblock diff --git a/include/linux/fs.h b/include/linux/fs.h index 04abead4b02..1deedf235d5 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1883,6 +1883,7 @@ extern loff_t vfs_llseek(struct file *file, loff_t offset, int origin); extern struct inode * inode_init_always(struct super_block *, struct inode *); extern void inode_init_once(struct inode *); +extern void inode_add_to_lists(struct super_block *, struct inode *); extern void iput(struct inode *); extern struct inode * igrab(struct inode *); extern ino_t iunique(struct super_block *, ino_t);