From a97c9bf33f4612e2aed6f000f6b1d268b6814f3c Mon Sep 17 00:00:00 2001 From: Dave Johnson Date: Tue, 6 Sep 2005 15:17:40 -0700 Subject: [PATCH] [PATCH] fix cramfs making duplicate entries in inode cache Every time cramfs_lookup() is called to lookup and inode for a dentry, get_cramfs_inode() will allocate a new inode without checking to see if that inode already exists in the inode cache. This is fine the first time, but if the dentry cache entry(ies) associated with that inode are aged out, but the inode entry is not aged out (which can be quite common if the inode has buffer cache linked to it), cramfs_lookup() will be called again and another inode will be allocated and added to the inode cache creating a duplicate in the inode cache. The big issue here is that the buffers associated with each inode cache entry are not shared between the duplicates! The older inode entries are now orphaned as no dentry points to it and won't be freed until the buffer cache assoicated with them are first freed. The newest entry will have to create all new buffer cache for each part of its file as the old buffer cache is now orphaned as well. Patch below fixes this by making get_cramfs_inode() use the inode cache before blindly creating a new entry every time. This eliminates the duplicate inodes and duplicate buffer cache. Cc: Phillip Lougher Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/cramfs/inode.c | 43 +++++++++++++++++++++++++++++++++++++++---- 1 file changed, 39 insertions(+), 4 deletions(-) diff --git a/fs/cramfs/inode.c b/fs/cramfs/inode.c index 6c285efa..7fe85415 100644 --- a/fs/cramfs/inode.c +++ b/fs/cramfs/inode.c @@ -39,12 +39,47 @@ static DECLARE_MUTEX(read_mutex); #define CRAMINO(x) ((x)->offset?(x)->offset<<2:1) #define OFFSET(x) ((x)->i_ino) -static struct inode *get_cramfs_inode(struct super_block *sb, struct cramfs_inode * cramfs_inode) + +static int cramfs_iget5_test(struct inode *inode, void *opaque) +{ + struct cramfs_inode *cramfs_inode = opaque; + + if (inode->i_ino != CRAMINO(cramfs_inode)) + return 0; /* does not match */ + + if (inode->i_ino != 1) + return 1; + + /* all empty directories, char, block, pipe, and sock, share inode #1 */ + + if ((inode->i_mode != cramfs_inode->mode) || + (inode->i_gid != cramfs_inode->gid) || + (inode->i_uid != cramfs_inode->uid)) + return 0; /* does not match */ + + if ((S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) && + (inode->i_rdev != old_decode_dev(cramfs_inode->size))) + return 0; /* does not match */ + + return 1; /* matches */ +} + +static int cramfs_iget5_set(struct inode *inode, void *opaque) +{ + struct cramfs_inode *cramfs_inode = opaque; + inode->i_ino = CRAMINO(cramfs_inode); + return 0; +} + +static struct inode *get_cramfs_inode(struct super_block *sb, + struct cramfs_inode * cramfs_inode) { - struct inode * inode = new_inode(sb); + struct inode *inode = iget5_locked(sb, CRAMINO(cramfs_inode), + cramfs_iget5_test, cramfs_iget5_set, + cramfs_inode); static struct timespec zerotime; - if (inode) { + if (inode && (inode->i_state & I_NEW)) { inode->i_mode = cramfs_inode->mode; inode->i_uid = cramfs_inode->uid; inode->i_size = cramfs_inode->size; @@ -58,7 +93,6 @@ static struct inode *get_cramfs_inode(struct super_block *sb, struct cramfs_inod but it's the best we can do without reading the directory contents. 1 yields the right result in GNU find, even without -noleaf option. */ - insert_inode_hash(inode); if (S_ISREG(inode->i_mode)) { inode->i_fop = &generic_ro_fops; inode->i_data.a_ops = &cramfs_aops; @@ -74,6 +108,7 @@ static struct inode *get_cramfs_inode(struct super_block *sb, struct cramfs_inod init_special_inode(inode, inode->i_mode, old_decode_dev(cramfs_inode->size)); } + unlock_new_inode(inode); } return inode; } -- 2.7.4