From 44396f4b5cb8566f7118aec55eeac99be7ad94cb Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Tue, 31 May 2011 11:58:49 -0400 Subject: fs: add a DCACHE_NEED_LOOKUP flag for d_flags Btrfs (and I'd venture most other fs's) stores its indexes in nice disk order for readdir, but unfortunately in the case of anything that stats the files in order that readdir spits back (like oh say ls) that means we still have to do the normal lookup of the file, which means looking up our other index and then looking up the inode. What I want is a way to create dummy dentries when we find them in readdir so that when ls or anything else subsequently does a stat(), we already have the location information in the dentry and can go straight to the inode itself. The lookup stuff just assumes that if it finds a dentry it is done, it doesn't perform a lookup. So add a DCACHE_NEED_LOOKUP flag so that the lookup code knows it still needs to run i_op->lookup() on the parent to get the inode for the dentry. I have tested this with btrfs and I went from something that looks like this http://people.redhat.com/jwhiter/ls-noreada.png To this http://people.redhat.com/jwhiter/ls-good.png Thats a savings of 1300 seconds, or 22 minutes. That is a significant savings. Thanks, Signed-off-by: Josef Bacik Signed-off-by: Al Viro --- include/linux/dcache.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include/linux/dcache.h') diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 19d90a55541..5fa5bd33b97 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -216,6 +216,7 @@ struct dentry_operations { #define DCACHE_MOUNTED 0x10000 /* is a mountpoint */ #define DCACHE_NEED_AUTOMOUNT 0x20000 /* handle automount on this dir */ #define DCACHE_MANAGE_TRANSIT 0x40000 /* manage transit from this dirent */ +#define DCACHE_NEED_LOOKUP 0x80000 /* dentry requires i_op->lookup */ #define DCACHE_MANAGED_DENTRY \ (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT) @@ -416,6 +417,12 @@ static inline bool d_mountpoint(struct dentry *dentry) return dentry->d_flags & DCACHE_MOUNTED; } +static inline bool d_need_lookup(struct dentry *dentry) +{ + return dentry->d_flags & DCACHE_NEED_LOOKUP; +} + +extern void d_clear_need_lookup(struct dentry *dentry); extern struct dentry *lookup_create(struct nameidata *nd, int is_dir); extern int sysctl_vfs_cache_pressure; -- cgit v1.2.3-70-g09d2 From ed75e95de574c99575e5f3e1d9ca59ea8c12a9cb Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 27 Jun 2011 16:53:43 -0400 Subject: kill lookup_create() folded into the only caller (kern_path_create()) Signed-off-by: Al Viro --- fs/namei.c | 54 +++++++++++++++++--------------------------------- include/linux/dcache.h | 1 - 2 files changed, 18 insertions(+), 37 deletions(-) (limited to 'include/linux/dcache.h') diff --git a/fs/namei.c b/fs/namei.c index b292eb03d9d..b45a039216c 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2258,35 +2258,29 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt, return file; } -/** - * lookup_create - lookup a dentry, creating it if it doesn't exist - * @nd: nameidata info - * @is_dir: directory flag - * - * Simple function to lookup and return a dentry and create it - * if it doesn't exist. Is SMP-safe. - * - * Returns with nd->path.dentry->d_inode->i_mutex locked. - */ -struct dentry *lookup_create(struct nameidata *nd, int is_dir) +struct dentry *kern_path_create(int dfd, const char *pathname, struct path *path, int is_dir) { struct dentry *dentry = ERR_PTR(-EEXIST); + struct nameidata nd; + int error = do_path_lookup(dfd, pathname, LOOKUP_PARENT, &nd); + if (error) + return ERR_PTR(error); - mutex_lock_nested(&nd->path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); /* * Yucky last component or no last component at all? * (foo/., foo/.., /////) */ - if (nd->last_type != LAST_NORM) - goto fail; - nd->flags &= ~LOOKUP_PARENT; - nd->flags |= LOOKUP_CREATE | LOOKUP_EXCL; - nd->intent.open.flags = O_EXCL; + if (nd.last_type != LAST_NORM) + goto out; + nd.flags &= ~LOOKUP_PARENT; + nd.flags |= LOOKUP_CREATE | LOOKUP_EXCL; + nd.intent.open.flags = O_EXCL; /* * Do the final lookup. */ - dentry = lookup_hash(nd); + mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); + dentry = lookup_hash(&nd); if (IS_ERR(dentry)) goto fail; @@ -2298,34 +2292,22 @@ struct dentry *lookup_create(struct nameidata *nd, int is_dir) * all is fine. Let's be bastards - you had / on the end, you've * been asking for (non-existent) directory. -ENOENT for you. */ - if (unlikely(!is_dir && nd->last.name[nd->last.len])) { + if (unlikely(!is_dir && nd.last.name[nd.last.len])) { dput(dentry); dentry = ERR_PTR(-ENOENT); + goto fail; } + *path = nd.path; return dentry; eexist: dput(dentry); dentry = ERR_PTR(-EEXIST); fail: + mutex_unlock(&nd.path.dentry->d_inode->i_mutex); +out: + path_put(&nd.path); return dentry; } -EXPORT_SYMBOL_GPL(lookup_create); - -struct dentry *kern_path_create(int dfd, const char *pathname, struct path *path, int is_dir) -{ - struct nameidata nd; - struct dentry *res; - int error = do_path_lookup(dfd, pathname, LOOKUP_PARENT, &nd); - if (error) - return ERR_PTR(error); - res = lookup_create(&nd, is_dir); - if (IS_ERR(res)) { - mutex_unlock(&nd.path.dentry->d_inode->i_mutex); - path_put(&nd.path); - } - *path = nd.path; - return res; -} EXPORT_SYMBOL(kern_path_create); struct dentry *user_path_create(int dfd, const char __user *pathname, struct path *path, int is_dir) diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 5fa5bd33b97..3f22d8d6d8a 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -423,7 +423,6 @@ static inline bool d_need_lookup(struct dentry *dentry) } extern void d_clear_need_lookup(struct dentry *dentry); -extern struct dentry *lookup_create(struct nameidata *nd, int is_dir); extern int sysctl_vfs_cache_pressure; -- cgit v1.2.3-70-g09d2