From baa0389073eb7beb9d36f6d13df97e16c1bfa626 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Wed, 18 Aug 2010 04:37:31 +1000 Subject: [PATCH] fs: dentry allocation consolidation fs: dentry allocation consolidation There are 2 duplicate copies of code in dentry allocation in path lookup. Consolidate them into a single function. Signed-off-by: Nick Piggin Signed-off-by: Al Viro --- fs/namei.c | 70 +++++++++++++++++++++++++----------------------------- 1 file changed, 33 insertions(+), 37 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index c2742b7dec59..b815a4d2e1d6 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -685,6 +685,35 @@ static __always_inline void follow_dotdot(struct nameidata *nd) follow_mount(&nd->path); } +/* + * Allocate a dentry with name and parent, and perform a parent + * directory ->lookup on it. Returns the new dentry, or ERR_PTR + * on error. parent->d_inode->i_mutex must be held. d_lookup must + * have verified that no child exists while under i_mutex. + */ +static struct dentry *d_alloc_and_lookup(struct dentry *parent, + struct qstr *name, struct nameidata *nd) +{ + struct inode *inode = parent->d_inode; + struct dentry *dentry; + struct dentry *old; + + /* Don't create child dentry for a dead directory. */ + if (unlikely(IS_DEADDIR(inode))) + return ERR_PTR(-ENOENT); + + dentry = d_alloc(parent, name); + if (unlikely(!dentry)) + return ERR_PTR(-ENOMEM); + + old = inode->i_op->lookup(inode, dentry, nd); + if (unlikely(old)) { + dput(dentry); + dentry = old; + } + return dentry; +} + /* * It's more convoluted than I'd like it to be, but... it's still fairly * small and for now I'd prefer to have fast path as straight as possible. @@ -738,30 +767,13 @@ need_lookup: * so doing d_lookup() (with seqlock), instead of lockfree __d_lookup */ dentry = d_lookup(parent, name); - if (!dentry) { - struct dentry *new; - - /* Don't create child dentry for a dead directory. */ - dentry = ERR_PTR(-ENOENT); - if (IS_DEADDIR(dir)) - goto out_unlock; - - new = d_alloc(parent, name); - dentry = ERR_PTR(-ENOMEM); - if (new) { - dentry = dir->i_op->lookup(dir, new, nd); - if (dentry) - dput(new); - else - dentry = new; - } -out_unlock: + if (likely(!dentry)) { + dentry = d_alloc_and_lookup(parent, name, nd); mutex_unlock(&dir->i_mutex); if (IS_ERR(dentry)) goto fail; goto done; } - /* * Uhhuh! Nasty case: the cache was re-populated while * we waited on the semaphore. Need to revalidate. @@ -1135,24 +1147,8 @@ static struct dentry *__lookup_hash(struct qstr *name, if (dentry && dentry->d_op && dentry->d_op->d_revalidate) dentry = do_revalidate(dentry, nd); - if (!dentry) { - struct dentry *new; - - /* Don't create child dentry for a dead directory. */ - dentry = ERR_PTR(-ENOENT); - if (IS_DEADDIR(inode)) - goto out; - - new = d_alloc(base, name); - dentry = ERR_PTR(-ENOMEM); - if (!new) - goto out; - dentry = inode->i_op->lookup(inode, new, nd); - if (!dentry) - dentry = new; - else - dput(new); - } + if (!dentry) + dentry = d_alloc_and_lookup(base, name, nd); out: return dentry; } -- 2.20.1