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 <npiggin@xxxxxxxxx>
---
fs/namei.c | 70 ++++++++++++++++++++++++++++---------------------------------
1 file changed, 33 insertions(+), 37 deletions(-)
Index: linux-2.6/fs/namei.c
===================================================================
--- linux-2.6.orig/fs/namei.c 2010-08-18 04:04:29.000000000 +1000
+++ linux-2.6/fs/namei.c 2010-08-18 04:05:12.000000000 +1000
@@ -686,6 +686,35 @@ static __always_inline void follow_dotdo
}
/*
+ * 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.
* It _is_ time-critical.
@@ -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(stru
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;
}
--
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