From: Sage Weil <sage@xxxxxxxxxxxx>
Get rid of the goto by flipping the if (!result) over. Make the comments
a bit more descriptive. Fix a few kernel style problems. No functional
changes.
Cc: Ian Kent <raven@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Andreas Dilger <adilger@xxxxxxx>
Signed-off-by: Yehuda Sadeh <yehuda@xxxxxxxxxxxx>
Signed-off-by: Sage Weil <sage@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/namei.c | 65 ++++++++++++++++++++++++++-------------------------
1 file changed, 34 insertions(+), 31 deletions(-)
diff -puN fs/namei.c~vfs-clean-up-real_lookup fs/namei.c
--- a/fs/namei.c~vfs-clean-up-real_lookup
+++ a/fs/namei.c
@@ -469,19 +469,20 @@ ok:
* This is called when everything else fails, and we actually have
* to go to the low-level filesystem to find out what we should do..
*
- * We get the directory semaphore, and after getting that we also
+ * We get the directory mutex, and after getting that we also
* make sure that nobody added the entry to the dcache in the meantime..
* SMP-safe
*/
-static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd)
+static struct dentry *real_lookup(struct dentry *parent, struct qstr *name,
+ struct nameidata *nd)
{
- struct dentry * result;
+ struct dentry *result, *dentry;
struct inode *dir = parent->d_inode;
mutex_lock(&dir->i_mutex);
/*
* First re-do the cached lookup just in case it was created
- * while we waited for the directory semaphore..
+ * while we waited for the directory mutex.
*
* FIXME! This could use version numbering or similar to
* avoid unnecessary cache lookups.
@@ -494,38 +495,40 @@ static struct dentry * real_lookup(struc
* so doing d_lookup() (with seqlock), instead of lockfree __d_lookup
*/
result = d_lookup(parent, name);
- if (!result) {
- struct dentry *dentry;
-
-do_the_lookup:
- /* Don't create child dentry for a dead directory. */
- result = ERR_PTR(-ENOENT);
- if (IS_DEADDIR(dir))
- goto out_unlock;
-
- dentry = d_alloc(parent, name);
- result = ERR_PTR(-ENOMEM);
- if (dentry) {
- result = dir->i_op->lookup(dir, dentry, nd);
+ if (result) {
+ /*
+ * The cache was re-populated while we waited on the
+ * mutex. We need to revalidate, this time while
+ * holding i_mutex (to avoid another race).
+ */
+ if (result->d_op && result->d_op->d_revalidate) {
+ result = do_revalidate(result, nd);
if (result)
- dput(dentry);
- else
- result = dentry;
+ goto out_unlock;
+ /*
+ * The dentry was left behind invalid. Just
+ * do the lookup.
+ */
+ } else {
+ goto out_unlock;
}
-out_unlock:
- mutex_unlock(&dir->i_mutex);
- return result;
}
- /*
- * Uhhuh! Nasty case: the cache was re-populated while
- * we waited on the semaphore. Need to revalidate.
- */
- if (result->d_op && result->d_op->d_revalidate) {
- result = do_revalidate(result, nd);
- if (!result)
- goto do_the_lookup;
+ /* Don't create child dentry for a dead directory. */
+ result = ERR_PTR(-ENOENT);
+ if (IS_DEADDIR(dir))
+ goto out_unlock;
+
+ dentry = d_alloc(parent, name);
+ result = ERR_PTR(-ENOMEM);
+ if (dentry) {
+ result = dir->i_op->lookup(dir, dentry, nd);
+ if (result)
+ dput(dentry);
+ else
+ result = dentry;
}
+out_unlock:
mutex_unlock(&dir->i_mutex);
return result;
}
_
--
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