cleanup d_add_ci

Make sure that comments describe what's going on and not how, and always
use __d_instantiate instead of two separate branches, one with
d_instantiate and one with __d_instantiate.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 18 insertions, 30 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index 07e2d4a44bda..90bbd7e1b116 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1247,15 +1247,18 @@ struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode,
         struct dentry *found;
         struct dentry *new;
 
-        /* Does a dentry matching the name exist already? */
+        /*
+         * First check if a dentry matching the name already exists,
+         * if not go ahead and create it now.
+         */
         found = d_hash_and_lookup(dentry->d_parent, name);
-        /* If not, create it now and return */
         if (!found) {
                 new = d_alloc(dentry->d_parent, name);
                 if (!new) {
                         error = -ENOMEM;
                         goto err_out;
                 }
+
                 found = d_splice_alias(inode, new);
                 if (found) {
                         dput(new);
@@ -1263,61 +1266,46 @@ struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode,
                 }
                 return new;
         }
-        /* Matching dentry exists, check if it is negative. */
+
+        /*
+         * If a matching dentry exists, and it's not negative use it.
+         *
+         * Decrement the reference count to balance the iget() done
+         * earlier on.
+         */
         if (found->d_inode) {
                 if (unlikely(found->d_inode != inode)) {
                         /* This can't happen because bad inodes are unhashed. */
                         BUG_ON(!is_bad_inode(inode));
                         BUG_ON(!is_bad_inode(found->d_inode));
                 }
-                /*
-                 * Already have the inode and the dentry attached, decrement
-                 * the reference count to balance the iget() done
-                 * earlier on.  We found the dentry using d_lookup() so it
-                 * cannot be disconnected and thus we do not need to worry
-                 * about any NFS/disconnectedness issues here.
-                 */
                 iput(inode);
                 return found;
         }
+
         /*
          * Negative dentry: instantiate it unless the inode is a directory and
-         * has a 'disconnected' dentry (i.e. IS_ROOT and DCACHE_DISCONNECTED),
-         * in which case d_move() that in place of the found dentry.
+         * already has a dentry.
          */
-        if (!S_ISDIR(inode->i_mode)) {
-                /* Not a directory; everything is easy. */
-                d_instantiate(found, inode);
-                return found;
-        }
         spin_lock(&dcache_lock);
-        if (list_empty(&inode->i_dentry)) {
-                /*
-                 * Directory without a 'disconnected' dentry; we need to do
-                 * d_instantiate() by hand because it takes dcache_lock which
-                 * we already hold.
-                 */
+        if (!S_ISDIR(inode->i_mode) || list_empty(&inode->i_dentry)) {
                 __d_instantiate(found, inode);
                 spin_unlock(&dcache_lock);
                 security_d_instantiate(found, inode);
                 return found;
         }
+
         /*
-         * Directory with a 'disconnected' dentry; get a reference to the
-         * 'disconnected' dentry.
+         * In case a directory already has a (disconnected) entry grab a
+         * reference to it, move it in place and use it.
          */
         new = list_entry(inode->i_dentry.next, struct dentry, d_alias);
         dget_locked(new);
         spin_unlock(&dcache_lock);
-        /* Do security vodoo. */
         security_d_instantiate(found, inode);
-        /* Move new in place of found. */
         d_move(new, found);
-        /* Balance the iget() we did above. */
         iput(inode);
-        /* Throw away found. */
         dput(found);
-        /* Use new as the actual dentry. */
         return new;
 
 err_out: