[PATCH 3/6] vfs: add __d_instantiate() helper

From: OGAWA Hirofumi
Date: Wed Oct 15 2008 - 10:08:46 EST



This adds __d_instantiate() for users which is already taking
dcache_lock, and replace with it.

The part of d_add_ci() isn't equivalent. But it should be needed
fsnotify_d_instantiate() actually, because the path is to add the
inode to negative dentry. fsnotify_d_instantiate() should be called
after change from negative to positive.

__d_instantiate_unique() and d_materialise_unique() does opencoded
optimized version. From history, it seems a intent, so just add comment.

Signed-off-by: OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
---

fs/dcache.c | 29 ++++++++++++++++-------------
1 file changed, 16 insertions(+), 13 deletions(-)

diff -puN fs/dcache.c~dcache-cleanup-3 fs/dcache.c
--- linux-2.6/fs/dcache.c~dcache-cleanup-3 2008-09-30 05:24:37.000000000 +0900
+++ linux-2.6-hirofumi/fs/dcache.c 2008-09-30 05:24:37.000000000 +0900
@@ -981,6 +981,15 @@ struct dentry *d_alloc_name(struct dentr
return d_alloc(parent, &q);
}

+/* the caller must hold dcache_lock */
+static void __d_instantiate(struct dentry *dentry, struct inode *inode)
+{
+ if (inode)
+ list_add(&dentry->d_alias, &inode->i_dentry);
+ dentry->d_inode = inode;
+ fsnotify_d_instantiate(dentry, inode);
+}
+
/**
* d_instantiate - fill in inode information for a dentry
* @entry: dentry to complete
@@ -1000,10 +1009,7 @@ void d_instantiate(struct dentry *entry,
{
BUG_ON(!list_empty(&entry->d_alias));
spin_lock(&dcache_lock);
- if (inode)
- list_add(&entry->d_alias, &inode->i_dentry);
- entry->d_inode = inode;
- fsnotify_d_instantiate(entry, inode);
+ __d_instantiate(entry, inode);
spin_unlock(&dcache_lock);
security_d_instantiate(entry, inode);
}
@@ -1033,6 +1039,7 @@ static struct dentry *__d_instantiate_un
unsigned int hash = entry->d_name.hash;

if (!inode) {
+ /* __d_instantiate() by hand */
entry->d_inode = NULL;
return NULL;
}
@@ -1052,9 +1059,7 @@ static struct dentry *__d_instantiate_un
return alias;
}

- list_add(&entry->d_alias, &inode->i_dentry);
- entry->d_inode = inode;
- fsnotify_d_instantiate(entry, inode);
+ __d_instantiate(entry, inode);
return NULL;
}

@@ -1211,10 +1216,8 @@ struct dentry *d_splice_alias(struct ino
d_move(new, dentry);
iput(inode);
} else {
- /* d_instantiate takes dcache_lock, so we do it by hand */
- list_add(&dentry->d_alias, &inode->i_dentry);
- dentry->d_inode = inode;
- fsnotify_d_instantiate(dentry, inode);
+ /* already taking dcache_lock, so d_add() by hand */
+ __d_instantiate(dentry, inode);
spin_unlock(&dcache_lock);
security_d_instantiate(dentry, inode);
d_rehash(dentry);
@@ -1297,8 +1300,7 @@ struct dentry *d_add_ci(struct dentry *d
* d_instantiate() by hand because it takes dcache_lock which
* we already hold.
*/
- list_add(&found->d_alias, &inode->i_dentry);
- found->d_inode = inode;
+ __d_instantiate(found, inode);
spin_unlock(&dcache_lock);
security_d_instantiate(found, inode);
return found;
@@ -1827,6 +1829,7 @@ struct dentry *d_materialise_unique(stru

if (!inode) {
actual = dentry;
+ /* __d_instantiate() by hand */
dentry->d_inode = NULL;
goto found_lock;
}
_
--
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