[PATCH 50/61] sysfs: make sysfs_drop_dentry() access inodes using ilookup()

Greg Kroah-Hartman
2007-07-11T23:57:09Z

sysfs_drop_dentry() used to go through sd->s_dentry and
sd->s_parent->s_dentry to access the inodes. This is incorrect
because inode can be cached without dentry.

This patch makes sysfs_drop_dentry() access inodes using ilookup() on
sd->s_ino. This is both correct and simpler.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
fs/sysfs/inode.c | 63 ++++++++++++++++++++++++------------------------------
1 files changed, 28 insertions(+), 35 deletions(-)

diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
index ee31bf3..63daa06 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -219,9 +219,9 @@ void sysfs_instantiate(struct dentry *dentry, struct inode *inode)
*/
void sysfs_drop_dentry(struct sysfs_dirent *sd)
{
- struct dentry *dentry = NULL, *parent = NULL;
- struct inode *dir;
+ struct dentry *dentry = NULL;
struct timespec curtime;
+ struct inode *inode;

/* We're not holding a reference to ->s_dentry dentry but the
* field will stay valid as long as sysfs_lock is held.
@@ -229,19 +229,9 @@ void sysfs_drop_dentry(struct sysfs_dirent *sd)
spin_lock(&sysfs_lock);
spin_lock(&dcache_lock);

+ /* drop dentry if it's there and dput() didn't kill it yet */
if (sd->s_dentry && sd->s_dentry->d_inode) {
- /* get dentry if it's there and dput() didn't kill it yet */
dentry = dget_locked(sd->s_dentry);
- parent = dentry->d_parent;
- } else if (sd->s_parent->s_dentry->d_inode) {
- /* We need to update the parent even if dentry for the
- * victim itself doesn't exist.
- */
- parent = dget_locked(sd->s_parent->s_dentry);
- }
-
- /* drop */
- if (dentry) {
spin_lock(&dentry->d_lock);
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
@@ -250,36 +240,39 @@ void sysfs_drop_dentry(struct sysfs_dirent *sd)
spin_unlock(&dcache_lock);
spin_unlock(&sysfs_lock);

- /* nothing to do if the parent isn't in dcache */
- if (!parent)
- return;
+ dput(dentry);
+ /* XXX: unpin if directory, this will go away soon */
+ if (sd->s_type & SYSFS_DIR)
+ dput(dentry);

/* adjust nlink and update timestamp */
- dir = parent->d_inode;
- mutex_lock(&dir->i_mutex);
-
curtime = CURRENT_TIME;

- dir->i_ctime = dir->i_mtime = curtime;
+ inode = ilookup(sysfs_sb, sd->s_ino);
+ if (inode) {
+ mutex_lock(&inode->i_mutex);

- if (dentry) {
- dentry->d_inode->i_ctime = curtime;
- drop_nlink(dentry->d_inode);
- if (sd->s_type & SYSFS_DIR) {
- drop_nlink(dentry->d_inode);
- drop_nlink(dir);
- /* XXX: unpin if directory, this will go away soon */
- dput(dentry);
- }
+ inode->i_ctime = curtime;
+ drop_nlink(inode);
+ if (sd->s_type & SYSFS_DIR)
+ drop_nlink(inode);
+
+ mutex_unlock(&inode->i_mutex);
+ iput(inode);
}

- mutex_unlock(&dir->i_mutex);
+ /* adjust nlink and udpate timestamp of the parent */
+ inode = ilookup(sysfs_sb, sd->s_parent->s_ino);
+ if (inode) {
+ mutex_lock(&inode->i_mutex);

- /* bye bye */
- if (dentry)
- dput(dentry);
- else
- dput(parent);
+ inode->i_ctime = inode->i_mtime = curtime;
+ if (sd->s_type & SYSFS_DIR)
+ drop_nlink(inode);
+
+ mutex_unlock(&inode->i_mutex);
+ iput(inode);
+ }
}

int sysfs_hash_and_remove(struct dentry * dir, const char * name)
--
1.5.2.2