diff options
| author | Tejun Heo <htejun@gmail.com> | 2007-06-14 03:45:14 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2007-07-11 16:09:04 -0700 |
| commit | 13b3086d2ea483cbcae5a4236446cecc082a72cf (patch) | |
| tree | f6932aaf486a302aa7b03857d780bafda33db2d6 /fs/sysfs/dir.c | |
| parent | a26cd7226c24c3be5dd5f48a74832fe64beb8489 (diff) | |
sysfs: add sysfs_dirent->s_parent
Add sysfs_dirent->s_parent. With this patch, each sd points to and
holds a reference to its parent. This allows walking sysfs tree
without referencing sd->s_dentry which can go away anytime if the user
doesn't control when it's deleted.
sd->s_parent is initialized and parent is referenced in
sysfs_attach_dirent(). Reference to parent is released when the sd is
released, so as long as reference to a sd is held, s_parent can be
followed.
dentry walk in sysfs_readdir() is convereted to s_parent walk.
This will be used to reimplement symlink such that it uses only
sysfs_dirent tree.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'fs/sysfs/dir.c')
| -rw-r--r-- | fs/sysfs/dir.c | 30 |
1 files changed, 23 insertions, 7 deletions
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c index f16aa7e3eafc..5d50e1ddfbd1 100644 --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -47,6 +47,11 @@ static void sysfs_free_ino(ino_t ino) void release_sysfs_dirent(struct sysfs_dirent * sd) { + struct sysfs_dirent *parent_sd; + + repeat: + parent_sd = sd->s_parent; + if (sd->s_type & SYSFS_KOBJ_LINK) { struct sysfs_symlink * sl = sd->s_element; kfree(sl->link_name); @@ -56,6 +61,10 @@ void release_sysfs_dirent(struct sysfs_dirent * sd) kfree(sd->s_iattr); sysfs_free_ino(sd->s_ino); kmem_cache_free(sysfs_dir_cachep, sd); + + sd = parent_sd; + if (sd && atomic_dec_and_test(&sd->s_count)) + goto repeat; } static void sysfs_d_iput(struct dentry * dentry, struct inode * inode) @@ -119,8 +128,10 @@ void sysfs_attach_dirent(struct sysfs_dirent *sd, dentry->d_op = &sysfs_dentry_ops; } - if (parent_sd) + if (parent_sd) { + sd->s_parent = sysfs_get(parent_sd); list_add(&sd->s_sibling, &parent_sd->s_children); + } } /* @@ -571,7 +582,10 @@ static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir) i++; /* fallthrough */ case 1: - ino = parent_ino(dentry); + if (parent_sd->s_parent) + ino = parent_sd->s_parent->s_ino; + else + ino = parent_sd->s_ino; if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) break; filp->f_pos++; @@ -688,13 +702,13 @@ int sysfs_make_shadowed_dir(struct kobject *kobj, struct dentry *sysfs_create_shadow_dir(struct kobject *kobj) { + struct dentry *dir = kobj->dentry; + struct inode *inode = dir->d_inode; + struct dentry *parent = dir->d_parent; + struct sysfs_dirent *parent_sd = parent->d_fsdata; + struct dentry *shadow; struct sysfs_dirent *sd; - struct dentry *parent, *dir, *shadow; - struct inode *inode; - dir = kobj->dentry; - inode = dir->d_inode; - parent = dir->d_parent; shadow = ERR_PTR(-EINVAL); if (!sysfs_is_shadowed_inode(inode)) goto out; @@ -706,6 +720,8 @@ struct dentry *sysfs_create_shadow_dir(struct kobject *kobj) sd = sysfs_new_dirent(kobj, inode->i_mode, SYSFS_DIR); if (!sd) goto nomem; + /* point to parent_sd but don't attach to it */ + sd->s_parent = sysfs_get(parent_sd); sysfs_attach_dirent(sd, NULL, shadow); d_instantiate(shadow, igrab(inode)); |