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Commit 319ba91d authored by Shaohua Li's avatar Shaohua Li Committed by Jens Axboe
Browse files

kernfs: don't set dentry->d_fsdata 



When working on adding exportfs operations in kernfs, I found it's hard
to initialize dentry->d_fsdata in the exportfs operations. Looks there
is no way to do it without race condition. Look at the kernfs code
closely, there is no point to set dentry->d_fsdata. inode->i_private
already points to kernfs_node, and we can get inode from a dentry. So
this patch just delete the d_fsdata usage.

Acked-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarShaohua Li <shli@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent ba16b284

fs/kernfs/dir.c

+9 −16
Original line number Diff line number Diff line
@@ -566,7 +566,7 @@ static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags) 
	if (d_really_is_negative(dentry))

		goto out_bad_unlocked;



	kn = dentry->d_fsdata;

	kn = kernfs_dentry_node(dentry);

	mutex_lock(&kernfs_mutex);



	/* The kernfs node has been deactivated */
@@ -574,7 +574,7 @@ static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags) 
		goto out_bad;



	/* The kernfs node has been moved? */

	if (dentry->d_parent->d_fsdata != kn->parent)

	if (kernfs_dentry_node(dentry->d_parent) != kn->parent)

		goto out_bad;



	/* The kernfs node has been renamed */
@@ -594,14 +594,8 @@ static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags) 
	return 0;

}



static void kernfs_dop_release(struct dentry *dentry)

{

	kernfs_put(dentry->d_fsdata);

}



const struct dentry_operations kernfs_dops = {

	.d_revalidate	= kernfs_dop_revalidate,

	.d_release	= kernfs_dop_release,

};



/**
@@ -617,8 +611,9 @@ const struct dentry_operations kernfs_dops = { 
 */

struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry)

{

	if (dentry->d_sb->s_op == &kernfs_sops)

		return dentry->d_fsdata;

	if (dentry->d_sb->s_op == &kernfs_sops &&

	    !d_really_is_negative(dentry))

		return kernfs_dentry_node(dentry);

	return NULL;

}
@@ -1056,7 +1051,7 @@ static struct dentry *kernfs_iop_lookup(struct inode *dir, 
					unsigned int flags)

{

	struct dentry *ret;

	struct kernfs_node *parent = dentry->d_parent->d_fsdata;

	struct kernfs_node *parent = dir->i_private;

	struct kernfs_node *kn;

	struct inode *inode;

	const void *ns = NULL;
@@ -1073,8 +1068,6 @@ static struct dentry *kernfs_iop_lookup(struct inode *dir, 
		ret = NULL;

		goto out_unlock;

	}

	kernfs_get(kn);

	dentry->d_fsdata = kn;



	/* attach dentry and inode */

	inode = kernfs_get_inode(dir->i_sb, kn);
@@ -1111,7 +1104,7 @@ static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry, 


static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry)

{

	struct kernfs_node *kn  = dentry->d_fsdata;

	struct kernfs_node *kn  = kernfs_dentry_node(dentry);

	struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops;

	int ret;
@@ -1131,7 +1124,7 @@ static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry, 
			     struct inode *new_dir, struct dentry *new_dentry,

			     unsigned int flags)

{

	struct kernfs_node *kn  = old_dentry->d_fsdata;

	struct kernfs_node *kn = kernfs_dentry_node(old_dentry);

	struct kernfs_node *new_parent = new_dir->i_private;

	struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops;

	int ret;
@@ -1644,7 +1637,7 @@ static struct kernfs_node *kernfs_dir_next_pos(const void *ns, 
static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx)

{

	struct dentry *dentry = file->f_path.dentry;

	struct kernfs_node *parent = dentry->d_fsdata;

	struct kernfs_node *parent = kernfs_dentry_node(dentry);

	struct kernfs_node *pos = file->private_data;

	const void *ns = NULL;

fs/kernfs/file.c

+3 −3
Original line number Diff line number Diff line
@@ -616,7 +616,7 @@ static void kernfs_put_open_node(struct kernfs_node *kn, 


static int kernfs_fop_open(struct inode *inode, struct file *file)

{

	struct kernfs_node *kn = file->f_path.dentry->d_fsdata;

	struct kernfs_node *kn = inode->i_private;

	struct kernfs_root *root = kernfs_root(kn);

	const struct kernfs_ops *ops;

	struct kernfs_open_file *of;
@@ -768,7 +768,7 @@ static void kernfs_release_file(struct kernfs_node *kn, 


static int kernfs_fop_release(struct inode *inode, struct file *filp)

{

	struct kernfs_node *kn = filp->f_path.dentry->d_fsdata;

	struct kernfs_node *kn = inode->i_private;

	struct kernfs_open_file *of = kernfs_of(filp);



	if (kn->flags & KERNFS_HAS_RELEASE) {
@@ -835,7 +835,7 @@ void kernfs_drain_open_files(struct kernfs_node *kn) 
static unsigned int kernfs_fop_poll(struct file *filp, poll_table *wait)

{

	struct kernfs_open_file *of = kernfs_of(filp);

	struct kernfs_node *kn = filp->f_path.dentry->d_fsdata;

	struct kernfs_node *kn = kernfs_dentry_node(filp->f_path.dentry);

	struct kernfs_open_node *on = kn->attr.open;



	if (!kernfs_get_active(kn))

fs/kernfs/inode.c

+3 −3
Original line number Diff line number Diff line
@@ -112,7 +112,7 @@ int kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr) 
int kernfs_iop_setattr(struct dentry *dentry, struct iattr *iattr)

{

	struct inode *inode = d_inode(dentry);

	struct kernfs_node *kn = dentry->d_fsdata;

	struct kernfs_node *kn = inode->i_private;

	int error;



	if (!kn)
@@ -154,7 +154,7 @@ static int kernfs_node_setsecdata(struct kernfs_iattrs *attrs, void **secdata, 


ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size)

{

	struct kernfs_node *kn = dentry->d_fsdata;

	struct kernfs_node *kn = kernfs_dentry_node(dentry);

	struct kernfs_iattrs *attrs;



	attrs = kernfs_iattrs(kn);
@@ -203,8 +203,8 @@ static void kernfs_refresh_inode(struct kernfs_node *kn, struct inode *inode) 
int kernfs_iop_getattr(const struct path *path, struct kstat *stat,

		       u32 request_mask, unsigned int query_flags)

{

	struct kernfs_node *kn = path->dentry->d_fsdata;

	struct inode *inode = d_inode(path->dentry);

	struct kernfs_node *kn = inode->i_private;



	mutex_lock(&kernfs_mutex);

	kernfs_refresh_inode(kn, inode);

fs/kernfs/kernfs-internal.h

+7 −0
Original line number Diff line number Diff line
@@ -70,6 +70,13 @@ struct kernfs_super_info { 
};

#define kernfs_info(SB) ((struct kernfs_super_info *)(SB->s_fs_info))



static inline struct kernfs_node *kernfs_dentry_node(struct dentry *dentry)

{

	if (d_really_is_negative(dentry))

		return NULL;

	return d_inode(dentry)->i_private;

}



extern const struct super_operations kernfs_sops;

extern struct kmem_cache *kernfs_node_cache;

fs/kernfs/mount.c

+2 −6
Original line number Diff line number Diff line
@@ -33,7 +33,7 @@ static int kernfs_sop_remount_fs(struct super_block *sb, int *flags, char *data) 


static int kernfs_sop_show_options(struct seq_file *sf, struct dentry *dentry)

{

	struct kernfs_root *root = kernfs_root(dentry->d_fsdata);

	struct kernfs_root *root = kernfs_root(kernfs_dentry_node(dentry));

	struct kernfs_syscall_ops *scops = root->syscall_ops;



	if (scops && scops->show_options)
@@ -43,7 +43,7 @@ static int kernfs_sop_show_options(struct seq_file *sf, struct dentry *dentry) 


static int kernfs_sop_show_path(struct seq_file *sf, struct dentry *dentry)

{

	struct kernfs_node *node = dentry->d_fsdata;

	struct kernfs_node *node = kernfs_dentry_node(dentry);

	struct kernfs_root *root = kernfs_root(node);

	struct kernfs_syscall_ops *scops = root->syscall_ops;
@@ -176,8 +176,6 @@ static int kernfs_fill_super(struct super_block *sb, unsigned long magic) 
		pr_debug("%s: could not get root dentry!\n", __func__);

		return -ENOMEM;

	}

	kernfs_get(info->root->kn);

	root->d_fsdata = info->root->kn;

	sb->s_root = root;

	sb->s_d_op = &kernfs_dops;

	return 0;
@@ -283,7 +281,6 @@ struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags, 
void kernfs_kill_sb(struct super_block *sb)

{

	struct kernfs_super_info *info = kernfs_info(sb);

	struct kernfs_node *root_kn = sb->s_root->d_fsdata;



	mutex_lock(&kernfs_mutex);

	list_del(&info->node);
@@ -295,7 +292,6 @@ void kernfs_kill_sb(struct super_block *sb) 
	 */

	kill_anon_super(sb);

	kfree(info);

	kernfs_put(root_kn);

}



/**