On Wed, 3 Jul 2013 16:12:33 -0400
"J. Bruce Fields" <bfields@xxxxxxxxxx> wrote:
> From: "J. Bruce Fields" <bfields@xxxxxxxxxx>
>
> We'll need the same logic for rename and link.
>
> Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
> ---
> fs/namei.c | 13 +++----------
> include/linux/fs.h | 33 +++++++++++++++++++++++++++++++--
> 2 files changed, 34 insertions(+), 12 deletions(-)
>
> diff --git a/fs/namei.c b/fs/namei.c
> index cba3db1..a9d4031 100644
> --- a/fs/namei.c
> +++ b/fs/namei.c
> @@ -3401,14 +3401,9 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegate
> else {
> error = security_inode_unlink(dir, dentry);
> if (!error) {
> - error = break_deleg(target, O_WRONLY|O_NONBLOCK);
> - if (error) {
> - if (error == -EWOULDBLOCK && delegated_inode) {
> - *delegated_inode = target;
> - ihold(target);
> - }
> + error = try_break_deleg(target, delegated_inode);
> + if (error)
> goto out;
> - }
> error = dir->i_op->unlink(dir, dentry);
> if (!error)
> dont_mount(dentry);
> @@ -3478,9 +3473,7 @@ exit2:
> iput(inode); /* truncate the inode here */
> inode = NULL;
> if (delegated_inode) {
> - error = break_deleg(delegated_inode, O_WRONLY);
> - iput(delegated_inode);
> - delegated_inode = NULL;
> + error = break_deleg_wait(&delegated_inode);
> if (!error)
> goto retry_deleg;
> }
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index f951588..c37e463 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1894,6 +1894,9 @@ extern bool our_mnt(struct vfsmount *mnt);
>
> extern int current_umask(void);
>
> +extern void ihold(struct inode * inode);
> +extern void iput(struct inode *);
> +
> /* /sys/fs */
> extern struct kobject *fs_kobj;
>
> @@ -1962,6 +1965,28 @@ static inline int break_deleg(struct inode *inode, unsigned int mode)
> return 0;
> }
>
> +static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)
> +{
> + int ret;
> +
> + ret = break_deleg(inode, O_WRONLY|O_NONBLOCK);
> + if (ret == -EWOULDBLOCK && delegated_inode) {
> + *delegated_inode = inode;
> + ihold(inode);
> + }
> + return ret;
> +}
> +
Actually, now that I look...
Suppose a vfs_unlink caller passes in a NULL delegated_inode pointer.
He'll get back a -EWOULDBLOCK here if there's a delegation on it.
Presumably he'll just treat that as a hard error and the delegation
would never get broken. Is that expected?
> +static inline int break_deleg_wait(struct inode **delegated_inode)
> +{
> + int ret;
> +
> + ret = break_deleg(*delegated_inode, O_WRONLY);
> + iput(*delegated_inode);
> + *delegated_inode = NULL;
> + return ret;
> +}
> +
> #else /* !CONFIG_FILE_LOCKING */
> static inline int locks_mandatory_locked(struct inode *inode)
> {
> @@ -2005,6 +2030,12 @@ static inline int break_deleg(struct inode *inode, unsigned int mode)
> {
> return 0;
> }
> +
> +static inline int try_break_deleg(struct inode *inode, struct delegated_inode **inode)
> +{
> + return 0;
> +}
> +
> #endif /* CONFIG_FILE_LOCKING */
>
> /* fs/open.c */
> @@ -2335,8 +2366,6 @@ extern loff_t vfs_llseek(struct file *file, loff_t offset, int whence);
> extern int inode_init_always(struct super_block *, struct inode *);
> extern void inode_init_once(struct inode *);
> extern void address_space_init_once(struct address_space *mapping);
> -extern void ihold(struct inode * inode);
> -extern void iput(struct inode *);
> extern struct inode * igrab(struct inode *);
> extern ino_t iunique(struct super_block *, ino_t);
> extern int inode_needs_sync(struct inode *inode);
--
Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
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