Hi,
On Thu, Apr 09, 2015 at 06:18:07PM +0200, Krzysztof Opasiak wrote:
> Sometimes it might be desirable to prohibit removing a directory
> in configfs. One example is USB gadget (mass_storage function):
> when gadget is already bound, if lun directory is removed,
> the gadget must be thrown away, too. A better solution would be
> to fail with e.g. -EBUSY.
>
> Currently configfs has configfs_depend/undepend_item() methods
> but they cannot be used in configfs callbacks. This commit
> adds unlocked version of this methods which can be used
> only in configfs callbacks.
>
> Signed-off-by: Krzysztof Opasiak <k.opasiak@xxxxxxxxxxx>
Joel, any comments to this patch ?
> ---
> fs/configfs/dir.c | 29 +++++++++++++++++++++++++++++
> include/linux/configfs.h | 9 +++++++++
> 2 files changed, 38 insertions(+)
>
> diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
> index cf0db00..7875a5e 100644
> --- a/fs/configfs/dir.c
> +++ b/fs/configfs/dir.c
> @@ -1152,6 +1152,35 @@ void configfs_undepend_item(struct configfs_subsystem *subsys,
> }
> EXPORT_SYMBOL(configfs_undepend_item);
>
> +int configfs_depend_item_unlocked(struct config_item *target)
> +{
> + struct configfs_dirent *sd;
> + int ret = -ENOENT;
> +
> + spin_lock(&configfs_dirent_lock);
> + BUG_ON(!target->ci_dentry);
> +
> + sd = target->ci_dentry->d_fsdata;
> + if ((sd->s_type & CONFIGFS_DIR) &&
> + ((sd->s_type & CONFIGFS_USET_DROPPING) ||
> + (sd->s_type & CONFIGFS_USET_CREATING)))
> + goto out_unlock_dirent_lock;
> +
> + sd->s_dependent_count += 1;
> + ret = 0;
> +
> +out_unlock_dirent_lock:
> + spin_unlock(&configfs_dirent_lock);
> + return ret;
> +}
> +EXPORT_SYMBOL(configfs_depend_item_unlocked);
> +
> +void configfs_undepend_item_unlocked(struct config_item *target)
> +{
> + configfs_undepend_item(NULL, target);
> +}
> +EXPORT_SYMBOL(configfs_undepend_item_unlocked);
> +
> static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
> {
> int ret = 0;
> diff --git a/include/linux/configfs.h b/include/linux/configfs.h
> index 34025df..e9dbf01 100644
> --- a/include/linux/configfs.h
> +++ b/include/linux/configfs.h
> @@ -257,4 +257,13 @@ void configfs_unregister_subsystem(struct configfs_subsystem *subsys);
> int configfs_depend_item(struct configfs_subsystem *subsys, struct config_item *target);
> void configfs_undepend_item(struct configfs_subsystem *subsys, struct config_item *target);
>
> +/*
> + * These functions can sleep and can alloc with GFP_KERNEL
> + * NOTE: These should be called only underneath configfs callbacks.
> + * WARNING: These cannot be called on newly created item
> + * (in make_group()/make_item callback)
> + */
> +int configfs_depend_item_unlocked(struct config_item *target);
> +void configfs_undepend_item_unlocked(struct config_item *target);
> +
> #endif /* _CONFIGFS_H_ */
> --
> 1.7.9.5
>
--
balbi
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