diff options
| -rw-r--r-- | fs/dcache.c | 39 | ||||
| -rw-r--r-- | include/linux/dcache.h | 1 |
2 files changed, 40 insertions, 0 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index 5c7cc953ac81..8515875854b6 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1306,6 +1306,45 @@ int have_submounts(struct dentry *parent) } EXPORT_SYMBOL(have_submounts); +struct check_mount { + struct vfsmount *mnt; + unsigned int mounted; +}; + +static enum d_walk_ret path_check_mount(void *data, struct dentry *dentry) +{ + struct check_mount *info = data; + struct path path = { .mnt = info->mnt, .dentry = dentry }; + + if (likely(!d_mountpoint(dentry))) + return D_WALK_CONTINUE; + if (__path_is_mountpoint(&path)) { + info->mounted = 1; + return D_WALK_QUIT; + } + return D_WALK_CONTINUE; +} + +/** + * path_has_submounts - check for mounts over a dentry in the + * current namespace. + * @parent: path to check. + * + * Return true if the parent or its subdirectories contain + * a mount point in the current namespace. + */ +int path_has_submounts(const struct path *parent) +{ + struct check_mount data = { .mnt = parent->mnt, .mounted = 0 }; + + read_seqlock_excl(&mount_lock); + d_walk(parent->dentry, &data, path_check_mount, NULL); + read_sequnlock_excl(&mount_lock); + + return data.mounted; +} +EXPORT_SYMBOL(path_has_submounts); + /* * Called by mount code to set a mountpoint and check if the mountpoint is * reachable (e.g. NFS can unhash a directory dentry and then the complete diff --git a/include/linux/dcache.h b/include/linux/dcache.h index bc529ce88ed0..0ffaf7aef9ae 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -255,6 +255,7 @@ extern void d_prune_aliases(struct inode *); /* test whether we have any submounts in a subdir tree */ extern int have_submounts(struct dentry *); +extern int path_has_submounts(const struct path *); /* * This adds the entry to the hash queues. |