diff options
| author | Tejun Heo <tj@kernel.org> | 2014-04-09 11:07:30 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-04-25 11:43:31 -0700 |
| commit | 7d568a8383bbb9c1f5167781075906acb2bb1550 (patch) | |
| tree | f25a2d70ce8851e991a53ed6391c899320f097a6 | |
| parent | a798c10faf62a505d24e5f6213fbaf904a39623f (diff) | |
| download | lwn-7d568a8383bbb9c1f5167781075906acb2bb1550.tar.gz lwn-7d568a8383bbb9c1f5167781075906acb2bb1550.zip | |
kernfs: implement kernfs_root->supers list
Currently, there's no way to find out which super_blocks are
associated with a given kernfs_root. Let's implement it - the planned
inotify extension to kernfs_notify() needs it.
Make kernfs_super_info point back to the super_block and chain it at
kernfs_root->supers.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/kernfs/dir.c | 1 | ||||
| -rw-r--r-- | fs/kernfs/kernfs-internal.h | 5 | ||||
| -rw-r--r-- | fs/kernfs/mount.c | 11 | ||||
| -rw-r--r-- | include/linux/kernfs.h | 4 |
4 files changed, 21 insertions, 0 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index 78f3403300af..43aa97988c31 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -711,6 +711,7 @@ struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops, return ERR_PTR(-ENOMEM); ida_init(&root->ino_ida); + INIT_LIST_HEAD(&root->supers); kn = __kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO, KERNFS_DIR); diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h index 8be13b2a079b..dc84a3ef9ca2 100644 --- a/fs/kernfs/kernfs-internal.h +++ b/fs/kernfs/kernfs-internal.h @@ -49,6 +49,8 @@ static inline struct kernfs_root *kernfs_root(struct kernfs_node *kn) * mount.c */ struct kernfs_super_info { + struct super_block *sb; + /* * The root associated with this super_block. Each super_block is * identified by the root and ns it's associated with. @@ -62,6 +64,9 @@ struct kernfs_super_info { * an array and compare kernfs_node tag against every entry. */ const void *ns; + + /* anchored at kernfs_root->supers, protected by kernfs_mutex */ + struct list_head node; }; #define kernfs_info(SB) ((struct kernfs_super_info *)(SB->s_fs_info)) diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c index 6a5f04ac8704..f25a7c0c3cdc 100644 --- a/fs/kernfs/mount.c +++ b/fs/kernfs/mount.c @@ -68,6 +68,7 @@ static int kernfs_fill_super(struct super_block *sb) struct inode *inode; struct dentry *root; + info->sb = sb; sb->s_blocksize = PAGE_CACHE_SIZE; sb->s_blocksize_bits = PAGE_CACHE_SHIFT; sb->s_magic = SYSFS_MAGIC; @@ -166,12 +167,18 @@ struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags, *new_sb_created = !sb->s_root; if (!sb->s_root) { + struct kernfs_super_info *info = kernfs_info(sb); + error = kernfs_fill_super(sb); if (error) { deactivate_locked_super(sb); return ERR_PTR(error); } sb->s_flags |= MS_ACTIVE; + + mutex_lock(&kernfs_mutex); + list_add(&info->node, &root->supers); + mutex_unlock(&kernfs_mutex); } return dget(sb->s_root); @@ -190,6 +197,10 @@ 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); + mutex_unlock(&kernfs_mutex); + /* * Remove the superblock from fs_supers/s_instances * so we can't find it, before freeing kernfs_super_info. diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h index b0122dc6f96a..589318b73e61 100644 --- a/include/linux/kernfs.h +++ b/include/linux/kernfs.h @@ -144,6 +144,10 @@ struct kernfs_root { /* private fields, do not use outside kernfs proper */ struct ida ino_ida; struct kernfs_syscall_ops *syscall_ops; + + /* list of kernfs_super_info of this root, protected by kernfs_mutex */ + struct list_head supers; + wait_queue_head_t deactivate_waitq; }; |