diff options
Diffstat (limited to 'fs/kernfs')
| -rw-r--r-- | fs/kernfs/dir.c | 1 | ||||
| -rw-r--r-- | fs/kernfs/file.c | 92 | ||||
| -rw-r--r-- | fs/kernfs/kernfs-internal.h | 5 | ||||
| -rw-r--r-- | fs/kernfs/mount.c | 11 |
4 files changed, 98 insertions, 11 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index ac127cd..a693f5b 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -714,6 +714,7 @@ 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/file.c b/fs/kernfs/file.c index 5e9a80c..d895b4b 100644 --- a/fs/kernfs/file.c +++ b/fs/kernfs/file.c @@ -14,6 +14,7 @@ #include <linux/poll.h> #include <linux/pagemap.h> #include <linux/sched.h> +#include <linux/fsnotify.h> #include "kernfs-internal.h" @@ -38,6 +39,19 @@ struct kernfs_open_node { struct list_head files; /* goes through kernfs_open_file.list */ }; +/* + * kernfs_notify() may be called from any context and bounces notifications + * through a work item. To minimize space overhead in kernfs_node, the + * pending queue is implemented as a singly linked list of kernfs_nodes. + * The list is terminated with the self pointer so that whether a + * kernfs_node is on the list or not can be determined by testing the next + * pointer for NULL. + */ +#define KERNFS_NOTIFY_EOL ((void *)&kernfs_notify_list) + +static DEFINE_SPINLOCK(kernfs_notify_lock); +static struct kernfs_node *kernfs_notify_list = KERNFS_NOTIFY_EOL; + static struct kernfs_open_file *kernfs_of(struct file *file) { return ((struct seq_file *)file->private_data)->private; @@ -782,28 +796,84 @@ static unsigned int kernfs_fop_poll(struct file *filp, poll_table *wait) return DEFAULT_POLLMASK|POLLERR|POLLPRI; } +static void kernfs_notify_workfn(struct work_struct *work) +{ + struct kernfs_node *kn; + struct kernfs_open_node *on; + struct kernfs_super_info *info; +repeat: + /* pop one off the notify_list */ + spin_lock_irq(&kernfs_notify_lock); + kn = kernfs_notify_list; + if (kn == KERNFS_NOTIFY_EOL) { + spin_unlock_irq(&kernfs_notify_lock); + return; + } + kernfs_notify_list = kn->attr.notify_next; + kn->attr.notify_next = NULL; + spin_unlock_irq(&kernfs_notify_lock); + + /* kick poll */ + spin_lock_irq(&kernfs_open_node_lock); + + on = kn->attr.open; + if (on) { + atomic_inc(&on->event); + wake_up_interruptible(&on->poll); + } + + spin_unlock_irq(&kernfs_open_node_lock); + + /* kick fsnotify */ + mutex_lock(&kernfs_mutex); + + list_for_each_entry(info, &kernfs_root(kn)->supers, node) { + struct inode *inode; + struct dentry *dentry; + + inode = ilookup(info->sb, kn->ino); + if (!inode) + continue; + + dentry = d_find_any_alias(inode); + if (dentry) { + fsnotify_parent(NULL, dentry, FS_MODIFY); + fsnotify(inode, FS_MODIFY, inode, FSNOTIFY_EVENT_INODE, + NULL, 0); + dput(dentry); + } + + iput(inode); + } + + mutex_unlock(&kernfs_mutex); + kernfs_put(kn); + goto repeat; +} + /** * kernfs_notify - notify a kernfs file * @kn: file to notify * - * Notify @kn such that poll(2) on @kn wakes up. + * Notify @kn such that poll(2) on @kn wakes up. Maybe be called from any + * context. */ void kernfs_notify(struct kernfs_node *kn) { - struct kernfs_open_node *on; + static DECLARE_WORK(kernfs_notify_work, kernfs_notify_workfn); unsigned long flags; - spin_lock_irqsave(&kernfs_open_node_lock, flags); + if (WARN_ON(kernfs_type(kn) != KERNFS_FILE)) + return; - if (!WARN_ON(kernfs_type(kn) != KERNFS_FILE)) { - on = kn->attr.open; - if (on) { - atomic_inc(&on->event); - wake_up_interruptible(&on->poll); - } + spin_lock_irqsave(&kernfs_notify_lock, flags); + if (!kn->attr.notify_next) { + kernfs_get(kn); + kn->attr.notify_next = kernfs_notify_list; + kernfs_notify_list = kn; + schedule_work(&kernfs_notify_work); } - - spin_unlock_irqrestore(&kernfs_open_node_lock, flags); + spin_unlock_irqrestore(&kernfs_notify_lock, flags); } EXPORT_SYMBOL_GPL(kernfs_notify); diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h index 8be13b2..dc84a3e 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 95dcd1d..d171b98 100644 --- a/fs/kernfs/mount.c +++ b/fs/kernfs/mount.c @@ -68,6 +68,7 @@ static int kernfs_fill_super(struct super_block *sb, unsigned long magic) 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 = magic; @@ -167,12 +168,18 @@ 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, magic); 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); @@ -191,6 +198,10 @@ 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. |
