diff options
Diffstat (limited to 'fs/namespace.c')
-rw-r--r-- | fs/namespace.c | 134 |
1 files changed, 69 insertions, 65 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index 3b93e5d750eb..79bd8a46e1e7 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -61,7 +61,7 @@ struct vfsmount *alloc_vfsmnt(const char *name) INIT_LIST_HEAD(&mnt->mnt_child); INIT_LIST_HEAD(&mnt->mnt_mounts); INIT_LIST_HEAD(&mnt->mnt_list); - INIT_LIST_HEAD(&mnt->mnt_fslink); + INIT_LIST_HEAD(&mnt->mnt_expire); if (name) { int size = strlen(name)+1; char *newname = kmalloc(size, GFP_KERNEL); @@ -160,13 +160,13 @@ clone_mnt(struct vfsmount *old, struct dentry *root) mnt->mnt_root = dget(root); mnt->mnt_mountpoint = mnt->mnt_root; mnt->mnt_parent = mnt; - mnt->mnt_namespace = old->mnt_namespace; + mnt->mnt_namespace = current->namespace; /* stick the duplicate mount on the same expiry list * as the original if that was on one */ spin_lock(&vfsmount_lock); - if (!list_empty(&old->mnt_fslink)) - list_add(&mnt->mnt_fslink, &old->mnt_fslink); + if (!list_empty(&old->mnt_expire)) + list_add(&mnt->mnt_expire, &old->mnt_expire); spin_unlock(&vfsmount_lock); } return mnt; @@ -337,7 +337,7 @@ int may_umount(struct vfsmount *mnt) EXPORT_SYMBOL(may_umount); -void umount_tree(struct vfsmount *mnt) +static void umount_tree(struct vfsmount *mnt) { struct vfsmount *p; LIST_HEAD(kill); @@ -345,12 +345,13 @@ void umount_tree(struct vfsmount *mnt) for (p = mnt; p; p = next_mnt(p, mnt)) { list_del(&p->mnt_list); list_add(&p->mnt_list, &kill); + p->mnt_namespace = NULL; } while (!list_empty(&kill)) { mnt = list_entry(kill.next, struct vfsmount, mnt_list); list_del_init(&mnt->mnt_list); - list_del_init(&mnt->mnt_fslink); + list_del_init(&mnt->mnt_expire); if (mnt->mnt_parent == mnt) { spin_unlock(&vfsmount_lock); } else { @@ -644,7 +645,7 @@ static int do_loopback(struct nameidata *nd, char *old_name, int recurse) if (mnt) { /* stop bind mounts from expiring */ spin_lock(&vfsmount_lock); - list_del_init(&mnt->mnt_fslink); + list_del_init(&mnt->mnt_expire); spin_unlock(&vfsmount_lock); err = graft_tree(mnt, nd); @@ -743,7 +744,7 @@ static int do_move_mount(struct nameidata *nd, char *old_name) /* if the mount is moved, it should no longer be expire * automatically */ - list_del_init(&old_nd.mnt->mnt_fslink); + list_del_init(&old_nd.mnt->mnt_expire); out2: spin_unlock(&vfsmount_lock); out1: @@ -807,12 +808,13 @@ int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd, goto unlock; newmnt->mnt_flags = mnt_flags; + newmnt->mnt_namespace = current->namespace; err = graft_tree(newmnt, nd); if (err == 0 && fslist) { /* add to the specified expiration list */ spin_lock(&vfsmount_lock); - list_add_tail(&newmnt->mnt_fslink, fslist); + list_add_tail(&newmnt->mnt_expire, fslist); spin_unlock(&vfsmount_lock); } @@ -824,6 +826,54 @@ unlock: EXPORT_SYMBOL_GPL(do_add_mount); +static void expire_mount(struct vfsmount *mnt, struct list_head *mounts) +{ + spin_lock(&vfsmount_lock); + + /* + * Check if mount is still attached, if not, let whoever holds it deal + * with the sucker + */ + if (mnt->mnt_parent == mnt) { + spin_unlock(&vfsmount_lock); + return; + } + + /* + * Check that it is still dead: the count should now be 2 - as + * contributed by the vfsmount parent and the mntget above + */ + if (atomic_read(&mnt->mnt_count) == 2) { + struct nameidata old_nd; + + /* delete from the namespace */ + list_del_init(&mnt->mnt_list); + mnt->mnt_namespace = NULL; + detach_mnt(mnt, &old_nd); + spin_unlock(&vfsmount_lock); + path_release(&old_nd); + + /* + * Now lay it to rest if this was the last ref on the superblock + */ + if (atomic_read(&mnt->mnt_sb->s_active) == 1) { + /* last instance - try to be smart */ + lock_kernel(); + DQUOT_OFF(mnt->mnt_sb); + acct_auto_close(mnt->mnt_sb); + unlock_kernel(); + } + mntput(mnt); + } else { + /* + * Someone brought it back to life whilst we didn't have any + * locks held so return it to the expiration list + */ + list_add_tail(&mnt->mnt_expire, mounts); + spin_unlock(&vfsmount_lock); + } +} + /* * process a list of expirable mountpoints with the intent of discarding any * mountpoints that aren't in use and haven't been touched since last we came @@ -846,13 +896,13 @@ void mark_mounts_for_expiry(struct list_head *mounts) * - still marked for expiry (marked on the last call here; marks are * cleared by mntput()) */ - list_for_each_entry_safe(mnt, next, mounts, mnt_fslink) { + list_for_each_entry_safe(mnt, next, mounts, mnt_expire) { if (!xchg(&mnt->mnt_expiry_mark, 1) || atomic_read(&mnt->mnt_count) != 1) continue; mntget(mnt); - list_move(&mnt->mnt_fslink, &graveyard); + list_move(&mnt->mnt_expire, &graveyard); } /* @@ -862,61 +912,19 @@ void mark_mounts_for_expiry(struct list_head *mounts) * - dispose of the corpse */ while (!list_empty(&graveyard)) { - mnt = list_entry(graveyard.next, struct vfsmount, mnt_fslink); - list_del_init(&mnt->mnt_fslink); + mnt = list_entry(graveyard.next, struct vfsmount, mnt_expire); + list_del_init(&mnt->mnt_expire); /* don't do anything if the namespace is dead - all the * vfsmounts from it are going away anyway */ namespace = mnt->mnt_namespace; - if (!namespace || atomic_read(&namespace->count) <= 0) + if (!namespace || !namespace->root) continue; get_namespace(namespace); spin_unlock(&vfsmount_lock); down_write(&namespace->sem); - spin_lock(&vfsmount_lock); - - /* check that it is still dead: the count should now be 2 - as - * contributed by the vfsmount parent and the mntget above */ - if (atomic_read(&mnt->mnt_count) == 2) { - struct vfsmount *xdmnt; - struct dentry *xdentry; - - /* delete from the namespace */ - list_del_init(&mnt->mnt_list); - list_del_init(&mnt->mnt_child); - list_del_init(&mnt->mnt_hash); - mnt->mnt_mountpoint->d_mounted--; - - xdentry = mnt->mnt_mountpoint; - mnt->mnt_mountpoint = mnt->mnt_root; - xdmnt = mnt->mnt_parent; - mnt->mnt_parent = mnt; - - spin_unlock(&vfsmount_lock); - - mntput(xdmnt); - dput(xdentry); - - /* now lay it to rest if this was the last ref on the - * superblock */ - if (atomic_read(&mnt->mnt_sb->s_active) == 1) { - /* last instance - try to be smart */ - lock_kernel(); - DQUOT_OFF(mnt->mnt_sb); - acct_auto_close(mnt->mnt_sb); - unlock_kernel(); - } - - mntput(mnt); - } else { - /* someone brought it back to life whilst we didn't - * have any locks held so return it to the expiration - * list */ - list_add_tail(&mnt->mnt_fslink, mounts); - spin_unlock(&vfsmount_lock); - } - + expire_mount(mnt, mounts); up_write(&namespace->sem); mntput(mnt); @@ -1449,16 +1457,12 @@ void __init mnt_init(unsigned long mempages) void __put_namespace(struct namespace *namespace) { - struct vfsmount *mnt; - + struct vfsmount *root = namespace->root; + namespace->root = NULL; + spin_unlock(&vfsmount_lock); down_write(&namespace->sem); spin_lock(&vfsmount_lock); - - list_for_each_entry(mnt, &namespace->list, mnt_list) { - mnt->mnt_namespace = NULL; - } - - umount_tree(namespace->root); + umount_tree(root); spin_unlock(&vfsmount_lock); up_write(&namespace->sem); kfree(namespace); |