diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-20 09:15:51 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-20 09:15:51 -0700 |
commit | 18253e034d2aeee140f82fc9fe89c4bce5c81799 (patch) | |
tree | 0a01610fbe16b24800977d2c7a3b93721ca5639c | |
parent | abdfd52a295fb5731ab07b5c9013e2e39f4d1cbe (diff) | |
parent | 56cbb429d911991170fe867b4bba14f0efed5829 (diff) | |
download | lwn-18253e034d2aeee140f82fc9fe89c4bce5c81799.tar.gz lwn-18253e034d2aeee140f82fc9fe89c4bce5c81799.zip |
Merge branch 'work.dcache2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull dcache and mountpoint updates from Al Viro:
"Saner handling of refcounts to mountpoints.
Transfer the counting reference from struct mount ->mnt_mountpoint
over to struct mountpoint ->m_dentry. That allows us to get rid of the
convoluted games with ordering of mount shutdowns.
The cost is in teaching shrink_dcache_{parent,for_umount} to cope with
mixed-filesystem shrink lists, which we'll also need for the Slab
Movable Objects patchset"
* 'work.dcache2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
switch the remnants of releasing the mountpoint away from fs_pin
get rid of detach_mnt()
make struct mountpoint bear the dentry reference to mountpoint, not struct mount
Teach shrink_dcache_parent() to cope with mixed-filesystem shrink lists
fs/namespace.c: shift put_mountpoint() to callers of unhash_mnt()
__detach_mounts(): lookup_mountpoint() can't return ERR_PTR() anymore
nfs: dget_parent() never returns NULL
ceph: don't open-code the check for dead lockref
-rw-r--r-- | fs/ceph/dir.c | 2 | ||||
-rw-r--r-- | fs/dcache.c | 100 | ||||
-rw-r--r-- | fs/fs_pin.c | 10 | ||||
-rw-r--r-- | fs/internal.h | 2 | ||||
-rw-r--r-- | fs/mount.h | 8 | ||||
-rw-r--r-- | fs/namespace.c | 159 | ||||
-rw-r--r-- | fs/nfs/super.c | 6 | ||||
-rw-r--r-- | include/linux/fs_pin.h | 1 |
8 files changed, 172 insertions, 116 deletions
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c index aab29f48c62d..4ca0b8ff9a72 100644 --- a/fs/ceph/dir.c +++ b/fs/ceph/dir.c @@ -1267,7 +1267,7 @@ __dentry_leases_walk(struct ceph_mds_client *mdsc, if (!spin_trylock(&dentry->d_lock)) continue; - if (dentry->d_lockref.count < 0) { + if (__lockref_is_dead(&dentry->d_lockref)) { list_del_init(&di->lease_list); goto next; } diff --git a/fs/dcache.c b/fs/dcache.c index f41121e5d1ec..e88cf0554e65 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -861,6 +861,32 @@ void dput(struct dentry *dentry) } EXPORT_SYMBOL(dput); +static void __dput_to_list(struct dentry *dentry, struct list_head *list) +__must_hold(&dentry->d_lock) +{ + if (dentry->d_flags & DCACHE_SHRINK_LIST) { + /* let the owner of the list it's on deal with it */ + --dentry->d_lockref.count; + } else { + if (dentry->d_flags & DCACHE_LRU_LIST) + d_lru_del(dentry); + if (!--dentry->d_lockref.count) + d_shrink_add(dentry, list); + } +} + +void dput_to_list(struct dentry *dentry, struct list_head *list) +{ + rcu_read_lock(); + if (likely(fast_dput(dentry))) { + rcu_read_unlock(); + return; + } + rcu_read_unlock(); + if (!retain_dentry(dentry)) + __dput_to_list(dentry, list); + spin_unlock(&dentry->d_lock); +} /* This must be called with d_lock held */ static inline void __dget_dlock(struct dentry *dentry) @@ -1067,7 +1093,7 @@ out: return false; } -static void shrink_dentry_list(struct list_head *list) +void shrink_dentry_list(struct list_head *list) { while (!list_empty(list)) { struct dentry *dentry, *parent; @@ -1089,18 +1115,9 @@ static void shrink_dentry_list(struct list_head *list) rcu_read_unlock(); d_shrink_del(dentry); parent = dentry->d_parent; + if (parent != dentry) + __dput_to_list(parent, list); __dentry_kill(dentry); - if (parent == dentry) - continue; - /* - * We need to prune ancestors too. This is necessary to prevent - * quadratic behavior of shrink_dcache_parent(), but is also - * expected to be beneficial in reducing dentry cache - * fragmentation. - */ - dentry = parent; - while (dentry && !lockref_put_or_lock(&dentry->d_lockref)) - dentry = dentry_kill(dentry); } } @@ -1445,8 +1462,11 @@ out: struct select_data { struct dentry *start; + union { + long found; + struct dentry *victim; + }; struct list_head dispose; - int found; }; static enum d_walk_ret select_collect(void *_data, struct dentry *dentry) @@ -1478,6 +1498,37 @@ out: return ret; } +static enum d_walk_ret select_collect2(void *_data, struct dentry *dentry) +{ + struct select_data *data = _data; + enum d_walk_ret ret = D_WALK_CONTINUE; + + if (data->start == dentry) + goto out; + + if (dentry->d_flags & DCACHE_SHRINK_LIST) { + if (!dentry->d_lockref.count) { + rcu_read_lock(); + data->victim = dentry; + return D_WALK_QUIT; + } + } else { + if (dentry->d_flags & DCACHE_LRU_LIST) + d_lru_del(dentry); + if (!dentry->d_lockref.count) + d_shrink_add(dentry, &data->dispose); + } + /* + * We can return to the caller if we have found some (this + * ensures forward progress). We'll be coming back to find + * the rest. + */ + if (!list_empty(&data->dispose)) + ret = need_resched() ? D_WALK_QUIT : D_WALK_NORETRY; +out: + return ret; +} + /** * shrink_dcache_parent - prune dcache * @parent: parent of entries to prune @@ -1487,12 +1538,9 @@ out: void shrink_dcache_parent(struct dentry *parent) { for (;;) { - struct select_data data; + struct select_data data = {.start = parent}; INIT_LIST_HEAD(&data.dispose); - data.start = parent; - data.found = 0; - d_walk(parent, &data, select_collect); if (!list_empty(&data.dispose)) { @@ -1503,6 +1551,24 @@ void shrink_dcache_parent(struct dentry *parent) cond_resched(); if (!data.found) break; + data.victim = NULL; + d_walk(parent, &data, select_collect2); + if (data.victim) { + struct dentry *parent; + spin_lock(&data.victim->d_lock); + if (!shrink_lock_dentry(data.victim)) { + spin_unlock(&data.victim->d_lock); + rcu_read_unlock(); + } else { + rcu_read_unlock(); + parent = data.victim->d_parent; + if (parent != data.victim) + __dput_to_list(parent, &data.dispose); + __dentry_kill(data.victim); + } + } + if (!list_empty(&data.dispose)) + shrink_dentry_list(&data.dispose); } } EXPORT_SYMBOL(shrink_dcache_parent); diff --git a/fs/fs_pin.c b/fs/fs_pin.c index a6497cf8ae53..47ef3c71ce90 100644 --- a/fs/fs_pin.c +++ b/fs/fs_pin.c @@ -19,20 +19,14 @@ void pin_remove(struct fs_pin *pin) spin_unlock_irq(&pin->wait.lock); } -void pin_insert_group(struct fs_pin *pin, struct vfsmount *m, struct hlist_head *p) +void pin_insert(struct fs_pin *pin, struct vfsmount *m) { spin_lock(&pin_lock); - if (p) - hlist_add_head(&pin->s_list, p); + hlist_add_head(&pin->s_list, &m->mnt_sb->s_pins); hlist_add_head(&pin->m_list, &real_mount(m)->mnt_pins); spin_unlock(&pin_lock); } -void pin_insert(struct fs_pin *pin, struct vfsmount *m) -{ - pin_insert_group(pin, m, &m->mnt_sb->s_pins); -} - void pin_kill(struct fs_pin *p) { wait_queue_entry_t wait; diff --git a/fs/internal.h b/fs/internal.h index ff5173212803..315fcd8d237c 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -157,6 +157,8 @@ extern long prune_dcache_sb(struct super_block *sb, struct shrink_control *sc); extern struct dentry *d_alloc_cursor(struct dentry *); extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *); extern char *simple_dname(struct dentry *, char *, int); +extern void dput_to_list(struct dentry *, struct list_head *); +extern void shrink_dentry_list(struct list_head *); /* * read_write.c diff --git a/fs/mount.h b/fs/mount.h index 6250de544760..711a4093e475 100644 --- a/fs/mount.h +++ b/fs/mount.h @@ -58,7 +58,10 @@ struct mount { struct mount *mnt_master; /* slave is on master->mnt_slave_list */ struct mnt_namespace *mnt_ns; /* containing namespace */ struct mountpoint *mnt_mp; /* where is it mounted */ - struct hlist_node mnt_mp_list; /* list mounts with the same mountpoint */ + union { + struct hlist_node mnt_mp_list; /* list mounts with the same mountpoint */ + struct hlist_node mnt_umount; + }; struct list_head mnt_umounting; /* list entry for umount propagation */ #ifdef CONFIG_FSNOTIFY struct fsnotify_mark_connector __rcu *mnt_fsnotify_marks; @@ -68,8 +71,7 @@ struct mount { int mnt_group_id; /* peer group identifier */ int mnt_expiry_mark; /* true if marked for expiry */ struct hlist_head mnt_pins; - struct fs_pin mnt_umount; - struct dentry *mnt_ex_mountpoint; + struct hlist_head mnt_stuck_children; } __randomize_layout; #define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */ diff --git a/fs/namespace.c b/fs/namespace.c index f0d664adb9ba..6464ea4acba9 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -70,6 +70,8 @@ static struct hlist_head *mount_hashtable __read_mostly; static struct hlist_head *mountpoint_hashtable __read_mostly; static struct kmem_cache *mnt_cache __read_mostly; static DECLARE_RWSEM(namespace_sem); +static HLIST_HEAD(unmounted); /* protected by namespace_sem */ +static LIST_HEAD(ex_mountpoints); /* protected by namespace_sem */ /* /sys/fs */ struct kobject *fs_kobj; @@ -170,14 +172,6 @@ unsigned int mnt_get_count(struct mount *mnt) #endif } -static void drop_mountpoint(struct fs_pin *p) -{ - struct mount *m = container_of(p, struct mount, mnt_umount); - dput(m->mnt_ex_mountpoint); - pin_remove(p); - mntput(&m->mnt); -} - static struct mount *alloc_vfsmnt(const char *name) { struct mount *mnt = kmem_cache_zalloc(mnt_cache, GFP_KERNEL); @@ -215,7 +209,7 @@ static struct mount *alloc_vfsmnt(const char *name) INIT_LIST_HEAD(&mnt->mnt_slave); INIT_HLIST_NODE(&mnt->mnt_mp_list); INIT_LIST_HEAD(&mnt->mnt_umounting); - init_fs_pin(&mnt->mnt_umount, drop_mountpoint); + INIT_HLIST_HEAD(&mnt->mnt_stuck_children); } return mnt; @@ -740,7 +734,7 @@ mountpoint: /* Add the new mountpoint to the hash table */ read_seqlock_excl(&mount_lock); - new->m_dentry = dentry; + new->m_dentry = dget(dentry); new->m_count = 1; hlist_add_head(&new->m_hash, mp_hash(dentry)); INIT_HLIST_HEAD(&new->m_list); @@ -753,7 +747,11 @@ done: return mp; } -static void put_mountpoint(struct mountpoint *mp) +/* + * vfsmount lock must be held. Additionally, the caller is responsible + * for serializing calls for given disposal list. + */ +static void __put_mountpoint(struct mountpoint *mp, struct list_head *list) { if (!--mp->m_count) { struct dentry *dentry = mp->m_dentry; @@ -761,11 +759,18 @@ static void put_mountpoint(struct mountpoint *mp) spin_lock(&dentry->d_lock); dentry->d_flags &= ~DCACHE_MOUNTED; spin_unlock(&dentry->d_lock); + dput_to_list(dentry, list); hlist_del(&mp->m_hash); kfree(mp); } } +/* called with namespace_lock and vfsmount lock */ +static void put_mountpoint(struct mountpoint *mp) +{ + __put_mountpoint(mp, &ex_mountpoints); +} + static inline int check_mnt(struct mount *mnt) { return mnt->mnt_ns == current->nsproxy->mnt_ns; @@ -796,25 +801,17 @@ static void __touch_mnt_namespace(struct mnt_namespace *ns) /* * vfsmount lock must be held for write */ -static void unhash_mnt(struct mount *mnt) +static struct mountpoint *unhash_mnt(struct mount *mnt) { + struct mountpoint *mp; mnt->mnt_parent = mnt; mnt->mnt_mountpoint = mnt->mnt.mnt_root; list_del_init(&mnt->mnt_child); hlist_del_init_rcu(&mnt->mnt_hash); hlist_del_init(&mnt->mnt_mp_list); - put_mountpoint(mnt->mnt_mp); + mp = mnt->mnt_mp; mnt->mnt_mp = NULL; -} - -/* - * vfsmount lock must be held for write - */ -static void detach_mnt(struct mount *mnt, struct path *old_path) -{ - old_path->dentry = mnt->mnt_mountpoint; - old_path->mnt = &mnt->mnt_parent->mnt; - unhash_mnt(mnt); + return mp; } /* @@ -822,9 +819,7 @@ static void detach_mnt(struct mount *mnt, struct path *old_path) */ static void umount_mnt(struct mount *mnt) { - /* old mountpoint will be dropped when we can do that */ - mnt->mnt_ex_mountpoint = mnt->mnt_mountpoint; - unhash_mnt(mnt); + put_mountpoint(unhash_mnt(mnt)); } /* @@ -836,7 +831,7 @@ void mnt_set_mountpoint(struct mount *mnt, { mp->m_count++; mnt_add_count(mnt, 1); /* essentially, that's mntget */ - child_mnt->mnt_mountpoint = dget(mp->m_dentry); + child_mnt->mnt_mountpoint = mp->m_dentry; child_mnt->mnt_parent = mnt; child_mnt->mnt_mp = mp; hlist_add_head(&child_mnt->mnt_mp_list, &mp->m_list); @@ -863,7 +858,6 @@ static void attach_mnt(struct mount *mnt, void mnt_change_mountpoint(struct mount *parent, struct mountpoint *mp, struct mount *mnt) { struct mountpoint *old_mp = mnt->mnt_mp; - struct dentry *old_mountpoint = mnt->mnt_mountpoint; struct mount *old_parent = mnt->mnt_parent; list_del_init(&mnt->mnt_child); @@ -873,22 +867,6 @@ void mnt_change_mountpoint(struct mount *parent, struct mountpoint *mp, struct m attach_mnt(mnt, parent, mp); put_mountpoint(old_mp); - - /* - * Safely avoid even the suggestion this code might sleep or - * lock the mount hash by taking advantage of the knowledge that - * mnt_change_mountpoint will not release the final reference - * to a mountpoint. - * - * During mounting, the mount passed in as the parent mount will - * continue to use the old mountpoint and during unmounting, the - * old mountpoint will continue to exist until namespace_unlock, - * which happens well after mnt_change_mountpoint. - */ - spin_lock(&old_mountpoint->d_lock); - old_mountpoint->d_lockref.count--; - spin_unlock(&old_mountpoint->d_lock); - mnt_add_count(old_parent, -1); } @@ -1103,19 +1081,22 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root, static void cleanup_mnt(struct mount *mnt) { + struct hlist_node *p; + struct mount *m; /* - * This probably indicates that somebody messed - * up a mnt_want/drop_write() pair. If this - * happens, the filesystem was probably unable - * to make r/w->r/o transitions. - */ - /* + * The warning here probably indicates that somebody messed + * up a mnt_want/drop_write() pair. If this happens, the + * filesystem was probably unable to make r/w->r/o transitions. * The locking used to deal with mnt_count decrement provides barriers, * so mnt_get_writers() below is safe. */ WARN_ON(mnt_get_writers(mnt)); if (unlikely(mnt->mnt_pins.first)) mnt_pin_kill(mnt); + hlist_for_each_entry_safe(m, p, &mnt->mnt_stuck_children, mnt_umount) { + hlist_del(&m->mnt_umount); + mntput(&m->mnt); + } fsnotify_vfsmount_delete(&mnt->mnt); dput(mnt->mnt.mnt_root); deactivate_super(mnt->mnt.mnt_sb); @@ -1141,6 +1122,8 @@ static DECLARE_DELAYED_WORK(delayed_mntput_work, delayed_mntput); static void mntput_no_expire(struct mount *mnt) { + LIST_HEAD(list); + rcu_read_lock(); if (likely(READ_ONCE(mnt->mnt_ns))) { /* @@ -1181,10 +1164,12 @@ static void mntput_no_expire(struct mount *mnt) if (unlikely(!list_empty(&mnt->mnt_mounts))) { struct mount *p, *tmp; list_for_each_entry_safe(p, tmp, &mnt->mnt_mounts, mnt_child) { - umount_mnt(p); + __put_mountpoint(unhash_mnt(p), &list); + hlist_add_head(&p->mnt_umount, &mnt->mnt_stuck_children); } } unlock_mount_hash(); + shrink_dentry_list(&list); if (likely(!(mnt->mnt.mnt_flags & MNT_INTERNAL))) { struct task_struct *task = current; @@ -1370,22 +1355,29 @@ int may_umount(struct vfsmount *mnt) EXPORT_SYMBOL(may_umount); -static HLIST_HEAD(unmounted); /* protected by namespace_sem */ - static void namespace_unlock(void) { struct hlist_head head; + struct hlist_node *p; + struct mount *m; + LIST_HEAD(list); hlist_move_list(&unmounted, &head); + list_splice_init(&ex_mountpoints, &list); up_write(&namespace_sem); + shrink_dentry_list(&list); + if (likely(hlist_empty(&head))) return; synchronize_rcu_expedited(); - group_pin_kill(&head); + hlist_for_each_entry_safe(m, p, &head, mnt_umount) { + hlist_del(&m->mnt_umount); + mntput(&m->mnt); + } } static inline void namespace_lock(void) @@ -1472,8 +1464,6 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how) disconnect = disconnect_mount(p, how); - pin_insert_group(&p->mnt_umount, &p->mnt_parent->mnt, - disconnect ? &unmounted : NULL); if (mnt_has_parent(p)) { mnt_add_count(p->mnt_parent, -1); if (!disconnect) { @@ -1481,6 +1471,7 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how) list_add_tail(&p->mnt_child, &p->mnt_parent->mnt_mounts); } else { umount_mnt(p); + hlist_add_head(&p->mnt_umount, &unmounted); } } change_mnt_propagation(p, MS_PRIVATE); @@ -1626,15 +1617,15 @@ void __detach_mounts(struct dentry *dentry) namespace_lock(); lock_mount_hash(); mp = lookup_mountpoint(dentry); - if (IS_ERR_OR_NULL(mp)) + if (!mp) goto out_unlock; event++; while (!hlist_empty(&mp->m_list)) { mnt = hlist_entry(mp->m_list.first, struct mount, mnt_mp_list); if (mnt->mnt.mnt_flags & MNT_UMOUNT) { - hlist_add_head(&mnt->mnt_umount.s_list, &unmounted); umount_mnt(mnt); + hlist_add_head(&mnt->mnt_umount, &unmounted); } else umount_tree(mnt, UMOUNT_CONNECTED); } @@ -2046,7 +2037,7 @@ int count_mounts(struct mnt_namespace *ns, struct mount *mnt) static int attach_recursive_mnt(struct mount *source_mnt, struct mount *dest_mnt, struct mountpoint *dest_mp, - struct path *parent_path) + bool moving) { struct user_namespace *user_ns = current->nsproxy->mnt_ns->user_ns; HLIST_HEAD(tree_list); @@ -2064,7 +2055,7 @@ static int attach_recursive_mnt(struct mount *source_mnt, return PTR_ERR(smp); /* Is there space to add these mounts to the mount namespace? */ - if (!parent_path) { + if (!moving) { err = count_mounts(ns, source_mnt); if (err) goto out; @@ -2083,8 +2074,8 @@ static int attach_recursive_mnt(struct mount *source_mnt, } else { lock_mount_hash(); } - if (parent_path) { - detach_mnt(source_mnt, parent_path); + if (moving) { + unhash_mnt(source_mnt); attach_mnt(source_mnt, dest_mnt, dest_mp); touch_mnt_namespace(source_mnt->mnt_ns); } else { @@ -2182,7 +2173,7 @@ static int graft_tree(struct mount *mnt, struct mount *p, struct mountpoint *mp) d_is_dir(mnt->mnt.mnt_root)) return -ENOTDIR; - return attach_recursive_mnt(mnt, p, mp, NULL); + return attach_recursive_mnt(mnt, p, mp, false); } /* @@ -2575,11 +2566,11 @@ out: static int do_move_mount(struct path *old_path, struct path *new_path) { - struct path parent_path = {.mnt = NULL, .dentry = NULL}; struct mnt_namespace *ns; struct mount *p; struct mount *old; - struct mountpoint *mp; + struct mount *parent; + struct mountpoint *mp, *old_mp; int err; bool attached; @@ -2589,7 +2580,9 @@ static int do_move_mount(struct path *old_path, struct path *new_path) old = real_mount(old_path->mnt); p = real_mount(new_path->mnt); + parent = old->mnt_parent; attached = mnt_has_parent(old); + old_mp = old->mnt_mp; ns = old->mnt_ns; err = -EINVAL; @@ -2617,7 +2610,7 @@ static int do_move_mount(struct path *old_path, struct path *new_path) /* * Don't move a mount residing in a shared parent. */ - if (attached && IS_MNT_SHARED(old->mnt_parent)) + if (attached && IS_MNT_SHARED(parent)) goto out; /* * Don't move a mount tree containing unbindable mounts to a destination @@ -2633,18 +2626,21 @@ static int do_move_mount(struct path *old_path, struct path *new_path) goto out; err = attach_recursive_mnt(old, real_mount(new_path->mnt), mp, - attached ? &parent_path : NULL); + attached); if (err) goto out; /* if the mount is moved, it should no longer be expire * automatically */ list_del_init(&old->mnt_expire); + if (attached) + put_mountpoint(old_mp); out: unlock_mount(mp); if (!err) { - path_put(&parent_path); - if (!attached) + if (attached) + mntput_no_expire(parent); + else free_mnt_ns(ns); } return err; @@ -3589,8 +3585,8 @@ EXPORT_SYMBOL(path_is_under); SYSCALL_DEFINE2(pivot_root, const char __user *, new_root, const char __user *, put_old) { - struct path new, old, parent_path, root_parent, root; - struct mount *new_mnt, *root_mnt, *old_mnt; + struct path new, old, root; + struct mount *new_mnt, *root_mnt, *old_mnt, *root_parent, *ex_parent; struct mountpoint *old_mp, *root_mp; int error; @@ -3619,9 +3615,11 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root, new_mnt = real_mount(new.mnt); root_mnt = real_mount(root.mnt); old_mnt = real_mount(old.mnt); + ex_parent = new_mnt->mnt_parent; + root_parent = root_mnt->mnt_parent; if (IS_MNT_SHARED(old_mnt) || - IS_MNT_SHARED(new_mnt->mnt_parent) || - IS_MNT_SHARED(root_mnt->mnt_parent)) + IS_MNT_SHARED(ex_parent) || + IS_MNT_SHARED(root_parent)) goto out4; if (!check_mnt(root_mnt) || !check_mnt(new_mnt)) goto out4; @@ -3638,7 +3636,6 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root, goto out4; /* not a mountpoint */ if (!mnt_has_parent(root_mnt)) goto out4; /* not attached */ - root_mp = root_mnt->mnt_mp; if (new.mnt->mnt_root != new.dentry) goto out4; /* not a mountpoint */ if (!mnt_has_parent(new_mnt)) @@ -3649,10 +3646,9 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root, /* make certain new is below the root */ if (!is_path_reachable(new_mnt, new.dentry, &root)) goto out4; - root_mp->m_count++; /* pin it so it won't go away */ lock_mount_hash(); - detach_mnt(new_mnt, &parent_path); - detach_mnt(root_mnt, &root_parent); + umount_mnt(new_mnt); + root_mp = unhash_mnt(root_mnt); /* we'll need its mountpoint */ if (root_mnt->mnt.mnt_flags & MNT_LOCKED) { new_mnt->mnt.mnt_flags |= MNT_LOCKED; root_mnt->mnt.mnt_flags &= ~MNT_LOCKED; @@ -3660,7 +3656,8 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root, /* mount old root on put_old */ attach_mnt(root_mnt, old_mnt, old_mp); /* mount new_root on / */ - attach_mnt(new_mnt, real_mount(root_parent.mnt), root_mp); + attach_mnt(new_mnt, root_parent, root_mp); + mnt_add_count(root_parent, -1); touch_mnt_namespace(current->nsproxy->mnt_ns); /* A moved mount should not expire automatically */ list_del_init(&new_mnt->mnt_expire); @@ -3670,10 +3667,8 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root, error = 0; out4: unlock_mount(old_mp); - if (!error) { - path_put(&root_parent); - path_put(&parent_path); - } + if (!error) + mntput_no_expire(ex_parent); out3: path_put(&root); out2: diff --git a/fs/nfs/super.c b/fs/nfs/super.c index 3683d2b1cc8e..628631e2e34f 100644 --- a/fs/nfs/super.c +++ b/fs/nfs/super.c @@ -457,10 +457,8 @@ int nfs_statfs(struct dentry *dentry, struct kstatfs *buf) struct dentry *pd_dentry; pd_dentry = dget_parent(dentry); - if (pd_dentry != NULL) { - nfs_zap_caches(d_inode(pd_dentry)); - dput(pd_dentry); - } + nfs_zap_caches(d_inode(pd_dentry)); + dput(pd_dentry); } nfs_free_fattr(res.fattr); if (error < 0) diff --git a/include/linux/fs_pin.h b/include/linux/fs_pin.h index 7cab74d66f85..bdd09fd2520c 100644 --- a/include/linux/fs_pin.h +++ b/include/linux/fs_pin.h @@ -20,6 +20,5 @@ static inline void init_fs_pin(struct fs_pin *p, void (*kill)(struct fs_pin *)) } void pin_remove(struct fs_pin *); -void pin_insert_group(struct fs_pin *, struct vfsmount *, struct hlist_head *); void pin_insert(struct fs_pin *, struct vfsmount *); void pin_kill(struct fs_pin *); |