fs: brlock vfsmount_lock
Use a brlock for the vfsmount lock. It must be taken for write whenever
modifying the mount hash or associated fields, and may be taken for read when
performing mount hash lookups.
A new lock is added for the mnt-id allocator, so it doesn't need to take
the heavy vfsmount write-lock.
The number of atomics should remain the same for fastpath rlock cases, though
code would be slightly slower due to per-cpu access. Scalability is not not be
much improved in common cases yet, due to other locks (ie. dcache_lock) getting
in the way. However path lookups crossing mountpoints should be one case where
scalability is improved (currently requiring the global lock).
The slowpath is slower due to use of brlock. On a 64 core, 64 socket, 32 node
Altix system (high latency to remote nodes), a simple umount microbenchmark
(mount --bind mnt mnt2 ; umount mnt2 loop 1000 times), before this patch it
took 6.8s, afterwards took 7.1s, about 5% slower.
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
bool slash = false;
int error = 0;
bool slash = false;
int error = 0;
- spin_lock(&vfsmount_lock);
+ br_read_lock(vfsmount_lock);
while (dentry != root->dentry || vfsmnt != root->mnt) {
struct dentry * parent;
while (dentry != root->dentry || vfsmnt != root->mnt) {
struct dentry * parent;
if (!error && !slash)
error = prepend(buffer, buflen, "/", 1);
if (!error && !slash)
error = prepend(buffer, buflen, "/", 1);
- spin_unlock(&vfsmount_lock);
+ br_read_unlock(vfsmount_lock);
return error;
global_root:
return error;
global_root:
struct vfsmount *mnt = path1->mnt;
struct dentry *dentry = path1->dentry;
int res;
struct vfsmount *mnt = path1->mnt;
struct dentry *dentry = path1->dentry;
int res;
- spin_lock(&vfsmount_lock);
+
+ br_read_lock(vfsmount_lock);
if (mnt != path2->mnt) {
for (;;) {
if (mnt->mnt_parent == mnt) {
if (mnt != path2->mnt) {
for (;;) {
if (mnt->mnt_parent == mnt) {
- spin_unlock(&vfsmount_lock);
+ br_read_unlock(vfsmount_lock);
return 0;
}
if (mnt->mnt_parent == path2->mnt)
return 0;
}
if (mnt->mnt_parent == path2->mnt)
dentry = mnt->mnt_mountpoint;
}
res = is_subdir(dentry, path2->dentry);
dentry = mnt->mnt_mountpoint;
}
res = is_subdir(dentry, path2->dentry);
- spin_unlock(&vfsmount_lock);
+ br_read_unlock(vfsmount_lock);
return res;
}
EXPORT_SYMBOL(path_is_under);
return res;
}
EXPORT_SYMBOL(path_is_under);
* 2 of the License, or (at your option) any later version.
*/
* 2 of the License, or (at your option) any later version.
*/
+#include <linux/lglock.h>
+
struct super_block;
struct linux_binprm;
struct path;
struct super_block;
struct linux_binprm;
struct path;
extern void __init mnt_init(void);
extern void __init mnt_init(void);
-extern spinlock_t vfsmount_lock;
+DECLARE_BRLOCK(vfsmount_lock);
+
{
struct vfsmount *parent;
struct dentry *mountpoint;
{
struct vfsmount *parent;
struct dentry *mountpoint;
- spin_lock(&vfsmount_lock);
+
+ br_read_lock(vfsmount_lock);
parent = path->mnt->mnt_parent;
if (parent == path->mnt) {
parent = path->mnt->mnt_parent;
if (parent == path->mnt) {
- spin_unlock(&vfsmount_lock);
+ br_read_unlock(vfsmount_lock);
return 0;
}
mntget(parent);
mountpoint = dget(path->mnt->mnt_mountpoint);
return 0;
}
mntget(parent);
mountpoint = dget(path->mnt->mnt_mountpoint);
- spin_unlock(&vfsmount_lock);
+ br_read_unlock(vfsmount_lock);
dput(path->dentry);
path->dentry = mountpoint;
mntput(path->mnt);
dput(path->dentry);
path->dentry = mountpoint;
mntput(path->mnt);
#include <linux/syscalls.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/syscalls.h>
#include <linux/slab.h>
#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/percpu.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
#include <linux/kernel.h>
#define HASH_SHIFT ilog2(PAGE_SIZE / sizeof(struct list_head))
#define HASH_SIZE (1UL << HASH_SHIFT)
#define HASH_SHIFT ilog2(PAGE_SIZE / sizeof(struct list_head))
#define HASH_SIZE (1UL << HASH_SHIFT)
-/* spinlock for vfsmount related operations, inplace of dcache_lock */
-__cacheline_aligned_in_smp DEFINE_SPINLOCK(vfsmount_lock);
-
static int event;
static DEFINE_IDA(mnt_id_ida);
static DEFINE_IDA(mnt_group_ida);
static int event;
static DEFINE_IDA(mnt_id_ida);
static DEFINE_IDA(mnt_group_ida);
+static DEFINE_SPINLOCK(mnt_id_lock);
static int mnt_id_start = 0;
static int mnt_group_start = 1;
static int mnt_id_start = 0;
static int mnt_group_start = 1;
struct kobject *fs_kobj;
EXPORT_SYMBOL_GPL(fs_kobj);
struct kobject *fs_kobj;
EXPORT_SYMBOL_GPL(fs_kobj);
+/*
+ * vfsmount lock may be taken for read to prevent changes to the
+ * vfsmount hash, ie. during mountpoint lookups or walking back
+ * up the tree.
+ *
+ * It should be taken for write in all cases where the vfsmount
+ * tree or hash is modified or when a vfsmount structure is modified.
+ */
+DEFINE_BRLOCK(vfsmount_lock);
+
static inline unsigned long hash(struct vfsmount *mnt, struct dentry *dentry)
{
unsigned long tmp = ((unsigned long)mnt / L1_CACHE_BYTES);
static inline unsigned long hash(struct vfsmount *mnt, struct dentry *dentry)
{
unsigned long tmp = ((unsigned long)mnt / L1_CACHE_BYTES);
#define MNT_WRITER_UNDERFLOW_LIMIT -(1<<16)
#define MNT_WRITER_UNDERFLOW_LIMIT -(1<<16)
-/* allocation is serialized by namespace_sem */
+/*
+ * allocation is serialized by namespace_sem, but we need the spinlock to
+ * serialize with freeing.
+ */
static int mnt_alloc_id(struct vfsmount *mnt)
{
int res;
retry:
ida_pre_get(&mnt_id_ida, GFP_KERNEL);
static int mnt_alloc_id(struct vfsmount *mnt)
{
int res;
retry:
ida_pre_get(&mnt_id_ida, GFP_KERNEL);
- spin_lock(&vfsmount_lock);
+ spin_lock(&mnt_id_lock);
res = ida_get_new_above(&mnt_id_ida, mnt_id_start, &mnt->mnt_id);
if (!res)
mnt_id_start = mnt->mnt_id + 1;
res = ida_get_new_above(&mnt_id_ida, mnt_id_start, &mnt->mnt_id);
if (!res)
mnt_id_start = mnt->mnt_id + 1;
- spin_unlock(&vfsmount_lock);
+ spin_unlock(&mnt_id_lock);
if (res == -EAGAIN)
goto retry;
if (res == -EAGAIN)
goto retry;
static void mnt_free_id(struct vfsmount *mnt)
{
int id = mnt->mnt_id;
static void mnt_free_id(struct vfsmount *mnt)
{
int id = mnt->mnt_id;
- spin_lock(&vfsmount_lock);
+ spin_lock(&mnt_id_lock);
ida_remove(&mnt_id_ida, id);
if (mnt_id_start > id)
mnt_id_start = id;
ida_remove(&mnt_id_ida, id);
if (mnt_id_start > id)
mnt_id_start = id;
- spin_unlock(&vfsmount_lock);
+ spin_unlock(&mnt_id_lock);
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
mnt->mnt_flags |= MNT_WRITE_HOLD;
/*
* After storing MNT_WRITE_HOLD, we'll read the counters. This store
mnt->mnt_flags |= MNT_WRITE_HOLD;
/*
* After storing MNT_WRITE_HOLD, we'll read the counters. This store
*/
smp_wmb();
mnt->mnt_flags &= ~MNT_WRITE_HOLD;
*/
smp_wmb();
mnt->mnt_flags &= ~MNT_WRITE_HOLD;
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
return ret;
}
static void __mnt_unmake_readonly(struct vfsmount *mnt)
{
return ret;
}
static void __mnt_unmake_readonly(struct vfsmount *mnt)
{
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
mnt->mnt_flags &= ~MNT_READONLY;
mnt->mnt_flags &= ~MNT_READONLY;
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
}
void simple_set_mnt(struct vfsmount *mnt, struct super_block *sb)
}
void simple_set_mnt(struct vfsmount *mnt, struct super_block *sb)
/*
* find the first or last mount at @dentry on vfsmount @mnt depending on
* @dir. If @dir is set return the first mount else return the last mount.
/*
* find the first or last mount at @dentry on vfsmount @mnt depending on
* @dir. If @dir is set return the first mount else return the last mount.
+ * vfsmount_lock must be held for read or write.
*/
struct vfsmount *__lookup_mnt(struct vfsmount *mnt, struct dentry *dentry,
int dir)
*/
struct vfsmount *__lookup_mnt(struct vfsmount *mnt, struct dentry *dentry,
int dir)
struct vfsmount *lookup_mnt(struct path *path)
{
struct vfsmount *child_mnt;
struct vfsmount *lookup_mnt(struct path *path)
{
struct vfsmount *child_mnt;
- spin_lock(&vfsmount_lock);
+
+ br_read_lock(vfsmount_lock);
if ((child_mnt = __lookup_mnt(path->mnt, path->dentry, 1)))
mntget(child_mnt);
if ((child_mnt = __lookup_mnt(path->mnt, path->dentry, 1)))
mntget(child_mnt);
- spin_unlock(&vfsmount_lock);
+ br_read_unlock(vfsmount_lock);
return mnt->mnt_ns == current->nsproxy->mnt_ns;
}
return mnt->mnt_ns == current->nsproxy->mnt_ns;
}
+/*
+ * vfsmount lock must be held for write
+ */
static void touch_mnt_namespace(struct mnt_namespace *ns)
{
if (ns) {
static void touch_mnt_namespace(struct mnt_namespace *ns)
{
if (ns) {
+/*
+ * vfsmount lock must be held for write
+ */
static void __touch_mnt_namespace(struct mnt_namespace *ns)
{
if (ns && ns->event != event) {
static void __touch_mnt_namespace(struct mnt_namespace *ns)
{
if (ns && ns->event != event) {
+/*
+ * vfsmount lock must be held for write
+ */
static void detach_mnt(struct vfsmount *mnt, struct path *old_path)
{
old_path->dentry = mnt->mnt_mountpoint;
static void detach_mnt(struct vfsmount *mnt, struct path *old_path)
{
old_path->dentry = mnt->mnt_mountpoint;
old_path->dentry->d_mounted--;
}
old_path->dentry->d_mounted--;
}
+/*
+ * vfsmount lock must be held for write
+ */
void mnt_set_mountpoint(struct vfsmount *mnt, struct dentry *dentry,
struct vfsmount *child_mnt)
{
void mnt_set_mountpoint(struct vfsmount *mnt, struct dentry *dentry,
struct vfsmount *child_mnt)
{
+/*
+ * vfsmount lock must be held for write
+ */
static void attach_mnt(struct vfsmount *mnt, struct path *path)
{
mnt_set_mountpoint(path->mnt, path->dentry, mnt);
static void attach_mnt(struct vfsmount *mnt, struct path *path)
{
mnt_set_mountpoint(path->mnt, path->dentry, mnt);
- * the caller must hold vfsmount_lock
+ * vfsmount lock must be held for write
*/
static void commit_tree(struct vfsmount *mnt)
{
*/
static void commit_tree(struct vfsmount *mnt)
{
void mntput_no_expire(struct vfsmount *mnt)
{
repeat:
void mntput_no_expire(struct vfsmount *mnt)
{
repeat:
- if (atomic_dec_and_lock(&mnt->mnt_count, &vfsmount_lock)) {
- if (likely(!mnt->mnt_pinned)) {
- spin_unlock(&vfsmount_lock);
- __mntput(mnt);
- return;
- }
- atomic_add(mnt->mnt_pinned + 1, &mnt->mnt_count);
- mnt->mnt_pinned = 0;
- spin_unlock(&vfsmount_lock);
- acct_auto_close_mnt(mnt);
- goto repeat;
+ if (atomic_add_unless(&mnt->mnt_count, -1, 1))
+ return;
+ br_write_lock(vfsmount_lock);
+ if (!atomic_dec_and_test(&mnt->mnt_count)) {
+ br_write_unlock(vfsmount_lock);
+ return;
+ }
+ if (likely(!mnt->mnt_pinned)) {
+ br_write_unlock(vfsmount_lock);
+ __mntput(mnt);
+ return;
+ atomic_add(mnt->mnt_pinned + 1, &mnt->mnt_count);
+ mnt->mnt_pinned = 0;
+ br_write_unlock(vfsmount_lock);
+ acct_auto_close_mnt(mnt);
+ goto repeat;
EXPORT_SYMBOL(mntput_no_expire);
void mnt_pin(struct vfsmount *mnt)
{
EXPORT_SYMBOL(mntput_no_expire);
void mnt_pin(struct vfsmount *mnt)
{
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
}
EXPORT_SYMBOL(mnt_pin);
void mnt_unpin(struct vfsmount *mnt)
{
}
EXPORT_SYMBOL(mnt_pin);
void mnt_unpin(struct vfsmount *mnt)
{
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
if (mnt->mnt_pinned) {
atomic_inc(&mnt->mnt_count);
mnt->mnt_pinned--;
}
if (mnt->mnt_pinned) {
atomic_inc(&mnt->mnt_count);
mnt->mnt_pinned--;
}
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
}
EXPORT_SYMBOL(mnt_unpin);
}
EXPORT_SYMBOL(mnt_unpin);
struct mnt_namespace *ns = p->ns;
int res = 0;
struct mnt_namespace *ns = p->ns;
int res = 0;
- spin_lock(&vfsmount_lock);
+ br_read_lock(vfsmount_lock);
if (p->event != ns->event) {
p->event = ns->event;
res = 1;
}
if (p->event != ns->event) {
p->event = ns->event;
res = 1;
}
- spin_unlock(&vfsmount_lock);
+ br_read_unlock(vfsmount_lock);
int minimum_refs = 0;
struct vfsmount *p;
int minimum_refs = 0;
struct vfsmount *p;
- spin_lock(&vfsmount_lock);
+ br_read_lock(vfsmount_lock);
for (p = mnt; p; p = next_mnt(p, mnt)) {
actual_refs += atomic_read(&p->mnt_count);
minimum_refs += 2;
}
for (p = mnt; p; p = next_mnt(p, mnt)) {
actual_refs += atomic_read(&p->mnt_count);
minimum_refs += 2;
}
- spin_unlock(&vfsmount_lock);
+ br_read_unlock(vfsmount_lock);
if (actual_refs > minimum_refs)
return 0;
if (actual_refs > minimum_refs)
return 0;
{
int ret = 1;
down_read(&namespace_sem);
{
int ret = 1;
down_read(&namespace_sem);
- spin_lock(&vfsmount_lock);
+ br_read_lock(vfsmount_lock);
if (propagate_mount_busy(mnt, 2))
ret = 0;
if (propagate_mount_busy(mnt, 2))
ret = 0;
- spin_unlock(&vfsmount_lock);
+ br_read_unlock(vfsmount_lock);
up_read(&namespace_sem);
return ret;
}
up_read(&namespace_sem);
return ret;
}
if (mnt->mnt_parent != mnt) {
struct dentry *dentry;
struct vfsmount *m;
if (mnt->mnt_parent != mnt) {
struct dentry *dentry;
struct vfsmount *m;
- spin_lock(&vfsmount_lock);
+
+ br_write_lock(vfsmount_lock);
dentry = mnt->mnt_mountpoint;
m = mnt->mnt_parent;
mnt->mnt_mountpoint = mnt->mnt_root;
mnt->mnt_parent = mnt;
m->mnt_ghosts--;
dentry = mnt->mnt_mountpoint;
m = mnt->mnt_parent;
mnt->mnt_mountpoint = mnt->mnt_root;
mnt->mnt_parent = mnt;
m->mnt_ghosts--;
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
dput(dentry);
mntput(m);
}
dput(dentry);
mntput(m);
}
+/*
+ * vfsmount lock must be held for write
+ * namespace_sem must be held for write
+ */
void umount_tree(struct vfsmount *mnt, int propagate, struct list_head *kill)
{
struct vfsmount *p;
void umount_tree(struct vfsmount *mnt, int propagate, struct list_head *kill)
{
struct vfsmount *p;
}
down_write(&namespace_sem);
}
down_write(&namespace_sem);
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
event++;
if (!(flags & MNT_DETACH))
event++;
if (!(flags & MNT_DETACH))
umount_tree(mnt, 1, &umount_list);
retval = 0;
}
umount_tree(mnt, 1, &umount_list);
retval = 0;
}
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
up_write(&namespace_sem);
release_mounts(&umount_list);
return retval;
up_write(&namespace_sem);
release_mounts(&umount_list);
return retval;
q = clone_mnt(p, p->mnt_root, flag);
if (!q)
goto Enomem;
q = clone_mnt(p, p->mnt_root, flag);
if (!q)
goto Enomem;
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
list_add_tail(&q->mnt_list, &res->mnt_list);
attach_mnt(q, &path);
list_add_tail(&q->mnt_list, &res->mnt_list);
attach_mnt(q, &path);
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
}
}
return res;
Enomem:
if (res) {
LIST_HEAD(umount_list);
}
}
return res;
Enomem:
if (res) {
LIST_HEAD(umount_list);
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
umount_tree(res, 0, &umount_list);
umount_tree(res, 0, &umount_list);
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
release_mounts(&umount_list);
}
return NULL;
release_mounts(&umount_list);
}
return NULL;
{
LIST_HEAD(umount_list);
down_write(&namespace_sem);
{
LIST_HEAD(umount_list);
down_write(&namespace_sem);
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
umount_tree(mnt, 0, &umount_list);
umount_tree(mnt, 0, &umount_list);
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
up_write(&namespace_sem);
release_mounts(&umount_list);
}
up_write(&namespace_sem);
release_mounts(&umount_list);
}
if (err)
goto out_cleanup_ids;
if (err)
goto out_cleanup_ids;
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
if (IS_MNT_SHARED(dest_mnt)) {
for (p = source_mnt; p; p = next_mnt(p, source_mnt))
if (IS_MNT_SHARED(dest_mnt)) {
for (p = source_mnt; p; p = next_mnt(p, source_mnt))
list_del_init(&child->mnt_hash);
commit_tree(child);
}
list_del_init(&child->mnt_hash);
commit_tree(child);
}
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
+
return 0;
out_cleanup_ids:
return 0;
out_cleanup_ids:
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
for (m = mnt; m; m = (recurse ? next_mnt(m, mnt) : NULL))
change_mnt_propagation(m, type);
for (m = mnt; m; m = (recurse ? next_mnt(m, mnt) : NULL))
change_mnt_propagation(m, type);
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
out_unlock:
up_write(&namespace_sem);
out_unlock:
up_write(&namespace_sem);
err = graft_tree(mnt, path);
if (err) {
LIST_HEAD(umount_list);
err = graft_tree(mnt, path);
if (err) {
LIST_HEAD(umount_list);
- spin_lock(&vfsmount_lock);
+
+ br_write_lock(vfsmount_lock);
umount_tree(mnt, 0, &umount_list);
umount_tree(mnt, 0, &umount_list);
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
release_mounts(&umount_list);
}
release_mounts(&umount_list);
}
else
err = do_remount_sb(sb, flags, data, 0);
if (!err) {
else
err = do_remount_sb(sb, flags, data, 0);
if (!err) {
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
mnt_flags |= path->mnt->mnt_flags & MNT_PROPAGATION_MASK;
path->mnt->mnt_flags = mnt_flags;
mnt_flags |= path->mnt->mnt_flags & MNT_PROPAGATION_MASK;
path->mnt->mnt_flags = mnt_flags;
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
}
up_write(&sb->s_umount);
if (!err) {
}
up_write(&sb->s_umount);
if (!err) {
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
touch_mnt_namespace(path->mnt->mnt_ns);
touch_mnt_namespace(path->mnt->mnt_ns);
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
return;
down_write(&namespace_sem);
return;
down_write(&namespace_sem);
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
/* extract from the expiration list every vfsmount that matches the
* following criteria:
/* extract from the expiration list every vfsmount that matches the
* following criteria:
touch_mnt_namespace(mnt->mnt_ns);
umount_tree(mnt, 1, &umounts);
}
touch_mnt_namespace(mnt->mnt_ns);
umount_tree(mnt, 1, &umounts);
}
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
up_write(&namespace_sem);
release_mounts(&umounts);
up_write(&namespace_sem);
release_mounts(&umounts);
/*
* process a list of expirable mountpoints with the intent of discarding any
* submounts of a specific parent mountpoint
/*
* process a list of expirable mountpoints with the intent of discarding any
* submounts of a specific parent mountpoint
+ *
+ * vfsmount_lock must be held for write
*/
static void shrink_submounts(struct vfsmount *mnt, struct list_head *umounts)
{
*/
static void shrink_submounts(struct vfsmount *mnt, struct list_head *umounts)
{
kfree(new_ns);
return ERR_PTR(-ENOMEM);
}
kfree(new_ns);
return ERR_PTR(-ENOMEM);
}
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
list_add_tail(&new_ns->list, &new_ns->root->mnt_list);
list_add_tail(&new_ns->list, &new_ns->root->mnt_list);
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
/*
* Second pass: switch the tsk->fs->* elements and mark new vfsmounts
/*
* Second pass: switch the tsk->fs->* elements and mark new vfsmounts
goto out2; /* not attached */
/* make sure we can reach put_old from new_root */
tmp = old.mnt;
goto out2; /* not attached */
/* make sure we can reach put_old from new_root */
tmp = old.mnt;
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
if (tmp != new.mnt) {
for (;;) {
if (tmp->mnt_parent == tmp)
if (tmp != new.mnt) {
for (;;) {
if (tmp->mnt_parent == tmp)
/* mount new_root on / */
attach_mnt(new.mnt, &root_parent);
touch_mnt_namespace(current->nsproxy->mnt_ns);
/* mount new_root on / */
attach_mnt(new.mnt, &root_parent);
touch_mnt_namespace(current->nsproxy->mnt_ns);
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
chroot_fs_refs(&root, &new);
error = 0;
path_put(&root_parent);
chroot_fs_refs(&root, &new);
error = 0;
path_put(&root_parent);
out0:
return error;
out3:
out0:
return error;
out3:
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
for (u = 0; u < HASH_SIZE; u++)
INIT_LIST_HEAD(&mount_hashtable[u]);
for (u = 0; u < HASH_SIZE; u++)
INIT_LIST_HEAD(&mount_hashtable[u]);
+ br_lock_init(vfsmount_lock);
+
err = sysfs_init();
if (err)
printk(KERN_WARNING "%s: sysfs_init error: %d\n",
err = sysfs_init();
if (err)
printk(KERN_WARNING "%s: sysfs_init error: %d\n",
if (!atomic_dec_and_test(&ns->count))
return;
down_write(&namespace_sem);
if (!atomic_dec_and_test(&ns->count))
return;
down_write(&namespace_sem);
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
umount_tree(ns->root, 0, &umount_list);
umount_tree(ns->root, 0, &umount_list);
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
up_write(&namespace_sem);
release_mounts(&umount_list);
kfree(ns);
up_write(&namespace_sem);
release_mounts(&umount_list);
kfree(ns);
+/*
+ * vfsmount lock must be held for write
+ */
void change_mnt_propagation(struct vfsmount *mnt, int type)
{
if (type == MS_SHARED) {
void change_mnt_propagation(struct vfsmount *mnt, int type)
{
if (type == MS_SHARED) {
prev_src_mnt = child;
}
out:
prev_src_mnt = child;
}
out:
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
while (!list_empty(&tmp_list)) {
child = list_first_entry(&tmp_list, struct vfsmount, mnt_hash);
umount_tree(child, 0, &umount_list);
}
while (!list_empty(&tmp_list)) {
child = list_first_entry(&tmp_list, struct vfsmount, mnt_hash);
umount_tree(child, 0, &umount_list);
}
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
release_mounts(&umount_list);
return ret;
}
release_mounts(&umount_list);
return ret;
}
* other mounts its parent propagates to.
* Check if any of these mounts that **do not have submounts**
* have more references than 'refcnt'. If so return busy.
* other mounts its parent propagates to.
* Check if any of these mounts that **do not have submounts**
* have more references than 'refcnt'. If so return busy.
+ *
+ * vfsmount lock must be held for read or write
*/
int propagate_mount_busy(struct vfsmount *mnt, int refcnt)
{
*/
int propagate_mount_busy(struct vfsmount *mnt, int refcnt)
{
* collect all mounts that receive propagation from the mount in @list,
* and return these additional mounts in the same list.
* @list: the list of mounts to be unmounted.
* collect all mounts that receive propagation from the mount in @list,
* and return these additional mounts in the same list.
* @list: the list of mounts to be unmounted.
+ *
+ * vfsmount lock must be held for write
*/
int propagate_umount(struct list_head *list)
{
*/
int propagate_umount(struct list_head *list)
{