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new helpers: lock_mount_hash/unlock_mount_hash 

aka br_write_{lock,unlock} of vfsmount_lock.  Inlines in fs/mount.h,
vfsmount_lock extern moved over there as well.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2013-09-29 11:24:49 -04:00
parent aab407fc5c
commit 719ea2fbb5
5 changed files with 64 additions and 54 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
fs/fs-writeback.c
View File

@ -26,6 +26,7 @@
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include <linux/tracepoint.h>
#include <linux/device.h>
#include "internal.h"
/*

4
fs/internal.h
View File

@ -9,8 +9,6 @@
* 2 of the License, or (at your option) any later version.
*/
#include <linux/lglock.h>
struct super_block;
struct file_system_type;
struct linux_binprm;
@ -62,8 +60,6 @@ extern int sb_prepare_remount_readonly(struct super_block *);
extern void __init mnt_init(void);
extern struct lglock vfsmount_lock;
extern int __mnt_want_write(struct vfsmount *);
extern int __mnt_want_write_file(struct file *);
extern void __mnt_drop_write(struct vfsmount *);

13
fs/mount.h
View File

@ -1,6 +1,7 @@
#include <linux/mount.h>
#include <linux/seq_file.h>
#include <linux/poll.h>
#include <linux/lglock.h>
struct mnt_namespace {
atomic_t count;
@ -83,6 +84,18 @@ static inline void get_mnt_ns(struct mnt_namespace *ns)
atomic_inc(&ns->count);
}
extern struct lglock vfsmount_lock;
static inline void lock_mount_hash(void)
{
br_write_lock(&vfsmount_lock);
}
static inline void unlock_mount_hash(void)
{
br_write_unlock(&vfsmount_lock);
}
struct proc_mounts {
struct seq_file m;
struct mnt_namespace *ns;

96
fs/namespace.c
View File

@ -456,7 +456,7 @@ static int mnt_make_readonly(struct mount *mnt)
{
int ret = 0;
br_write_lock(&vfsmount_lock);
lock_mount_hash();
mnt->mnt.mnt_flags |= MNT_WRITE_HOLD;
/*
* After storing MNT_WRITE_HOLD, we'll read the counters. This store
@ -490,15 +490,15 @@ static int mnt_make_readonly(struct mount *mnt)
*/
smp_wmb();
mnt->mnt.mnt_flags &= ~MNT_WRITE_HOLD;
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
return ret;
}
static void __mnt_unmake_readonly(struct mount *mnt)
{
br_write_lock(&vfsmount_lock);
lock_mount_hash();
mnt->mnt.mnt_flags &= ~MNT_READONLY;
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
}
int sb_prepare_remount_readonly(struct super_block *sb)
@ -510,7 +510,7 @@ int sb_prepare_remount_readonly(struct super_block *sb)
if (atomic_long_read(&sb->s_remove_count))
return -EBUSY;
br_write_lock(&vfsmount_lock);
lock_mount_hash();
list_for_each_entry(mnt, &sb->s_mounts, mnt_instance) {
if (!(mnt->mnt.mnt_flags & MNT_READONLY)) {
mnt->mnt.mnt_flags |= MNT_WRITE_HOLD;
@ -532,7 +532,7 @@ int sb_prepare_remount_readonly(struct super_block *sb)
if (mnt->mnt.mnt_flags & MNT_WRITE_HOLD)
mnt->mnt.mnt_flags &= ~MNT_WRITE_HOLD;
}
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
return err;
}
@ -794,9 +794,9 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void
mnt->mnt.mnt_sb = root->d_sb;
mnt->mnt_mountpoint = mnt->mnt.mnt_root;
mnt->mnt_parent = mnt;
br_write_lock(&vfsmount_lock);
lock_mount_hash();
list_add_tail(&mnt->mnt_instance, &root->d_sb->s_mounts);
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
return &mnt->mnt;
}
EXPORT_SYMBOL_GPL(vfs_kern_mount);
@ -837,9 +837,9 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root,
mnt->mnt.mnt_root = dget(root);
mnt->mnt_mountpoint = mnt->mnt.mnt_root;
mnt->mnt_parent = mnt;
br_write_lock(&vfsmount_lock);
lock_mount_hash();
list_add_tail(&mnt->mnt_instance, &sb->s_mounts);
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
if ((flag & CL_SLAVE) ||
((flag & CL_SHARED_TO_SLAVE) && IS_MNT_SHARED(old))) {
@ -883,28 +883,28 @@ put_again:
}
br_read_unlock(&vfsmount_lock);
br_write_lock(&vfsmount_lock);
lock_mount_hash();
mnt_add_count(mnt, -1);
if (mnt_get_count(mnt)) {
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
return;
}
#else
mnt_add_count(mnt, -1);
if (likely(mnt_get_count(mnt)))
return;
br_write_lock(&vfsmount_lock);
lock_mount_hash();
#endif
if (unlikely(mnt->mnt_pinned)) {
mnt_add_count(mnt, mnt->mnt_pinned + 1);
mnt->mnt_pinned = 0;
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
acct_auto_close_mnt(&mnt->mnt);
goto put_again;
}
list_del(&mnt->mnt_instance);
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
/*
* This probably indicates that somebody messed
@ -945,21 +945,21 @@ EXPORT_SYMBOL(mntget);
void mnt_pin(struct vfsmount *mnt)
{
br_write_lock(&vfsmount_lock);
lock_mount_hash();
real_mount(mnt)->mnt_pinned++;
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
}
EXPORT_SYMBOL(mnt_pin);
void mnt_unpin(struct vfsmount *m)
{
struct mount *mnt = real_mount(m);
br_write_lock(&vfsmount_lock);
lock_mount_hash();
if (mnt->mnt_pinned) {
mnt_add_count(mnt, 1);
mnt->mnt_pinned--;
}
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
}
EXPORT_SYMBOL(mnt_unpin);
@ -1076,12 +1076,12 @@ int may_umount_tree(struct vfsmount *m)
BUG_ON(!m);
/* write lock needed for mnt_get_count */
br_write_lock(&vfsmount_lock);
lock_mount_hash();
for (p = mnt; p; p = next_mnt(p, mnt)) {
actual_refs += mnt_get_count(p);
minimum_refs += 2;
}
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
if (actual_refs > minimum_refs)
return 0;
@ -1108,10 +1108,10 @@ int may_umount(struct vfsmount *mnt)
{
int ret = 1;
down_read(&namespace_sem);
br_write_lock(&vfsmount_lock);
lock_mount_hash();
if (propagate_mount_busy(real_mount(mnt), 2))
ret = 0;
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
up_read(&namespace_sem);
return ret;
}
@ -1208,12 +1208,12 @@ static int do_umount(struct mount *mnt, int flags)
* probably don't strictly need the lock here if we examined
* all race cases, but it's a slowpath.
*/
br_write_lock(&vfsmount_lock);
lock_mount_hash();
if (mnt_get_count(mnt) != 2) {
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
return -EBUSY;
}
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
if (!xchg(&mnt->mnt_expiry_mark, 1))
return -EAGAIN;
@ -1255,7 +1255,7 @@ static int do_umount(struct mount *mnt, int flags)
}
namespace_lock();
br_write_lock(&vfsmount_lock);
lock_mount_hash();
event++;
if (!(flags & MNT_DETACH))
@ -1267,7 +1267,7 @@ static int do_umount(struct mount *mnt, int flags)
umount_tree(mnt, 1);
retval = 0;
}
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
namespace_unlock();
return retval;
}
@ -1410,18 +1410,18 @@ struct mount *copy_tree(struct mount *mnt, struct dentry *dentry,
q = clone_mnt(p, p->mnt.mnt_root, flag);
if (IS_ERR(q))
goto out;
br_write_lock(&vfsmount_lock);
lock_mount_hash();
list_add_tail(&q->mnt_list, &res->mnt_list);
attach_mnt(q, parent, p->mnt_mp);
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
}
}
return res;
out:
if (res) {
br_write_lock(&vfsmount_lock);
lock_mount_hash();
umount_tree(res, 0);
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
}
return q;
}
@ -1443,9 +1443,9 @@ struct vfsmount *collect_mounts(struct path *path)
void drop_collected_mounts(struct vfsmount *mnt)
{
namespace_lock();
br_write_lock(&vfsmount_lock);
lock_mount_hash();
umount_tree(real_mount(mnt), 0);
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
namespace_unlock();
}
@ -1572,7 +1572,7 @@ static int attach_recursive_mnt(struct mount *source_mnt,
if (err)
goto out_cleanup_ids;
br_write_lock(&vfsmount_lock);
lock_mount_hash();
if (IS_MNT_SHARED(dest_mnt)) {
for (p = source_mnt; p; p = next_mnt(p, source_mnt))
@ -1591,7 +1591,7 @@ static int attach_recursive_mnt(struct mount *source_mnt,
list_del_init(&child->mnt_hash);
commit_tree(child);
}
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
return 0;
@ -1693,10 +1693,10 @@ static int do_change_type(struct path *path, int flag)
goto out_unlock;
}
br_write_lock(&vfsmount_lock);
lock_mount_hash();
for (m = mnt; m; m = (recurse ? next_mnt(m, mnt) : NULL))
change_mnt_propagation(m, type);
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
out_unlock:
namespace_unlock();
@ -1768,9 +1768,9 @@ static int do_loopback(struct path *path, const char *old_name,
err = graft_tree(mnt, parent, mp);
if (err) {
br_write_lock(&vfsmount_lock);
lock_mount_hash();
umount_tree(mnt, 0);
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
}
out2:
unlock_mount(mp);
@ -1829,11 +1829,11 @@ static int do_remount(struct path *path, int flags, int mnt_flags,
else
err = do_remount_sb(sb, flags, data, 0);
if (!err) {
br_write_lock(&vfsmount_lock);
lock_mount_hash();
mnt_flags |= mnt->mnt.mnt_flags & MNT_PROPAGATION_MASK;
mnt->mnt.mnt_flags = mnt_flags;
touch_mnt_namespace(mnt->mnt_ns);
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
}
up_write(&sb->s_umount);
return err;
@ -2093,7 +2093,7 @@ void mark_mounts_for_expiry(struct list_head *mounts)
return;
namespace_lock();
br_write_lock(&vfsmount_lock);
lock_mount_hash();
/* extract from the expiration list every vfsmount that matches the
* following criteria:
@ -2112,7 +2112,7 @@ void mark_mounts_for_expiry(struct list_head *mounts)
touch_mnt_namespace(mnt->mnt_ns);
umount_tree(mnt, 1);
}
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
namespace_unlock();
}
@ -2662,7 +2662,7 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root,
if (!is_path_reachable(old_mnt, old.dentry, &new))
goto out4;
root_mp->m_count++; /* pin it so it won't go away */
br_write_lock(&vfsmount_lock);
lock_mount_hash();
detach_mnt(new_mnt, &parent_path);
detach_mnt(root_mnt, &root_parent);
if (root_mnt->mnt.mnt_flags & MNT_LOCKED) {
@ -2674,7 +2674,7 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root,
/* mount new_root on / */
attach_mnt(new_mnt, real_mount(root_parent.mnt), root_mp);
touch_mnt_namespace(current->nsproxy->mnt_ns);
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
chroot_fs_refs(&root, &new);
put_mountpoint(root_mp);
error = 0;
@ -2784,9 +2784,9 @@ void kern_unmount(struct vfsmount *mnt)
{
/* release long term mount so mount point can be released */
if (!IS_ERR_OR_NULL(mnt)) {
br_write_lock(&vfsmount_lock);
lock_mount_hash();
real_mount(mnt)->mnt_ns = NULL;
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
mntput(mnt);
}
}

4
fs/pnode.c
View File

@ -264,12 +264,12 @@ int propagate_mnt(struct mount *dest_mnt, struct mountpoint *dest_mp,
prev_src_mnt = child;
}
out:
br_write_lock(&vfsmount_lock);
lock_mount_hash();
while (!list_empty(&tmp_list)) {
child = list_first_entry(&tmp_list, struct mount, mnt_hash);
umount_tree(child, 0);
}
br_write_unlock(&vfsmount_lock);
unlock_mount_hash();
return ret;
}