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Commit 719ea2fb authored by Al Viro's avatar Al Viro
Browse files

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: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent aab407fc

fs/fs-writeback.c

+1 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
#include <linux/blkdev.h>

#include <linux/backing-dev.h>

#include <linux/tracepoint.h>

#include <linux/device.h>

#include "internal.h"



/*

fs/internal.h

+0 −4
Original line number Diff line number Diff line
@@ -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 *);

fs/mount.h

+13 −0
Original line number Diff line number Diff line 
#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;

fs/namespace.c

+48 −48
Original line number Diff line number Diff line
@@ -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 @@ static void mntput_no_expire(struct mount *mnt) 
	}

	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);

	}

}

fs/pnode.c

+2 −2
Original line number Diff line number Diff line
@@ -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;

}