Commit 83adc753 authored by Al Viro's avatar Al Viro
Browse files

vfs: spread struct mount - work with counters 



Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent a73324da

fs/namespace.c

+64 −60
Original line number Diff line number Diff line
@@ -141,13 +141,13 @@ void mnt_release_group_id(struct mount *mnt) 
/*

 * vfsmount lock must be held for read

 */

static inline void mnt_add_count(struct vfsmount *mnt, int n)

static inline void mnt_add_count(struct mount *mnt, int n)

{

#ifdef CONFIG_SMP

	this_cpu_add(mnt->mnt_pcp->mnt_count, n);

	this_cpu_add(mnt->mnt.mnt_pcp->mnt_count, n);

#else

	preempt_disable();

	mnt->mnt_count += n;

	mnt->mnt.mnt_count += n;

	preempt_enable();

#endif

}
@@ -155,19 +155,19 @@ static inline void mnt_add_count(struct vfsmount *mnt, int n) 
/*

 * vfsmount lock must be held for write

 */

unsigned int mnt_get_count(struct vfsmount *mnt)

unsigned int mnt_get_count(struct mount *mnt)

{

#ifdef CONFIG_SMP

	unsigned int count = 0;

	int cpu;



	for_each_possible_cpu(cpu) {

		count += per_cpu_ptr(mnt->mnt_pcp, cpu)->mnt_count;

		count += per_cpu_ptr(mnt->mnt.mnt_pcp, cpu)->mnt_count;

	}



	return count;

#else

	return mnt->mnt_count;

	return mnt->mnt.mnt_count;

#endif

}
@@ -253,32 +253,32 @@ int __mnt_is_readonly(struct vfsmount *mnt) 
}

EXPORT_SYMBOL_GPL(__mnt_is_readonly);



static inline void mnt_inc_writers(struct vfsmount *mnt)

static inline void mnt_inc_writers(struct mount *mnt)

{

#ifdef CONFIG_SMP

	this_cpu_inc(mnt->mnt_pcp->mnt_writers);

	this_cpu_inc(mnt->mnt.mnt_pcp->mnt_writers);

#else

	mnt->mnt_writers++;

	mnt->mnt.mnt_writers++;

#endif

}



static inline void mnt_dec_writers(struct vfsmount *mnt)

static inline void mnt_dec_writers(struct mount *mnt)

{

#ifdef CONFIG_SMP

	this_cpu_dec(mnt->mnt_pcp->mnt_writers);

	this_cpu_dec(mnt->mnt.mnt_pcp->mnt_writers);

#else

	mnt->mnt_writers--;

	mnt->mnt.mnt_writers--;

#endif

}



static unsigned int mnt_get_writers(struct vfsmount *mnt)

static unsigned int mnt_get_writers(struct mount *mnt)

{

#ifdef CONFIG_SMP

	unsigned int count = 0;

	int cpu;



	for_each_possible_cpu(cpu) {

		count += per_cpu_ptr(mnt->mnt_pcp, cpu)->mnt_writers;

		count += per_cpu_ptr(mnt->mnt.mnt_pcp, cpu)->mnt_writers;

	}



	return count;
@@ -297,7 +297,7 @@ static unsigned int mnt_get_writers(struct vfsmount *mnt) 
 */

/**

 * mnt_want_write - get write access to a mount

 * @mnt: the mount on which to take a write

 * @m: the mount on which to take a write

 *

 * This tells the low-level filesystem that a write is

 * about to be performed to it, and makes sure that
@@ -305,8 +305,9 @@ static unsigned int mnt_get_writers(struct vfsmount *mnt) 
 * the write operation is finished, mnt_drop_write()

 * must be called.  This is effectively a refcount.

 */

int mnt_want_write(struct vfsmount *mnt)

int mnt_want_write(struct vfsmount *m)

{

	struct mount *mnt = real_mount(m);

	int ret = 0;



	preempt_disable();
@@ -317,7 +318,7 @@ int mnt_want_write(struct vfsmount *mnt) 
	 * incremented count after it has set MNT_WRITE_HOLD.

	 */

	smp_mb();

	while (mnt->mnt_flags & MNT_WRITE_HOLD)

	while (mnt->mnt.mnt_flags & MNT_WRITE_HOLD)

		cpu_relax();

	/*

	 * After the slowpath clears MNT_WRITE_HOLD, mnt_is_readonly will
@@ -325,7 +326,7 @@ int mnt_want_write(struct vfsmount *mnt) 
	 * MNT_WRITE_HOLD is cleared.

	 */

	smp_rmb();

	if (__mnt_is_readonly(mnt)) {

	if (__mnt_is_readonly(m)) {

		mnt_dec_writers(mnt);

		ret = -EROFS;

		goto out;
@@ -354,7 +355,7 @@ int mnt_clone_write(struct vfsmount *mnt) 
	if (__mnt_is_readonly(mnt))

		return -EROFS;

	preempt_disable();

	mnt_inc_writers(mnt);

	mnt_inc_writers(real_mount(mnt));

	preempt_enable();

	return 0;

}
@@ -388,7 +389,7 @@ EXPORT_SYMBOL_GPL(mnt_want_write_file); 
void mnt_drop_write(struct vfsmount *mnt)

{

	preempt_disable();

	mnt_dec_writers(mnt);

	mnt_dec_writers(real_mount(mnt));

	preempt_enable();

}

EXPORT_SYMBOL_GPL(mnt_drop_write);
@@ -399,12 +400,12 @@ void mnt_drop_write_file(struct file *file) 
}

EXPORT_SYMBOL(mnt_drop_write_file);



static int mnt_make_readonly(struct vfsmount *mnt)

static int mnt_make_readonly(struct mount *mnt)

{

	int ret = 0;



	br_write_lock(vfsmount_lock);

	mnt->mnt_flags |= MNT_WRITE_HOLD;

	mnt->mnt.mnt_flags |= MNT_WRITE_HOLD;

	/*

	 * After storing MNT_WRITE_HOLD, we'll read the counters. This store

	 * should be visible before we do.
@@ -430,21 +431,21 @@ static int mnt_make_readonly(struct vfsmount *mnt) 
	if (mnt_get_writers(mnt) > 0)

		ret = -EBUSY;

	else

		mnt->mnt_flags |= MNT_READONLY;

		mnt->mnt.mnt_flags |= MNT_READONLY;

	/*

	 * MNT_READONLY must become visible before ~MNT_WRITE_HOLD, so writers

	 * that become unheld will see MNT_READONLY.

	 */

	smp_wmb();

	mnt->mnt_flags &= ~MNT_WRITE_HOLD;

	mnt->mnt.mnt_flags &= ~MNT_WRITE_HOLD;

	br_write_unlock(vfsmount_lock);

	return ret;

}



static void __mnt_unmake_readonly(struct vfsmount *mnt)

static void __mnt_unmake_readonly(struct mount *mnt)

{

	br_write_lock(vfsmount_lock);

	mnt->mnt_flags &= ~MNT_READONLY;

	mnt->mnt.mnt_flags &= ~MNT_READONLY;

	br_write_unlock(vfsmount_lock);

}
@@ -590,18 +591,18 @@ static void attach_mnt(struct mount *mnt, struct path *path) 
	list_add_tail(&mnt->mnt.mnt_child, &path->mnt->mnt_mounts);

}



static inline void __mnt_make_longterm(struct vfsmount *mnt)

static inline void __mnt_make_longterm(struct mount *mnt)

{

#ifdef CONFIG_SMP

	atomic_inc(&mnt->mnt_longterm);

	atomic_inc(&mnt->mnt.mnt_longterm);

#endif

}



/* needs vfsmount lock for write */

static inline void __mnt_make_shortterm(struct vfsmount *mnt)

static inline void __mnt_make_shortterm(struct mount *mnt)

{

#ifdef CONFIG_SMP

	atomic_dec(&mnt->mnt_longterm);

	atomic_dec(&mnt->mnt.mnt_longterm);

#endif

}
@@ -611,15 +612,15 @@ static inline void __mnt_make_shortterm(struct vfsmount *mnt) 
static void commit_tree(struct mount *mnt)

{

	struct mount *parent = mnt->mnt_parent;

	struct vfsmount *m;

	struct mount *m;

	LIST_HEAD(head);

	struct mnt_namespace *n = parent->mnt.mnt_ns;



	BUG_ON(parent == mnt);



	list_add_tail(&head, &mnt->mnt.mnt_list);

	list_for_each_entry(m, &head, mnt_list) {

		m->mnt_ns = n;

	list_for_each_entry(m, &head, mnt.mnt_list) {

		m->mnt.mnt_ns = n;

		__mnt_make_longterm(m);

	}
@@ -740,9 +741,10 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root, 
	return NULL;

}



static inline void mntfree(struct vfsmount *mnt)

static inline void mntfree(struct mount *mnt)

{

	struct super_block *sb = mnt->mnt_sb;

	struct vfsmount *m = &mnt->mnt;

	struct super_block *sb = m->mnt_sb;



	/*

	 * This probably indicates that somebody messed
@@ -755,18 +757,19 @@ static inline void mntfree(struct vfsmount *mnt) 
	 * so mnt_get_writers() below is safe.

	 */

	WARN_ON(mnt_get_writers(mnt));

	fsnotify_vfsmount_delete(mnt);

	dput(mnt->mnt_root);

	free_vfsmnt(real_mount(mnt));

	fsnotify_vfsmount_delete(m);

	dput(m->mnt_root);

	free_vfsmnt(mnt);

	deactivate_super(sb);

}



static void mntput_no_expire(struct vfsmount *mnt)

static void mntput_no_expire(struct vfsmount *m)

{

	struct mount *mnt = real_mount(m);

put_again:

#ifdef CONFIG_SMP

	br_read_lock(vfsmount_lock);

	if (likely(atomic_read(&mnt->mnt_longterm))) {

	if (likely(atomic_read(&mnt->mnt.mnt_longterm))) {

		mnt_add_count(mnt, -1);

		br_read_unlock(vfsmount_lock);

		return;
@@ -785,11 +788,11 @@ put_again: 
		return;

	br_write_lock(vfsmount_lock);

#endif

	if (unlikely(mnt->mnt_pinned)) {

		mnt_add_count(mnt, mnt->mnt_pinned + 1);

		mnt->mnt_pinned = 0;

	if (unlikely(mnt->mnt.mnt_pinned)) {

		mnt_add_count(mnt, mnt->mnt.mnt_pinned + 1);

		mnt->mnt.mnt_pinned = 0;

		br_write_unlock(vfsmount_lock);

		acct_auto_close_mnt(mnt);

		acct_auto_close_mnt(m);

		goto put_again;

	}

	br_write_unlock(vfsmount_lock);
@@ -810,7 +813,7 @@ EXPORT_SYMBOL(mntput); 
struct vfsmount *mntget(struct vfsmount *mnt)

{

	if (mnt)

		mnt_add_count(mnt, 1);

		mnt_add_count(real_mount(mnt), 1);

	return mnt;

}

EXPORT_SYMBOL(mntget);
@@ -827,7 +830,7 @@ void mnt_unpin(struct vfsmount *mnt) 
{

	br_write_lock(vfsmount_lock);

	if (mnt->mnt_pinned) {

		mnt_add_count(mnt, 1);

		mnt_add_count(real_mount(mnt), 1);

		mnt->mnt_pinned--;

	}

	br_write_unlock(vfsmount_lock);
@@ -1150,7 +1153,7 @@ int may_umount_tree(struct vfsmount *mnt) 
	/* write lock needed for mnt_get_count */

	br_write_lock(vfsmount_lock);

	for (p = real_mount(mnt); p; p = next_mnt(p, mnt)) {

		actual_refs += mnt_get_count(&p->mnt);

		actual_refs += mnt_get_count(p);

		minimum_refs += 2;

	}

	br_write_unlock(vfsmount_lock);
@@ -1234,7 +1237,7 @@ void umount_tree(struct mount *mnt, int propagate, struct list_head *kill) 
		list_del_init(&p->mnt.mnt_list);

		__touch_mnt_namespace(p->mnt.mnt_ns);

		p->mnt.mnt_ns = NULL;

		__mnt_make_shortterm(&p->mnt);

		__mnt_make_shortterm(p);

		list_del_init(&p->mnt.mnt_child);

		if (mnt_has_parent(p)) {

			p->mnt_parent->mnt.mnt_ghosts++;
@@ -1273,7 +1276,7 @@ static int do_umount(struct mount *mnt, int flags) 
		 * all race cases, but it's a slowpath.

		 */

		br_write_lock(vfsmount_lock);

		if (mnt_get_count(&mnt->mnt) != 2) {

		if (mnt_get_count(mnt) != 2) {

			br_write_unlock(vfsmount_lock);

			return -EBUSY;

		}
@@ -1798,9 +1801,9 @@ static int change_mount_flags(struct vfsmount *mnt, int ms_flags) 
		return 0;



	if (readonly_request)

		error = mnt_make_readonly(mnt);

		error = mnt_make_readonly(real_mount(mnt));

	else

		__mnt_unmake_readonly(mnt);

		__mnt_unmake_readonly(real_mount(mnt));

	return error;

}
@@ -2034,7 +2037,7 @@ int finish_automount(struct vfsmount *m, struct path *path) 
	/* The new mount record should have at least 2 refs to prevent it being

	 * expired before we get a chance to add it

	 */

	BUG_ON(mnt_get_count(m) < 2);

	BUG_ON(mnt_get_count(real_mount(m)) < 2);



	if (m->mnt_sb == path->mnt->mnt_sb &&

	    m->mnt_root == path->dentry) {
@@ -2365,16 +2368,17 @@ static struct mnt_namespace *alloc_mnt_ns(void) 


void mnt_make_longterm(struct vfsmount *mnt)

{

	__mnt_make_longterm(mnt);

	__mnt_make_longterm(real_mount(mnt));

}



void mnt_make_shortterm(struct vfsmount *mnt)

void mnt_make_shortterm(struct vfsmount *m)

{

#ifdef CONFIG_SMP

	if (atomic_add_unless(&mnt->mnt_longterm, -1, 1))

	struct mount *mnt = real_mount(m);

	if (atomic_add_unless(&mnt->mnt.mnt_longterm, -1, 1))

		return;

	br_write_lock(vfsmount_lock);

	atomic_dec(&mnt->mnt_longterm);

	atomic_dec(&mnt->mnt.mnt_longterm);

	br_write_unlock(vfsmount_lock);

#endif

}
@@ -2418,17 +2422,17 @@ static struct mnt_namespace *dup_mnt_ns(struct mnt_namespace *mnt_ns, 
	q = new;

	while (p) {

		q->mnt.mnt_ns = new_ns;

		__mnt_make_longterm(&q->mnt);

		__mnt_make_longterm(q);

		if (fs) {

			if (&p->mnt == fs->root.mnt) {

				fs->root.mnt = mntget(&q->mnt);

				__mnt_make_longterm(&q->mnt);

				__mnt_make_longterm(q);

				mnt_make_shortterm(&p->mnt);

				rootmnt = &p->mnt;

			}

			if (&p->mnt == fs->pwd.mnt) {

				fs->pwd.mnt = mntget(&q->mnt);

				__mnt_make_longterm(&q->mnt);

				__mnt_make_longterm(q);

				mnt_make_shortterm(&p->mnt);

				pwdmnt = &p->mnt;

			}
@@ -2474,7 +2478,7 @@ static struct mnt_namespace *create_mnt_ns(struct vfsmount *mnt) 
	new_ns = alloc_mnt_ns();

	if (!IS_ERR(new_ns)) {

		mnt->mnt_ns = new_ns;

		__mnt_make_longterm(mnt);

		__mnt_make_longterm(real_mount(mnt));

		new_ns->root = mnt;

		list_add(&new_ns->list, &new_ns->root->mnt_list);

	} else {

fs/pnode.c

+1 −1
Original line number Diff line number Diff line
@@ -274,7 +274,7 @@ out: 
 */

static inline int do_refcount_check(struct mount *mnt, int count)

{

	int mycount = mnt_get_count(&mnt->mnt) - mnt->mnt.mnt_ghosts;

	int mycount = mnt_get_count(mnt) - mnt->mnt.mnt_ghosts;

	return (mycount > count);

}

fs/pnode.h

+1 −1
Original line number Diff line number Diff line
@@ -36,7 +36,7 @@ int propagate_umount(struct list_head *); 
int propagate_mount_busy(struct mount *, int);

void mnt_release_group_id(struct mount *);

int get_dominating_id(struct vfsmount *mnt, const struct path *root);

unsigned int mnt_get_count(struct vfsmount *mnt);

unsigned int mnt_get_count(struct mount *mnt);

void mnt_set_mountpoint(struct vfsmount *, struct dentry *,

			struct mount *);

void release_mounts(struct list_head *);

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