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Date: Thu, 03 Oct 2013 07:19:26 +0100
From: Al Viro <viro@....linux.org.uk>
To: torvalds@...ux-foundation.org
Cc: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 12/17] 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@...iv.linux.org.uk>
---
fs/internal.h | 4 --
fs/mount.h | 13 +++++++
fs/namespace.c | 96 ++++++++++++++++++++++++++++----------------------------
fs/pnode.c | 4 +-
4 files changed, 63 insertions(+), 54 deletions(-)
diff --git a/fs/internal.h b/fs/internal.h
index 513e0d8..4a11e75 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -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 *);
diff --git a/fs/mount.h b/fs/mount.h
index 3168dc4..7076f25 100644
--- a/fs/mount.h
+++ b/fs/mount.h
@@ -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;
diff --git a/fs/namespace.c b/fs/namespace.c
index 6985d52..aa6dd93 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -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;
@@ -2788,9 +2788,9 @@ 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);
}
}
diff --git a/fs/pnode.c b/fs/pnode.c
index 3cfd48c..58933fd 100644
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -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;
}
--
1.7.2.5
--
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