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Diffstat (limited to 'fs/namespace.c')
-rw-r--r--fs/namespace.c130
1 files changed, 67 insertions, 63 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index 208c079e9fd..587eb0d707e 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -61,7 +61,7 @@ struct vfsmount *alloc_vfsmnt(const char *name)
INIT_LIST_HEAD(&mnt->mnt_child);
INIT_LIST_HEAD(&mnt->mnt_mounts);
INIT_LIST_HEAD(&mnt->mnt_list);
- INIT_LIST_HEAD(&mnt->mnt_fslink);
+ INIT_LIST_HEAD(&mnt->mnt_expire);
if (name) {
int size = strlen(name)+1;
char *newname = kmalloc(size, GFP_KERNEL);
@@ -165,8 +165,8 @@ clone_mnt(struct vfsmount *old, struct dentry *root)
/* stick the duplicate mount on the same expiry list
* as the original if that was on one */
spin_lock(&vfsmount_lock);
- if (!list_empty(&old->mnt_fslink))
- list_add(&mnt->mnt_fslink, &old->mnt_fslink);
+ if (!list_empty(&old->mnt_expire))
+ list_add(&mnt->mnt_expire, &old->mnt_expire);
spin_unlock(&vfsmount_lock);
}
return mnt;
@@ -345,12 +345,13 @@ static void umount_tree(struct vfsmount *mnt)
for (p = mnt; p; p = next_mnt(p, mnt)) {
list_del(&p->mnt_list);
list_add(&p->mnt_list, &kill);
+ p->mnt_namespace = NULL;
}
while (!list_empty(&kill)) {
mnt = list_entry(kill.next, struct vfsmount, mnt_list);
list_del_init(&mnt->mnt_list);
- list_del_init(&mnt->mnt_fslink);
+ list_del_init(&mnt->mnt_expire);
if (mnt->mnt_parent == mnt) {
spin_unlock(&vfsmount_lock);
} else {
@@ -644,7 +645,7 @@ static int do_loopback(struct nameidata *nd, char *old_name, int recurse)
if (mnt) {
/* stop bind mounts from expiring */
spin_lock(&vfsmount_lock);
- list_del_init(&mnt->mnt_fslink);
+ list_del_init(&mnt->mnt_expire);
spin_unlock(&vfsmount_lock);
err = graft_tree(mnt, nd);
@@ -743,7 +744,7 @@ static int do_move_mount(struct nameidata *nd, char *old_name)
/* if the mount is moved, it should no longer be expire
* automatically */
- list_del_init(&old_nd.mnt->mnt_fslink);
+ list_del_init(&old_nd.mnt->mnt_expire);
out2:
spin_unlock(&vfsmount_lock);
out1:
@@ -807,12 +808,13 @@ int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd,
goto unlock;
newmnt->mnt_flags = mnt_flags;
+ newmnt->mnt_namespace = current->namespace;
err = graft_tree(newmnt, nd);
if (err == 0 && fslist) {
/* add to the specified expiration list */
spin_lock(&vfsmount_lock);
- list_add_tail(&newmnt->mnt_fslink, fslist);
+ list_add_tail(&newmnt->mnt_expire, fslist);
spin_unlock(&vfsmount_lock);
}
@@ -824,6 +826,54 @@ unlock:
EXPORT_SYMBOL_GPL(do_add_mount);
+static void expire_mount(struct vfsmount *mnt, struct list_head *mounts)
+{
+ spin_lock(&vfsmount_lock);
+
+ /*
+ * Check if mount is still attached, if not, let whoever holds it deal
+ * with the sucker
+ */
+ if (mnt->mnt_parent == mnt) {
+ spin_unlock(&vfsmount_lock);
+ return;
+ }
+
+ /*
+ * Check that it is still dead: the count should now be 2 - as
+ * contributed by the vfsmount parent and the mntget above
+ */
+ if (atomic_read(&mnt->mnt_count) == 2) {
+ struct nameidata old_nd;
+
+ /* delete from the namespace */
+ list_del_init(&mnt->mnt_list);
+ mnt->mnt_namespace = NULL;
+ detach_mnt(mnt, &old_nd);
+ spin_unlock(&vfsmount_lock);
+ path_release(&old_nd);
+
+ /*
+ * Now lay it to rest if this was the last ref on the superblock
+ */
+ if (atomic_read(&mnt->mnt_sb->s_active) == 1) {
+ /* last instance - try to be smart */
+ lock_kernel();
+ DQUOT_OFF(mnt->mnt_sb);
+ acct_auto_close(mnt->mnt_sb);
+ unlock_kernel();
+ }
+ mntput(mnt);
+ } else {
+ /*
+ * Someone brought it back to life whilst we didn't have any
+ * locks held so return it to the expiration list
+ */
+ list_add_tail(&mnt->mnt_expire, mounts);
+ spin_unlock(&vfsmount_lock);
+ }
+}
+
/*
* process a list of expirable mountpoints with the intent of discarding any
* mountpoints that aren't in use and haven't been touched since last we came
@@ -846,13 +896,13 @@ void mark_mounts_for_expiry(struct list_head *mounts)
* - still marked for expiry (marked on the last call here; marks are
* cleared by mntput())
*/
- list_for_each_entry_safe(mnt, next, mounts, mnt_fslink) {
+ list_for_each_entry_safe(mnt, next, mounts, mnt_expire) {
if (!xchg(&mnt->mnt_expiry_mark, 1) ||
atomic_read(&mnt->mnt_count) != 1)
continue;
mntget(mnt);
- list_move(&mnt->mnt_fslink, &graveyard);
+ list_move(&mnt->mnt_expire, &graveyard);
}
/*
@@ -862,61 +912,19 @@ void mark_mounts_for_expiry(struct list_head *mounts)
* - dispose of the corpse
*/
while (!list_empty(&graveyard)) {
- mnt = list_entry(graveyard.next, struct vfsmount, mnt_fslink);
- list_del_init(&mnt->mnt_fslink);
+ mnt = list_entry(graveyard.next, struct vfsmount, mnt_expire);
+ list_del_init(&mnt->mnt_expire);
/* don't do anything if the namespace is dead - all the
* vfsmounts from it are going away anyway */
namespace = mnt->mnt_namespace;
- if (!namespace || atomic_read(&namespace->count) <= 0)
+ if (!namespace || !namespace->root)
continue;
get_namespace(namespace);
spin_unlock(&vfsmount_lock);
down_write(&namespace->sem);
- spin_lock(&vfsmount_lock);
-
- /* check that it is still dead: the count should now be 2 - as
- * contributed by the vfsmount parent and the mntget above */
- if (atomic_read(&mnt->mnt_count) == 2) {
- struct vfsmount *xdmnt;
- struct dentry *xdentry;
-
- /* delete from the namespace */
- list_del_init(&mnt->mnt_list);
- list_del_init(&mnt->mnt_child);
- list_del_init(&mnt->mnt_hash);
- mnt->mnt_mountpoint->d_mounted--;
-
- xdentry = mnt->mnt_mountpoint;
- mnt->mnt_mountpoint = mnt->mnt_root;
- xdmnt = mnt->mnt_parent;
- mnt->mnt_parent = mnt;
-
- spin_unlock(&vfsmount_lock);
-
- mntput(xdmnt);
- dput(xdentry);
-
- /* now lay it to rest if this was the last ref on the
- * superblock */
- if (atomic_read(&mnt->mnt_sb->s_active) == 1) {
- /* last instance - try to be smart */
- lock_kernel();
- DQUOT_OFF(mnt->mnt_sb);
- acct_auto_close(mnt->mnt_sb);
- unlock_kernel();
- }
-
- mntput(mnt);
- } else {
- /* someone brought it back to life whilst we didn't
- * have any locks held so return it to the expiration
- * list */
- list_add_tail(&mnt->mnt_fslink, mounts);
- spin_unlock(&vfsmount_lock);
- }
-
+ expire_mount(mnt, mounts);
up_write(&namespace->sem);
mntput(mnt);
@@ -1449,16 +1457,12 @@ void __init mnt_init(unsigned long mempages)
void __put_namespace(struct namespace *namespace)
{
- struct vfsmount *mnt;
-
+ struct vfsmount *root = namespace->root;
+ namespace->root = NULL;
+ spin_unlock(&vfsmount_lock);
down_write(&namespace->sem);
spin_lock(&vfsmount_lock);
-
- list_for_each_entry(mnt, &namespace->list, mnt_list) {
- mnt->mnt_namespace = NULL;
- }
-
- umount_tree(namespace->root);
+ umount_tree(root);
spin_unlock(&vfsmount_lock);
up_write(&namespace->sem);
kfree(namespace);
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-11 18:05:40 +0000