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-rw-r--r--fs/Makefile2
-rw-r--r--fs/dquot.c18
-rw-r--r--fs/namespace.c697
-rw-r--r--fs/pnode.c305
-rw-r--r--fs/pnode.h37
-rw-r--r--fs/proc/base.c62
-rw-r--r--fs/seq_file.c12
-rw-r--r--fs/super.c1
8 files changed, 881 insertions, 253 deletions
diff --git a/fs/Makefile b/fs/Makefile
index 1972da18627..4c265575907 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -10,7 +10,7 @@ obj-y := open.o read_write.o file_table.o buffer.o bio.o super.o \
ioctl.o readdir.o select.o fifo.o locks.o dcache.o inode.o \
attr.o bad_inode.o file.o filesystems.o namespace.o aio.o \
seq_file.o xattr.o libfs.o fs-writeback.o mpage.o direct-io.o \
- ioprio.o
+ ioprio.o pnode.o
obj-$(CONFIG_INOTIFY) += inotify.o
obj-$(CONFIG_EPOLL) += eventpoll.o
diff --git a/fs/dquot.c b/fs/dquot.c
index afa06a89346..05b60283c9c 100644
--- a/fs/dquot.c
+++ b/fs/dquot.c
@@ -1321,13 +1321,11 @@ int vfs_quota_off(struct super_block *sb, int type)
int cnt;
struct quota_info *dqopt = sb_dqopt(sb);
struct inode *toputinode[MAXQUOTAS];
- struct vfsmount *toputmnt[MAXQUOTAS];
/* We need to serialize quota_off() for device */
down(&dqopt->dqonoff_sem);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
toputinode[cnt] = NULL;
- toputmnt[cnt] = NULL;
if (type != -1 && cnt != type)
continue;
if (!sb_has_quota_enabled(sb, cnt))
@@ -1348,9 +1346,7 @@ int vfs_quota_off(struct super_block *sb, int type)
put_quota_format(dqopt->info[cnt].dqi_format);
toputinode[cnt] = dqopt->files[cnt];
- toputmnt[cnt] = dqopt->mnt[cnt];
dqopt->files[cnt] = NULL;
- dqopt->mnt[cnt] = NULL;
dqopt->info[cnt].dqi_flags = 0;
dqopt->info[cnt].dqi_igrace = 0;
dqopt->info[cnt].dqi_bgrace = 0;
@@ -1358,10 +1354,7 @@ int vfs_quota_off(struct super_block *sb, int type)
}
up(&dqopt->dqonoff_sem);
/* Sync the superblock so that buffers with quota data are written to
- * disk (and so userspace sees correct data afterwards).
- * The reference to vfsmnt we are still holding protects us from
- * umount (we don't have it only when quotas are turned on/off for
- * journal replay but in that case we are guarded by the fs anyway). */
+ * disk (and so userspace sees correct data afterwards). */
if (sb->s_op->sync_fs)
sb->s_op->sync_fs(sb, 1);
sync_blockdev(sb->s_bdev);
@@ -1385,10 +1378,6 @@ int vfs_quota_off(struct super_block *sb, int type)
iput(toputinode[cnt]);
}
up(&dqopt->dqonoff_sem);
- /* We don't hold the reference when we turned on quotas
- * just for the journal replay... */
- if (toputmnt[cnt])
- mntput(toputmnt[cnt]);
}
if (sb->s_bdev)
invalidate_bdev(sb->s_bdev, 0);
@@ -1503,11 +1492,8 @@ int vfs_quota_on(struct super_block *sb, int type, int format_id, char *path)
/* Quota file not on the same filesystem? */
if (nd.mnt->mnt_sb != sb)
error = -EXDEV;
- else {
+ else
error = vfs_quota_on_inode(nd.dentry->d_inode, type, format_id);
- if (!error)
- sb_dqopt(sb)->mnt[type] = mntget(nd.mnt);
- }
out_path:
path_release(&nd);
return error;
diff --git a/fs/namespace.c b/fs/namespace.c
index 2fa9fdf7d6f..caa9187f67e 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -24,6 +24,7 @@
#include <linux/mount.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
+#include "pnode.h"
extern int __init init_rootfs(void);
@@ -37,33 +38,39 @@ static inline int sysfs_init(void)
#endif
/* spinlock for vfsmount related operations, inplace of dcache_lock */
- __cacheline_aligned_in_smp DEFINE_SPINLOCK(vfsmount_lock);
+__cacheline_aligned_in_smp DEFINE_SPINLOCK(vfsmount_lock);
+
+static int event;
static struct list_head *mount_hashtable;
static int hash_mask __read_mostly, hash_bits __read_mostly;
-static kmem_cache_t *mnt_cache;
+static kmem_cache_t *mnt_cache;
+static struct rw_semaphore namespace_sem;
static inline unsigned long hash(struct vfsmount *mnt, struct dentry *dentry)
{
- unsigned long tmp = ((unsigned long) mnt / L1_CACHE_BYTES);
- tmp += ((unsigned long) dentry / L1_CACHE_BYTES);
+ unsigned long tmp = ((unsigned long)mnt / L1_CACHE_BYTES);
+ tmp += ((unsigned long)dentry / L1_CACHE_BYTES);
tmp = tmp + (tmp >> hash_bits);
return tmp & hash_mask;
}
struct vfsmount *alloc_vfsmnt(const char *name)
{
- struct vfsmount *mnt = kmem_cache_alloc(mnt_cache, GFP_KERNEL);
+ struct vfsmount *mnt = kmem_cache_alloc(mnt_cache, GFP_KERNEL);
if (mnt) {
memset(mnt, 0, sizeof(struct vfsmount));
- atomic_set(&mnt->mnt_count,1);
+ atomic_set(&mnt->mnt_count, 1);
INIT_LIST_HEAD(&mnt->mnt_hash);
INIT_LIST_HEAD(&mnt->mnt_child);
INIT_LIST_HEAD(&mnt->mnt_mounts);
INIT_LIST_HEAD(&mnt->mnt_list);
INIT_LIST_HEAD(&mnt->mnt_expire);
+ INIT_LIST_HEAD(&mnt->mnt_share);
+ INIT_LIST_HEAD(&mnt->mnt_slave_list);
+ INIT_LIST_HEAD(&mnt->mnt_slave);
if (name) {
- int size = strlen(name)+1;
+ int size = strlen(name) + 1;
char *newname = kmalloc(size, GFP_KERNEL);
if (newname) {
memcpy(newname, name, size);
@@ -81,36 +88,65 @@ void free_vfsmnt(struct vfsmount *mnt)
}
/*
- * Now, lookup_mnt increments the ref count before returning
- * the vfsmount struct.
+ * find the first or last mount at @dentry on vfsmount @mnt depending on
+ * @dir. If @dir is set return the first mount else return the last mount.
*/
-struct vfsmount *lookup_mnt(struct vfsmount *mnt, struct dentry *dentry)
+struct vfsmount *__lookup_mnt(struct vfsmount *mnt, struct dentry *dentry,
+ int dir)
{
- struct list_head * head = mount_hashtable + hash(mnt, dentry);
- struct list_head * tmp = head;
+ struct list_head *head = mount_hashtable + hash(mnt, dentry);
+ struct list_head *tmp = head;
struct vfsmount *p, *found = NULL;
- spin_lock(&vfsmount_lock);
for (;;) {
- tmp = tmp->next;
+ tmp = dir ? tmp->next : tmp->prev;
p = NULL;
if (tmp == head)
break;
p = list_entry(tmp, struct vfsmount, mnt_hash);
if (p->mnt_parent == mnt && p->mnt_mountpoint == dentry) {
- found = mntget(p);
+ found = p;
break;
}
}
- spin_unlock(&vfsmount_lock);
return found;
}
+/*
+ * lookup_mnt increments the ref count before returning
+ * the vfsmount struct.
+ */
+struct vfsmount *lookup_mnt(struct vfsmount *mnt, struct dentry *dentry)
+{
+ struct vfsmount *child_mnt;
+ spin_lock(&vfsmount_lock);
+ if ((child_mnt = __lookup_mnt(mnt, dentry, 1)))
+ mntget(child_mnt);
+ spin_unlock(&vfsmount_lock);
+ return child_mnt;
+}
+
static inline int check_mnt(struct vfsmount *mnt)
{
return mnt->mnt_namespace == current->namespace;
}
+static void touch_namespace(struct namespace *ns)
+{
+ if (ns) {
+ ns->event = ++event;
+ wake_up_interruptible(&ns->poll);
+ }
+}
+
+static void __touch_namespace(struct namespace *ns)
+{
+ if (ns && ns->event != event) {
+ ns->event = event;
+ wake_up_interruptible(&ns->poll);
+ }
+}
+
static void detach_mnt(struct vfsmount *mnt, struct nameidata *old_nd)
{
old_nd->dentry = mnt->mnt_mountpoint;
@@ -122,13 +158,43 @@ static void detach_mnt(struct vfsmount *mnt, struct nameidata *old_nd)
old_nd->dentry->d_mounted--;
}
+void mnt_set_mountpoint(struct vfsmount *mnt, struct dentry *dentry,
+ struct vfsmount *child_mnt)
+{
+ child_mnt->mnt_parent = mntget(mnt);
+ child_mnt->mnt_mountpoint = dget(dentry);
+ dentry->d_mounted++;
+}
+
static void attach_mnt(struct vfsmount *mnt, struct nameidata *nd)
{
- mnt->mnt_parent = mntget(nd->mnt);
- mnt->mnt_mountpoint = dget(nd->dentry);
- list_add(&mnt->mnt_hash, mount_hashtable+hash(nd->mnt, nd->dentry));
+ mnt_set_mountpoint(nd->mnt, nd->dentry, mnt);
+ list_add_tail(&mnt->mnt_hash, mount_hashtable +
+ hash(nd->mnt, nd->dentry));
list_add_tail(&mnt->mnt_child, &nd->mnt->mnt_mounts);
- nd->dentry->d_mounted++;
+}
+
+/*
+ * the caller must hold vfsmount_lock
+ */
+static void commit_tree(struct vfsmount *mnt)
+{
+ struct vfsmount *parent = mnt->mnt_parent;
+ struct vfsmount *m;
+ LIST_HEAD(head);
+ struct namespace *n = parent->mnt_namespace;
+
+ BUG_ON(parent == mnt);
+
+ list_add_tail(&head, &mnt->mnt_list);
+ list_for_each_entry(m, &head, mnt_list)
+ m->mnt_namespace = n;
+ list_splice(&head, n->list.prev);
+
+ list_add_tail(&mnt->mnt_hash, mount_hashtable +
+ hash(parent, mnt->mnt_mountpoint));
+ list_add_tail(&mnt->mnt_child, &parent->mnt_mounts);
+ touch_namespace(n);
}
static struct vfsmount *next_mnt(struct vfsmount *p, struct vfsmount *root)
@@ -147,8 +213,18 @@ static struct vfsmount *next_mnt(struct vfsmount *p, struct vfsmount *root)
return list_entry(next, struct vfsmount, mnt_child);
}
-static struct vfsmount *
-clone_mnt(struct vfsmount *old, struct dentry *root)
+static struct vfsmount *skip_mnt_tree(struct vfsmount *p)
+{
+ struct list_head *prev = p->mnt_mounts.prev;
+ while (prev != &p->mnt_mounts) {
+ p = list_entry(prev, struct vfsmount, mnt_child);
+ prev = p->mnt_mounts.prev;
+ }
+ return p;
+}
+
+static struct vfsmount *clone_mnt(struct vfsmount *old, struct dentry *root,
+ int flag)
{
struct super_block *sb = old->mnt_sb;
struct vfsmount *mnt = alloc_vfsmnt(old->mnt_devname);
@@ -160,19 +236,34 @@ clone_mnt(struct vfsmount *old, struct dentry *root)
mnt->mnt_root = dget(root);
mnt->mnt_mountpoint = mnt->mnt_root;
mnt->mnt_parent = mnt;
- mnt->mnt_namespace = current->namespace;
+
+ if (flag & CL_SLAVE) {
+ list_add(&mnt->mnt_slave, &old->mnt_slave_list);
+ mnt->mnt_master = old;
+ CLEAR_MNT_SHARED(mnt);
+ } else {
+ if ((flag & CL_PROPAGATION) || IS_MNT_SHARED(old))
+ list_add(&mnt->mnt_share, &old->mnt_share);
+ if (IS_MNT_SLAVE(old))
+ list_add(&mnt->mnt_slave, &old->mnt_slave);
+ mnt->mnt_master = old->mnt_master;
+ }
+ if (flag & CL_MAKE_SHARED)
+ set_mnt_shared(mnt);
/* 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_expire))
- list_add(&mnt->mnt_expire, &old->mnt_expire);
- spin_unlock(&vfsmount_lock);
+ if (flag & CL_EXPIRE) {
+ spin_lock(&vfsmount_lock);
+ if (!list_empty(&old->mnt_expire))
+ list_add(&mnt->mnt_expire, &old->mnt_expire);
+ spin_unlock(&vfsmount_lock);
+ }
}
return mnt;
}
-void __mntput(struct vfsmount *mnt)
+static inline void __mntput(struct vfsmount *mnt)
{
struct super_block *sb = mnt->mnt_sb;
dput(mnt->mnt_root);
@@ -180,7 +271,46 @@ void __mntput(struct vfsmount *mnt)
deactivate_super(sb);
}
-EXPORT_SYMBOL(__mntput);
+void mntput_no_expire(struct vfsmount *mnt)
+{
+repeat:
+ if (atomic_dec_and_lock(&mnt->mnt_count, &vfsmount_lock)) {
+ if (likely(!mnt->mnt_pinned)) {
+ spin_unlock(&vfsmount_lock);
+ __mntput(mnt);
+ return;
+ }
+ atomic_add(mnt->mnt_pinned + 1, &mnt->mnt_count);
+ mnt->mnt_pinned = 0;
+ spin_unlock(&vfsmount_lock);
+ acct_auto_close_mnt(mnt);
+ security_sb_umount_close(mnt);
+ goto repeat;
+ }
+}
+
+EXPORT_SYMBOL(mntput_no_expire);
+
+void mnt_pin(struct vfsmount *mnt)
+{
+ spin_lock(&vfsmount_lock);
+ mnt->mnt_pinned++;
+ spin_unlock(&vfsmount_lock);
+}
+
+EXPORT_SYMBOL(mnt_pin);
+
+void mnt_unpin(struct vfsmount *mnt)
+{
+ spin_lock(&vfsmount_lock);
+ if (mnt->mnt_pinned) {
+ atomic_inc(&mnt->mnt_count);
+ mnt->mnt_pinned--;
+ }
+ spin_unlock(&vfsmount_lock);
+}
+
+EXPORT_SYMBOL(mnt_unpin);
/* iterator */
static void *m_start(struct seq_file *m, loff_t *pos)
@@ -189,7 +319,7 @@ static void *m_start(struct seq_file *m, loff_t *pos)
struct list_head *p;
loff_t l = *pos;
- down_read(&n->sem);
+ down_read(&namespace_sem);
list_for_each(p, &n->list)
if (!l--)
return list_entry(p, struct vfsmount, mnt_list);
@@ -201,13 +331,12 @@ static void *m_next(struct seq_file *m, void *v, loff_t *pos)
struct namespace *n = m->private;
struct list_head *p = ((struct vfsmount *)v)->mnt_list.next;
(*pos)++;
- return p==&n->list ? NULL : list_entry(p, struct vfsmount, mnt_list);
+ return p == &n->list ? NULL : list_entry(p, struct vfsmount, mnt_list);
}
static void m_stop(struct seq_file *m, void *v)
{
- struct namespace *n = m->private;
- up_read(&n->sem);
+ up_read(&namespace_sem);
}
static inline void mangle(struct seq_file *m, const char *s)
@@ -275,35 +404,14 @@ struct seq_operations mounts_op = {
*/
int may_umount_tree(struct vfsmount *mnt)
{
- struct list_head *next;
- struct vfsmount *this_parent = mnt;
- int actual_refs;
- int minimum_refs;
+ int actual_refs = 0;
+ int minimum_refs = 0;
+ struct vfsmount *p;
spin_lock(&vfsmount_lock);
- actual_refs = atomic_read(&mnt->mnt_count);
- minimum_refs = 2;
-repeat:
- next = this_parent->mnt_mounts.next;
-resume:
- while (next != &this_parent->mnt_mounts) {
- struct vfsmount *p = list_entry(next, struct vfsmount, mnt_child);
-
- next = next->next;
-
+ for (p = mnt; p; p = next_mnt(p, mnt)) {
actual_refs += atomic_read(&p->mnt_count);
minimum_refs += 2;
-
- if (!list_empty(&p->mnt_mounts)) {
- this_parent = p;
- goto repeat;
- }
- }
-
- if (this_parent != mnt) {
- next = this_parent->mnt_child.next;
- this_parent = this_parent->mnt_parent;
- goto resume;
}
spin_unlock(&vfsmount_lock);
@@ -330,45 +438,67 @@ EXPORT_SYMBOL(may_umount_tree);
*/
int may_umount(struct vfsmount *mnt)
{
- if (atomic_read(&mnt->mnt_count) > 2)
- return -EBUSY;
- return 0;
+ int ret = 0;
+ spin_lock(&vfsmount_lock);
+ if (propagate_mount_busy(mnt, 2))
+ ret = -EBUSY;
+ spin_unlock(&vfsmount_lock);
+ return ret;
}
EXPORT_SYMBOL(may_umount);
-static void umount_tree(struct vfsmount *mnt)
+void release_mounts(struct list_head *head)
+{
+ struct vfsmount *mnt;
+ while(!list_empty(head)) {
+ mnt = list_entry(head->next, struct vfsmount, mnt_hash);
+ list_del_init(&mnt->mnt_hash);
+ if (mnt->mnt_parent != mnt) {
+ struct dentry *dentry;
+ struct vfsmount *m;
+ spin_lock(&vfsmount_lock);
+ dentry = mnt->mnt_mountpoint;
+ m = mnt->mnt_parent;
+ mnt->mnt_mountpoint = mnt->mnt_root;
+ mnt->mnt_parent = mnt;
+ spin_unlock(&vfsmount_lock);
+ dput(dentry);
+ mntput(m);
+ }
+ mntput(mnt);
+ }
+}
+
+void umount_tree(struct vfsmount *mnt, int propagate, struct list_head *kill)
{
struct vfsmount *p;
- LIST_HEAD(kill);
for (p = mnt; p; p = next_mnt(p, mnt)) {
- list_del(&p->mnt_list);
- list_add(&p->mnt_list, &kill);
- p->mnt_namespace = NULL;
+ list_del(&p->mnt_hash);
+ list_add(&p->mnt_hash, kill);
}
- while (!list_empty(&kill)) {
- mnt = list_entry(kill.next, struct vfsmount, mnt_list);
- list_del_init(&mnt->mnt_list);
- list_del_init(&mnt->mnt_expire);
- if (mnt->mnt_parent == mnt) {
- spin_unlock(&vfsmount_lock);
- } else {
- struct nameidata old_nd;
- detach_mnt(mnt, &old_nd);
- spin_unlock(&vfsmount_lock);
- path_release(&old_nd);
- }
- mntput(mnt);
- spin_lock(&vfsmount_lock);
+ if (propagate)
+ propagate_umount(kill);
+
+ list_for_each_entry(p, kill, mnt_hash) {
+ list_del_init(&p->mnt_expire);
+ list_del_init(&p->mnt_list);
+ __touch_namespace(p->mnt_namespace);
+ p->mnt_namespace = NULL;
+ list_del_init(&p->mnt_child);
+ if (p->mnt_parent != p)
+ mnt->mnt_mountpoint->d_mounted--;
+ change_mnt_propagation(p, MS_PRIVATE);
}
}
static int do_umount(struct vfsmount *mnt, int flags)
{
- struct super_block * sb = mnt->mnt_sb;
+ struct super_block *sb = mnt->mnt_sb;
int retval;
+ LIST_HEAD(umount_list);
retval = security_sb_umount(mnt, flags);
if (retval)
@@ -403,7 +533,7 @@ static int do_umount(struct vfsmount *mnt, int flags)
*/
lock_kernel();
- if( (flags&MNT_FORCE) && sb->s_op->umount_begin)
+ if ((flags & MNT_FORCE) && sb->s_op->umount_begin)
sb->s_op->umount_begin(sb);
unlock_kernel();
@@ -432,29 +562,21 @@ static int do_umount(struct vfsmount *mnt, int flags)
return retval;
}
- down_write(&current->namespace->sem);
+ down_write(&namespace_sem);
spin_lock(&vfsmount_lock);
+ event++;
- if (atomic_read(&sb->s_active) == 1) {
- /* last instance - try to be smart */
- spin_unlock(&vfsmount_lock);
- lock_kernel();
- DQUOT_OFF(sb);
- acct_auto_close(sb);
- unlock_kernel();
- security_sb_umount_close(mnt);
- spin_lock(&vfsmount_lock);
- }
retval = -EBUSY;
- if (atomic_read(&mnt->mnt_count) == 2 || flags & MNT_DETACH) {
+ if (flags & MNT_DETACH || !propagate_mount_busy(mnt, 2)) {
if (!list_empty(&mnt->mnt_list))
- umount_tree(mnt);
+ umount_tree(mnt, 1, &umount_list);
retval = 0;
}
spin_unlock(&vfsmount_lock);
if (retval)
security_sb_umount_busy(mnt);
- up_write(&current->namespace->sem);
+ up_write(&namespace_sem);
+ release_mounts(&umount_list);
return retval;
}
@@ -494,12 +616,11 @@ out:
#ifdef __ARCH_WANT_SYS_OLDUMOUNT
/*
- * The 2.0 compatible umount. No flags.
+ * The 2.0 compatible umount. No flags.
*/
-
asmlinkage long sys_oldumount(char __user * name)
{
- return sys_umount(name,0);
+ return sys_umount(name, 0);
}
#endif
@@ -522,8 +643,7 @@ static int mount_is_safe(struct nameidata *nd)
#endif
}
-static int
-lives_below_in_same_fs(struct dentry *d, struct dentry *dentry)
+static int lives_below_in_same_fs(struct dentry *d, struct dentry *dentry)
{
while (1) {
if (d == dentry)
@@ -534,12 +654,16 @@ lives_below_in_same_fs(struct dentry *d, struct dentry *dentry)
}
}
-static struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry)
+struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry,
+ int flag)
{
struct vfsmount *res, *p, *q, *r, *s;
struct nameidata nd;
- res = q = clone_mnt(mnt, dentry);
+ if (!(flag & CL_COPY_ALL) && IS_MNT_UNBINDABLE(mnt))
+ return NULL;
+
+ res = q = clone_mnt(mnt, dentry, flag);
if (!q)
goto Enomem;
q->mnt_mountpoint = mnt->mnt_mountpoint;
@@ -550,6 +674,10 @@ static struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry)
continue;
for (s = r; s; s = next_mnt(s, r)) {
+ if (!(flag & CL_COPY_ALL) && IS_MNT_UNBINDABLE(s)) {
+ s = skip_mnt_tree(s);
+ continue;
+ }
while (p != s->mnt_parent) {
p = p->mnt_parent;
q = q->mnt_parent;
@@ -557,7 +685,7 @@ static struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry)
p = s;
nd.mnt = q;
nd.dentry = p->mnt_mountpoint;
- q = clone_mnt(p, p->mnt_root);
+ q = clone_mnt(p, p->mnt_root, flag);
if (!q)
goto Enomem;
spin_lock(&vfsmount_lock);
@@ -567,15 +695,114 @@ static struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry)
}
}
return res;
- Enomem:
+Enomem:
if (res) {
+ LIST_HEAD(umount_list);
spin_lock(&vfsmount_lock);
- umount_tree(res);
+ umount_tree(res, 0, &umount_list);
spin_unlock(&vfsmount_lock);
+ release_mounts(&umount_list);
}
return NULL;
}
+/*
+ * @source_mnt : mount tree to be attached
+ * @nd : place the mount tree @source_mnt is attached
+ * @parent_nd : if non-null, detach the source_mnt from its parent and
+ * store the parent mount and mountpoint dentry.
+ * (done when source_mnt is moved)
+ *
+ * NOTE: in the table below explains the semantics when a source mount
+ * of a given type is attached to a destination mount of a given type.
+ * ---------------------------------------------------------------------------
+ * | BIND MOUNT OPERATION |
+ * |**************************************************************************
+ * | source-->| shared | private | slave | unbindable |
+ * | dest | | | | |
+ * | | | | | | |
+ * | v | | | | |
+ * |**************************************************************************
+ * | shared | shared (++) | shared (+) | shared(+++)| invalid |
+ * | | | | | |
+ * |non-shared| shared (+) | private | slave (*) | invalid |
+ * ***************************************************************************
+ * A bind operation clones the source mount and mounts the clone on the
+ * destination mount.
+ *
+ * (++) the cloned mount is propagated to all the mounts in the propagation
+ * tree of the destination mount and the cloned mount is added to
+ * the peer group of the source mount.
+ * (+) the cloned mount is created under the destination mount and is marked
+ * as shared. The cloned mount is added to the peer group of the source
+ * mount.
+ * (+++) the mount is propagated to all the mounts in the propagation tree
+ * of the destination mount and the cloned mount is made slave
+ * of the same master as that of the source mount. The cloned mount
+ * is marked as 'shared and slave'.
+ * (*) the cloned mount is made a slave of the same master as that of the
+ * source mount.
+ *
+ * ---------------------------------------------------------------------------
+ * | MOVE MOUNT OPERATION |
+ * |**************************************************************************
+ * | source-->| shared | private | slave | unbindable |
+ * | dest | | | | |
+ * | | | | | | |
+ * | v | | | | |
+ * |**************************************************************************
+ * | shared | shared (+) | shared (+) | shared(+++) | invalid |
+ * | | | | | |
+ * |non-shared| shared (+*) | private | slave (*) | unbindable |
+ * ***************************************************************************
+ *
+ * (+) the mount is moved to the destination. And is then propagated to
+ * all the mounts in the propagation tree of the destination mount.
+ * (+*) the mount is moved to the destination.
+ * (+++) the mount is moved to the destination and is then propagated to
+ * all the mounts belonging to the destination mount's propagation tree.
+ * the mount is marked as 'shared and slave'.
+ * (*) the mount continues to be a slave at the new location.
+ *
+ * if the source mount is a tree, the operations explained above is
+ * applied to each mount in the tree.
+ * Must be called without spinlocks held, since this function can sleep
+ * in allocations.
+ */
+static int attach_recursive_mnt(struct vfsmount *source_mnt,
+ struct nameidata *nd, struct nameidata *parent_nd)
+{
+ LIST_HEAD(tree_list);
+ struct vfsmount *dest_mnt = nd->mnt;
+ struct dentry *dest_dentry = nd->dentry;
+ struct vfsmount *child, *p;
+
+ if (propagate_mnt(dest_mnt, dest_dentry, source_mnt, &tree_list))
+ return -EINVAL;
+
+ if (IS_MNT_SHARED(dest_mnt)) {
+ for (p = source_mnt; p; p = next_mnt(p, source_mnt))
+ set_mnt_shared(p);
+ }
+
+ spin_lock(&vfsmount_lock);
+ if (parent_nd) {
+ detach_mnt(source_mnt, parent_nd);
+ attach_mnt(source_mnt, nd);
+ touch_namespace(current->namespace);
+ } else {
+ mnt_set_mountpoint(dest_mnt, dest_dentry, source_mnt);
+ commit_tree(source_mnt);
+ }
+
+ list_for_each_entry_safe(child, p, &tree_list, mnt_hash) {
+ list_del_init(&child->mnt_hash);
+ commit_tree(child);
+ }
+ spin_unlock(&vfsmount_lock);
+ return 0;
+}
+
static int graft_tree(struct vfsmount *mnt, struct nameidata *nd)
{
int err;
@@ -596,17 +823,8 @@ static int graft_tree(struct vfsmount *mnt, struct nameidata *nd)
goto out_unlock;
err = -ENOENT;
- spin_lock(&vfsmount_lock);
- if (IS_ROOT(nd->dentry) || !d_unhashed(nd->dentry)) {
- struct list_head head;
-
- attach_mnt(mnt, nd);
- list_add_tail(&head, &mnt->mnt_list);
- list_splice(&head, current->namespace->list.prev);
- mntget(mnt);
- err = 0;
- }
- spin_unlock(&vfsmount_lock);
+ if (IS_ROOT(nd->dentry) || !d_unhashed(nd->dentry))
+ err = attach_recursive_mnt(mnt, nd, NULL);
out_unlock:
up(&nd->dentry->d_inode->i_sem);
if (!err)
@@ -615,6 +833,27 @@ out_unlock:
}
/*
+ * recursively change the type of the mountpoint.
+ */
+static int do_change_type(struct nameidata *nd, int flag)
+{
+ struct vfsmount *m, *mnt = nd->mnt;
+ int recurse = flag & MS_REC;
+ int type = flag & ~MS_REC;
+
+ if (nd->dentry != nd->mnt->mnt_root)
+ return -EINVAL;
+
+ down_write(&namespace_sem);
+ spin_lock(&vfsmount_lock);
+ for (m = mnt; m; m = (recurse ? next_mnt(m, mnt) : NULL))
+ change_mnt_propagation(m, type);
+ spin_unlock(&vfsmount_lock);
+ up_write(&namespace_sem);
+ return 0;
+}
+
+/*
* do loopback mount.
*/
static int do_loopback(struct nameidata *nd, char *old_name, int recurse)
@@ -630,32 +869,34 @@ static int do_loopback(struct nameidata *nd, char *old_name, int recurse)
if (err)
return err;
- down_write(&current->namespace->sem);
+ down_write(&namespace_sem);
err = -EINVAL;
- if (check_mnt(nd->mnt) && (!recurse || check_mnt(old_nd.mnt))) {
- err = -ENOMEM;
- if (recurse)
- mnt = copy_tree(old_nd.mnt, old_nd.dentry);
- else
- mnt = clone_mnt(old_nd.mnt, old_nd.dentry);
- }
+ if (IS_MNT_UNBINDABLE(old_nd.mnt))
+ goto out;
- if (mnt) {
- /* stop bind mounts from expiring */
+ if (!check_mnt(nd->mnt) || !check_mnt(old_nd.mnt))
+ goto out;
+
+ err = -ENOMEM;
+ if (recurse)
+ mnt = copy_tree(old_nd.mnt, old_nd.dentry, 0);
+ else
+ mnt = clone_mnt(old_nd.mnt, old_nd.dentry, 0);
+
+ if (!mnt)
+ goto out;
+
+ err = graft_tree(mnt, nd);
+ if (err) {
+ LIST_HEAD(umount_list);
spin_lock(&vfsmount_lock);
- list_del_init(&mnt->mnt_expire);
+ umount_tree(mnt, 0, &umount_list);
spin_unlock(&vfsmount_lock);
-
- err = graft_tree(mnt, nd);
- if (err) {
- spin_lock(&vfsmount_lock);
- umount_tree(mnt);
- spin_unlock(&vfsmount_lock);
- } else
- mntput(mnt);
+ release_mounts(&umount_list);
}
- up_write(&current->namespace->sem);
+out:
+ up_write(&namespace_sem);
path_release(&old_nd);
return err;
}
@@ -665,12 +906,11 @@ static int do_loopback(struct nameidata *nd, char *old_name, int recurse)
* If you've mounted a non-root directory somewhere and want to do remount
* on it - tough luck.
*/
-
static int do_remount(struct nameidata *nd, int flags, int mnt_flags,
void *data)
{
int err;
- struct super_block * sb = nd->mnt->mnt_sb;
+ struct super_block *sb = nd->mnt->mnt_sb;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
@@ -684,13 +924,23 @@ static int do_remount(struct nameidata *nd, int flags, int mnt_flags,
down_write(&sb->s_umount);
err = do_remount_sb(sb, flags, data, 0);
if (!err)
- nd->mnt->mnt_flags=mnt_flags;
+ nd->mnt->mnt_flags = mnt_flags;
up_write(&sb->s_umount);
if (!err)
security_sb_post_remount(nd->mnt, flags, data);
return err;
}
+static inline int tree_contains_unbindable(struct vfsmount *mnt)
+{
+ struct vfsmount *p;
+ for (p = mnt; p; p = next_mnt(p, mnt)) {
+ if (IS_MNT_UNBINDABLE(p))
+ return 1;
+ }
+ return 0;
+}
+
static int do_move_mount(struct nameidata *nd, char *old_name)
{
struct nameidata old_nd, parent_nd;
@@ -704,8 +954,8 @@ static int do_move_mount(struct nameidata *nd, char *old_name)
if (err)
return err;
- down_write(&current->namespace->sem);
- while(d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry))
+ down_write(&namespace_sem);
+ while (d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry))
;
err = -EINVAL;
if (!check_mnt(nd->mnt) || !check_mnt(old_nd.mnt))
@@ -716,39 +966,47 @@ static int do_move_mount(struct nameidata *nd, char *old_name)
if (IS_DEADDIR(nd->dentry->d_inode))
goto out1;
- spin_lock(&vfsmount_lock);
if (!IS_ROOT(nd->dentry) && d_unhashed(nd->dentry))
- goto out2;
+ goto out1;
err = -EINVAL;
if (old_nd.dentry != old_nd.mnt->mnt_root)
- goto out2;
+ goto out1;
if (old_nd.mnt == old_nd.mnt->mnt_parent)
- goto out2;
+ goto out1;
if (S_ISDIR(nd->dentry->d_inode->i_mode) !=
S_ISDIR(old_nd.dentry->d_inode->i_mode))
- goto out2;
-
+ goto out1;
+ /*
+ * Don't move a mount residing in a shared parent.
+ */
+ if (old_nd.mnt->mnt_parent && IS_MNT_SHARED(old_nd.mnt->mnt_parent))
+ goto out1;
+ /*
+ * Don't move a mount tree containing unbindable mounts to a destination
+ * mount which is shared.
+ */
+ if (IS_MNT_SHARED(nd->mnt) && tree_contains_unbindable(old_nd.mnt))
+ goto out1;
err = -ELOOP;
- for (p = nd->mnt; p->mnt_parent!=p; p = p->mnt_parent)
+ for (p = nd->mnt; p->mnt_parent != p; p = p->mnt_parent)
if (p == old_nd.mnt)
- goto out2;
- err = 0;
+ goto out1;
- detach_mnt(old_nd.mnt, &parent_nd);
- attach_mnt(old_nd.mnt, nd);
+ if ((err = attach_recursive_mnt(old_nd.mnt, nd, &parent_nd)))
+ goto out1;
+ spin_lock(&vfsmount_lock);
/* if the mount is moved, it should no longer be expire
* automatically */
list_del_init(&old_nd.mnt->mnt_expire);
-out2:
spin_unlock(&vfsmount_lock);
out1:
up(&nd->dentry->d_inode->i_sem);
out:
- up_write(&current->namespace->sem);
+ up_write(&namespace_sem);
if (!err)
path_release(&parent_nd);
path_release(&old_nd);
@@ -787,9 +1045,9 @@ int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd,
{
int err;
- down_write(&current->namespace->sem);
+ down_write(&namespace_sem);
/* Something was mounted here while we slept */
- while(d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry))
+ while (d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry))
;
err = -EINVAL;
if (!check_mnt(nd->mnt))
@@ -806,25 +1064,28 @@ 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 = graft_tree(newmnt, nd)))
+ goto unlock;
- if (err == 0 && fslist) {
+ if (fslist) {
/* add to the specified expiration list */
spin_lock(&vfsmount_lock);
list_add_tail(&newmnt->mnt_expire, fslist);
spin_unlock(&vfsmount_lock);
}
+ up_write(&namespace_sem);
+ return 0;
unlock:
- up_write(&current->namespace->sem);
+ up_write(&namespace_sem);
mntput(newmnt);
return err;
}
EXPORT_SYMBOL_GPL(do_add_mount);
-static void expire_mount(struct vfsmount *mnt, struct list_head *mounts)
+static void expire_mount(struct vfsmount *mnt, struct list_head *mounts,
+ struct list_head *umounts)
{
spin_lock(&vfsmount_lock);
@@ -841,27 +1102,13 @@ static void expire_mount(struct vfsmount *mnt, struct list_head *mounts)
* 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;
-
+ if (!propagate_mount_busy(mnt, 2)) {
/* delete from the namespace */
+ touch_namespace(mnt->mnt_namespace);
list_del_init(&mnt->mnt_list);
mnt->mnt_namespace = NULL;
- detach_mnt(mnt, &old_nd);
+ umount_tree(mnt, 1, umounts);
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
@@ -910,6 +1157,7 @@ void mark_mounts_for_expiry(struct list_head *mounts)
* - dispose of the corpse
*/
while (!list_empty(&graveyard)) {
+ LIST_HEAD(umounts);
mnt = list_entry(graveyard.next, struct vfsmount, mnt_expire);
list_del_init(&mnt->mnt_expire);
@@ -921,13 +1169,12 @@ void mark_mounts_for_expiry(struct list_head *mounts)
get_namespace(namespace);
spin_unlock(&vfsmount_lock);
- down_write(&namespace->sem);
- expire_mount(mnt, mounts);
- up_write(&namespace->sem);
-
+ down_write(&namespace_sem);
+ expire_mount(mnt, mounts, &umounts);
+ up_write(&namespace_sem);
+ release_mounts(&umounts);
mntput(mnt);
put_namespace(namespace);
-
spin_lock(&vfsmount_lock);
}
@@ -942,8 +1189,8 @@ EXPORT_SYMBOL_GPL(mark_mounts_for_expiry);
* Note that this function differs from copy_from_user() in that it will oops
* on bad values of `to', rather than returning a short copy.
*/
-static long
-exact_copy_from_user(void *to, const void __user *from, unsigned long n)
+static long exact_copy_from_user(void *to, const void __user * from,
+ unsigned long n)
{
char *t = to;
const char __user *f = from;
@@ -964,12 +1211,12 @@ exact_copy_from_user(void *to, const void __user *from, unsigned long n)
return n;
}
-int copy_mount_options(const void __user *data, unsigned long *where)
+int copy_mount_options(const void __user * data, unsigned long *where)
{
int i;
unsigned long page;
unsigned long size;
-
+
*where = 0;
if (!data)
return 0;
@@ -988,7 +1235,7 @@ int copy_mount_options(const void __user *data, unsigned long *where)
i = size - exact_copy_from_user((void *)page, data, size);
if (!i) {
- free_page(page);
+ free_page(page);
return -EFAULT;
}
if (i != PAGE_SIZE)
@@ -1011,7 +1258,7 @@ int copy_mount_options(const void __user *data, unsigned long *where)
* Therefore, if this magic number is present, it carries no information
* and must be discarded.
*/
-long do_mount(char * dev_name, char * dir_name, char *type_page,
+long do_mount(char *dev_name, char *dir_name, char *type_page,
unsigned long flags, void *data_page)
{
struct nameidata nd;
@@ -1039,7 +1286,7 @@ long do_mount(char * dev_name, char * dir_name, char *type_page,
mnt_flags |= MNT_NODEV;
if (flags & MS_NOEXEC)
mnt_flags |= MNT_NOEXEC;
- flags &= ~(MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_ACTIVE);
+ flags &= ~(MS_NOSUID | MS_NOEXEC | MS_NODEV | MS_ACTIVE);
/* ... and get the mountpoint */
retval = path_lookup(dir_name, LOOKUP_FOLLOW, &nd);
@@ -1055,6 +1302,8 @@ long do_mount(char * dev_name, char * dir_name, char *type_page,
data_page);
else if (flags & MS_BIND)
retval = do_loopback(&nd, dev_name, flags & MS_REC);
+ else if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE))
+ retval = do_change_type(&nd, flags);
else if (flags & MS_MOVE)
retval = do_move_mount(&nd, dev_name);
else
@@ -1091,14 +1340,16 @@ int copy_namespace(int flags, struct task_struct *tsk)
goto out;
atomic_set(&new_ns->count, 1);
- init_rwsem(&new_ns->sem);
INIT_LIST_HEAD(&new_ns->list);
+ init_waitqueue_head(&new_ns->poll);
+ new_ns->event = 0;
- down_write(&tsk->namespace->sem);
+ down_write(&namespace_sem);
/* First pass: copy the tree topology */
- new_ns->root = copy_tree(namespace->root, namespace->root->mnt_root);
+ new_ns->root = copy_tree(namespace->root, namespace->root->mnt_root,
+ CL_COPY_ALL | CL_EXPIRE);
if (!new_ns->root) {
- up_write(&tsk->namespace->sem);
+ up_write(&namespace_sem);
kfree(new_ns);
goto out;
}
@@ -1132,7 +1383,7 @@ int copy_namespace(int flags, struct task_struct *tsk)
p = next_mnt(p, namespace->root);
q = next_mnt(q, new_ns->root);
}
- up_write(&tsk->namespace->sem);
+ up_write(&namespace_sem);
tsk->namespace = new_ns;
@@ -1161,7 +1412,7 @@ asmlinkage long sys_mount(char __user * dev_name, char __user * dir_name,
unsigned long dev_page;
char *dir_page;
- retval = copy_mount_options (type, &type_page);
+ retval = copy_mount_options(type, &type_page);
if (retval < 0)
return retval;
@@ -1170,17 +1421,17 @@ asmlinkage long sys_mount(char __user * dev_name, char __user * dir_name,
if (IS_ERR(dir_page))
goto out1;
- retval = copy_mount_options (dev_name, &dev_page);
+ retval = copy_mount_options(dev_name, &dev_page);
if (retval < 0)
goto out2;
- retval = copy_mount_options (data, &data_page);
+ retval = copy_mount_options(data, &data_page);
if (retval < 0)
goto out3;
lock_kernel();
- retval = do_mount((char*)dev_page, dir_page, (char*)type_page,
- flags, (void*)data_page);
+ retval = do_mount((char *)dev_page, dir_page, (char *)type_page,
+ flags, (void *)data_page);
unlock_kernel();
free_page(data_page);
@@ -1249,9 +1500,11 @@ static void chroot_fs_refs(struct nameidata *old_nd, struct nameidata *new_nd)
if (fs) {
atomic_inc(&fs->count);
task_unlock(p);
- if (fs->root==old_nd->dentry&&fs->rootmnt==old_nd->mnt)
+ if (fs->root == old_nd->dentry
+ && fs->rootmnt == old_nd->mnt)
set_fs_root(fs, new_nd->mnt, new_nd->dentry);
- if (fs->pwd==old_nd->dentry&&fs->pwdmnt==old_nd->mnt)
+ if (fs->pwd == old_nd->dentry
+ && fs->pwdmnt == old_nd->mnt)
set_fs_pwd(fs, new_nd->mnt, new_nd->dentry);
put_fs_struct(fs);
} else
@@ -1281,8 +1534,8 @@ static void chroot_fs_refs(struct nameidata *old_nd, struct nameidata *new_nd)
* though, so you may need to say mount --bind /nfs/my_root /nfs/my_root
* first.
*/
-
-asmlinkage long sys_pivot_root(const char __user *new_root, const char __user *put_old)
+asmlinkage long sys_pivot_root(const char __user * new_root,
+ const char __user * put_old)
{
struct vfsmount *tmp;
struct nameidata new_nd, old_nd, parent_nd, root_parent, user_nd;
@@ -1293,14 +1546,15 @@ asmlinkage long sys_pivot_root(const char __user *new_root, const char __user *p
lock_kernel();
- error = __user_walk(new_root, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &new_nd);
+ error = __user_walk(new_root, LOOKUP_FOLLOW | LOOKUP_DIRECTORY,
+ &new_nd);
if (error)
goto out0;
error = -EINVAL;
if (!check_mnt(new_nd.mnt))
goto out1;
- error = __user_walk(put_old, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &old_nd);
+ error = __user_walk(put_old, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &old_nd);
if (error)
goto out1;
@@ -1314,9 +1568,13 @@ asmlinkage long sys_pivot_root(const char __user *new_root, const char __user *p
user_nd.mnt = mntget(current->fs->rootmnt);
user_nd.dentry = dget(current->fs->root);
read_unlock(&current->fs->lock);
- down_write(&current->namespace->sem);
+ down_write(&namespace_sem);
down(&old_nd.dentry->d_inode->i_sem);
error = -EINVAL;
+ if (IS_MNT_SHARED(old_nd.mnt) ||
+ IS_MNT_SHARED(new_nd.mnt->mnt_parent) ||
+ IS_MNT_SHARED(user_nd.mnt->mnt_parent))
+ goto out2;
if (!check_mnt(user_nd.mnt))
goto out2;
error = -ENOENT;
@@ -1356,6 +1614,7 @@ asmlinkage long sys_pivot_root(const char __user *new_root, const char __user *p
detach_mnt(user_nd.mnt, &root_parent);
attach_mnt(user_nd.mnt, &old_nd); /* mount old root on put_old */
attach_mnt(new_nd.mnt, &root_parent); /* mount new_root on / */
+ touch_namespace(current->namespace);
spin_unlock(&vfsmount_lock);
chroot_fs_refs(&user_nd, &new_nd);
security_sb_post_pivotroot(&user_nd, &new_nd);
@@ -1364,7 +1623,7 @@ asmlinkage long sys_pivot_root(const char __user *new_root, const char __user *p
path_release(&parent_nd);
out2:
up(&old_nd.dentry->d_inode->i_sem);
- up_write(&current->namespace->sem);
+ up_write(&namespace_sem);
path_release(&user_nd);
path_release(&old_nd);
out1:
@@ -1391,7 +1650,8 @@ static void __init init_mount_tree(void)
panic("Can't allocate initial namespace");
atomic_set(&namespace->count, 1);
INIT_LIST_HEAD(&namespace->list);
- init_rwsem(&namespace->sem);
+ init_waitqueue_head(&namespace->poll);
+ namespace->event = 0;
list_add(&mnt->mnt_list, &namespace->list);
namespace->root = mnt;
mnt->mnt_namespace = namespace;
@@ -1414,11 +1674,12 @@ void __init mnt_init(unsigned long mempages)
unsigned int nr_hash;
int i;
+ init_rwsem(&namespace_sem);
+
mnt_cache = kmem_cache_create("mnt_cache", sizeof(struct vfsmount),
- 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
+ 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL, NULL);
- mount_hashtable = (struct list_head *)
- __get_free_page(GFP_ATOMIC);
+ mount_hashtable = (struct list_head *)__get_free_page(GFP_ATOMIC);
if (!mount_hashtable)
panic("Failed to allocate mount hash table\n");
@@ -1440,7 +1701,7 @@ void __init mnt_init(unsigned long mempages)
* from the number of bits we can fit.
*/
nr_hash = 1UL << hash_bits;
- hash_mask = nr_hash-1;
+ hash_mask = nr_hash - 1;
printk("Mount-cache hash table entries: %d\n", nr_hash);
@@ -1460,12 +1721,14 @@ void __init mnt_init(unsigned long mempages)
void __put_namespace(struct namespace *namespace)
{
struct vfsmount *root = namespace->root;
+ LIST_HEAD(umount_list);
namespace->root = NULL;
spin_unlock(&vfsmount_lock);
- down_write(&namespace->sem);
+ down_write(&namespace_sem);
spin_lock(&vfsmount_lock);
- umount_tree(root);
+ umount_tree(root, 0, &umount_list);
spin_unlock(&vfsmount_lock);
- up_write(&namespace->sem);
+ up_write(&namespace_sem);
+ release_mounts(&umount_list);
kfree(namespace);
}
diff --git a/fs/pnode.c b/fs/pnode.c
new file mode 100644
index 00000000000..aeeec8ba8dd
--- /dev/null
+++ b/fs/pnode.c
@@ -0,0 +1,305 @@
+/*
+ * linux/fs/pnode.c
+ *
+ * (C) Copyright IBM Corporation 2005.
+ * Released under GPL v2.
+ * Author : Ram Pai (linuxram@us.ibm.com)
+ *
+ */
+#include <linux/namespace.h>
+#include <linux/mount.h>
+#include <linux/fs.h>
+#include "pnode.h"
+
+/* return the next shared peer mount of @p */
+static inline struct vfsmount *next_peer(struct vfsmount *p)
+{
+ return list_entry(p->mnt_share.next, struct vfsmount, mnt_share);
+}
+
+static inline struct vfsmount *first_slave(struct vfsmount *p)
+{
+ return list_entry(p->mnt_slave_list.next, struct vfsmount, mnt_slave);
+}
+
+static inline struct vfsmount *next_slave(struct vfsmount *p)
+{
+ return list_entry(p->mnt_slave.next, struct vfsmount, mnt_slave);
+}
+
+static int do_make_slave(struct vfsmount *mnt)
+{
+ struct vfsmount *peer_mnt = mnt, *master = mnt->mnt_master;
+ struct vfsmount *slave_mnt;
+
+ /*
+ * slave 'mnt' to a peer mount that has the
+ * same root dentry. If none is available than
+ * slave it to anything that is available.
+ */
+ while ((peer_mnt = next_peer(peer_mnt)) != mnt &&
+ peer_mnt->mnt_root != mnt->mnt_root) ;
+
+ if (peer_mnt == mnt) {
+ peer_mnt = next_peer(mnt);
+ if (peer_mnt == mnt)
+ peer_mnt = NULL;
+ }
+ list_del_init(&mnt->mnt_share);
+
+ if (peer_mnt)
+ master = peer_mnt;
+
+ if (master) {
+ list_for_each_entry(slave_mnt, &mnt->mnt_slave_list, mnt_slave)
+ slave_mnt->mnt_master = master;
+ list_del(&mnt->mnt_slave);
+ list_add(&mnt->mnt_slave, &master->mnt_slave_list);
+ list_splice(&mnt->mnt_slave_list, master->mnt_slave_list.prev);
+ INIT_LIST_HEAD(&mnt->mnt_slave_list);
+ } else {
+ struct list_head *p = &mnt->mnt_slave_list;
+ while (!list_empty(p)) {
+ slave_mnt = list_entry(p->next,
+ struct vfsmount, mnt_slave);
+ list_del_init(&slave_mnt->mnt_slave);
+ slave_mnt->mnt_master = NULL;
+ }
+ }
+ mnt->mnt_master = master;
+ CLEAR_MNT_SHARED(mnt);
+ INIT_LIST_HEAD(&mnt->mnt_slave_list);
+ return 0;
+}
+
+void change_mnt_propagation(struct vfsmount *mnt, int type)
+{
+ if (type == MS_SHARED) {
+ set_mnt_shared(mnt);
+ return;
+ }
+ do_make_slave(mnt);
+ if (type != MS_SLAVE) {
+ list_del_init(&mnt->mnt_slave);
+ mnt->mnt_master = NULL;
+ if (type == MS_UNBINDABLE)
+ mnt->mnt_flags |= MNT_UNBINDABLE;
+ }
+}
+
+/*
+ * get the next mount in the propagation tree.
+ * @m: the mount seen last
+ * @origin: the original mount from where the tree walk initiated
+ */
+static struct vfsmount *propagation_next(struct vfsmount *m,
+ struct vfsmount *origin)
+{
+ /* are there any slaves of this mount? */
+ if (!IS_MNT_NEW(m) && !list_empty(&m->mnt_slave_list))
+ return first_slave(m);
+
+ while (1) {
+ struct vfsmount *next;
+ struct vfsmount *master = m->mnt_master;
+
+ if ( master == origin->mnt_master ) {
+ next = next_peer(m);
+ return ((next == origin) ? NULL : next);
+ } else if (m->mnt_slave.next != &master->mnt_slave_list)
+ return next_slave(m);
+
+ /* back at master */
+ m = master;
+ }
+}
+
+/*
+ * return the source mount to be used for cloning
+ *
+ * @dest the current destination mount
+ * @last_dest the last seen destination mount
+ * @last_src the last seen source mount
+ * @type return CL_SLAVE if the new mount has to be
+ * cloned as a slave.
+ */
+static struct vfsmount *get_source(struct vfsmount *dest,
+ struct vfsmount *last_dest,
+ struct vfsmount *last_src,
+ int *type)
+{
+ struct vfsmount *p_last_src = NULL;
+ struct vfsmount *p_last_dest = NULL;
+ *type = CL_PROPAGATION;;
+
+ if (IS_MNT_SHARED(dest))
+ *type |= CL_MAKE_SHARED;
+
+ while (last_dest != dest->mnt_master) {
+ p_last_dest = last_dest;
+ p_last_src = last_src;
+ last_dest = last_dest->mnt_master;
+ last_src = last_src->mnt_master;
+ }
+
+ if (p_last_dest) {
+ do {
+ p_last_dest = next_peer(p_last_dest);
+ } while (IS_MNT_NEW(p_last_dest));
+ }
+
+ if (dest != p_last_dest) {
+ *type |= CL_SLAVE;
+ return last_src;
+ } else
+ return p_last_src;
+}
+
+/*
+ * mount 'source_mnt' under the destination 'dest_mnt' at
+ * dentry 'dest_dentry'. And propagate that mount to
+ * all the peer and slave mounts of 'dest_mnt'.
+ * Link all the new mounts into a propagation tree headed at
+ * source_mnt. Also link all the new mounts using ->mnt_list
+ * headed at source_mnt's ->mnt_list
+ *
+ * @dest_mnt: destination mount.
+ * @dest_dentry: destination dentry.
+ * @source_mnt: source mount.
+ * @tree_list : list of heads of trees to be attached.
+ */
+int propagate_mnt(struct vfsmount *dest_mnt, struct dentry *dest_dentry,
+ struct vfsmount *source_mnt, struct list_head *tree_list)
+{
+ struct vfsmount *m, *child;
+ int ret = 0;
+ struct vfsmount *prev_dest_mnt = dest_mnt;
+ struct vfsmount *prev_src_mnt = source_mnt;
+ LIST_HEAD(tmp_list);
+ LIST_HEAD(umount_list);
+
+ for (m = propagation_next(dest_mnt, dest_mnt); m;
+ m = propagation_next(m, dest_mnt)) {
+ int type;
+ struct vfsmount *source;
+
+ if (IS_MNT_NEW(m))
+ continue;
+
+ source = get_source(m, prev_dest_mnt, prev_src_mnt, &type);
+
+ if (!(child = copy_tree(source, source->mnt_root, type))) {
+ ret = -ENOMEM;
+ list_splice(tree_list, tmp_list.prev);
+ goto out;
+ }
+
+ if (is_subdir(dest_dentry, m->mnt_root)) {
+ mnt_set_mountpoint(m, dest_dentry, child);
+ list_add_tail(&child->mnt_hash, tree_list);
+ } else {
+ /*
+ * This can happen if the parent mount was bind mounted
+ * on some subdirectory of a shared/slave mount.
+ */
+ list_add_tail(&child->mnt_hash, &tmp_list);
+ }
+ prev_dest_mnt = m;
+ prev_src_mnt = child;
+ }
+out:
+ spin_lock(&vfsmount_lock);
+ while (!list_empty(&tmp_list)) {
+ child = list_entry(tmp_list.next, struct vfsmount, mnt_hash);
+ list_del_init(&child->mnt_hash);
+ umount_tree(child, 0, &umount_list);
+ }
+ spin_unlock(&vfsmount_lock);
+ release_mounts(&umount_list);
+ return ret;
+}
+
+/*
+ * return true if the refcount is greater than count
+ */
+static inline int do_refcount_check(struct vfsmount *mnt, int count)
+{
+ int mycount = atomic_read(&mnt->mnt_count);
+ return (mycount > count);
+}
+
+/*
+ * check if the mount 'mnt' can be unmounted successfully.
+ * @mnt: the mount to be checked for unmount
+ * NOTE: unmounting 'mnt' would naturally propagate to all
+ * other mounts its parent propagates to.
+ * Check if any of these mounts that **do not have submounts**
+ * have more references than 'refcnt'. If so return busy.
+ */
+int propagate_mount_busy(struct vfsmount *mnt, int refcnt)
+{
+ struct vfsmount *m, *child;
+ struct vfsmount *parent = mnt->mnt_parent;
+ int ret = 0;
+
+ if (mnt == parent)
+ return do_refcount_check(mnt, refcnt);
+
+ /*
+ * quickly check if the current mount can be unmounted.
+ * If not, we don't have to go checking for all other
+ * mounts
+ */
+ if (!list_empty(&mnt->mnt_mounts) || do_refcount_check(mnt, refcnt))
+ return 1;
+
+ for (m = propagation_next(parent, parent); m;
+ m = propagation_next(m, parent)) {
+ child = __lookup_mnt(m, mnt->mnt_mountpoint, 0);
+ if (child && list_empty(&child->mnt_mounts) &&
+ (ret = do_refcount_check(child, 1)))
+ break;
+ }
+ return ret;
+}
+
+/*
+ * NOTE: unmounting 'mnt' naturally propagates to all other mounts its
+ * parent propagates to.
+ */
+static void __propagate_umount(struct vfsmount *mnt)
+{
+ struct vfsmount *parent = mnt->mnt_parent;
+ struct vfsmount *m;
+
+ BUG_ON(parent == mnt);
+
+ for (m = propagation_next(parent, parent); m;
+ m = propagation_next(m, parent)) {
+
+ struct vfsmount *child = __lookup_mnt(m,
+ mnt->mnt_mountpoint, 0);
+ /*
+ * umount the child only if the child has no
+ * other children
+ */
+ if (child && list_empty(&child->mnt_mounts)) {
+ list_del(&child->mnt_hash);
+ list_add_tail(&child->mnt_hash, &mnt->mnt_hash);
+ }
+ }
+}
+
+/*
+ * collect all mounts that receive propagation from the mount in @list,
+ * and return these additional mounts in the same list.
+ * @list: the list of mounts to be unmounted.
+ */
+int propagate_umount(struct list_head *list)
+{
+ struct vfsmount *mnt;
+
+ list_for_each_entry(mnt, list, mnt_hash)
+ __propagate_umount(mnt);
+ return 0;
+}
diff --git a/fs/pnode.h b/fs/pnode.h
new file mode 100644
index 00000000000..020e1bb60fd
--- /dev/null
+++ b/fs/pnode.h
@@ -0,0 +1,37 @@
+/*
+ * linux/fs/pnode.h
+ *
+ * (C) Copyright IBM Corporation 2005.
+ * Released under GPL v2.
+ *
+ */
+#ifndef _LINUX_PNODE_H
+#define _LINUX_PNODE_H
+
+#include <linux/list.h>
+#include <linux/mount.h>
+
+#define IS_MNT_SHARED(mnt) (mnt->mnt_flags & MNT_SHARED)
+#define IS_MNT_SLAVE(mnt) (mnt->mnt_master)
+#define IS_MNT_NEW(mnt) (!mnt->mnt_namespace)
+#define CLEAR_MNT_SHARED(mnt) (mnt->mnt_flags &= ~MNT_SHARED)
+#define IS_MNT_UNBINDABLE(mnt) (mnt->mnt_flags & MNT_UNBINDABLE)
+
+#define CL_EXPIRE 0x01
+#define CL_SLAVE 0x02
+#define CL_COPY_ALL 0x04
+#define CL_MAKE_SHARED 0x08
+#define CL_PROPAGATION 0x10
+
+static inline void set_mnt_shared(struct vfsmount *mnt)
+{
+ mnt->mnt_flags &= ~MNT_PNODE_MASK;
+ mnt->mnt_flags |= MNT_SHARED;
+}
+
+void change_mnt_propagation(struct vfsmount *, int);
+int propagate_mnt(struct vfsmount *, struct dentry *, struct vfsmount *,
+ struct list_head *);
+int propagate_umount(struct list_head *);
+int propagate_mount_busy(struct vfsmount *, int);
+#endif /* _LINUX_PNODE_H */
diff --git a/fs/proc/base.c b/fs/proc/base.c
index a170450aadb..634355e1698 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -70,6 +70,7 @@
#include <linux/seccomp.h>
#include <linux/cpuset.h>
#include <linux/audit.h>
+#include <linux/poll.h>
#include "internal.h"
/*
@@ -660,26 +661,38 @@ static struct file_operations proc_smaps_operations = {
#endif
extern struct seq_operations mounts_op;
+struct proc_mounts {
+ struct seq_file m;
+ int event;
+};
+
static int mounts_open(struct inode *inode, struct file *file)
{
struct task_struct *task = proc_task(inode);
- int ret = seq_open(file, &mounts_op);
+ struct namespace *namespace;
+ struct proc_mounts *p;
+ int ret = -EINVAL;
- if (!ret) {
- struct seq_file *m = file->private_data;
- struct namespace *namespace;
- task_lock(task);
- namespace = task->namespace;
- if (namespace)
- get_namespace(namespace);
- task_unlock(task);
-
- if (namespace)
- m->private = namespace;
- else {
- seq_release(inode, file);
- ret = -EINVAL;
+ task_lock(task);
+ namespace = task->namespace;
+ if (namespace)
+ get_namespace(namespace);
+ task_unlock(task);
+
+ if (namespace) {
+ ret = -ENOMEM;
+ p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
+ if (p) {
+ file->private_data = &p->m;
+ ret = seq_open(file, &mounts_op);
+ if (!ret) {
+ p->m.private = namespace;
+ p->event = namespace->event;
+ return 0;
+ }
+ kfree(p);
}
+ put_namespace(namespace);
}
return ret;
}
@@ -692,11 +705,30 @@ static int mounts_release(struct inode *inode, struct file *file)
return seq_release(inode, file);
}
+static unsigned mounts_poll(struct file *file, poll_table *wait)
+{
+ struct proc_mounts *p = file->private_data;
+ struct namespace *ns = p->m.private;
+ unsigned res = 0;
+
+ poll_wait(file, &ns->poll, wait);
+
+ spin_lock(&vfsmount_lock);
+ if (p->event != ns->event) {
+ p->event = ns->event;
+ res = POLLERR;
+ }
+ spin_unlock(&vfsmount_lock);
+
+ return res;
+}
+
static struct file_operations proc_mounts_operations = {
.open = mounts_open,
.read = seq_read,
.llseek = seq_lseek,
.release = mounts_release,
+ .poll = mounts_poll,
};
#define PROC_BLOCK_SIZE (3*1024) /* 4K page size but our output routines use some slack for overruns */
diff --git a/fs/seq_file.c b/fs/seq_file.c
index 38ef913767f..7c40570b71d 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -28,13 +28,17 @@
*/
int seq_open(struct file *file, struct seq_operations *op)
{
- struct seq_file *p = kmalloc(sizeof(*p), GFP_KERNEL);
- if (!p)
- return -ENOMEM;
+ struct seq_file *p = file->private_data;
+
+ if (!p) {
+ p = kmalloc(sizeof(*p), GFP_KERNEL);
+ if (!p)
+ return -ENOMEM;
+ file->private_data = p;
+ }
memset(p, 0, sizeof(*p));
sema_init(&p->sem, 1);
p->op = op;
- file->private_data = p;
/*
* Wrappers around seq_open(e.g. swaps_open) need to be
diff --git a/fs/super.c b/fs/super.c
index eed6c313290..6689dded3c8 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -171,6 +171,7 @@ void deactivate_super(struct super_block *s)
if (atomic_dec_and_lock(&s->s_active, &sb_lock)) {
s->s_count -= S_BIAS-1;
spin_unlock(&sb_lock);
+ DQUOT_OFF(s);
down_write(&s->s_umount);
fs->kill_sb(s);
put_filesystem(fs);
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-04 01:56:07 +0000