#include <linux/syscalls.h>
#include <linux/slab.h>
#include <linux/sched.h>
-#include <linux/smp_lock.h>
+#include <linux/spinlock.h>
+#include <linux/percpu.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/acct.h>
#include <linux/seq_file.h>
#include <linux/mnt_namespace.h>
#include <linux/namei.h>
+#include <linux/nsproxy.h>
#include <linux/security.h>
#include <linux/mount.h>
#include <linux/ramfs.h>
#include <linux/log2.h>
#include <linux/idr.h>
#include <linux/fs_struct.h>
+#include <linux/fsnotify.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include "pnode.h"
#define HASH_SHIFT ilog2(PAGE_SIZE / sizeof(struct list_head))
#define HASH_SIZE (1UL << HASH_SHIFT)
-/* spinlock for vfsmount related operations, inplace of dcache_lock */
-__cacheline_aligned_in_smp DEFINE_SPINLOCK(vfsmount_lock);
-
static int event;
static DEFINE_IDA(mnt_id_ida);
static DEFINE_IDA(mnt_group_ida);
+static DEFINE_SPINLOCK(mnt_id_lock);
+static int mnt_id_start = 0;
+static int mnt_group_start = 1;
static struct list_head *mount_hashtable __read_mostly;
static struct kmem_cache *mnt_cache __read_mostly;
struct kobject *fs_kobj;
EXPORT_SYMBOL_GPL(fs_kobj);
+/*
+ * vfsmount lock may be taken for read to prevent changes to the
+ * vfsmount hash, ie. during mountpoint lookups or walking back
+ * up the tree.
+ *
+ * It should be taken for write in all cases where the vfsmount
+ * tree or hash is modified or when a vfsmount structure is modified.
+ */
+DEFINE_BRLOCK(vfsmount_lock);
+
static inline unsigned long hash(struct vfsmount *mnt, struct dentry *dentry)
{
unsigned long tmp = ((unsigned long)mnt / L1_CACHE_BYTES);
#define MNT_WRITER_UNDERFLOW_LIMIT -(1<<16)
-/* allocation is serialized by namespace_sem */
+/*
+ * allocation is serialized by namespace_sem, but we need the spinlock to
+ * serialize with freeing.
+ */
static int mnt_alloc_id(struct vfsmount *mnt)
{
int res;
retry:
ida_pre_get(&mnt_id_ida, GFP_KERNEL);
- spin_lock(&vfsmount_lock);
- res = ida_get_new(&mnt_id_ida, &mnt->mnt_id);
- spin_unlock(&vfsmount_lock);
+ spin_lock(&mnt_id_lock);
+ res = ida_get_new_above(&mnt_id_ida, mnt_id_start, &mnt->mnt_id);
+ if (!res)
+ mnt_id_start = mnt->mnt_id + 1;
+ spin_unlock(&mnt_id_lock);
if (res == -EAGAIN)
goto retry;
static void mnt_free_id(struct vfsmount *mnt)
{
- spin_lock(&vfsmount_lock);
- ida_remove(&mnt_id_ida, mnt->mnt_id);
- spin_unlock(&vfsmount_lock);
+ int id = mnt->mnt_id;
+ spin_lock(&mnt_id_lock);
+ ida_remove(&mnt_id_ida, id);
+ if (mnt_id_start > id)
+ mnt_id_start = id;
+ spin_unlock(&mnt_id_lock);
}
/*
*/
static int mnt_alloc_group_id(struct vfsmount *mnt)
{
+ int res;
+
if (!ida_pre_get(&mnt_group_ida, GFP_KERNEL))
return -ENOMEM;
- return ida_get_new_above(&mnt_group_ida, 1, &mnt->mnt_group_id);
+ res = ida_get_new_above(&mnt_group_ida,
+ mnt_group_start,
+ &mnt->mnt_group_id);
+ if (!res)
+ mnt_group_start = mnt->mnt_group_id + 1;
+
+ return res;
}
/*
*/
void mnt_release_group_id(struct vfsmount *mnt)
{
- ida_remove(&mnt_group_ida, mnt->mnt_group_id);
+ int id = mnt->mnt_group_id;
+ ida_remove(&mnt_group_ida, id);
+ if (mnt_group_start > id)
+ mnt_group_start = id;
mnt->mnt_group_id = 0;
}
+/*
+ * vfsmount lock must be held for read
+ */
+static inline void mnt_add_count(struct vfsmount *mnt, int n)
+{
+#ifdef CONFIG_SMP
+ this_cpu_add(mnt->mnt_pcp->mnt_count, n);
+#else
+ preempt_disable();
+ mnt->mnt_count += n;
+ preempt_enable();
+#endif
+}
+
+static inline void mnt_set_count(struct vfsmount *mnt, int n)
+{
+#ifdef CONFIG_SMP
+ this_cpu_write(mnt->mnt_pcp->mnt_count, n);
+#else
+ mnt->mnt_count = n;
+#endif
+}
+
+/*
+ * vfsmount lock must be held for read
+ */
+static inline void mnt_inc_count(struct vfsmount *mnt)
+{
+ mnt_add_count(mnt, 1);
+}
+
+/*
+ * vfsmount lock must be held for read
+ */
+static inline void mnt_dec_count(struct vfsmount *mnt)
+{
+ mnt_add_count(mnt, -1);
+}
+
+/*
+ * vfsmount lock must be held for write
+ */
+unsigned int mnt_get_count(struct vfsmount *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;
+ }
+
+ return count;
+#else
+ return mnt->mnt_count;
+#endif
+}
+
struct vfsmount *alloc_vfsmnt(const char *name)
{
struct vfsmount *mnt = kmem_cache_zalloc(mnt_cache, GFP_KERNEL);
goto out_free_id;
}
- atomic_set(&mnt->mnt_count, 1);
+#ifdef CONFIG_SMP
+ mnt->mnt_pcp = alloc_percpu(struct mnt_pcp);
+ if (!mnt->mnt_pcp)
+ goto out_free_devname;
+
+ this_cpu_add(mnt->mnt_pcp->mnt_count, 1);
+#else
+ mnt->mnt_count = 1;
+ mnt->mnt_writers = 0;
+#endif
+
INIT_LIST_HEAD(&mnt->mnt_hash);
INIT_LIST_HEAD(&mnt->mnt_child);
INIT_LIST_HEAD(&mnt->mnt_mounts);
INIT_LIST_HEAD(&mnt->mnt_share);
INIT_LIST_HEAD(&mnt->mnt_slave_list);
INIT_LIST_HEAD(&mnt->mnt_slave);
- atomic_set(&mnt->__mnt_writers, 0);
+#ifdef CONFIG_FSNOTIFY
+ INIT_HLIST_HEAD(&mnt->mnt_fsnotify_marks);
+#endif
}
return mnt;
+#ifdef CONFIG_SMP
+out_free_devname:
+ kfree(mnt->mnt_devname);
+#endif
out_free_id:
mnt_free_id(mnt);
out_free_cache:
}
EXPORT_SYMBOL_GPL(__mnt_is_readonly);
-struct mnt_writer {
- /*
- * If holding multiple instances of this lock, they
- * must be ordered by cpu number.
- */
- spinlock_t lock;
- struct lock_class_key lock_class; /* compiles out with !lockdep */
- unsigned long count;
- struct vfsmount *mnt;
-} ____cacheline_aligned_in_smp;
-static DEFINE_PER_CPU(struct mnt_writer, mnt_writers);
+static inline void mnt_inc_writers(struct vfsmount *mnt)
+{
+#ifdef CONFIG_SMP
+ this_cpu_inc(mnt->mnt_pcp->mnt_writers);
+#else
+ mnt->mnt_writers++;
+#endif
+}
-static int __init init_mnt_writers(void)
+static inline void mnt_dec_writers(struct vfsmount *mnt)
{
- int cpu;
- for_each_possible_cpu(cpu) {
- struct mnt_writer *writer = &per_cpu(mnt_writers, cpu);
- spin_lock_init(&writer->lock);
- lockdep_set_class(&writer->lock, &writer->lock_class);
- writer->count = 0;
- }
- return 0;
+#ifdef CONFIG_SMP
+ this_cpu_dec(mnt->mnt_pcp->mnt_writers);
+#else
+ mnt->mnt_writers--;
+#endif
}
-fs_initcall(init_mnt_writers);
-static void unlock_mnt_writers(void)
+static unsigned int mnt_get_writers(struct vfsmount *mnt)
{
+#ifdef CONFIG_SMP
+ unsigned int count = 0;
int cpu;
- struct mnt_writer *cpu_writer;
for_each_possible_cpu(cpu) {
- cpu_writer = &per_cpu(mnt_writers, cpu);
- spin_unlock(&cpu_writer->lock);
+ count += per_cpu_ptr(mnt->mnt_pcp, cpu)->mnt_writers;
}
-}
-static inline void __clear_mnt_count(struct mnt_writer *cpu_writer)
-{
- if (!cpu_writer->mnt)
- return;
- /*
- * This is in case anyone ever leaves an invalid,
- * old ->mnt and a count of 0.
- */
- if (!cpu_writer->count)
- return;
- atomic_add(cpu_writer->count, &cpu_writer->mnt->__mnt_writers);
- cpu_writer->count = 0;
-}
- /*
- * must hold cpu_writer->lock
- */
-static inline void use_cpu_writer_for_mount(struct mnt_writer *cpu_writer,
- struct vfsmount *mnt)
-{
- if (cpu_writer->mnt == mnt)
- return;
- __clear_mnt_count(cpu_writer);
- cpu_writer->mnt = mnt;
+ return count;
+#else
+ return mnt->mnt_writers;
+#endif
}
/*
int mnt_want_write(struct vfsmount *mnt)
{
int ret = 0;
- struct mnt_writer *cpu_writer;
- cpu_writer = &get_cpu_var(mnt_writers);
- spin_lock(&cpu_writer->lock);
+ preempt_disable();
+ mnt_inc_writers(mnt);
+ /*
+ * The store to mnt_inc_writers must be visible before we pass
+ * MNT_WRITE_HOLD loop below, so that the slowpath can see our
+ * incremented count after it has set MNT_WRITE_HOLD.
+ */
+ smp_mb();
+ while (mnt->mnt_flags & MNT_WRITE_HOLD)
+ cpu_relax();
+ /*
+ * After the slowpath clears MNT_WRITE_HOLD, mnt_is_readonly will
+ * be set to match its requirements. So we must not load that until
+ * MNT_WRITE_HOLD is cleared.
+ */
+ smp_rmb();
if (__mnt_is_readonly(mnt)) {
+ mnt_dec_writers(mnt);
ret = -EROFS;
goto out;
}
- use_cpu_writer_for_mount(cpu_writer, mnt);
- cpu_writer->count++;
out:
- spin_unlock(&cpu_writer->lock);
- put_cpu_var(mnt_writers);
+ preempt_enable();
return ret;
}
EXPORT_SYMBOL_GPL(mnt_want_write);
-static void lock_mnt_writers(void)
-{
- int cpu;
- struct mnt_writer *cpu_writer;
-
- for_each_possible_cpu(cpu) {
- cpu_writer = &per_cpu(mnt_writers, cpu);
- spin_lock(&cpu_writer->lock);
- __clear_mnt_count(cpu_writer);
- cpu_writer->mnt = NULL;
- }
+/**
+ * mnt_clone_write - get write access to a mount
+ * @mnt: the mount on which to take a write
+ *
+ * This is effectively like mnt_want_write, except
+ * it must only be used to take an extra write reference
+ * on a mountpoint that we already know has a write reference
+ * on it. This allows some optimisation.
+ *
+ * After finished, mnt_drop_write must be called as usual to
+ * drop the reference.
+ */
+int mnt_clone_write(struct vfsmount *mnt)
+{
+ /* superblock may be r/o */
+ if (__mnt_is_readonly(mnt))
+ return -EROFS;
+ preempt_disable();
+ mnt_inc_writers(mnt);
+ preempt_enable();
+ return 0;
}
+EXPORT_SYMBOL_GPL(mnt_clone_write);
-/*
- * These per-cpu write counts are not guaranteed to have
- * matched increments and decrements on any given cpu.
- * A file open()ed for write on one cpu and close()d on
- * another cpu will imbalance this count. Make sure it
- * does not get too far out of whack.
+/**
+ * mnt_want_write_file - get write access to a file's mount
+ * @file: the file who's mount on which to take a write
+ *
+ * This is like mnt_want_write, but it takes a file and can
+ * do some optimisations if the file is open for write already
*/
-static void handle_write_count_underflow(struct vfsmount *mnt)
+int mnt_want_write_file(struct file *file)
{
- if (atomic_read(&mnt->__mnt_writers) >=
- MNT_WRITER_UNDERFLOW_LIMIT)
- return;
- /*
- * It isn't necessary to hold all of the locks
- * at the same time, but doing it this way makes
- * us share a lot more code.
- */
- lock_mnt_writers();
- /*
- * vfsmount_lock is for mnt_flags.
- */
- spin_lock(&vfsmount_lock);
- /*
- * If coalescing the per-cpu writer counts did not
- * get us back to a positive writer count, we have
- * a bug.
- */
- if ((atomic_read(&mnt->__mnt_writers) < 0) &&
- !(mnt->mnt_flags & MNT_IMBALANCED_WRITE_COUNT)) {
- WARN(1, KERN_DEBUG "leak detected on mount(%p) writers "
- "count: %d\n",
- mnt, atomic_read(&mnt->__mnt_writers));
- /* use the flag to keep the dmesg spam down */
- mnt->mnt_flags |= MNT_IMBALANCED_WRITE_COUNT;
- }
- spin_unlock(&vfsmount_lock);
- unlock_mnt_writers();
+ struct inode *inode = file->f_dentry->d_inode;
+ if (!(file->f_mode & FMODE_WRITE) || special_file(inode->i_mode))
+ return mnt_want_write(file->f_path.mnt);
+ else
+ return mnt_clone_write(file->f_path.mnt);
}
+EXPORT_SYMBOL_GPL(mnt_want_write_file);
/**
* mnt_drop_write - give up write access to a mount
*/
void mnt_drop_write(struct vfsmount *mnt)
{
- int must_check_underflow = 0;
- struct mnt_writer *cpu_writer;
-
- cpu_writer = &get_cpu_var(mnt_writers);
- spin_lock(&cpu_writer->lock);
-
- use_cpu_writer_for_mount(cpu_writer, mnt);
- if (cpu_writer->count > 0) {
- cpu_writer->count--;
- } else {
- must_check_underflow = 1;
- atomic_dec(&mnt->__mnt_writers);
- }
-
- spin_unlock(&cpu_writer->lock);
- /*
- * Logically, we could call this each time,
- * but the __mnt_writers cacheline tends to
- * be cold, and makes this expensive.
- */
- if (must_check_underflow)
- handle_write_count_underflow(mnt);
- /*
- * This could be done right after the spinlock
- * is taken because the spinlock keeps us on
- * the cpu, and disables preemption. However,
- * putting it here bounds the amount that
- * __mnt_writers can underflow. Without it,
- * we could theoretically wrap __mnt_writers.
- */
- put_cpu_var(mnt_writers);
+ preempt_disable();
+ mnt_dec_writers(mnt);
+ preempt_enable();
}
EXPORT_SYMBOL_GPL(mnt_drop_write);
{
int ret = 0;
- lock_mnt_writers();
+ br_write_lock(vfsmount_lock);
+ mnt->mnt_flags |= MNT_WRITE_HOLD;
/*
- * With all the locks held, this value is stable
+ * After storing MNT_WRITE_HOLD, we'll read the counters. This store
+ * should be visible before we do.
*/
- if (atomic_read(&mnt->__mnt_writers) > 0) {
- ret = -EBUSY;
- goto out;
- }
+ smp_mb();
+
/*
- * nobody can do a successful mnt_want_write() with all
- * of the counts in MNT_DENIED_WRITE and the locks held.
+ * With writers on hold, if this value is zero, then there are
+ * definitely no active writers (although held writers may subsequently
+ * increment the count, they'll have to wait, and decrement it after
+ * seeing MNT_READONLY).
+ *
+ * It is OK to have counter incremented on one CPU and decremented on
+ * another: the sum will add up correctly. The danger would be when we
+ * sum up each counter, if we read a counter before it is incremented,
+ * but then read another CPU's count which it has been subsequently
+ * decremented from -- we would see more decrements than we should.
+ * MNT_WRITE_HOLD protects against this scenario, because
+ * mnt_want_write first increments count, then smp_mb, then spins on
+ * MNT_WRITE_HOLD, so it can't be decremented by another CPU while
+ * we're counting up here.
*/
- spin_lock(&vfsmount_lock);
- if (!ret)
+ if (mnt_get_writers(mnt) > 0)
+ ret = -EBUSY;
+ else
mnt->mnt_flags |= MNT_READONLY;
- spin_unlock(&vfsmount_lock);
-out:
- unlock_mnt_writers();
+ /*
+ * 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;
+ br_write_unlock(vfsmount_lock);
return ret;
}
static void __mnt_unmake_readonly(struct vfsmount *mnt)
{
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
mnt->mnt_flags &= ~MNT_READONLY;
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
}
void simple_set_mnt(struct vfsmount *mnt, struct super_block *sb)
{
kfree(mnt->mnt_devname);
mnt_free_id(mnt);
+#ifdef CONFIG_SMP
+ free_percpu(mnt->mnt_pcp);
+#endif
kmem_cache_free(mnt_cache, mnt);
}
/*
* 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.
+ * vfsmount_lock must be held for read or write.
*/
struct vfsmount *__lookup_mnt(struct vfsmount *mnt, struct dentry *dentry,
int dir)
* lookup_mnt increments the ref count before returning
* the vfsmount struct.
*/
-struct vfsmount *lookup_mnt(struct vfsmount *mnt, struct dentry *dentry)
+struct vfsmount *lookup_mnt(struct path *path)
{
struct vfsmount *child_mnt;
- spin_lock(&vfsmount_lock);
- if ((child_mnt = __lookup_mnt(mnt, dentry, 1)))
+
+ br_read_lock(vfsmount_lock);
+ if ((child_mnt = __lookup_mnt(path->mnt, path->dentry, 1)))
mntget(child_mnt);
- spin_unlock(&vfsmount_lock);
+ br_read_unlock(vfsmount_lock);
return child_mnt;
}
return mnt->mnt_ns == current->nsproxy->mnt_ns;
}
+/*
+ * vfsmount lock must be held for write
+ */
static void touch_mnt_namespace(struct mnt_namespace *ns)
{
if (ns) {
}
}
+/*
+ * vfsmount lock must be held for write
+ */
static void __touch_mnt_namespace(struct mnt_namespace *ns)
{
if (ns && ns->event != event) {
}
}
+/*
+ * Clear dentry's mounted state if it has no remaining mounts.
+ * vfsmount_lock must be held for write.
+ */
+static void dentry_reset_mounted(struct vfsmount *mnt, struct dentry *dentry)
+{
+ unsigned u;
+
+ for (u = 0; u < HASH_SIZE; u++) {
+ struct vfsmount *p;
+
+ list_for_each_entry(p, &mount_hashtable[u], mnt_hash) {
+ if (p->mnt_mountpoint == dentry)
+ return;
+ }
+ }
+ spin_lock(&dentry->d_lock);
+ dentry->d_flags &= ~DCACHE_MOUNTED;
+ spin_unlock(&dentry->d_lock);
+}
+
+/*
+ * vfsmount lock must be held for write
+ */
static void detach_mnt(struct vfsmount *mnt, struct path *old_path)
{
old_path->dentry = mnt->mnt_mountpoint;
mnt->mnt_mountpoint = mnt->mnt_root;
list_del_init(&mnt->mnt_child);
list_del_init(&mnt->mnt_hash);
- old_path->dentry->d_mounted--;
+ dentry_reset_mounted(old_path->mnt, old_path->dentry);
}
+/*
+ * vfsmount lock must be held for write
+ */
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++;
+ spin_lock(&dentry->d_lock);
+ dentry->d_flags |= DCACHE_MOUNTED;
+ spin_unlock(&dentry->d_lock);
}
+/*
+ * vfsmount lock must be held for write
+ */
static void attach_mnt(struct vfsmount *mnt, struct path *path)
{
mnt_set_mountpoint(path->mnt, path->dentry, mnt);
list_add_tail(&mnt->mnt_child, &path->mnt->mnt_mounts);
}
+static inline void __mnt_make_longterm(struct vfsmount *mnt)
+{
+#ifdef CONFIG_SMP
+ atomic_inc(&mnt->mnt_longterm);
+#endif
+}
+
+/* needs vfsmount lock for write */
+static inline void __mnt_make_shortterm(struct vfsmount *mnt)
+{
+#ifdef CONFIG_SMP
+ atomic_dec(&mnt->mnt_longterm);
+#endif
+}
+
/*
- * the caller must hold vfsmount_lock
+ * vfsmount lock must be held for write
*/
static void commit_tree(struct vfsmount *mnt)
{
BUG_ON(parent == mnt);
list_add_tail(&head, &mnt->mnt_list);
- list_for_each_entry(m, &head, mnt_list)
+ list_for_each_entry(m, &head, mnt_list) {
m->mnt_ns = n;
+ __mnt_make_longterm(m);
+ }
+
list_splice(&head, n->list.prev);
list_add_tail(&mnt->mnt_hash, mount_hashtable +
goto out_free;
}
- mnt->mnt_flags = old->mnt_flags;
+ mnt->mnt_flags = old->mnt_flags & ~MNT_WRITE_HOLD;
atomic_inc(&sb->s_active);
mnt->mnt_sb = sb;
mnt->mnt_root = dget(root);
mnt->mnt_master = old;
CLEAR_MNT_SHARED(mnt);
} else if (!(flag & CL_PRIVATE)) {
- if ((flag & CL_PROPAGATION) || IS_MNT_SHARED(old))
+ if ((flag & CL_MAKE_SHARED) || 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);
return NULL;
}
-static inline void __mntput(struct vfsmount *mnt)
+static inline void mntfree(struct vfsmount *mnt)
{
- int cpu;
struct super_block *sb = mnt->mnt_sb;
- /*
- * We don't have to hold all of the locks at the
- * same time here because we know that we're the
- * last reference to mnt and that no new writers
- * can come in.
- */
- for_each_possible_cpu(cpu) {
- struct mnt_writer *cpu_writer = &per_cpu(mnt_writers, cpu);
- spin_lock(&cpu_writer->lock);
- if (cpu_writer->mnt != mnt) {
- spin_unlock(&cpu_writer->lock);
- continue;
- }
- atomic_add(cpu_writer->count, &mnt->__mnt_writers);
- cpu_writer->count = 0;
- /*
- * Might as well do this so that no one
- * ever sees the pointer and expects
- * it to be valid.
- */
- cpu_writer->mnt = NULL;
- spin_unlock(&cpu_writer->lock);
- }
+
/*
* This probably indicates that somebody messed
* up a mnt_want/drop_write() pair. If this
* happens, the filesystem was probably unable
* to make r/w->r/o transitions.
*/
- WARN_ON(atomic_read(&mnt->__mnt_writers));
+ /*
+ * The locking used to deal with mnt_count decrement provides barriers,
+ * so mnt_get_writers() below is safe.
+ */
+ WARN_ON(mnt_get_writers(mnt));
+ fsnotify_vfsmount_delete(mnt);
dput(mnt->mnt_root);
free_vfsmnt(mnt);
deactivate_super(sb);
}
-void mntput_no_expire(struct vfsmount *mnt)
+static 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);
+put_again:
+#ifdef CONFIG_SMP
+ br_read_lock(vfsmount_lock);
+ if (likely(atomic_read(&mnt->mnt_longterm))) {
+ mnt_dec_count(mnt);
+ br_read_unlock(vfsmount_lock);
+ return;
+ }
+ br_read_unlock(vfsmount_lock);
+
+ br_write_lock(vfsmount_lock);
+ mnt_dec_count(mnt);
+ if (mnt_get_count(mnt)) {
+ br_write_unlock(vfsmount_lock);
+ return;
+ }
+#else
+ mnt_dec_count(mnt);
+ if (likely(mnt_get_count(mnt)))
+ return;
+ br_write_lock(vfsmount_lock);
+#endif
+ if (unlikely(mnt->mnt_pinned)) {
+ mnt_add_count(mnt, mnt->mnt_pinned + 1);
mnt->mnt_pinned = 0;
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
acct_auto_close_mnt(mnt);
- security_sb_umount_close(mnt);
- goto repeat;
+ goto put_again;
}
+ br_write_unlock(vfsmount_lock);
+ mntfree(mnt);
}
-EXPORT_SYMBOL(mntput_no_expire);
+void mntput(struct vfsmount *mnt)
+{
+ if (mnt) {
+ /* avoid cacheline pingpong, hope gcc doesn't get "smart" */
+ if (unlikely(mnt->mnt_expiry_mark))
+ mnt->mnt_expiry_mark = 0;
+ mntput_no_expire(mnt);
+ }
+}
+EXPORT_SYMBOL(mntput);
+
+struct vfsmount *mntget(struct vfsmount *mnt)
+{
+ if (mnt)
+ mnt_inc_count(mnt);
+ return mnt;
+}
+EXPORT_SYMBOL(mntget);
void mnt_pin(struct vfsmount *mnt)
{
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
mnt->mnt_pinned++;
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
}
-
EXPORT_SYMBOL(mnt_pin);
void mnt_unpin(struct vfsmount *mnt)
{
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
if (mnt->mnt_pinned) {
- atomic_inc(&mnt->mnt_count);
+ mnt_inc_count(mnt);
mnt->mnt_pinned--;
}
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
}
-
EXPORT_SYMBOL(mnt_unpin);
static inline void mangle(struct seq_file *m, const char *s)
up_read(&namespace_sem);
}
+int mnt_had_events(struct proc_mounts *p)
+{
+ struct mnt_namespace *ns = p->ns;
+ int res = 0;
+
+ br_read_lock(vfsmount_lock);
+ if (p->event != ns->event) {
+ p->event = ns->event;
+ res = 1;
+ }
+ br_read_unlock(vfsmount_lock);
+
+ return res;
+}
+
struct proc_fs_info {
int flag;
const char *str;
{ MNT_NOATIME, ",noatime" },
{ MNT_NODIRATIME, ",nodiratime" },
{ MNT_RELATIME, ",relatime" },
- { MNT_STRICTATIME, ",strictatime" },
{ 0, NULL }
};
const struct proc_fs_info *fs_infop;
int minimum_refs = 0;
struct vfsmount *p;
- spin_lock(&vfsmount_lock);
+ /* write lock needed for mnt_get_count */
+ br_write_lock(vfsmount_lock);
for (p = mnt; p; p = next_mnt(p, mnt)) {
- actual_refs += atomic_read(&p->mnt_count);
+ actual_refs += mnt_get_count(p);
minimum_refs += 2;
}
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
if (actual_refs > minimum_refs)
return 0;
int may_umount(struct vfsmount *mnt)
{
int ret = 1;
- spin_lock(&vfsmount_lock);
+ down_read(&namespace_sem);
+ br_write_lock(vfsmount_lock);
if (propagate_mount_busy(mnt, 2))
ret = 0;
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
+ up_read(&namespace_sem);
return ret;
}
if (mnt->mnt_parent != mnt) {
struct dentry *dentry;
struct vfsmount *m;
- spin_lock(&vfsmount_lock);
+
+ br_write_lock(vfsmount_lock);
dentry = mnt->mnt_mountpoint;
m = mnt->mnt_parent;
mnt->mnt_mountpoint = mnt->mnt_root;
mnt->mnt_parent = mnt;
m->mnt_ghosts--;
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
dput(dentry);
mntput(m);
}
}
}
+/*
+ * vfsmount lock must be held for write
+ * namespace_sem must be held for write
+ */
void umount_tree(struct vfsmount *mnt, int propagate, struct list_head *kill)
{
+ LIST_HEAD(tmp_list);
struct vfsmount *p;
for (p = mnt; p; p = next_mnt(p, mnt))
- list_move(&p->mnt_hash, kill);
+ list_move(&p->mnt_hash, &tmp_list);
if (propagate)
- propagate_umount(kill);
+ propagate_umount(&tmp_list);
- list_for_each_entry(p, kill, mnt_hash) {
+ list_for_each_entry(p, &tmp_list, mnt_hash) {
list_del_init(&p->mnt_expire);
list_del_init(&p->mnt_list);
__touch_mnt_namespace(p->mnt_ns);
p->mnt_ns = NULL;
+ __mnt_make_shortterm(p);
list_del_init(&p->mnt_child);
if (p->mnt_parent != p) {
p->mnt_parent->mnt_ghosts++;
- p->mnt_mountpoint->d_mounted--;
+ dentry_reset_mounted(p->mnt_parent, p->mnt_mountpoint);
}
change_mnt_propagation(p, MS_PRIVATE);
}
+ list_splice(&tmp_list, kill);
}
static void shrink_submounts(struct vfsmount *mnt, struct list_head *umounts);
flags & (MNT_FORCE | MNT_DETACH))
return -EINVAL;
- if (atomic_read(&mnt->mnt_count) != 2)
+ /*
+ * probably don't strictly need the lock here if we examined
+ * all race cases, but it's a slowpath.
+ */
+ br_write_lock(vfsmount_lock);
+ if (mnt_get_count(mnt) != 2) {
+ br_write_unlock(vfsmount_lock);
return -EBUSY;
+ }
+ br_write_unlock(vfsmount_lock);
if (!xchg(&mnt->mnt_expiry_mark, 1))
return -EAGAIN;
* we just try to remount it readonly.
*/
down_write(&sb->s_umount);
- if (!(sb->s_flags & MS_RDONLY)) {
- lock_kernel();
+ if (!(sb->s_flags & MS_RDONLY))
retval = do_remount_sb(sb, MS_RDONLY, NULL, 0);
- unlock_kernel();
- }
up_write(&sb->s_umount);
return retval;
}
down_write(&namespace_sem);
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
event++;
if (!(flags & MNT_DETACH))
umount_tree(mnt, 1, &umount_list);
retval = 0;
}
- spin_unlock(&vfsmount_lock);
- if (retval)
- security_sb_umount_busy(mnt);
+ br_write_unlock(vfsmount_lock);
up_write(&namespace_sem);
release_mounts(&umount_list);
return retval;
{
struct path path;
int retval;
+ int lookup_flags = 0;
+
+ if (flags & ~(MNT_FORCE | MNT_DETACH | MNT_EXPIRE | UMOUNT_NOFOLLOW))
+ return -EINVAL;
- retval = user_path(name, &path);
+ if (!(flags & UMOUNT_NOFOLLOW))
+ lookup_flags |= LOOKUP_FOLLOW;
+
+ retval = user_path_at(AT_FDCWD, name, lookup_flags, &path);
if (retval)
goto out;
retval = -EINVAL;
q = clone_mnt(p, p->mnt_root, flag);
if (!q)
goto Enomem;
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
list_add_tail(&q->mnt_list, &res->mnt_list);
attach_mnt(q, &path);
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
}
}
return res;
Enomem:
if (res) {
LIST_HEAD(umount_list);
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
umount_tree(res, 0, &umount_list);
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
release_mounts(&umount_list);
}
return NULL;
{
LIST_HEAD(umount_list);
down_write(&namespace_sem);
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
umount_tree(mnt, 0, &umount_list);
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
up_write(&namespace_sem);
release_mounts(&umount_list);
}
+int iterate_mounts(int (*f)(struct vfsmount *, void *), void *arg,
+ struct vfsmount *root)
+{
+ struct vfsmount *mnt;
+ int res = f(root, arg);
+ if (res)
+ return res;
+ list_for_each_entry(mnt, &root->mnt_list, mnt_list) {
+ res = f(mnt, arg);
+ if (res)
+ return res;
+ }
+ return 0;
+}
+EXPORT_SYMBOL(iterate_mounts);
+
static void cleanup_group_ids(struct vfsmount *mnt, struct vfsmount *end)
{
struct vfsmount *p;
if (err)
goto out_cleanup_ids;
+ br_write_lock(vfsmount_lock);
+
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_path) {
detach_mnt(source_mnt, parent_path);
attach_mnt(source_mnt, path);
list_del_init(&child->mnt_hash);
commit_tree(child);
}
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
+
return 0;
out_cleanup_ids:
err = -ENOENT;
mutex_lock(&path->dentry->d_inode->i_mutex);
- if (IS_DEADDIR(path->dentry->d_inode))
+ if (cant_mount(path->dentry))
goto out_unlock;
- err = security_sb_check_sb(mnt, path);
- if (err)
- goto out_unlock;
-
- err = -ENOENT;
- if (IS_ROOT(path->dentry) || !d_unhashed(path->dentry))
+ if (!d_unlinked(path->dentry))
err = attach_recursive_mnt(mnt, path, NULL);
out_unlock:
mutex_unlock(&path->dentry->d_inode->i_mutex);
- if (!err)
- security_sb_post_addmount(mnt, path);
return err;
}
/*
+ * Sanity check the flags to change_mnt_propagation.
+ */
+
+static int flags_to_propagation_type(int flags)
+{
+ int type = flags & ~MS_REC;
+
+ /* Fail if any non-propagation flags are set */
+ if (type & ~(MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE))
+ return 0;
+ /* Only one propagation flag should be set */
+ if (!is_power_of_2(type))
+ return 0;
+ return type;
+}
+
+/*
* recursively change the type of the mountpoint.
*/
static int do_change_type(struct path *path, int flag)
{
struct vfsmount *m, *mnt = path->mnt;
int recurse = flag & MS_REC;
- int type = flag & ~MS_REC;
+ int type;
int err = 0;
if (!capable(CAP_SYS_ADMIN))
if (path->dentry != path->mnt->mnt_root)
return -EINVAL;
+ type = flags_to_propagation_type(flag);
+ if (!type)
+ return -EINVAL;
+
down_write(&namespace_sem);
if (type == MS_SHARED) {
err = invent_group_ids(mnt, recurse);
goto out_unlock;
}
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
for (m = mnt; m; m = (recurse ? next_mnt(m, mnt) : NULL))
change_mnt_propagation(m, type);
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
out_unlock:
up_write(&namespace_sem);
err = graft_tree(mnt, path);
if (err) {
LIST_HEAD(umount_list);
- spin_lock(&vfsmount_lock);
+
+ br_write_lock(vfsmount_lock);
umount_tree(mnt, 0, &umount_list);
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
release_mounts(&umount_list);
}
err = change_mount_flags(path->mnt, flags);
else
err = do_remount_sb(sb, flags, data, 0);
- if (!err)
+ if (!err) {
+ br_write_lock(vfsmount_lock);
+ mnt_flags |= path->mnt->mnt_flags & MNT_PROPAGATION_MASK;
path->mnt->mnt_flags = mnt_flags;
+ br_write_unlock(vfsmount_lock);
+ }
up_write(&sb->s_umount);
if (!err) {
- security_sb_post_remount(path->mnt, flags, data);
-
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
touch_mnt_namespace(path->mnt->mnt_ns);
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
}
return err;
}
return err;
down_write(&namespace_sem);
- while (d_mountpoint(path->dentry) &&
- follow_down(&path->mnt, &path->dentry))
- ;
+ err = follow_down(path, true);
+ if (err < 0)
+ goto out;
+
err = -EINVAL;
if (!check_mnt(path->mnt) || !check_mnt(old_path.mnt))
goto out;
err = -ENOENT;
mutex_lock(&path->dentry->d_inode->i_mutex);
- if (IS_DEADDIR(path->dentry->d_inode))
+ if (cant_mount(path->dentry))
goto out1;
- if (!IS_ROOT(path->dentry) && d_unhashed(path->dentry))
+ if (d_unlinked(path->dentry))
goto out1;
err = -EINVAL;
return err;
}
+static int do_add_mount(struct vfsmount *, struct path *, int);
+
/*
* create a new mount for userspace and request it to be added into the
* namespace's tree
int mnt_flags, char *name, void *data)
{
struct vfsmount *mnt;
+ int err;
- if (!type || !memchr(type, 0, PAGE_SIZE))
+ if (!type)
return -EINVAL;
/* we need capabilities... */
if (IS_ERR(mnt))
return PTR_ERR(mnt);
- return do_add_mount(mnt, path, mnt_flags, NULL);
+ err = do_add_mount(mnt, path, mnt_flags);
+ if (err)
+ mntput(mnt);
+ return err;
+}
+
+int finish_automount(struct vfsmount *m, struct path *path)
+{
+ int err;
+ /* 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);
+
+ if (m->mnt_sb == path->mnt->mnt_sb &&
+ m->mnt_root == path->dentry) {
+ err = -ELOOP;
+ goto fail;
+ }
+
+ err = do_add_mount(m, path, path->mnt->mnt_flags | MNT_SHRINKABLE);
+ if (!err)
+ return 0;
+fail:
+ /* remove m from any expiration list it may be on */
+ if (!list_empty(&m->mnt_expire)) {
+ down_write(&namespace_sem);
+ br_write_lock(vfsmount_lock);
+ list_del_init(&m->mnt_expire);
+ br_write_unlock(vfsmount_lock);
+ up_write(&namespace_sem);
+ }
+ mntput(m);
+ mntput(m);
+ return err;
}
/*
* add a mount into a namespace's mount tree
- * - provide the option of adding the new mount to an expiration list
*/
-int do_add_mount(struct vfsmount *newmnt, struct path *path,
- int mnt_flags, struct list_head *fslist)
+static int do_add_mount(struct vfsmount *newmnt, struct path *path, int mnt_flags)
{
int err;
+ mnt_flags &= ~(MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL);
+
down_write(&namespace_sem);
/* Something was mounted here while we slept */
- while (d_mountpoint(path->dentry) &&
- follow_down(&path->mnt, &path->dentry))
- ;
+ err = follow_down(path, true);
+ if (err < 0)
+ goto unlock;
+
err = -EINVAL;
if (!(mnt_flags & MNT_SHRINKABLE) && !check_mnt(path->mnt))
goto unlock;
goto unlock;
newmnt->mnt_flags = mnt_flags;
- if ((err = graft_tree(newmnt, path)))
- goto unlock;
-
- if (fslist) /* add to the specified expiration list */
- list_add_tail(&newmnt->mnt_expire, fslist);
-
- up_write(&namespace_sem);
- return 0;
+ err = graft_tree(newmnt, path);
unlock:
up_write(&namespace_sem);
- mntput(newmnt);
return err;
}
-EXPORT_SYMBOL_GPL(do_add_mount);
+/**
+ * mnt_set_expiry - Put a mount on an expiration list
+ * @mnt: The mount to list.
+ * @expiry_list: The list to add the mount to.
+ */
+void mnt_set_expiry(struct vfsmount *mnt, struct list_head *expiry_list)
+{
+ down_write(&namespace_sem);
+ br_write_lock(vfsmount_lock);
+
+ list_add_tail(&mnt->mnt_expire, expiry_list);
+
+ br_write_unlock(vfsmount_lock);
+ up_write(&namespace_sem);
+}
+EXPORT_SYMBOL(mnt_set_expiry);
/*
* process a list of expirable mountpoints with the intent of discarding any
return;
down_write(&namespace_sem);
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
/* extract from the expiration list every vfsmount that matches the
* following criteria:
touch_mnt_namespace(mnt->mnt_ns);
umount_tree(mnt, 1, &umounts);
}
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
up_write(&namespace_sem);
release_mounts(&umounts);
/*
* process a list of expirable mountpoints with the intent of discarding any
* submounts of a specific parent mountpoint
+ *
+ * vfsmount_lock must be held for write
*/
static void shrink_submounts(struct vfsmount *mnt, struct list_head *umounts)
{
return 0;
}
+int copy_mount_string(const void __user *data, char **where)
+{
+ char *tmp;
+
+ if (!data) {
+ *where = NULL;
+ return 0;
+ }
+
+ tmp = strndup_user(data, PAGE_SIZE);
+ if (IS_ERR(tmp))
+ return PTR_ERR(tmp);
+
+ *where = tmp;
+ return 0;
+}
+
/*
* Flags is a 32-bit value that allows up to 31 non-fs dependent flags to
* be given to the mount() call (ie: read-only, no-dev, no-suid etc).
if (!dir_name || !*dir_name || !memchr(dir_name, 0, PAGE_SIZE))
return -EINVAL;
- if (dev_name && !memchr(dev_name, 0, PAGE_SIZE))
- return -EINVAL;
if (data_page)
((char *)data_page)[PAGE_SIZE - 1] = 0;
+ /* ... and get the mountpoint */
+ retval = kern_path(dir_name, LOOKUP_FOLLOW, &path);
+ if (retval)
+ return retval;
+
+ retval = security_sb_mount(dev_name, &path,
+ type_page, flags, data_page);
+ if (retval)
+ goto dput_out;
+
/* Default to relatime unless overriden */
if (!(flags & MS_NOATIME))
mnt_flags |= MNT_RELATIME;
if (flags & MS_RDONLY)
mnt_flags |= MNT_READONLY;
- flags &= ~(MS_NOSUID | MS_NOEXEC | MS_NODEV | MS_ACTIVE |
+ flags &= ~(MS_NOSUID | MS_NOEXEC | MS_NODEV | MS_ACTIVE | MS_BORN |
MS_NOATIME | MS_NODIRATIME | MS_RELATIME| MS_KERNMOUNT |
MS_STRICTATIME);
- /* ... and get the mountpoint */
- retval = kern_path(dir_name, LOOKUP_FOLLOW, &path);
- if (retval)
- return retval;
-
- retval = security_sb_mount(dev_name, &path,
- type_page, flags, data_page);
- if (retval)
- goto dput_out;
-
if (flags & MS_REMOUNT)
retval = do_remount(&path, flags & ~MS_REMOUNT, mnt_flags,
data_page);
return retval;
}
+static struct mnt_namespace *alloc_mnt_ns(void)
+{
+ struct mnt_namespace *new_ns;
+
+ new_ns = kmalloc(sizeof(struct mnt_namespace), GFP_KERNEL);
+ if (!new_ns)
+ return ERR_PTR(-ENOMEM);
+ atomic_set(&new_ns->count, 1);
+ new_ns->root = NULL;
+ INIT_LIST_HEAD(&new_ns->list);
+ init_waitqueue_head(&new_ns->poll);
+ new_ns->event = 0;
+ return new_ns;
+}
+
+void mnt_make_longterm(struct vfsmount *mnt)
+{
+ __mnt_make_longterm(mnt);
+}
+
+void mnt_make_shortterm(struct vfsmount *mnt)
+{
+#ifdef CONFIG_SMP
+ if (atomic_add_unless(&mnt->mnt_longterm, -1, 1))
+ return;
+ br_write_lock(vfsmount_lock);
+ atomic_dec(&mnt->mnt_longterm);
+ br_write_unlock(vfsmount_lock);
+#endif
+}
+
/*
* Allocate a new namespace structure and populate it with contents
* copied from the namespace of the passed in task structure.
struct vfsmount *rootmnt = NULL, *pwdmnt = NULL;
struct vfsmount *p, *q;
- new_ns = kmalloc(sizeof(struct mnt_namespace), GFP_KERNEL);
- if (!new_ns)
- return ERR_PTR(-ENOMEM);
-
- atomic_set(&new_ns->count, 1);
- INIT_LIST_HEAD(&new_ns->list);
- init_waitqueue_head(&new_ns->poll);
- new_ns->event = 0;
+ new_ns = alloc_mnt_ns();
+ if (IS_ERR(new_ns))
+ return new_ns;
down_write(&namespace_sem);
/* First pass: copy the tree topology */
kfree(new_ns);
return ERR_PTR(-ENOMEM);
}
- spin_lock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
list_add_tail(&new_ns->list, &new_ns->root->mnt_list);
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
/*
* Second pass: switch the tsk->fs->* elements and mark new vfsmounts
q = new_ns->root;
while (p) {
q->mnt_ns = new_ns;
+ __mnt_make_longterm(q);
if (fs) {
if (p == fs->root.mnt) {
- rootmnt = p;
fs->root.mnt = mntget(q);
+ __mnt_make_longterm(q);
+ mnt_make_shortterm(p);
+ rootmnt = p;
}
if (p == fs->pwd.mnt) {
- pwdmnt = p;
fs->pwd.mnt = mntget(q);
+ __mnt_make_longterm(q);
+ mnt_make_shortterm(p);
+ pwdmnt = p;
}
}
p = next_mnt(p, mnt_ns->root);
return new_ns;
}
+/**
+ * create_mnt_ns - creates a private namespace and adds a root filesystem
+ * @mnt: pointer to the new root filesystem mountpoint
+ */
+struct mnt_namespace *create_mnt_ns(struct vfsmount *mnt)
+{
+ struct mnt_namespace *new_ns;
+
+ new_ns = alloc_mnt_ns();
+ if (!IS_ERR(new_ns)) {
+ mnt->mnt_ns = new_ns;
+ __mnt_make_longterm(mnt);
+ new_ns->root = mnt;
+ list_add(&new_ns->list, &new_ns->root->mnt_list);
+ }
+ return new_ns;
+}
+EXPORT_SYMBOL(create_mnt_ns);
+
SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name,
char __user *, type, unsigned long, flags, void __user *, data)
{
- int retval;
+ int ret;
+ char *kernel_type;
+ char *kernel_dir;
+ char *kernel_dev;
unsigned long data_page;
- unsigned long type_page;
- unsigned long dev_page;
- char *dir_page;
- retval = copy_mount_options(type, &type_page);
- if (retval < 0)
- return retval;
+ ret = copy_mount_string(type, &kernel_type);
+ if (ret < 0)
+ goto out_type;
- dir_page = getname(dir_name);
- retval = PTR_ERR(dir_page);
- if (IS_ERR(dir_page))
- goto out1;
+ kernel_dir = getname(dir_name);
+ if (IS_ERR(kernel_dir)) {
+ ret = PTR_ERR(kernel_dir);
+ goto out_dir;
+ }
- retval = copy_mount_options(dev_name, &dev_page);
- if (retval < 0)
- goto out2;
+ ret = copy_mount_string(dev_name, &kernel_dev);
+ if (ret < 0)
+ goto out_dev;
- retval = copy_mount_options(data, &data_page);
- if (retval < 0)
- goto out3;
+ ret = copy_mount_options(data, &data_page);
+ if (ret < 0)
+ goto out_data;
- lock_kernel();
- retval = do_mount((char *)dev_page, dir_page, (char *)type_page,
- flags, (void *)data_page);
- unlock_kernel();
- free_page(data_page);
+ ret = do_mount(kernel_dev, kernel_dir, kernel_type, flags,
+ (void *) data_page);
-out3:
- free_page(dev_page);
-out2:
- putname(dir_page);
-out1:
- free_page(type_page);
- return retval;
+ free_page(data_page);
+out_data:
+ kfree(kernel_dev);
+out_dev:
+ putname(kernel_dir);
+out_dir:
+ kfree(kernel_type);
+out_type:
+ return ret;
}
/*
error = user_path_dir(new_root, &new);
if (error)
goto out0;
- error = -EINVAL;
- if (!check_mnt(new.mnt))
- goto out1;
error = user_path_dir(put_old, &old);
if (error)
goto out1;
}
- read_lock(¤t->fs->lock);
- root = current->fs->root;
- path_get(¤t->fs->root);
- read_unlock(¤t->fs->lock);
+ get_fs_root(current->fs, &root);
down_write(&namespace_sem);
mutex_lock(&old.dentry->d_inode->i_mutex);
error = -EINVAL;
IS_MNT_SHARED(new.mnt->mnt_parent) ||
IS_MNT_SHARED(root.mnt->mnt_parent))
goto out2;
- if (!check_mnt(root.mnt))
+ if (!check_mnt(root.mnt) || !check_mnt(new.mnt))
goto out2;
error = -ENOENT;
- if (IS_DEADDIR(new.dentry->d_inode))
+ if (cant_mount(old.dentry))
goto out2;
- if (d_unhashed(new.dentry) && !IS_ROOT(new.dentry))
+ if (d_unlinked(new.dentry))
goto out2;
- if (d_unhashed(old.dentry) && !IS_ROOT(old.dentry))
+ if (d_unlinked(old.dentry))
goto out2;
error = -EBUSY;
if (new.mnt == root.mnt ||
goto out2; /* not attached */
/* make sure we can reach put_old from new_root */
tmp = old.mnt;
- spin_lock(&vfsmount_lock);
if (tmp != new.mnt) {
for (;;) {
if (tmp->mnt_parent == tmp)
- goto out3; /* already mounted on put_old */
+ goto out2; /* already mounted on put_old */
if (tmp->mnt_parent == new.mnt)
break;
tmp = tmp->mnt_parent;
}
if (!is_subdir(tmp->mnt_mountpoint, new.dentry))
- goto out3;
+ goto out2;
} else if (!is_subdir(old.dentry, new.dentry))
- goto out3;
+ goto out2;
+ br_write_lock(vfsmount_lock);
detach_mnt(new.mnt, &parent_path);
detach_mnt(root.mnt, &root_parent);
/* mount old root on put_old */
/* mount new_root on / */
attach_mnt(new.mnt, &root_parent);
touch_mnt_namespace(current->nsproxy->mnt_ns);
- spin_unlock(&vfsmount_lock);
+ br_write_unlock(vfsmount_lock);
chroot_fs_refs(&root, &new);
- security_sb_post_pivotroot(&root, &new);
+
error = 0;
path_put(&root_parent);
path_put(&parent_path);
path_put(&new);
out0:
return error;
-out3:
- spin_unlock(&vfsmount_lock);
- goto out2;
}
static void __init init_mount_tree(void)
mnt = do_kern_mount("rootfs", 0, "rootfs", NULL);
if (IS_ERR(mnt))
panic("Can't create rootfs");
- ns = kmalloc(sizeof(*ns), GFP_KERNEL);
- if (!ns)
+
+ ns = create_mnt_ns(mnt);
+ if (IS_ERR(ns))
panic("Can't allocate initial namespace");
- atomic_set(&ns->count, 1);
- INIT_LIST_HEAD(&ns->list);
- init_waitqueue_head(&ns->poll);
- ns->event = 0;
- list_add(&mnt->mnt_list, &ns->list);
- ns->root = mnt;
- mnt->mnt_ns = ns;
init_task.nsproxy->mnt_ns = ns;
get_mnt_ns(ns);
for (u = 0; u < HASH_SIZE; u++)
INIT_LIST_HEAD(&mount_hashtable[u]);
+ br_lock_init(vfsmount_lock);
+
err = sysfs_init();
if (err)
printk(KERN_WARNING "%s: sysfs_init error: %d\n",
init_mount_tree();
}
-void __put_mnt_ns(struct mnt_namespace *ns)
+void put_mnt_ns(struct mnt_namespace *ns)
{
- struct vfsmount *root = ns->root;
LIST_HEAD(umount_list);
- ns->root = NULL;
- spin_unlock(&vfsmount_lock);
+
+ if (!atomic_dec_and_test(&ns->count))
+ return;
down_write(&namespace_sem);
- spin_lock(&vfsmount_lock);
- umount_tree(root, 0, &umount_list);
- spin_unlock(&vfsmount_lock);
+ br_write_lock(vfsmount_lock);
+ umount_tree(ns->root, 0, &umount_list);
+ br_write_unlock(vfsmount_lock);
up_write(&namespace_sem);
release_mounts(&umount_list);
kfree(ns);
}
+EXPORT_SYMBOL(put_mnt_ns);
projects / linux-flexiantxendom0-natty.git / blobdiff