KVM: x86: Check non-canonical addresses upon WRMSR

[pandora-kernel.git] / fs / dcache.c

diff --git a/fs/dcache.c b/fs/dcache.c
index 108116e..d322929 100644 (file)
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -242,6 +242,7 @@ static void dentry_lru_add(struct dentry *dentry)
 static void __dentry_lru_del(struct dentry *dentry)
 {
        list_del_init(&dentry->d_lru);
+       dentry->d_flags &= ~DCACHE_SHRINK_LIST;
        dentry->d_sb->s_nr_dentry_unused--;
        dentry_stat.nr_unused--;
 }
@@ -310,7 +311,7 @@ static struct dentry *d_kill(struct dentry *dentry, struct dentry *parent)
         * Inform try_to_ascend() that we are no longer attached to the
         * dentry tree
         */
-       dentry->d_flags |= DCACHE_DISCONNECTED;
+       dentry->d_flags |= DCACHE_DENTRY_KILLED;
        if (parent)
                spin_unlock(&parent->d_lock);
        dentry_iput(dentry);
@@ -805,6 +806,7 @@ relock:
                        spin_unlock(&dentry->d_lock);
                } else {
                        list_move_tail(&dentry->d_lru, &tmp);
+                       dentry->d_flags |= DCACHE_SHRINK_LIST;
                        spin_unlock(&dentry->d_lock);
                        if (!--count)
                                break;
@@ -966,7 +968,7 @@ static struct dentry *try_to_ascend(struct dentry *old, int locked, unsigned seq
         * or deletion
         */
        if (new != old->d_parent ||
-                (old->d_flags & DCACHE_DISCONNECTED) ||
+                (old->d_flags & DCACHE_DENTRY_KILLED) ||
                 (!locked && read_seqretry(&rename_lock, seq))) {
                spin_unlock(&new->d_lock);
                new = NULL;
@@ -1052,6 +1054,8 @@ positive:
        return 1;
 
 rename_retry:
+       if (locked)
+               goto again;
        locked = 1;
        write_seqlock(&rename_lock);
        goto again;
@@ -1096,14 +1100,19 @@ resume:
 
                /*
                 * move only zero ref count dentries to the dispose list.
+                *
+                * Those which are presently on the shrink list, being processed
+                * by shrink_dentry_list(), shouldn't be moved.  Otherwise the
+                * loop in shrink_dcache_parent() might not make any progress
+                * and loop forever.
                 */
-               if (!dentry->d_count) {
+               if (dentry->d_count) {
+                       dentry_lru_del(dentry);
+               } else if (!(dentry->d_flags & DCACHE_SHRINK_LIST)) {
                        dentry_lru_move_list(dentry, dispose);
+                       dentry->d_flags |= DCACHE_SHRINK_LIST;
                        found++;
-               } else {
-                       dentry_lru_del(dentry);
                }
-
                /*
                 * We can return to the caller if we have found some (this
                 * ensures forward progress). We'll be coming back to find
@@ -1149,6 +1158,8 @@ out:
 rename_retry:
        if (found)
                return found;
+       if (locked)
+               goto again;
        locked = 1;
        write_seqlock(&rename_lock);
        goto again;
@@ -1165,8 +1176,10 @@ void shrink_dcache_parent(struct dentry * parent)
        LIST_HEAD(dispose);
        int found;
 
-       while ((found = select_parent(parent, &dispose)) != 0)
+       while ((found = select_parent(parent, &dispose)) != 0) {
                shrink_dentry_list(&dispose);
+               cond_resched();
+       }
 }
 EXPORT_SYMBOL(shrink_dcache_parent);
 
@@ -1481,7 +1494,7 @@ static struct dentry * d_find_any_alias(struct inode *inode)
  */
 struct dentry *d_obtain_alias(struct inode *inode)
 {
-       static const struct qstr anonstring = { .name = "" };
+       static const struct qstr anonstring = { .name = "/", .len = 1 };
        struct dentry *tmp;
        struct dentry *res;
 
@@ -2350,6 +2363,7 @@ struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode)
                        if (d_ancestor(alias, dentry)) {
                                /* Check for loops */
                                actual = ERR_PTR(-ELOOP);
+                               spin_unlock(&inode->i_lock);
                        } else if (IS_ROOT(alias)) {
                                /* Is this an anonymous mountpoint that we
                                 * could splice into our tree? */
@@ -2359,7 +2373,7 @@ struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode)
                                goto found;
                        } else {
                                /* Nope, but we must(!) avoid directory
-                                * aliasing */
+                                * aliasing. This drops inode->i_lock */
                                actual = __d_unalias(inode, dentry, alias);
                        }
                        write_sequnlock(&rename_lock);
@@ -2433,7 +2447,6 @@ static int prepend_path(const struct path *path,
        bool slash = false;
        int error = 0;
 
-       br_read_lock(vfsmount_lock);
        while (dentry != root->dentry || vfsmnt != root->mnt) {
                struct dentry * parent;
 
@@ -2463,8 +2476,6 @@ static int prepend_path(const struct path *path,
        if (!error && !slash)
                error = prepend(buffer, buflen, "/", 1);
 
-out:
-       br_read_unlock(vfsmount_lock);
        return error;
 
 global_root:
@@ -2481,7 +2492,7 @@ global_root:
                error = prepend(buffer, buflen, "/", 1);
        if (!error)
                error = vfsmnt->mnt_ns ? 1 : 2;
-       goto out;
+       return error;
 }
 
 /**
@@ -2508,9 +2519,11 @@ char *__d_path(const struct path *path,
        int error;
 
        prepend(&res, &buflen, "\0", 1);
+       br_read_lock(vfsmount_lock);
        write_seqlock(&rename_lock);
        error = prepend_path(path, root, &res, &buflen);
        write_sequnlock(&rename_lock);
+       br_read_unlock(vfsmount_lock);
 
        if (error < 0)
                return ERR_PTR(error);
@@ -2527,9 +2540,11 @@ char *d_absolute_path(const struct path *path,
        int error;
 
        prepend(&res, &buflen, "\0", 1);
+       br_read_lock(vfsmount_lock);
        write_seqlock(&rename_lock);
        error = prepend_path(path, &root, &res, &buflen);
        write_sequnlock(&rename_lock);
+       br_read_unlock(vfsmount_lock);
 
        if (error > 1)
                error = -EINVAL;
@@ -2593,11 +2608,13 @@ char *d_path(const struct path *path, char *buf, int buflen)
                return path->dentry->d_op->d_dname(path->dentry, buf, buflen);
 
        get_fs_root(current->fs, &root);
+       br_read_lock(vfsmount_lock);
        write_seqlock(&rename_lock);
        error = path_with_deleted(path, &root, &res, &buflen);
+       write_sequnlock(&rename_lock);
+       br_read_unlock(vfsmount_lock);
        if (error < 0)
                res = ERR_PTR(error);
-       write_sequnlock(&rename_lock);
        path_put(&root);
        return res;
 }
@@ -2752,6 +2769,7 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size)
        get_fs_root_and_pwd(current->fs, &root, &pwd);
 
        error = -ENOENT;
+       br_read_lock(vfsmount_lock);
        write_seqlock(&rename_lock);
        if (!d_unlinked(pwd.dentry)) {
                unsigned long len;
@@ -2761,6 +2779,7 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size)
                prepend(&cwd, &buflen, "\0", 1);
                error = prepend_path(&pwd, &root, &cwd, &buflen);
                write_sequnlock(&rename_lock);
+               br_read_unlock(vfsmount_lock);
 
                if (error < 0)
                        goto out;
@@ -2781,6 +2800,7 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size)
                }
        } else {
                write_sequnlock(&rename_lock);
+               br_read_unlock(vfsmount_lock);
        }
 
 out:
@@ -2914,6 +2934,8 @@ resume:
        return;
 
 rename_retry:
+       if (locked)
+               goto again;
        locked = 1;
        write_seqlock(&rename_lock);
        goto again;