UBUNTU: Ubuntu-2.6.38-12.51
[linux-flexiantxendom0-natty.git] / fs / super.c
index a38e6e9..0d89e93 100644 (file)
 #include <linux/slab.h>
 #include <linux/acct.h>
 #include <linux/blkdev.h>
-#include <linux/quotaops.h>
 #include <linux/mount.h>
 #include <linux/security.h>
 #include <linux/writeback.h>           /* for the emergency remount stuff */
 #include <linux/idr.h>
 #include <linux/mutex.h>
 #include <linux/backing-dev.h>
+#include <linux/rculist_bl.h>
 #include "internal.h"
 
 
@@ -55,9 +55,25 @@ static struct super_block *alloc_super(struct file_system_type *type)
                        s = NULL;
                        goto out;
                }
+#ifdef CONFIG_SMP
+               s->s_files = alloc_percpu(struct list_head);
+               if (!s->s_files) {
+                       security_sb_free(s);
+                       kfree(s);
+                       s = NULL;
+                       goto out;
+               } else {
+                       int i;
+
+                       for_each_possible_cpu(i)
+                               INIT_LIST_HEAD(per_cpu_ptr(s->s_files, i));
+               }
+#else
                INIT_LIST_HEAD(&s->s_files);
+#endif
+               s->s_bdi = &default_backing_dev_info;
                INIT_LIST_HEAD(&s->s_instances);
-               INIT_HLIST_HEAD(&s->s_anon);
+               INIT_HLIST_BL_HEAD(&s->s_anon);
                INIT_LIST_HEAD(&s->s_inodes);
                INIT_LIST_HEAD(&s->s_dentry_lru);
                init_rwsem(&s->s_umount);
@@ -94,8 +110,6 @@ static struct super_block *alloc_super(struct file_system_type *type)
                init_rwsem(&s->s_dquot.dqptr_sem);
                init_waitqueue_head(&s->s_wait_unfrozen);
                s->s_maxbytes = MAX_NON_LFS;
-               s->dq_op = sb_dquot_ops;
-               s->s_qcop = sb_quotactl_ops;
                s->s_op = &default_op;
                s->s_time_gran = 1000000000;
        }
@@ -111,6 +125,9 @@ out:
  */
 static inline void destroy_super(struct super_block *s)
 {
+#ifdef CONFIG_SMP
+       free_percpu(s->s_files);
+#endif
        security_sb_free(s);
        kfree(s->s_subtype);
        kfree(s->s_options);
@@ -160,8 +177,12 @@ void deactivate_locked_super(struct super_block *s)
 {
        struct file_system_type *fs = s->s_type;
        if (atomic_dec_and_test(&s->s_active)) {
-               vfs_dq_off(s, 0);
                fs->kill_sb(s);
+               /*
+                * We need to call rcu_barrier so all the delayed rcu free
+                * inodes are flushed before we release the fs module.
+                */
+               rcu_barrier();
                put_filesystem(fs);
                put_super(s);
        } else {
@@ -259,14 +280,14 @@ void generic_shutdown_super(struct super_block *sb)
                get_fs_excl();
                sb->s_flags &= ~MS_ACTIVE;
 
-               /* bad name - it should be evict_inodes() */
-               invalidate_inodes(sb);
+               fsnotify_unmount_inodes(&sb->s_inodes);
+
+               evict_inodes(sb);
 
                if (sop->put_super)
                        sop->put_super(sb);
 
-               /* Forget any remaining inodes */
-               if (invalidate_inodes(sb)) {
+               if (!list_empty(&sb->s_inodes)) {
                        printk("VFS: Busy inodes after unmount of %s. "
                           "Self-destruct in 5 seconds.  Have a nice day...\n",
                           sb->s_id);
@@ -309,8 +330,13 @@ retry:
                        if (s) {
                                up_write(&s->s_umount);
                                destroy_super(s);
+                               s = NULL;
                        }
                        down_write(&old->s_umount);
+                       if (unlikely(!(old->s_flags & MS_BORN))) {
+                               deactivate_locked_super(old);
+                               goto retry;
+                       }
                        return old;
                }
        }
@@ -362,10 +388,10 @@ EXPORT_SYMBOL(drop_super);
  */
 void sync_supers(void)
 {
-       struct super_block *sb, *n;
+       struct super_block *sb, *p = NULL;
 
        spin_lock(&sb_lock);
-       list_for_each_entry_safe(sb, n, &super_blocks, s_list) {
+       list_for_each_entry(sb, &super_blocks, s_list) {
                if (list_empty(&sb->s_instances))
                        continue;
                if (sb->s_op->write_super && sb->s_dirt) {
@@ -378,9 +404,13 @@ void sync_supers(void)
                        up_read(&sb->s_umount);
 
                        spin_lock(&sb_lock);
-                       __put_super(sb);
+                       if (p)
+                               __put_super(p);
+                       p = sb;
                }
        }
+       if (p)
+               __put_super(p);
        spin_unlock(&sb_lock);
 }
 
@@ -394,10 +424,10 @@ void sync_supers(void)
  */
 void iterate_supers(void (*f)(struct super_block *, void *), void *arg)
 {
-       struct super_block *sb, *n;
+       struct super_block *sb, *p = NULL;
 
        spin_lock(&sb_lock);
-       list_for_each_entry_safe(sb, n, &super_blocks, s_list) {
+       list_for_each_entry(sb, &super_blocks, s_list) {
                if (list_empty(&sb->s_instances))
                        continue;
                sb->s_count++;
@@ -409,8 +439,12 @@ void iterate_supers(void (*f)(struct super_block *, void *), void *arg)
                up_read(&sb->s_umount);
 
                spin_lock(&sb_lock);
-               __put_super(sb);
+               if (p)
+                       __put_super(p);
+               p = sb;
        }
+       if (p)
+               __put_super(p);
        spin_unlock(&sb_lock);
 }
 
@@ -572,10 +606,10 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
 
 static void do_emergency_remount(struct work_struct *work)
 {
-       struct super_block *sb, *n;
+       struct super_block *sb, *p = NULL;
 
        spin_lock(&sb_lock);
-       list_for_each_entry_safe(sb, n, &super_blocks, s_list) {
+       list_for_each_entry(sb, &super_blocks, s_list) {
                if (list_empty(&sb->s_instances))
                        continue;
                sb->s_count++;
@@ -589,8 +623,12 @@ static void do_emergency_remount(struct work_struct *work)
                }
                up_write(&sb->s_umount);
                spin_lock(&sb_lock);
-               __put_super(sb);
+               if (p)
+                       __put_super(p);
+               p = sb;
        }
+       if (p)
+               __put_super(p);
        spin_unlock(&sb_lock);
        kfree(work);
        printk("Emergency Remount complete\n");
@@ -684,15 +722,14 @@ static int ns_set_super(struct super_block *sb, void *data)
        return set_anon_super(sb, NULL);
 }
 
-int get_sb_ns(struct file_system_type *fs_type, int flags, void *data,
-       int (*fill_super)(struct super_block *, void *, int),
-       struct vfsmount *mnt)
+struct dentry *mount_ns(struct file_system_type *fs_type, int flags,
+       void *data, int (*fill_super)(struct super_block *, void *, int))
 {
        struct super_block *sb;
 
        sb = sget(fs_type, ns_test_super, ns_set_super, data);
        if (IS_ERR(sb))
-               return PTR_ERR(sb);
+               return ERR_CAST(sb);
 
        if (!sb->s_root) {
                int err;
@@ -700,17 +737,16 @@ int get_sb_ns(struct file_system_type *fs_type, int flags, void *data,
                err = fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
                if (err) {
                        deactivate_locked_super(sb);
-                       return err;
+                       return ERR_PTR(err);
                }
 
                sb->s_flags |= MS_ACTIVE;
        }
 
-       simple_set_mnt(mnt, sb);
-       return 0;
+       return dget(sb->s_root);
 }
 
-EXPORT_SYMBOL(get_sb_ns);
+EXPORT_SYMBOL(mount_ns);
 
 #ifdef CONFIG_BLOCK
 static int set_bdev_super(struct super_block *s, void *data)
@@ -731,22 +767,21 @@ static int test_bdev_super(struct super_block *s, void *data)
        return (void *)s->s_bdev == data;
 }
 
-int get_sb_bdev(struct file_system_type *fs_type,
+struct dentry *mount_bdev(struct file_system_type *fs_type,
        int flags, const char *dev_name, void *data,
-       int (*fill_super)(struct super_block *, void *, int),
-       struct vfsmount *mnt)
+       int (*fill_super)(struct super_block *, void *, int))
 {
        struct block_device *bdev;
        struct super_block *s;
-       fmode_t mode = FMODE_READ;
+       fmode_t mode = FMODE_READ | FMODE_EXCL;
        int error = 0;
 
        if (!(flags & MS_RDONLY))
                mode |= FMODE_WRITE;
 
-       bdev = open_bdev_exclusive(dev_name, mode, fs_type);
+       bdev = blkdev_get_by_path(dev_name, mode, fs_type);
        if (IS_ERR(bdev))
-               return PTR_ERR(bdev);
+               return ERR_CAST(bdev);
 
        /*
         * once the super is inserted into the list by sget, s_umount
@@ -771,7 +806,16 @@ int get_sb_bdev(struct file_system_type *fs_type,
                        goto error_bdev;
                }
 
-               close_bdev_exclusive(bdev, mode);
+               /*
+                * s_umount nests inside bd_mutex during
+                * __invalidate_device().  blkdev_put() acquires
+                * bd_mutex and can't be called under s_umount.  Drop
+                * s_umount temporarily.  This is safe as we're
+                * holding an active reference.
+                */
+               up_write(&s->s_umount);
+               blkdev_put(bdev, mode);
+               down_write(&s->s_umount);
        } else {
                char b[BDEVNAME_SIZE];
 
@@ -789,15 +833,30 @@ int get_sb_bdev(struct file_system_type *fs_type,
                bdev->bd_super = s;
        }
 
-       simple_set_mnt(mnt, s);
-       return 0;
+       return dget(s->s_root);
 
 error_s:
        error = PTR_ERR(s);
 error_bdev:
-       close_bdev_exclusive(bdev, mode);
+       blkdev_put(bdev, mode);
 error:
-       return error;
+       return ERR_PTR(error);
+}
+EXPORT_SYMBOL(mount_bdev);
+
+int get_sb_bdev(struct file_system_type *fs_type,
+       int flags, const char *dev_name, void *data,
+       int (*fill_super)(struct super_block *, void *, int),
+       struct vfsmount *mnt)
+{
+       struct dentry *root;
+
+       root = mount_bdev(fs_type, flags, dev_name, data, fill_super);
+       if (IS_ERR(root))
+               return PTR_ERR(root);
+       mnt->mnt_root = root;
+       mnt->mnt_sb = root->d_sb;
+       return 0;
 }
 
 EXPORT_SYMBOL(get_sb_bdev);
@@ -810,35 +869,49 @@ void kill_block_super(struct super_block *sb)
        bdev->bd_super = NULL;
        generic_shutdown_super(sb);
        sync_blockdev(bdev);
-       close_bdev_exclusive(bdev, mode);
+       WARN_ON_ONCE(!(mode & FMODE_EXCL));
+       blkdev_put(bdev, mode | FMODE_EXCL);
 }
 
 EXPORT_SYMBOL(kill_block_super);
 #endif
 
-int get_sb_nodev(struct file_system_type *fs_type,
+struct dentry *mount_nodev(struct file_system_type *fs_type,
        int flags, void *data,
-       int (*fill_super)(struct super_block *, void *, int),
-       struct vfsmount *mnt)
+       int (*fill_super)(struct super_block *, void *, int))
 {
        int error;
        struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL);
 
        if (IS_ERR(s))
-               return PTR_ERR(s);
+               return ERR_CAST(s);
 
        s->s_flags = flags;
 
        error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
        if (error) {
                deactivate_locked_super(s);
-               return error;
+               return ERR_PTR(error);
        }
        s->s_flags |= MS_ACTIVE;
-       simple_set_mnt(mnt, s);
-       return 0;
+       return dget(s->s_root);
 }
+EXPORT_SYMBOL(mount_nodev);
 
+int get_sb_nodev(struct file_system_type *fs_type,
+       int flags, void *data,
+       int (*fill_super)(struct super_block *, void *, int),
+       struct vfsmount *mnt)
+{
+       struct dentry *root;
+
+       root = mount_nodev(fs_type, flags, data, fill_super);
+       if (IS_ERR(root))
+               return PTR_ERR(root);
+       mnt->mnt_root = root;
+       mnt->mnt_sb = root->d_sb;
+       return 0;
+}
 EXPORT_SYMBOL(get_sb_nodev);
 
 static int compare_single(struct super_block *s, void *p)
@@ -846,29 +919,42 @@ static int compare_single(struct super_block *s, void *p)
        return 1;
 }
 
-int get_sb_single(struct file_system_type *fs_type,
+struct dentry *mount_single(struct file_system_type *fs_type,
        int flags, void *data,
-       int (*fill_super)(struct super_block *, void *, int),
-       struct vfsmount *mnt)
+       int (*fill_super)(struct super_block *, void *, int))
 {
        struct super_block *s;
        int error;
 
        s = sget(fs_type, compare_single, set_anon_super, NULL);
        if (IS_ERR(s))
-               return PTR_ERR(s);
+               return ERR_CAST(s);
        if (!s->s_root) {
                s->s_flags = flags;
                error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
                if (error) {
                        deactivate_locked_super(s);
-                       return error;
+                       return ERR_PTR(error);
                }
                s->s_flags |= MS_ACTIVE;
        } else {
                do_remount_sb(s, flags, data, 0);
        }
-       simple_set_mnt(mnt, s);
+       return dget(s->s_root);
+}
+EXPORT_SYMBOL(mount_single);
+
+int get_sb_single(struct file_system_type *fs_type,
+       int flags, void *data,
+       int (*fill_super)(struct super_block *, void *, int),
+       struct vfsmount *mnt)
+{
+       struct dentry *root;
+       root = mount_single(fs_type, flags, data, fill_super);
+       if (IS_ERR(root))
+               return PTR_ERR(root);
+       mnt->mnt_root = root;
+       mnt->mnt_sb = root->d_sb;
        return 0;
 }
 
@@ -878,6 +964,7 @@ struct vfsmount *
 vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data)
 {
        struct vfsmount *mnt;
+       struct dentry *root;
        char *secdata = NULL;
        int error;
 
@@ -902,11 +989,23 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void
                        goto out_free_secdata;
        }
 
-       error = type->get_sb(type, flags, name, data, mnt);
-       if (error < 0)
-               goto out_free_secdata;
+       if (type->mount) {
+               root = type->mount(type, flags, name, data);
+               if (IS_ERR(root)) {
+                       error = PTR_ERR(root);
+                       goto out_free_secdata;
+               }
+               mnt->mnt_root = root;
+               mnt->mnt_sb = root->d_sb;
+       } else {
+               error = type->get_sb(type, flags, name, data, mnt);
+               if (error < 0)
+                       goto out_free_secdata;
+       }
        BUG_ON(!mnt->mnt_sb);
        WARN_ON(!mnt->mnt_sb->s_bdi);
+       WARN_ON(mnt->mnt_sb->s_bdi == &default_backing_dev_info);
+       mnt->mnt_sb->s_flags |= MS_BORN;
 
        error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata);
        if (error)
@@ -941,8 +1040,8 @@ out:
 EXPORT_SYMBOL_GPL(vfs_kern_mount);
 
 /**
- * freeze_super -- lock the filesystem and force it into a consistent state
- * @super: the super to lock
+ * freeze_super - lock the filesystem and force it into a consistent state
+ * @sb: the super to lock
  *
  * Syncs the super to make sure the filesystem is consistent and calls the fs's
  * freeze_fs.  Subsequent calls to this without first thawing the fs will return