Merge branch 'mpi-master' into wip-k-fmlpwip-k-fmlp

Conflicts:
	litmus/sched_cedf.c

1 files changed, 390 insertions, 516 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 50e8c8582faa..610e8e0b04b8 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -11,7 +11,6 @@
 #include <linux/slab.h>
 #include <linux/kmod.h>
 #include <linux/major.h>
-#include <linux/smp_lock.h>
 #include <linux/device_cgroup.h>
 #include <linux/highmem.h>
 #include <linux/blkdev.h>
@@ -48,6 +47,23 @@ inline struct block_device *I_BDEV(struct inode *inode)
 
 EXPORT_SYMBOL(I_BDEV);
 
+/*
+ * move the inode from it's current bdi to the a new bdi. if the inode is dirty
+ * we need to move it onto the dirty list of @dst so that the inode is always
+ * on the right list.
+ */
+static void bdev_inode_switch_bdi(struct inode *inode,
+                        struct backing_dev_info *dst)
+{
+        spin_lock(&inode_wb_list_lock);
+        spin_lock(&inode->i_lock);
+        inode->i_data.backing_dev_info = dst;
+        if (inode->i_state & I_DIRTY)
+                list_move(&inode->i_wb_list, &dst->wb.b_dirty);
+        spin_unlock(&inode->i_lock);
+        spin_unlock(&inode_wb_list_lock);
+}
+
 static sector_t max_block(struct block_device *bdev)
 {
         sector_t retval = ~((sector_t)0);
@@ -370,7 +386,7 @@ int blkdev_fsync(struct file *filp, int datasync)
          */
         mutex_unlock(&bd_inode->i_mutex);
 
-        error = blkdev_issue_flush(bdev, GFP_KERNEL, NULL, BLKDEV_IFL_WAIT);
+        error = blkdev_issue_flush(bdev, GFP_KERNEL, NULL);
         if (error == -EOPNOTSUPP)
                 error = 0;
 
@@ -395,13 +411,20 @@ static struct inode *bdev_alloc_inode(struct super_block *sb)
         return &ei->vfs_inode;
 }
 
-static void bdev_destroy_inode(struct inode *inode)
+static void bdev_i_callback(struct rcu_head *head)
 {
+        struct inode *inode = container_of(head, struct inode, i_rcu);
         struct bdev_inode *bdi = BDEV_I(inode);
 
+        INIT_LIST_HEAD(&inode->i_dentry);
         kmem_cache_free(bdev_cachep, bdi);
 }
 
+static void bdev_destroy_inode(struct inode *inode)
+{
+        call_rcu(&inode->i_rcu, bdev_i_callback);
+}
+
 static void init_once(void *foo)
 {
         struct bdev_inode *ei = (struct bdev_inode *) foo;
@@ -412,7 +435,7 @@ static void init_once(void *foo)
         INIT_LIST_HEAD(&bdev->bd_inodes);
         INIT_LIST_HEAD(&bdev->bd_list);
 #ifdef CONFIG_SYSFS
-        INIT_LIST_HEAD(&bdev->bd_holder_list);
+        INIT_LIST_HEAD(&bdev->bd_holder_disks);
 #endif
         inode_init_once(&ei->vfs_inode);
         /* Initialize mutex for freeze. */
@@ -449,15 +472,15 @@ static const struct super_operations bdev_sops = {
         .evict_inode = bdev_evict_inode,
 };
 
-static int bd_get_sb(struct file_system_type *fs_type,
-        int flags, const char *dev_name, void *data, struct vfsmount *mnt)
+static struct dentry *bd_mount(struct file_system_type *fs_type,
+        int flags, const char *dev_name, void *data)
 {
-        return get_sb_pseudo(fs_type, "bdev:", &bdev_sops, 0x62646576, mnt);
+        return mount_pseudo(fs_type, "bdev:", &bdev_sops, NULL, 0x62646576);
 }
 
 static struct file_system_type bd_type = {
         .name           = "bdev",
-        .get_sb         = bd_get_sb,
+        .mount          = bd_mount,
         .kill_sb        = kill_anon_super,
 };
 
@@ -550,7 +573,7 @@ EXPORT_SYMBOL(bdget);
  */
 struct block_device *bdgrab(struct block_device *bdev)
 {
-        atomic_inc(&bdev->bd_inode->i_count);
+        ihold(bdev->bd_inode);
         return bdev;
 }
 
@@ -580,7 +603,7 @@ static struct block_device *bd_acquire(struct inode *inode)
         spin_lock(&bdev_lock);
         bdev = inode->i_bdev;
         if (bdev) {
-                atomic_inc(&bdev->bd_inode->i_count);
+                ihold(bdev->bd_inode);
                 spin_unlock(&bdev_lock);
                 return bdev;
         }
@@ -591,12 +614,12 @@ static struct block_device *bd_acquire(struct inode *inode)
                 spin_lock(&bdev_lock);
                 if (!inode->i_bdev) {
                         /*
-                         * We take an additional bd_inode->i_count for inode,
+                         * We take an additional reference to bd_inode,
                          * and it's released in clear_inode() of inode.
                          * So, we can access it via ->i_mapping always
                          * without igrab().
                          */
-                        atomic_inc(&bdev->bd_inode->i_count);
+                        ihold(bdev->bd_inode);
                         inode->i_bdev = bdev;
                         inode->i_mapping = bdev->bd_inode->i_mapping;
                         list_add(&inode->i_devices, &bdev->bd_inodes);
@@ -630,7 +653,7 @@ void bd_forget(struct inode *inode)
  * @whole: whole block device containing @bdev, may equal @bdev
  * @holder: holder trying to claim @bdev
  *
- * Test whther @bdev can be claimed by @holder.
+ * Test whether @bdev can be claimed by @holder.
  *
  * CONTEXT:
  * spin_lock(&bdev_lock).
@@ -648,7 +671,7 @@ static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
         else if (bdev->bd_contains == bdev)
                 return true;     /* is a whole device which isn't held */
 
-        else if (whole->bd_holder == bd_claim)
+        else if (whole->bd_holder == bd_may_claim)
                 return true;     /* is a partition of a device that is being partitioned */
         else if (whole->bd_holder != NULL)
                 return false;    /* is a partition of a held device */
@@ -739,7 +762,19 @@ static struct block_device *bd_start_claiming(struct block_device *bdev,
         if (!disk)
                 return ERR_PTR(-ENXIO);
 
-        whole = bdget_disk(disk, 0);
+        /*
+         * Normally, @bdev should equal what's returned from bdget_disk()
+         * if partno is 0; however, some drivers (floppy) use multiple
+         * bdev's for the same physical device and @bdev may be one of the
+         * aliases.  Keep @bdev if partno is 0.  This means claimer
+         * tracking is broken for those devices but it has always been that
+         * way.
+         */
+        if (partno)
+                whole = bdget_disk(disk, 0);
+        else
+                whole = bdgrab(bdev);
+
         module_put(disk->fops->owner);
         put_disk(disk);
         if (!whole)
@@ -760,452 +795,162 @@ static struct block_device *bd_start_claiming(struct block_device *bdev,
         }
 }
 
-/* releases bdev_lock */
-static void __bd_abort_claiming(struct block_device *whole, void *holder)
-{
-        BUG_ON(whole->bd_claiming != holder);
-        whole->bd_claiming = NULL;
-        wake_up_bit(&whole->bd_claiming, 0);
-
-        spin_unlock(&bdev_lock);
-        bdput(whole);
-}
-
-/**
- * bd_abort_claiming - abort claiming a block device
- * @whole: whole block device returned by bd_start_claiming()
- * @holder: holder trying to claim @bdev
- *
- * Abort a claiming block started by bd_start_claiming().  Note that
- * @whole is not the block device to be claimed but the whole device
- * returned by bd_start_claiming().
- *
- * CONTEXT:
- * Grabs and releases bdev_lock.
- */
-static void bd_abort_claiming(struct block_device *whole, void *holder)
-{
-        spin_lock(&bdev_lock);
-        __bd_abort_claiming(whole, holder);             /* releases bdev_lock */
-}
-
-/* increment holders when we have a legitimate claim. requires bdev_lock */
-static void __bd_claim(struct block_device *bdev, struct block_device *whole,
-                                        void *holder)
-{
-        /* note that for a whole device bd_holders
-         * will be incremented twice, and bd_holder will
-         * be set to bd_claim before being set to holder
-         */
-        whole->bd_holders++;
-        whole->bd_holder = bd_claim;
-        bdev->bd_holders++;
-        bdev->bd_holder = holder;
-}
+#ifdef CONFIG_SYSFS
+struct bd_holder_disk {
+        struct list_head        list;
+        struct gendisk          *disk;
+        int                     refcnt;
+};
 
-/**
- * bd_finish_claiming - finish claiming a block device
- * @bdev: block device of interest (passed to bd_start_claiming())
- * @whole: whole block device returned by bd_start_claiming()
- * @holder: holder trying to claim @bdev
- *
- * Finish a claiming block started by bd_start_claiming().
- *
- * CONTEXT:
- * Grabs and releases bdev_lock.
- */
-static void bd_finish_claiming(struct block_device *bdev,
-                                struct block_device *whole, void *holder)
+static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev,
+                                                  struct gendisk *disk)
 {
-        spin_lock(&bdev_lock);
-        BUG_ON(!bd_may_claim(bdev, whole, holder));
-        __bd_claim(bdev, whole, holder);
-        __bd_abort_claiming(whole, holder); /* not actually an abort */
-}
+        struct bd_holder_disk *holder;
 
-/**
- * bd_claim - claim a block device
- * @bdev: block device to claim
- * @holder: holder trying to claim @bdev
- *
- * Try to claim @bdev which must have been opened successfully.
- *
- * CONTEXT:
- * Might sleep.
- *
- * RETURNS:
- * 0 if successful, -EBUSY if @bdev is already claimed.
- */
-int bd_claim(struct block_device *bdev, void *holder)
-{
-        struct block_device *whole = bdev->bd_contains;
-        int res;
-
-        might_sleep();
-
-        spin_lock(&bdev_lock);
-        res = bd_prepare_to_claim(bdev, whole, holder);
-        if (res == 0)
-                __bd_claim(bdev, whole, holder);
-        spin_unlock(&bdev_lock);
-
-        return res;
-}
-EXPORT_SYMBOL(bd_claim);
-
-void bd_release(struct block_device *bdev)
-{
-        spin_lock(&bdev_lock);
-        if (!--bdev->bd_contains->bd_holders)
-                bdev->bd_contains->bd_holder = NULL;
-        if (!--bdev->bd_holders)
-                bdev->bd_holder = NULL;
-        spin_unlock(&bdev_lock);
+        list_for_each_entry(holder, &bdev->bd_holder_disks, list)
+                if (holder->disk == disk)
+                        return holder;
+        return NULL;
 }
 
-EXPORT_SYMBOL(bd_release);
-
-#ifdef CONFIG_SYSFS
-/*
- * Functions for bd_claim_by_kobject / bd_release_from_kobject
- *
- *     If a kobject is passed to bd_claim_by_kobject()
- *     and the kobject has a parent directory,
- *     following symlinks are created:
- *        o from the kobject to the claimed bdev
- *        o from "holders" directory of the bdev to the parent of the kobject
- *     bd_release_from_kobject() removes these symlinks.
- *
- *     Example:
- *        If /dev/dm-0 maps to /dev/sda, kobject corresponding to
- *        /sys/block/dm-0/slaves is passed to bd_claim_by_kobject(), then:
- *           /sys/block/dm-0/slaves/sda --> /sys/block/sda
- *           /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
- */
-
 static int add_symlink(struct kobject *from, struct kobject *to)
 {
-        if (!from || !to)
-                return 0;
         return sysfs_create_link(from, to, kobject_name(to));
 }
 
 static void del_symlink(struct kobject *from, struct kobject *to)
 {
-        if (!from || !to)
-                return;
         sysfs_remove_link(from, kobject_name(to));
 }
 
-/*
- * 'struct bd_holder' contains pointers to kobjects symlinked by
- * bd_claim_by_kobject.
- * It's connected to bd_holder_list which is protected by bdev->bd_sem.
- */
-struct bd_holder {
-        struct list_head list;  /* chain of holders of the bdev */
-        int count;              /* references from the holder */
-        struct kobject *sdir;   /* holder object, e.g. "/block/dm-0/slaves" */
-        struct kobject *hdev;   /* e.g. "/block/dm-0" */
-        struct kobject *hdir;   /* e.g. "/block/sda/holders" */
-        struct kobject *sdev;   /* e.g. "/block/sda" */
-};
-
-/*
- * Get references of related kobjects at once.
- * Returns 1 on success. 0 on failure.
- *
- * Should call bd_holder_release_dirs() after successful use.
- */
-static int bd_holder_grab_dirs(struct block_device *bdev,
-                        struct bd_holder *bo)
-{
-        if (!bdev || !bo)
-                return 0;
-
-        bo->sdir = kobject_get(bo->sdir);
-        if (!bo->sdir)
-                return 0;
-
-        bo->hdev = kobject_get(bo->sdir->parent);
-        if (!bo->hdev)
-                goto fail_put_sdir;
-
-        bo->sdev = kobject_get(&part_to_dev(bdev->bd_part)->kobj);
-        if (!bo->sdev)
-                goto fail_put_hdev;
-
-        bo->hdir = kobject_get(bdev->bd_part->holder_dir);
-        if (!bo->hdir)
-                goto fail_put_sdev;
-
-        return 1;
-
-fail_put_sdev:
-        kobject_put(bo->sdev);
-fail_put_hdev:
-        kobject_put(bo->hdev);
-fail_put_sdir:
-        kobject_put(bo->sdir);
-
-        return 0;
-}
-
-/* Put references of related kobjects at once. */
-static void bd_holder_release_dirs(struct bd_holder *bo)
-{
-        kobject_put(bo->hdir);
-        kobject_put(bo->sdev);
-        kobject_put(bo->hdev);
-        kobject_put(bo->sdir);
-}
-
-static struct bd_holder *alloc_bd_holder(struct kobject *kobj)
-{
-        struct bd_holder *bo;
-
-        bo = kzalloc(sizeof(*bo), GFP_KERNEL);
-        if (!bo)
-                return NULL;
-
-        bo->count = 1;
-        bo->sdir = kobj;
-
-        return bo;
-}
-
-static void free_bd_holder(struct bd_holder *bo)
-{
-        kfree(bo);
-}
-
 /**
- * find_bd_holder - find matching struct bd_holder from the block device
+ * bd_link_disk_holder - create symlinks between holding disk and slave bdev
+ * @bdev: the claimed slave bdev
+ * @disk: the holding disk
  *
- * @bdev:       struct block device to be searched
- * @bo:         target struct bd_holder
+ * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
  *
- * Returns matching entry with @bo in @bdev->bd_holder_list.
- * If found, increment the reference count and return the pointer.
- * If not found, returns NULL.
- */
-static struct bd_holder *find_bd_holder(struct block_device *bdev,
-                                        struct bd_holder *bo)
-{
-        struct bd_holder *tmp;
-
-        list_for_each_entry(tmp, &bdev->bd_holder_list, list)
-                if (tmp->sdir == bo->sdir) {
-                        tmp->count++;
-                        return tmp;
-                }
-
-        return NULL;
-}
-
-/**
- * add_bd_holder - create sysfs symlinks for bd_claim() relationship
+ * This functions creates the following sysfs symlinks.
+ *
+ * - from "slaves" directory of the holder @disk to the claimed @bdev
+ * - from "holders" directory of the @bdev to the holder @disk
  *
- * @bdev:       block device to be bd_claimed
- * @bo:         preallocated and initialized by alloc_bd_holder()
+ * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is
+ * passed to bd_link_disk_holder(), then:
  *
- * Add @bo to @bdev->bd_holder_list, create symlinks.
+ *   /sys/block/dm-0/slaves/sda --> /sys/block/sda
+ *   /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
  *
- * Returns 0 if symlinks are created.
- * Returns -ve if something fails.
+ * The caller must have claimed @bdev before calling this function and
+ * ensure that both @bdev and @disk are valid during the creation and
+ * lifetime of these symlinks.
+ *
+ * CONTEXT:
+ * Might sleep.
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
  */
-static int add_bd_holder(struct block_device *bdev, struct bd_holder *bo)
+int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
 {
-        int err;
+        struct bd_holder_disk *holder;
+        int ret = 0;
 
-        if (!bo)
-                return -EINVAL;
+        mutex_lock(&bdev->bd_mutex);
 
-        if (!bd_holder_grab_dirs(bdev, bo))
-                return -EBUSY;
+        WARN_ON_ONCE(!bdev->bd_holder);
 
-        err = add_symlink(bo->sdir, bo->sdev);
-        if (err)
-                return err;
+        /* FIXME: remove the following once add_disk() handles errors */
+        if (WARN_ON(!disk->slave_dir || !bdev->bd_part->holder_dir))
+                goto out_unlock;
 
-        err = add_symlink(bo->hdir, bo->hdev);
-        if (err) {
-                del_symlink(bo->sdir, bo->sdev);
-                return err;
+        holder = bd_find_holder_disk(bdev, disk);
+        if (holder) {
+                holder->refcnt++;
+                goto out_unlock;
         }
 
-        list_add_tail(&bo->list, &bdev->bd_holder_list);
-        return 0;
-}
-
-/**
- * del_bd_holder - delete sysfs symlinks for bd_claim() relationship
- *
- * @bdev:       block device to be bd_claimed
- * @kobj:       holder's kobject
- *
- * If there is matching entry with @kobj in @bdev->bd_holder_list
- * and no other bd_claim() from the same kobject,
- * remove the struct bd_holder from the list, delete symlinks for it.
- *
- * Returns a pointer to the struct bd_holder when it's removed from the list
- * and ready to be freed.
- * Returns NULL if matching claim isn't found or there is other bd_claim()
- * by the same kobject.
- */
-static struct bd_holder *del_bd_holder(struct block_device *bdev,
-                                        struct kobject *kobj)
-{
-        struct bd_holder *bo;
-
-        list_for_each_entry(bo, &bdev->bd_holder_list, list) {
-                if (bo->sdir == kobj) {
-                        bo->count--;
-                        BUG_ON(bo->count < 0);
-                        if (!bo->count) {
-                                list_del(&bo->list);
-                                del_symlink(bo->sdir, bo->sdev);
-                                del_symlink(bo->hdir, bo->hdev);
-                                bd_holder_release_dirs(bo);
-                                return bo;
-                        }
-                        break;
-                }
+        holder = kzalloc(sizeof(*holder), GFP_KERNEL);
+        if (!holder) {
+                ret = -ENOMEM;
+                goto out_unlock;
         }
 
-        return NULL;
-}
+        INIT_LIST_HEAD(&holder->list);
+        holder->disk = disk;
+        holder->refcnt = 1;
 
-/**
- * bd_claim_by_kobject - bd_claim() with additional kobject signature
- *
- * @bdev:       block device to be claimed
- * @holder:     holder's signature
- * @kobj:       holder's kobject
- *
- * Do bd_claim() and if it succeeds, create sysfs symlinks between
- * the bdev and the holder's kobject.
- * Use bd_release_from_kobject() when relesing the claimed bdev.
- *
- * Returns 0 on success. (same as bd_claim())
- * Returns errno on failure.
- */
-static int bd_claim_by_kobject(struct block_device *bdev, void *holder,
-                                struct kobject *kobj)
-{
-        int err;
-        struct bd_holder *bo, *found;
+        ret = add_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
+        if (ret)
+                goto out_free;
 
-        if (!kobj)
-                return -EINVAL;
-
-        bo = alloc_bd_holder(kobj);
-        if (!bo)
-                return -ENOMEM;
-
-        mutex_lock(&bdev->bd_mutex);
-
-        err = bd_claim(bdev, holder);
-        if (err)
-                goto fail;
+        ret = add_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj);
+        if (ret)
+                goto out_del;
+        /*
+         * bdev could be deleted beneath us which would implicitly destroy
+         * the holder directory.  Hold on to it.
+         */
+        kobject_get(bdev->bd_part->holder_dir);
 
-        found = find_bd_holder(bdev, bo);
-        if (found)
-                goto fail;
+        list_add(&holder->list, &bdev->bd_holder_disks);
+        goto out_unlock;
 
-        err = add_bd_holder(bdev, bo);
-        if (err)
-                bd_release(bdev);
-        else
-                bo = NULL;
-fail:
+out_del:
+        del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
+out_free:
+        kfree(holder);
+out_unlock:
         mutex_unlock(&bdev->bd_mutex);
-        free_bd_holder(bo);
-        return err;
+        return ret;
 }
+EXPORT_SYMBOL_GPL(bd_link_disk_holder);
 
 /**
- * bd_release_from_kobject - bd_release() with additional kobject signature
+ * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder()
+ * @bdev: the calimed slave bdev
+ * @disk: the holding disk
  *
- * @bdev:       block device to be released
- * @kobj:       holder's kobject
+ * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
  *
- * Do bd_release() and remove sysfs symlinks created by bd_claim_by_kobject().
+ * CONTEXT:
+ * Might sleep.
  */
-static void bd_release_from_kobject(struct block_device *bdev,
-                                        struct kobject *kobj)
+void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
 {
-        if (!kobj)
-                return;
+        struct bd_holder_disk *holder;
 
         mutex_lock(&bdev->bd_mutex);
-        bd_release(bdev);
-        free_bd_holder(del_bd_holder(bdev, kobj));
-        mutex_unlock(&bdev->bd_mutex);
-}
 
-/**
- * bd_claim_by_disk - wrapper function for bd_claim_by_kobject()
- *
- * @bdev:       block device to be claimed
- * @holder:     holder's signature
- * @disk:       holder's gendisk
- *
- * Call bd_claim_by_kobject() with getting @disk->slave_dir.
- */
-int bd_claim_by_disk(struct block_device *bdev, void *holder,
-                        struct gendisk *disk)
-{
-        return bd_claim_by_kobject(bdev, holder, kobject_get(disk->slave_dir));
-}
-EXPORT_SYMBOL_GPL(bd_claim_by_disk);
+        holder = bd_find_holder_disk(bdev, disk);
 
-/**
- * bd_release_from_disk - wrapper function for bd_release_from_kobject()
- *
- * @bdev:       block device to be claimed
- * @disk:       holder's gendisk
- *
- * Call bd_release_from_kobject() and put @disk->slave_dir.
- */
-void bd_release_from_disk(struct block_device *bdev, struct gendisk *disk)
-{
-        bd_release_from_kobject(bdev, disk->slave_dir);
-        kobject_put(disk->slave_dir);
-}
-EXPORT_SYMBOL_GPL(bd_release_from_disk);
-#endif
+        if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) {
+                del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
+                del_symlink(bdev->bd_part->holder_dir,
+                            &disk_to_dev(disk)->kobj);
+                kobject_put(bdev->bd_part->holder_dir);
+                list_del_init(&holder->list);
+                kfree(holder);
+        }
 
-/*
- * Tries to open block device by device number.  Use it ONLY if you
- * really do not have anything better - i.e. when you are behind a
- * truly sucky interface and all you are given is a device number.  _Never_
- * to be used for internal purposes.  If you ever need it - reconsider
- * your API.
- */
-struct block_device *open_by_devnum(dev_t dev, fmode_t mode)
-{
-        struct block_device *bdev = bdget(dev);
-        int err = -ENOMEM;
-        if (bdev)
-                err = blkdev_get(bdev, mode);
-        return err ? ERR_PTR(err) : bdev;
+        mutex_unlock(&bdev->bd_mutex);
 }
-
-EXPORT_SYMBOL(open_by_devnum);
+EXPORT_SYMBOL_GPL(bd_unlink_disk_holder);
+#endif
 
 /**
  * flush_disk - invalidates all buffer-cache entries on a disk
  *
  * @bdev:      struct block device to be flushed
+ * @kill_dirty: flag to guide handling of dirty inodes
  *
  * Invalidates all buffer-cache entries on a disk. It should be called
  * when a disk has been changed -- either by a media change or online
  * resize.
  */
-static void flush_disk(struct block_device *bdev)
+static void flush_disk(struct block_device *bdev, bool kill_dirty)
 {
-        if (__invalidate_device(bdev)) {
+        if (__invalidate_device(bdev, kill_dirty)) {
                 char name[BDEVNAME_SIZE] = "";
 
                 if (bdev->bd_disk)
@@ -1242,7 +987,7 @@ void check_disk_size_change(struct gendisk *disk, struct block_device *bdev)
                        "%s: detected capacity change from %lld to %lld\n",
                        name, bdev_size, disk_size);
                 i_size_write(bdev->bd_inode, disk_size);
-                flush_disk(bdev);
+                flush_disk(bdev, false);
         }
 }
 EXPORT_SYMBOL(check_disk_size_change);
@@ -1288,13 +1033,14 @@ int check_disk_change(struct block_device *bdev)
 {
         struct gendisk *disk = bdev->bd_disk;
         const struct block_device_operations *bdops = disk->fops;
+        unsigned int events;
 
-        if (!bdops->media_changed)
-                return 0;
-        if (!bdops->media_changed(bdev->bd_disk))
+        events = disk_clear_events(disk, DISK_EVENT_MEDIA_CHANGE |
+                                   DISK_EVENT_EJECT_REQUEST);
+        if (!(events & DISK_EVENT_MEDIA_CHANGE))
                 return 0;
 
-        flush_disk(bdev);
+        flush_disk(bdev, true);
         if (bdops->revalidate_disk)
                 bdops->revalidate_disk(bdev->bd_disk);
         return 1;
@@ -1355,6 +1101,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
         if (!disk)
                 goto out;
 
+        disk_block_events(disk);
         mutex_lock_nested(&bdev->bd_mutex, for_part);
         if (!bdev->bd_openers) {
                 bdev->bd_disk = disk;
@@ -1367,6 +1114,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
                         if (!bdev->bd_part)
                                 goto out_clear;
 
+                        ret = 0;
                         if (disk->fops->open) {
                                 ret = disk->fops->open(bdev, mode);
                                 if (ret == -ERESTARTSYS) {
@@ -1376,24 +1124,33 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
                                          */
                                         disk_put_part(bdev->bd_part);
                                         bdev->bd_part = NULL;
-                                        module_put(disk->fops->owner);
-                                        put_disk(disk);
                                         bdev->bd_disk = NULL;
                                         mutex_unlock(&bdev->bd_mutex);
+                                        disk_unblock_events(disk);
+                                        module_put(disk->fops->owner);
+                                        put_disk(disk);
                                         goto restart;
                                 }
-                                if (ret)
-                                        goto out_clear;
                         }
-                        if (!bdev->bd_openers) {
+
+                        if (!ret && !bdev->bd_openers) {
                                 bd_set_size(bdev,(loff_t)get_capacity(disk)<<9);
                                 bdi = blk_get_backing_dev_info(bdev);
                                 if (bdi == NULL)
                                         bdi = &default_backing_dev_info;
-                                bdev->bd_inode->i_data.backing_dev_info = bdi;
+                                bdev_inode_switch_bdi(bdev->bd_inode, bdi);
                         }
-                        if (bdev->bd_invalidated)
+
+                        /*
+                         * If the device is invalidated, rescan partition
+                         * if open succeeded or failed with -ENOMEDIUM.
+                         * The latter is necessary to prevent ghost
+                         * partitions on a removed medium.
+                         */
+                        if (bdev->bd_invalidated && (!ret || ret == -ENOMEDIUM))
                                 rescan_partitions(disk, bdev);
+                        if (ret)
+                                goto out_clear;
                 } else {
                         struct block_device *whole;
                         whole = bdget_disk(disk, 0);
@@ -1405,8 +1162,8 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
                         if (ret)
                                 goto out_clear;
                         bdev->bd_contains = whole;
-                        bdev->bd_inode->i_data.backing_dev_info =
-                           whole->bd_inode->i_data.backing_dev_info;
+                        bdev_inode_switch_bdi(bdev->bd_inode,
+                                whole->bd_inode->i_data.backing_dev_info);
                         bdev->bd_part = disk_get_part(disk, partno);
                         if (!(disk->flags & GENHD_FL_UP) ||
                             !bdev->bd_part || !bdev->bd_part->nr_sects) {
@@ -1416,55 +1173,213 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
                         bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9);
                 }
         } else {
-                module_put(disk->fops->owner);
-                put_disk(disk);
-                disk = NULL;
                 if (bdev->bd_contains == bdev) {
-                        if (bdev->bd_disk->fops->open) {
+                        ret = 0;
+                        if (bdev->bd_disk->fops->open)
                                 ret = bdev->bd_disk->fops->open(bdev, mode);
-                                if (ret)
-                                        goto out_unlock_bdev;
-                        }
-                        if (bdev->bd_invalidated)
+                        /* the same as first opener case, read comment there */
+                        if (bdev->bd_invalidated && (!ret || ret == -ENOMEDIUM))
                                 rescan_partitions(bdev->bd_disk, bdev);
+                        if (ret)
+                                goto out_unlock_bdev;
                 }
+                /* only one opener holds refs to the module and disk */
+                module_put(disk->fops->owner);
+                put_disk(disk);
         }
         bdev->bd_openers++;
         if (for_part)
                 bdev->bd_part_count++;
         mutex_unlock(&bdev->bd_mutex);
+        disk_unblock_events(disk);
         return 0;
 
  out_clear:
         disk_put_part(bdev->bd_part);
         bdev->bd_disk = NULL;
         bdev->bd_part = NULL;
-        bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
+        bdev_inode_switch_bdi(bdev->bd_inode, &default_backing_dev_info);
         if (bdev != bdev->bd_contains)
                 __blkdev_put(bdev->bd_contains, mode, 1);
         bdev->bd_contains = NULL;
  out_unlock_bdev:
         mutex_unlock(&bdev->bd_mutex);
- out:
-        if (disk)
-                module_put(disk->fops->owner);
+        disk_unblock_events(disk);
+        module_put(disk->fops->owner);
         put_disk(disk);
+ out:
         bdput(bdev);
 
         return ret;
 }
 
-int blkdev_get(struct block_device *bdev, fmode_t mode)
+/**
+ * blkdev_get - open a block device
+ * @bdev: block_device to open
+ * @mode: FMODE_* mask
+ * @holder: exclusive holder identifier
+ *
+ * Open @bdev with @mode.  If @mode includes %FMODE_EXCL, @bdev is
+ * open with exclusive access.  Specifying %FMODE_EXCL with %NULL
+ * @holder is invalid.  Exclusive opens may nest for the same @holder.
+ *
+ * On success, the reference count of @bdev is unchanged.  On failure,
+ * @bdev is put.
+ *
+ * CONTEXT:
+ * Might sleep.
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
 {
-        return __blkdev_get(bdev, mode, 0);
+        struct block_device *whole = NULL;
+        int res;
+
+        WARN_ON_ONCE((mode & FMODE_EXCL) && !holder);
+
+        if ((mode & FMODE_EXCL) && holder) {
+                whole = bd_start_claiming(bdev, holder);
+                if (IS_ERR(whole)) {
+                        bdput(bdev);
+                        return PTR_ERR(whole);
+                }
+        }
+
+        res = __blkdev_get(bdev, mode, 0);
+
+        if (whole) {
+                struct gendisk *disk = whole->bd_disk;
+
+                /* finish claiming */
+                mutex_lock(&bdev->bd_mutex);
+                spin_lock(&bdev_lock);
+
+                if (!res) {
+                        BUG_ON(!bd_may_claim(bdev, whole, holder));
+                        /*
+                         * Note that for a whole device bd_holders
+                         * will be incremented twice, and bd_holder
+                         * will be set to bd_may_claim before being
+                         * set to holder
+                         */
+                        whole->bd_holders++;
+                        whole->bd_holder = bd_may_claim;
+                        bdev->bd_holders++;
+                        bdev->bd_holder = holder;
+                }
+
+                /* tell others that we're done */
+                BUG_ON(whole->bd_claiming != holder);
+                whole->bd_claiming = NULL;
+                wake_up_bit(&whole->bd_claiming, 0);
+
+                spin_unlock(&bdev_lock);
+
+                /*
+                 * Block event polling for write claims if requested.  Any
+                 * write holder makes the write_holder state stick until
+                 * all are released.  This is good enough and tracking
+                 * individual writeable reference is too fragile given the
+                 * way @mode is used in blkdev_get/put().
+                 */
+                if (!res && (mode & FMODE_WRITE) && !bdev->bd_write_holder &&
+                    (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) {
+                        bdev->bd_write_holder = true;
+                        disk_block_events(disk);
+                }
+
+                mutex_unlock(&bdev->bd_mutex);
+                bdput(whole);
+        }
+
+        return res;
 }
 EXPORT_SYMBOL(blkdev_get);
 
+/**
+ * blkdev_get_by_path - open a block device by name
+ * @path: path to the block device to open
+ * @mode: FMODE_* mask
+ * @holder: exclusive holder identifier
+ *
+ * Open the blockdevice described by the device file at @path.  @mode
+ * and @holder are identical to blkdev_get().
+ *
+ * On success, the returned block_device has reference count of one.
+ *
+ * CONTEXT:
+ * Might sleep.
+ *
+ * RETURNS:
+ * Pointer to block_device on success, ERR_PTR(-errno) on failure.
+ */
+struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
+                                        void *holder)
+{
+        struct block_device *bdev;
+        int err;
+
+        bdev = lookup_bdev(path);
+        if (IS_ERR(bdev))
+                return bdev;
+
+        err = blkdev_get(bdev, mode, holder);
+        if (err)
+                return ERR_PTR(err);
+
+        if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) {
+                blkdev_put(bdev, mode);
+                return ERR_PTR(-EACCES);
+        }
+
+        return bdev;
+}
+EXPORT_SYMBOL(blkdev_get_by_path);
+
+/**
+ * blkdev_get_by_dev - open a block device by device number
+ * @dev: device number of block device to open
+ * @mode: FMODE_* mask
+ * @holder: exclusive holder identifier
+ *
+ * Open the blockdevice described by device number @dev.  @mode and
+ * @holder are identical to blkdev_get().
+ *
+ * Use it ONLY if you really do not have anything better - i.e. when
+ * you are behind a truly sucky interface and all you are given is a
+ * device number.  _Never_ to be used for internal purposes.  If you
+ * ever need it - reconsider your API.
+ *
+ * On success, the returned block_device has reference count of one.
+ *
+ * CONTEXT:
+ * Might sleep.
+ *
+ * RETURNS:
+ * Pointer to block_device on success, ERR_PTR(-errno) on failure.
+ */
+struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
+{
+        struct block_device *bdev;
+        int err;
+
+        bdev = bdget(dev);
+        if (!bdev)
+                return ERR_PTR(-ENOMEM);
+
+        err = blkdev_get(bdev, mode, holder);
+        if (err)
+                return ERR_PTR(err);
+
+        return bdev;
+}
+EXPORT_SYMBOL(blkdev_get_by_dev);
+
 static int blkdev_open(struct inode * inode, struct file * filp)
 {
-        struct block_device *whole = NULL;
         struct block_device *bdev;
-        int res;
 
         /*
          * Preserve backwards compatibility and allow large file access
@@ -1485,26 +1400,9 @@ static int blkdev_open(struct inode * inode, struct file * filp)
         if (bdev == NULL)
                 return -ENOMEM;
 
-        if (filp->f_mode & FMODE_EXCL) {
-                whole = bd_start_claiming(bdev, filp);
-                if (IS_ERR(whole)) {
-                        bdput(bdev);
-                        return PTR_ERR(whole);
-                }
-        }
-
         filp->f_mapping = bdev->bd_inode->i_mapping;
 
-        res = blkdev_get(bdev, filp->f_mode);
-
-        if (whole) {
-                if (res == 0)
-                        bd_finish_claiming(bdev, whole, filp);
-                else
-                        bd_abort_claiming(whole, filp);
-        }
-
-        return res;
+        return blkdev_get(bdev, filp->f_mode, filp);
 }
 
 static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
@@ -1518,6 +1416,7 @@ static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
                 bdev->bd_part_count--;
 
         if (!--bdev->bd_openers) {
+                WARN_ON_ONCE(bdev->bd_holders);
                 sync_blockdev(bdev);
                 kill_bdev(bdev);
         }
@@ -1533,7 +1432,8 @@ static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
                 disk_put_part(bdev->bd_part);
                 bdev->bd_part = NULL;
                 bdev->bd_disk = NULL;
-                bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
+                bdev_inode_switch_bdi(bdev->bd_inode,
+                                        &default_backing_dev_info);
                 if (bdev != bdev->bd_contains)
                         victim = bdev->bd_contains;
                 bdev->bd_contains = NULL;
@@ -1547,6 +1447,43 @@ static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
 
 int blkdev_put(struct block_device *bdev, fmode_t mode)
 {
+        if (mode & FMODE_EXCL) {
+                bool bdev_free;
+
+                /*
+                 * Release a claim on the device.  The holder fields
+                 * are protected with bdev_lock.  bd_mutex is to
+                 * synchronize disk_holder unlinking.
+                 */
+                mutex_lock(&bdev->bd_mutex);
+                spin_lock(&bdev_lock);
+
+                WARN_ON_ONCE(--bdev->bd_holders < 0);
+                WARN_ON_ONCE(--bdev->bd_contains->bd_holders < 0);
+
+                /* bd_contains might point to self, check in a separate step */
+                if ((bdev_free = !bdev->bd_holders))
+                        bdev->bd_holder = NULL;
+                if (!bdev->bd_contains->bd_holders)
+                        bdev->bd_contains->bd_holder = NULL;
+
+                spin_unlock(&bdev_lock);
+
+                /*
+                 * If this was the last claim, remove holder link and
+                 * unblock evpoll if it was a write holder.
+                 */
+                if (bdev_free) {
+                        if (bdev->bd_write_holder) {
+                                disk_unblock_events(bdev->bd_disk);
+                                disk_check_events(bdev->bd_disk);
+                                bdev->bd_write_holder = false;
+                        }
+                }
+
+                mutex_unlock(&bdev->bd_mutex);
+        }
+
         return __blkdev_put(bdev, mode, 0);
 }
 EXPORT_SYMBOL(blkdev_put);
@@ -1554,8 +1491,7 @@ EXPORT_SYMBOL(blkdev_put);
 static int blkdev_close(struct inode * inode, struct file * filp)
 {
         struct block_device *bdev = I_BDEV(filp->f_mapping->host);
-        if (bdev->bd_holder == filp)
-                bd_release(bdev);
+
         return blkdev_put(bdev, filp->f_mode);
 }
 
@@ -1620,7 +1556,6 @@ static int blkdev_releasepage(struct page *page, gfp_t wait)
 static const struct address_space_operations def_blk_aops = {
         .readpage       = blkdev_readpage,
         .writepage      = blkdev_writepage,
-        .sync_page      = block_sync_page,
         .write_begin    = blkdev_write_begin,
         .write_end      = blkdev_write_end,
         .writepages     = generic_writepages,
@@ -1700,68 +1635,7 @@ fail:
 }
 EXPORT_SYMBOL(lookup_bdev);
 
-/**
- * open_bdev_exclusive  -  open a block device by name and set it up for use
- *
- * @path:       special file representing the block device
- * @mode:       FMODE_... combination to pass be used
- * @holder:     owner for exclusion
- *
- * Open the blockdevice described by the special file at @path, claim it
- * for the @holder.
- */
-struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *holder)
-{
-        struct block_device *bdev, *whole;
-        int error;
-
-        bdev = lookup_bdev(path);
-        if (IS_ERR(bdev))
-                return bdev;
-
-        whole = bd_start_claiming(bdev, holder);
-        if (IS_ERR(whole)) {
-                bdput(bdev);
-                return whole;
-        }
-
-        error = blkdev_get(bdev, mode);
-        if (error)
-                goto out_abort_claiming;
-
-        error = -EACCES;
-        if ((mode & FMODE_WRITE) && bdev_read_only(bdev))
-                goto out_blkdev_put;
-
-        bd_finish_claiming(bdev, whole, holder);
-        return bdev;
-
-out_blkdev_put:
-        blkdev_put(bdev, mode);
-out_abort_claiming:
-        bd_abort_claiming(whole, holder);
-        return ERR_PTR(error);
-}
-
-EXPORT_SYMBOL(open_bdev_exclusive);
-
-/**
- * close_bdev_exclusive  -  close a blockdevice opened by open_bdev_exclusive()
- *
- * @bdev:       blockdevice to close
- * @mode:       mode, must match that used to open.
- *
- * This is the counterpart to open_bdev_exclusive().
- */
-void close_bdev_exclusive(struct block_device *bdev, fmode_t mode)
-{
-        bd_release(bdev);
-        blkdev_put(bdev, mode);
-}
-
-EXPORT_SYMBOL(close_bdev_exclusive);
-
-int __invalidate_device(struct block_device *bdev)
+int __invalidate_device(struct block_device *bdev, bool kill_dirty)
 {
         struct super_block *sb = get_super(bdev);
         int res = 0;
@@ -1774,7 +1648,7 @@ int __invalidate_device(struct block_device *bdev)
                  * hold).
                  */
                 shrink_dcache_sb(sb);
-                res = invalidate_inodes(sb);
+                res = invalidate_inodes(sb, kill_dirty);
                 drop_super(sb);
         }
         invalidate_bdev(bdev);