Merge branch 'linux-next' of git://git.infradead.org/ubi-2.6

* 'linux-next' of git://git.infradead.org/ubi-2.6: (21 commits)
  UBI: add reboot notifier
  UBI: handle more error codes
  UBI: fix multiple spelling typos
  UBI: fix kmem_cache_free on error patch
  UBI: print amount of reserved PEBs
  UBI: improve messages in the WL worker
  UBI: make gluebi a separate module
  UBI: remove built-in gluebi
  UBI: add notification API
  UBI: do not switch to R/O mode on read errors
  UBI: fix and clean-up error paths in WL worker
  UBI: introduce new constants
  UBI: fix race condition
  UBI: minor serialization fix
  UBI: do not panic if volume check fails
  UBI: add dump_stack in checking code
  UBI: fix races in I/O debugging checks
  UBI: small debugging code optimization
  UBI: improve debugging messages
  UBI: re-name volumes_mutex to device_mutex
  ...

13 files changed, 922 insertions, 335 deletions

diff --git a/drivers/mtd/ubi/Kconfig b/drivers/mtd/ubi/Kconfig
index 3f063108e95..b1cd7a1a219 100644
--- a/drivers/mtd/ubi/Kconfig
+++ b/drivers/mtd/ubi/Kconfig
@@ -49,15 +49,16 @@ config MTD_UBI_BEB_RESERVE
 	  reserved. Leave the default value if unsure.
 
 config MTD_UBI_GLUEBI
-	bool "Emulate MTD devices"
+	tristate "MTD devices emulation driver (gluebi)"
 	default n
 	depends on MTD_UBI
 	help
-	   This option enables MTD devices emulation on top of UBI volumes: for
-	   each UBI volumes an MTD device is created, and all I/O to this MTD
-	   device is redirected to the UBI volume. This is handy to make
-	   MTD-oriented software (like JFFS2) work on top of UBI. Do not enable
-	   this if no legacy software will be used.
+	   This option enables gluebi - an additional driver which emulates MTD
+	   devices on top of UBI volumes: for each UBI volumes an MTD device is
+	   created, and all I/O to this MTD device is redirected to the UBI
+	   volume. This is handy to make MTD-oriented software (like JFFS2)
+	   work on top of UBI. Do not enable this unless you use legacy
+	   software.
 
 source "drivers/mtd/ubi/Kconfig.debug"
 endmenu
diff --git a/drivers/mtd/ubi/Makefile b/drivers/mtd/ubi/Makefile
index dd834e04151..c9302a5452b 100644
--- a/drivers/mtd/ubi/Makefile
+++ b/drivers/mtd/ubi/Makefile
@@ -4,4 +4,4 @@ ubi-y += vtbl.o vmt.o upd.o build.o cdev.o kapi.o eba.o io.o wl.o scan.o
 ubi-y += misc.o
 
 ubi-$(CONFIG_MTD_UBI_DEBUG) += debug.o
-ubi-$(CONFIG_MTD_UBI_GLUEBI) += gluebi.o
+obj-$(CONFIG_MTD_UBI_GLUEBI) += gluebi.o
diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index 4048db83aef..286ed594e5a 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -41,6 +41,7 @@
 #include <linux/miscdevice.h>
 #include <linux/log2.h>
 #include <linux/kthread.h>
+#include <linux/reboot.h>
 #include "ubi.h"
 
 /* Maximum length of the 'mtd=' parameter */
@@ -122,6 +123,94 @@ static struct device_attribute dev_mtd_num =
 	__ATTR(mtd_num, S_IRUGO, dev_attribute_show, NULL);
 
 /**
+ * ubi_volume_notify - send a volume change notification.
+ * @ubi: UBI device description object
+ * @vol: volume description object of the changed volume
+ * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
+ *
+ * This is a helper function which notifies all subscribers about a volume
+ * change event (creation, removal, re-sizing, re-naming, updating). Returns
+ * zero in case of success and a negative error code in case of failure.
+ */
+int ubi_volume_notify(struct ubi_device *ubi, struct ubi_volume *vol, int ntype)
+{
+	struct ubi_notification nt;
+
+	ubi_do_get_device_info(ubi, &nt.di);
+	ubi_do_get_volume_info(ubi, vol, &nt.vi);
+	return blocking_notifier_call_chain(&ubi_notifiers, ntype, &nt);
+}
+
+/**
+ * ubi_notify_all - send a notification to all volumes.
+ * @ubi: UBI device description object
+ * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
+ * @nb: the notifier to call
+ *
+ * This function walks all volumes of UBI device @ubi and sends the @ntype
+ * notification for each volume. If @nb is %NULL, then all registered notifiers
+ * are called, otherwise only the @nb notifier is called. Returns the number of
+ * sent notifications.
+ */
+int ubi_notify_all(struct ubi_device *ubi, int ntype, struct notifier_block *nb)
+{
+	struct ubi_notification nt;
+	int i, count = 0;
+
+	ubi_do_get_device_info(ubi, &nt.di);
+
+	mutex_lock(&ubi->device_mutex);
+	for (i = 0; i < ubi->vtbl_slots; i++) {
+		/*
+		 * Since the @ubi->device is locked, and we are not going to
+		 * change @ubi->volumes, we do not have to lock
+		 * @ubi->volumes_lock.
+		 */
+		if (!ubi->volumes[i])
+			continue;
+
+		ubi_do_get_volume_info(ubi, ubi->volumes[i], &nt.vi);
+		if (nb)
+			nb->notifier_call(nb, ntype, &nt);
+		else
+			blocking_notifier_call_chain(&ubi_notifiers, ntype,
+						     &nt);
+		count += 1;
+	}
+	mutex_unlock(&ubi->device_mutex);
+
+	return count;
+}
+
+/**
+ * ubi_enumerate_volumes - send "add" notification for all existing volumes.
+ * @nb: the notifier to call
+ *
+ * This function walks all UBI devices and volumes and sends the
+ * %UBI_VOLUME_ADDED notification for each volume. If @nb is %NULL, then all
+ * registered notifiers are called, otherwise only the @nb notifier is called.
+ * Returns the number of sent notifications.
+ */
+int ubi_enumerate_volumes(struct notifier_block *nb)
+{
+	int i, count = 0;
+
+	/*
+	 * Since the @ubi_devices_mutex is locked, and we are not going to
+	 * change @ubi_devices, we do not have to lock @ubi_devices_lock.
+	 */
+	for (i = 0; i < UBI_MAX_DEVICES; i++) {
+		struct ubi_device *ubi = ubi_devices[i];
+
+		if (!ubi)
+			continue;
+		count += ubi_notify_all(ubi, UBI_VOLUME_ADDED, nb);
+	}
+
+	return count;
+}
+
+/**
  * ubi_get_device - get UBI device.
  * @ubi_num: UBI device number
  *
@@ -380,7 +469,7 @@ static void free_user_volumes(struct ubi_device *ubi)
  * @ubi: UBI device description object
  *
  * This function returns zero in case of success and a negative error code in
- * case of failure. Note, this function destroys all volumes if it failes.
+ * case of failure. Note, this function destroys all volumes if it fails.
  */
 static int uif_init(struct ubi_device *ubi)
 {
@@ -633,6 +722,15 @@ static int io_init(struct ubi_device *ubi)
 	}
 
 	/*
+	 * Set maximum amount of physical erroneous eraseblocks to be 10%.
+	 * Erroneous PEB are those which have read errors.
+	 */
+	ubi->max_erroneous = ubi->peb_count / 10;
+	if (ubi->max_erroneous < 16)
+		ubi->max_erroneous = 16;
+	dbg_msg("max_erroneous    %d", ubi->max_erroneous);
+
+	/*
 	 * It may happen that EC and VID headers are situated in one minimal
 	 * I/O unit. In this case we can only accept this UBI image in
 	 * read-only mode.
@@ -726,6 +824,34 @@ static int autoresize(struct ubi_device *ubi, int vol_id)
 }
 
 /**
+ * ubi_reboot_notifier - halt UBI transactions immediately prior to a reboot.
+ * @n: reboot notifier object
+ * @state: SYS_RESTART, SYS_HALT, or SYS_POWER_OFF
+ * @cmd: pointer to command string for RESTART2
+ *
+ * This function stops the UBI background thread so that the flash device
+ * remains quiescent when Linux restarts the system. Any queued work will be
+ * discarded, but this function will block until do_work() finishes if an
+ * operation is already in progress.
+ *
+ * This function solves a real-life problem observed on NOR flashes when an
+ * PEB erase operation starts, then the system is rebooted before the erase is
+ * finishes, and the boot loader gets confused and dies. So we prefer to finish
+ * the ongoing operation before rebooting.
+ */
+static int ubi_reboot_notifier(struct notifier_block *n, unsigned long state,
+			       void *cmd)
+{
+	struct ubi_device *ubi;
+
+	ubi = container_of(n, struct ubi_device, reboot_notifier);
+	if (ubi->bgt_thread)
+		kthread_stop(ubi->bgt_thread);
+	ubi_sync(ubi->ubi_num);
+	return NOTIFY_DONE;
+}
+
+/**
  * ubi_attach_mtd_dev - attach an MTD device.
  * @mtd: MTD device description object
  * @ubi_num: number to assign to the new UBI device
@@ -806,8 +932,7 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num, int vid_hdr_offset)
 
 	mutex_init(&ubi->buf_mutex);
 	mutex_init(&ubi->ckvol_mutex);
-	mutex_init(&ubi->mult_mutex);
-	mutex_init(&ubi->volumes_mutex);
+	mutex_init(&ubi->device_mutex);
 	spin_lock_init(&ubi->volumes_lock);
 
 	ubi_msg("attaching mtd%d to ubi%d", mtd->index, ubi_num);
@@ -825,7 +950,7 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num, int vid_hdr_offset)
 	if (!ubi->peb_buf2)
 		goto out_free;
 
-#ifdef CONFIG_MTD_UBI_DEBUG
+#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
 	mutex_init(&ubi->dbg_buf_mutex);
 	ubi->dbg_peb_buf = vmalloc(ubi->peb_size);
 	if (!ubi->dbg_peb_buf)
@@ -872,11 +997,23 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num, int vid_hdr_offset)
 		ubi->beb_rsvd_pebs);
 	ubi_msg("max/mean erase counter: %d/%d", ubi->max_ec, ubi->mean_ec);
 
+	/*
+	 * The below lock makes sure we do not race with 'ubi_thread()' which
+	 * checks @ubi->thread_enabled. Otherwise we may fail to wake it up.
+	 */
+	spin_lock(&ubi->wl_lock);
 	if (!DBG_DISABLE_BGT)
 		ubi->thread_enabled = 1;
 	wake_up_process(ubi->bgt_thread);
+	spin_unlock(&ubi->wl_lock);
+
+	/* Flash device priority is 0 - UBI needs to shut down first */
+	ubi->reboot_notifier.priority = 1;
+	ubi->reboot_notifier.notifier_call = ubi_reboot_notifier;
+	register_reboot_notifier(&ubi->reboot_notifier);
 
 	ubi_devices[ubi_num] = ubi;
+	ubi_notify_all(ubi, UBI_VOLUME_ADDED, NULL);
 	return ubi_num;
 
 out_uif:
@@ -892,7 +1029,7 @@ out_detach:
 out_free:
 	vfree(ubi->peb_buf1);
 	vfree(ubi->peb_buf2);
-#ifdef CONFIG_MTD_UBI_DEBUG
+#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
 	vfree(ubi->dbg_peb_buf);
 #endif
 	kfree(ubi);
@@ -919,13 +1056,13 @@ int ubi_detach_mtd_dev(int ubi_num, int anyway)
 	if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
 		return -EINVAL;
 
-	spin_lock(&ubi_devices_lock);
-	ubi = ubi_devices[ubi_num];
-	if (!ubi) {
-		spin_unlock(&ubi_devices_lock);
+	ubi = ubi_get_device(ubi_num);
+	if (!ubi)
 		return -EINVAL;
-	}
 
+	spin_lock(&ubi_devices_lock);
+	put_device(&ubi->dev);
+	ubi->ref_count -= 1;
 	if (ubi->ref_count) {
 		if (!anyway) {
 			spin_unlock(&ubi_devices_lock);
@@ -939,12 +1076,14 @@ int ubi_detach_mtd_dev(int ubi_num, int anyway)
 	spin_unlock(&ubi_devices_lock);
 
 	ubi_assert(ubi_num == ubi->ubi_num);
+	ubi_notify_all(ubi, UBI_VOLUME_REMOVED, NULL);
 	dbg_msg("detaching mtd%d from ubi%d", ubi->mtd->index, ubi_num);
 
 	/*
 	 * Before freeing anything, we have to stop the background thread to
 	 * prevent it from doing anything on this device while we are freeing.
 	 */
+	unregister_reboot_notifier(&ubi->reboot_notifier);
 	if (ubi->bgt_thread)
 		kthread_stop(ubi->bgt_thread);
 
@@ -961,7 +1100,7 @@ int ubi_detach_mtd_dev(int ubi_num, int anyway)
 	put_mtd_device(ubi->mtd);
 	vfree(ubi->peb_buf1);
 	vfree(ubi->peb_buf2);
-#ifdef CONFIG_MTD_UBI_DEBUG
+#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
 	vfree(ubi->dbg_peb_buf);
 #endif
 	ubi_msg("mtd%d is detached from ubi%d", ubi->mtd->index, ubi->ubi_num);
diff --git a/drivers/mtd/ubi/cdev.c b/drivers/mtd/ubi/cdev.c
index f8e0f68f218..f237ddbb271 100644
--- a/drivers/mtd/ubi/cdev.c
+++ b/drivers/mtd/ubi/cdev.c
@@ -113,7 +113,8 @@ static int vol_cdev_open(struct inode *inode, struct file *file)
 	else
 		mode = UBI_READONLY;
 
-	dbg_gen("open volume %d, mode %d", vol_id, mode);
+	dbg_gen("open device %d, volume %d, mode %d",
+	        ubi_num, vol_id, mode);
 
 	desc = ubi_open_volume(ubi_num, vol_id, mode);
 	if (IS_ERR(desc))
@@ -128,7 +129,8 @@ static int vol_cdev_release(struct inode *inode, struct file *file)
 	struct ubi_volume_desc *desc = file->private_data;
 	struct ubi_volume *vol = desc->vol;
 
-	dbg_gen("release volume %d, mode %d", vol->vol_id, desc->mode);
+	dbg_gen("release device %d, volume %d, mode %d",
+		vol->ubi->ubi_num, vol->vol_id, desc->mode);
 
 	if (vol->updating) {
 		ubi_warn("update of volume %d not finished, volume is damaged",
@@ -393,7 +395,7 @@ static ssize_t vol_cdev_write(struct file *file, const char __user *buf,
 			vol->corrupted = 1;
 		}
 		vol->checked = 1;
-		ubi_gluebi_updated(vol);
+		ubi_volume_notify(ubi, vol, UBI_VOLUME_UPDATED);
 		revoke_exclusive(desc, UBI_READWRITE);
 	}
 
@@ -558,7 +560,7 @@ static long vol_cdev_ioctl(struct file *file, unsigned int cmd,
 		break;
 	}
 
-	/* Set volume property command*/
+	/* Set volume property command */
 	case UBI_IOCSETPROP:
 	{
 		struct ubi_set_prop_req req;
@@ -571,9 +573,9 @@ static long vol_cdev_ioctl(struct file *file, unsigned int cmd,
 		}
 		switch (req.property) {
 		case UBI_PROP_DIRECT_WRITE:
-			mutex_lock(&ubi->volumes_mutex);
+			mutex_lock(&ubi->device_mutex);
 			desc->vol->direct_writes = !!req.value;
-			mutex_unlock(&ubi->volumes_mutex);
+			mutex_unlock(&ubi->device_mutex);
 			break;
 		default:
 			err = -EINVAL;
@@ -810,9 +812,9 @@ static int rename_volumes(struct ubi_device *ubi,
 			re->desc->vol->vol_id, re->desc->vol->name);
 	}
 
-	mutex_lock(&ubi->volumes_mutex);
+	mutex_lock(&ubi->device_mutex);
 	err = ubi_rename_volumes(ubi, &rename_list);
-	mutex_unlock(&ubi->volumes_mutex);
+	mutex_unlock(&ubi->device_mutex);
 
 out_free:
 	list_for_each_entry_safe(re, re1, &rename_list, list) {
@@ -856,9 +858,9 @@ static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
 		if (err)
 			break;
 
-		mutex_lock(&ubi->volumes_mutex);
+		mutex_lock(&ubi->device_mutex);
 		err = ubi_create_volume(ubi, &req);
-		mutex_unlock(&ubi->volumes_mutex);
+		mutex_unlock(&ubi->device_mutex);
 		if (err)
 			break;
 
@@ -887,9 +889,9 @@ static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
 			break;
 		}
 
-		mutex_lock(&ubi->volumes_mutex);
+		mutex_lock(&ubi->device_mutex);
 		err = ubi_remove_volume(desc, 0);
-		mutex_unlock(&ubi->volumes_mutex);
+		mutex_unlock(&ubi->device_mutex);
 
 		/*
 		 * The volume is deleted (unless an error occurred), and the
@@ -926,9 +928,9 @@ static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
 		pebs = div_u64(req.bytes + desc->vol->usable_leb_size - 1,
 			       desc->vol->usable_leb_size);
 
-		mutex_lock(&ubi->volumes_mutex);
+		mutex_lock(&ubi->device_mutex);
 		err = ubi_resize_volume(desc, pebs);
-		mutex_unlock(&ubi->volumes_mutex);
+		mutex_unlock(&ubi->device_mutex);
 		ubi_close_volume(desc);
 		break;
 	}
@@ -952,9 +954,7 @@ static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
 			break;
 		}
 
-		mutex_lock(&ubi->mult_mutex);
 		err = rename_volumes(ubi, req);
-		mutex_unlock(&ubi->mult_mutex);
 		kfree(req);
 		break;
 	}
diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
index 25def348e5b..0f2034c3ed2 100644
--- a/drivers/mtd/ubi/eba.c
+++ b/drivers/mtd/ubi/eba.c
@@ -419,8 +419,9 @@ retry:
 				 * not implemented.
 				 */
 				if (err == UBI_IO_BAD_VID_HDR) {
-					ubi_warn("bad VID header at PEB %d, LEB"
-						 "%d:%d", pnum, vol_id, lnum);
+					ubi_warn("corrupted VID header at PEB "
+						 "%d, LEB %d:%d", pnum, vol_id,
+						 lnum);
 					err = -EBADMSG;
 				} else
 					ubi_ro_mode(ubi);
@@ -940,6 +941,33 @@ write_error:
 }
 
 /**
+ * is_error_sane - check whether a read error is sane.
+ * @err: code of the error happened during reading
+ *
+ * This is a helper function for 'ubi_eba_copy_leb()' which is called when we
+ * cannot read data from the target PEB (an error @err happened). If the error
+ * code is sane, then we treat this error as non-fatal. Otherwise the error is
+ * fatal and UBI will be switched to R/O mode later.
+ *
+ * The idea is that we try not to switch to R/O mode if the read error is
+ * something which suggests there was a real read problem. E.g., %-EIO. Or a
+ * memory allocation failed (-%ENOMEM). Otherwise, it is safer to switch to R/O
+ * mode, simply because we do not know what happened at the MTD level, and we
+ * cannot handle this. E.g., the underlying driver may have become crazy, and
+ * it is safer to switch to R/O mode to preserve the data.
+ *
+ * And bear in mind, this is about reading from the target PEB, i.e. the PEB
+ * which we have just written.
+ */
+static int is_error_sane(int err)
+{
+	if (err == -EIO || err == -ENOMEM || err == UBI_IO_BAD_VID_HDR ||
+	    err == -ETIMEDOUT)
+		return 0;
+	return 1;
+}
+
+/**
  * ubi_eba_copy_leb - copy logical eraseblock.
  * @ubi: UBI device description object
  * @from: physical eraseblock number from where to copy
@@ -950,12 +978,7 @@ write_error:
  * physical eraseblock @to. The @vid_hdr buffer may be changed by this
  * function. Returns:
  *   o %0 in case of success;
- *   o %1 if the operation was canceled because the volume is being deleted
- *        or because the PEB was put meanwhile;
- *   o %2 if the operation was canceled because there was a write error to the
- *        target PEB;
- *   o %-EAGAIN if the operation was canceled because a bit-flip was detected
- *     in the target PEB;
+ *   o %MOVE_CANCEL_RACE, %MOVE_TARGET_WR_ERR, %MOVE_CANCEL_BITFLIPS, etc;
  *   o a negative error code in case of failure.
  */
 int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
@@ -968,7 +991,7 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
 	vol_id = be32_to_cpu(vid_hdr->vol_id);
 	lnum = be32_to_cpu(vid_hdr->lnum);
 
-	dbg_eba("copy LEB %d:%d, PEB %d to PEB %d", vol_id, lnum, from, to);
+	dbg_wl("copy LEB %d:%d, PEB %d to PEB %d", vol_id, lnum, from, to);
 
 	if (vid_hdr->vol_type == UBI_VID_STATIC) {
 		data_size = be32_to_cpu(vid_hdr->data_size);
@@ -986,13 +1009,12 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
 	 * be locked in 'ubi_wl_put_peb()' and wait for the WL worker to finish.
 	 */
 	vol = ubi->volumes[idx];
+	spin_unlock(&ubi->volumes_lock);
 	if (!vol) {
 		/* No need to do further work, cancel */
-		dbg_eba("volume %d is being removed, cancel", vol_id);
-		spin_unlock(&ubi->volumes_lock);
-		return 1;
+		dbg_wl("volume %d is being removed, cancel", vol_id);
+		return MOVE_CANCEL_RACE;
 	}
-	spin_unlock(&ubi->volumes_lock);
 
 	/*
 	 * We do not want anybody to write to this logical eraseblock while we
@@ -1004,12 +1026,13 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
 	 * (@from). This task locks the LEB and goes sleep in the
 	 * 'ubi_wl_put_peb()' function on the @ubi->move_mutex. In turn, we are
 	 * holding @ubi->move_mutex and go sleep on the LEB lock. So, if the
-	 * LEB is already locked, we just do not move it and return %1.
+	 * LEB is already locked, we just do not move it and return
+	 * %MOVE_CANCEL_RACE, which means that UBI will re-try, but later.
 	 */
 	err = leb_write_trylock(ubi, vol_id, lnum);
 	if (err) {
-		dbg_eba("contention on LEB %d:%d, cancel", vol_id, lnum);
-		return err;
+		dbg_wl("contention on LEB %d:%d, cancel", vol_id, lnum);
+		return MOVE_CANCEL_RACE;
 	}
 
 	/*
@@ -1018,25 +1041,26 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
 	 * cancel it.
 	 */
 	if (vol->eba_tbl[lnum] != from) {
-		dbg_eba("LEB %d:%d is no longer mapped to PEB %d, mapped to "
-			"PEB %d, cancel", vol_id, lnum, from,
-			vol->eba_tbl[lnum]);
-		err = 1;
+		dbg_wl("LEB %d:%d is no longer mapped to PEB %d, mapped to "
+		       "PEB %d, cancel", vol_id, lnum, from,
+		       vol->eba_tbl[lnum]);
+		err = MOVE_CANCEL_RACE;
 		goto out_unlock_leb;
 	}
 
 	/*
 	 * OK, now the LEB is locked and we can safely start moving it. Since
-	 * this function utilizes the @ubi->peb1_buf buffer which is shared
-	 * with some other functions, so lock the buffer by taking the
+	 * this function utilizes the @ubi->peb_buf1 buffer which is shared
+	 * with some other functions - we lock the buffer by taking the
 	 * @ubi->buf_mutex.
 	 */
 	mutex_lock(&ubi->buf_mutex);
-	dbg_eba("read %d bytes of data", aldata_size);
+	dbg_wl("read %d bytes of data", aldata_size);
 	err = ubi_io_read_data(ubi, ubi->peb_buf1, from, 0, aldata_size);
 	if (err && err != UBI_IO_BITFLIPS) {
 		ubi_warn("error %d while reading data from PEB %d",
 			 err, from);
+		err = MOVE_SOURCE_RD_ERR;
 		goto out_unlock_buf;
 	}
 
@@ -1059,7 +1083,7 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
 	cond_resched();
 
 	/*
-	 * It may turn out to me that the whole @from physical eraseblock
+	 * It may turn out to be that the whole @from physical eraseblock
 	 * contains only 0xFF bytes. Then we have to only write the VID header
 	 * and do not write any data. This also means we should not set
 	 * @vid_hdr->copy_flag, @vid_hdr->data_size, and @vid_hdr->data_crc.
@@ -1074,7 +1098,7 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
 	err = ubi_io_write_vid_hdr(ubi, to, vid_hdr);
 	if (err) {
 		if (err == -EIO)
-			err = 2;
+			err = MOVE_TARGET_WR_ERR;
 		goto out_unlock_buf;
 	}
 
@@ -1083,10 +1107,13 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
 	/* Read the VID header back and check if it was written correctly */
 	err = ubi_io_read_vid_hdr(ubi, to, vid_hdr, 1);
 	if (err) {
-		if (err != UBI_IO_BITFLIPS)
-			ubi_warn("cannot read VID header back from PEB %d", to);
-		else
-			err = -EAGAIN;
+		if (err != UBI_IO_BITFLIPS) {
+			ubi_warn("error %d while reading VID header back from "
+				  "PEB %d", err, to);
+			if (is_error_sane(err))
+				err = MOVE_TARGET_RD_ERR;
+		} else
+			err = MOVE_CANCEL_BITFLIPS;
 		goto out_unlock_buf;
 	}
 
@@ -1094,7 +1121,7 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
 		err = ubi_io_write_data(ubi, ubi->peb_buf1, to, 0, aldata_size);
 		if (err) {
 			if (err == -EIO)
-				err = 2;
+				err = MOVE_TARGET_WR_ERR;
 			goto out_unlock_buf;
 		}
 
@@ -1107,11 +1134,13 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
 
 		err = ubi_io_read_data(ubi, ubi->peb_buf2, to, 0, aldata_size);
 		if (err) {
-			if (err != UBI_IO_BITFLIPS)
-				ubi_warn("cannot read data back from PEB %d",
-					 to);
-			else
-				err = -EAGAIN;
+			if (err != UBI_IO_BITFLIPS) {
+				ubi_warn("error %d while reading data back "
+					 "from PEB %d", err, to);
+				if (is_error_sane(err))
+					err = MOVE_TARGET_RD_ERR;
+			} else
+				err = MOVE_CANCEL_BITFLIPS;
 			goto out_unlock_buf;
 		}
 
diff --git a/drivers/mtd/ubi/gluebi.c b/drivers/mtd/ubi/gluebi.c
index 49cd55ade9c..95aaac03f93 100644
--- a/drivers/mtd/ubi/gluebi.c
+++ b/drivers/mtd/ubi/gluebi.c
@@ -19,17 +19,71 @@
  */
 
 /*
- * This file includes implementation of fake MTD devices for each UBI volume.
- * This sounds strange, but it is in fact quite useful to make MTD-oriented
- * software (including all the legacy software) to work on top of UBI.
+ * This is a small driver which implements fake MTD devices on top of UBI
+ * volumes. This sounds strange, but it is in fact quite useful to make
+ * MTD-oriented software (including all the legacy software) work on top of
+ * UBI.
  *
  * Gluebi emulates MTD devices of "MTD_UBIVOLUME" type. Their minimal I/O unit
- * size (mtd->writesize) is equivalent to the UBI minimal I/O unit. The
+ * size (@mtd->writesize) is equivalent to the UBI minimal I/O unit. The
  * eraseblock size is equivalent to the logical eraseblock size of the volume.
  */
 
+#include <linux/err.h>
+#include <linux/list.h>
+#include <linux/sched.h>
 #include <linux/math64.h>
-#include "ubi.h"
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/mtd/ubi.h>
+#include <linux/mtd/mtd.h>
+#include "ubi-media.h"
+
+#define err_msg(fmt, ...)                                   \
+	printk(KERN_DEBUG "gluebi (pid %d): %s: " fmt "\n", \
+	       current->pid, __func__, ##__VA_ARGS__)
+
+/**
+ * struct gluebi_device - a gluebi device description data structure.
+ * @mtd: emulated MTD device description object
+ * @refcnt: gluebi device reference count
+ * @desc: UBI volume descriptor
+ * @ubi_num: UBI device number this gluebi device works on
+ * @vol_id: ID of UBI volume this gluebi device works on
+ * @list: link in a list of gluebi devices
+ */
+struct gluebi_device {
+	struct mtd_info mtd;
+	int refcnt;
+	struct ubi_volume_desc *desc;
+	int ubi_num;
+	int vol_id;
+	struct list_head list;
+};
+
+/* List of all gluebi devices */
+static LIST_HEAD(gluebi_devices);
+static DEFINE_MUTEX(devices_mutex);
+
+/**
+ * find_gluebi_nolock - find a gluebi device.
+ * @ubi_num: UBI device number
+ * @vol_id: volume ID
+ *
+ * This function seraches for gluebi device corresponding to UBI device
+ * @ubi_num and UBI volume @vol_id. Returns the gluebi device description
+ * object in case of success and %NULL in case of failure. The caller has to
+ * have the &devices_mutex locked.
+ */
+static struct gluebi_device *find_gluebi_nolock(int ubi_num, int vol_id)
+{
+	struct gluebi_device *gluebi;
+
+	list_for_each_entry(gluebi, &gluebi_devices, list)
+		if (gluebi->ubi_num == ubi_num && gluebi->vol_id == vol_id)
+			return gluebi;
+	return NULL;
+}
 
 /**
  * gluebi_get_device - get MTD device reference.
@@ -41,15 +95,18 @@
  */
 static int gluebi_get_device(struct mtd_info *mtd)
 {
-	struct ubi_volume *vol;
+	struct gluebi_device *gluebi;
+	int ubi_mode = UBI_READONLY;
 
-	vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
+	if (!try_module_get(THIS_MODULE))
+		return -ENODEV;
 
-	/*
-	 * We do not introduce locks for gluebi reference count because the
-	 * get_device()/put_device() calls are already serialized at MTD.
-	 */
-	if (vol->gluebi_refcount > 0) {
+	if (mtd->flags & MTD_WRITEABLE)
+		ubi_mode = UBI_READWRITE;
+
+	gluebi = container_of(mtd, struct gluebi_device, mtd);
+	mutex_lock(&devices_mutex);
+	if (gluebi->refcnt > 0) {
 		/*
 		 * The MTD device is already referenced and this is just one
 		 * more reference. MTD allows many users to open the same
@@ -58,7 +115,8 @@ static int gluebi_get_device(struct mtd_info *mtd)
 		 * open the UBI volume again - just increase the reference
 		 * counter and return.
 		 */
-		vol->gluebi_refcount += 1;
+		gluebi->refcnt += 1;
+		mutex_unlock(&devices_mutex);
 		return 0;
 	}
 
@@ -66,11 +124,15 @@ static int gluebi_get_device(struct mtd_info *mtd)
 	 * This is the first reference to this UBI volume via the MTD device
 	 * interface. Open the corresponding volume in read-write mode.
 	 */
-	vol->gluebi_desc = ubi_open_volume(vol->ubi->ubi_num, vol->vol_id,
-					   UBI_READWRITE);
-	if (IS_ERR(vol->gluebi_desc))
-		return PTR_ERR(vol->gluebi_desc);
-	vol->gluebi_refcount += 1;
+	gluebi->desc = ubi_open_volume(gluebi->ubi_num, gluebi->vol_id,
+				       ubi_mode);
+	if (IS_ERR(gluebi->desc)) {
+		mutex_unlock(&devices_mutex);
+		module_put(THIS_MODULE);
+		return PTR_ERR(gluebi->desc);
+	}
+	gluebi->refcnt += 1;
+	mutex_unlock(&devices_mutex);
 	return 0;
 }
 
@@ -83,13 +145,15 @@ static int gluebi_get_device(struct mtd_info *mtd)
  */
 static void gluebi_put_device(struct mtd_info *mtd)
 {
-	struct ubi_volume *vol;
-
-	vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
-	vol->gluebi_refcount -= 1;
-	ubi_assert(vol->gluebi_refcount >= 0);
-	if (vol->gluebi_refcount == 0)
-		ubi_close_volume(vol->gluebi_desc);
+	struct gluebi_device *gluebi;
+
+	gluebi = container_of(mtd, struct gluebi_device, mtd);
+	mutex_lock(&devices_mutex);
+	gluebi->refcnt -= 1;
+	if (gluebi->refcnt == 0)
+		ubi_close_volume(gluebi->desc);
+	module_put(THIS_MODULE);
+	mutex_unlock(&devices_mutex);
 }
 
 /**
@@ -107,16 +171,12 @@ static int gluebi_read(struct mtd_info *mtd, loff_t from, size_t len,
 		       size_t *retlen, unsigned char *buf)
 {
 	int err = 0, lnum, offs, total_read;
-	struct ubi_volume *vol;
-	struct ubi_device *ubi;
-
-	dbg_gen("read %zd bytes from offset %lld", len, from);
+	struct gluebi_device *gluebi;
 
 	if (len < 0 || from < 0 || from + len > mtd->size)
 		return -EINVAL;
 
-	vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
-	ubi = vol->ubi;
+	gluebi = container_of(mtd, struct gluebi_device, mtd);
 
 	lnum = div_u64_rem(from, mtd->erasesize, &offs);
 	total_read = len;
@@ -126,7 +186,7 @@ static int gluebi_read(struct mtd_info *mtd, loff_t from, size_t len,
 		if (to_read > total_read)
 			to_read = total_read;
 
-		err = ubi_eba_read_leb(ubi, vol, lnum, buf, offs, to_read, 0);
+		err = ubi_read(gluebi->desc, lnum, buf, offs, to_read);
 		if (err)
 			break;
 
@@ -152,21 +212,17 @@ static int gluebi_read(struct mtd_info *mtd, loff_t from, size_t len,
  * case of failure.
  */
 static int gluebi_write(struct mtd_info *mtd, loff_t to, size_t len,
-		       size_t *retlen, const u_char *buf)
+			size_t *retlen, const u_char *buf)
 {
 	int err = 0, lnum, offs, total_written;
-	struct ubi_volume *vol;
-	struct ubi_device *ubi;
-
-	dbg_gen("write %zd bytes to offset %lld", len, to);
+	struct gluebi_device *gluebi;
 
 	if (len < 0 || to < 0 || len + to > mtd->size)
 		return -EINVAL;
 
-	vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
-	ubi = vol->ubi;
+	gluebi = container_of(mtd, struct gluebi_device, mtd);
 
-	if (ubi->ro_mode)
+	if (!(mtd->flags & MTD_WRITEABLE))
 		return -EROFS;
 
 	lnum = div_u64_rem(to, mtd->erasesize, &offs);
@@ -181,8 +237,7 @@ static int gluebi_write(struct mtd_info *mtd, loff_t to, size_t len,
 		if (to_write > total_written)
 			to_write = total_written;
 
-		err = ubi_eba_write_leb(ubi, vol, lnum, buf, offs, to_write,
-					UBI_UNKNOWN);
+		err = ubi_write(gluebi->desc, lnum, buf, offs, to_write);
 		if (err)
 			break;
 
@@ -207,41 +262,36 @@ static int gluebi_write(struct mtd_info *mtd, loff_t to, size_t len,
 static int gluebi_erase(struct mtd_info *mtd, struct erase_info *instr)
 {
 	int err, i, lnum, count;
-	struct ubi_volume *vol;
-	struct ubi_device *ubi;
-
-	dbg_gen("erase %llu bytes at offset %llu", (unsigned long long)instr->len,
-		 (unsigned long long)instr->addr);
+	struct gluebi_device *gluebi;
 
 	if (instr->addr < 0 || instr->addr > mtd->size - mtd->erasesize)
 		return -EINVAL;
-
 	if (instr->len < 0 || instr->addr + instr->len > mtd->size)
 		return -EINVAL;
-
 	if (mtd_mod_by_ws(instr->addr, mtd) || mtd_mod_by_ws(instr->len, mtd))
 		return -EINVAL;
 
 	lnum = mtd_div_by_eb(instr->addr, mtd);
 	count = mtd_div_by_eb(instr->len, mtd);
 
-	vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
-	ubi = vol->ubi;
+	gluebi = container_of(mtd, struct gluebi_device, mtd);
 
-	if (ubi->ro_mode)
+	if (!(mtd->flags & MTD_WRITEABLE))
 		return -EROFS;
 
-	for (i = 0; i < count; i++) {
-		err = ubi_eba_unmap_leb(ubi, vol, lnum + i);
+	for (i = 0; i < count - 1; i++) {
+		err = ubi_leb_unmap(gluebi->desc, lnum + i);
 		if (err)
 			goto out_err;
 	}
-
 	/*
 	 * MTD erase operations are synchronous, so we have to make sure the
 	 * physical eraseblock is wiped out.
+	 *
+	 * Thus, perform leb_erase instead of leb_unmap operation - leb_erase
+	 * will wait for the end of operations
 	 */
-	err = ubi_wl_flush(ubi);
+	err = ubi_leb_erase(gluebi->desc, lnum + i);
 	if (err)
 		goto out_err;
 
@@ -256,28 +306,38 @@ out_err:
 }
 
 /**
- * ubi_create_gluebi - initialize gluebi for an UBI volume.
- * @ubi: UBI device description object
- * @vol: volume description object
+ * gluebi_create - create a gluebi device for an UBI volume.
+ * @di: UBI device description object
+ * @vi: UBI volume description object
  *
- * This function is called when an UBI volume is created in order to create
+ * This function is called when a new UBI volume is created in order to create
  * corresponding fake MTD device. Returns zero in case of success and a
  * negative error code in case of failure.
  */
-int ubi_create_gluebi(struct ubi_device *ubi, struct ubi_volume *vol)
+static int gluebi_create(struct ubi_device_info *di,
+			 struct ubi_volume_info *vi)
 {
-	struct mtd_info *mtd = &vol->gluebi_mtd;
+	struct gluebi_device *gluebi, *g;
+	struct mtd_info *mtd;
 
-	mtd->name = kmemdup(vol->name, vol->name_len + 1, GFP_KERNEL);
-	if (!mtd->name)
+	gluebi = kzalloc(sizeof(struct gluebi_device), GFP_KERNEL);
+	if (!gluebi)
 		return -ENOMEM;
 
+	mtd = &gluebi->mtd;
+	mtd->name = kmemdup(vi->name, vi->name_len + 1, GFP_KERNEL);
+	if (!mtd->name) {
+		kfree(gluebi);
+		return -ENOMEM;
+	}
+
+	gluebi->vol_id = vi->vol_id;