Commit d05c77a8 authored by Artem Bityutskiy's avatar Artem Bityutskiy
Browse files

UBI: introduce volume refcounting 



Add ref_count field to UBI volumes and remove weired "vol->removed"
field. This way things are better understandable and we do not have
to do whold show_attr operation under spinlock.

Signed-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
parent db6e5770

drivers/mtd/ubi/eba.c

+10 −0
Original line number Diff line number Diff line
@@ -301,6 +301,8 @@ int ubi_eba_unmap_leb(struct ubi_device *ubi, struct ubi_volume *vol, 
{

	int err, pnum, vol_id = vol->vol_id;



	ubi_assert(vol->ref_count > 0);



	if (ubi->ro_mode)

		return -EROFS;
@@ -349,6 +351,8 @@ int ubi_eba_read_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum, 
	struct ubi_vid_hdr *vid_hdr;

	uint32_t uninitialized_var(crc);



	ubi_assert(vol->ref_count > 0);



	err = leb_read_lock(ubi, vol_id, lnum);

	if (err)

		return err;
@@ -572,6 +576,8 @@ int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum, 
	int err, pnum, tries = 0, vol_id = vol->vol_id;

	struct ubi_vid_hdr *vid_hdr;



	ubi_assert(vol->ref_count > 0);



	if (ubi->ro_mode)

		return -EROFS;
@@ -705,6 +711,8 @@ int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol, 
	struct ubi_vid_hdr *vid_hdr;

	uint32_t crc;



	ubi_assert(vol->ref_count > 0);



	if (ubi->ro_mode)

		return -EROFS;
@@ -819,6 +827,8 @@ int ubi_eba_atomic_leb_change(struct ubi_device *ubi, struct ubi_volume *vol, 
	struct ubi_vid_hdr *vid_hdr;

	uint32_t crc;



	ubi_assert(vol->ref_count > 0);



	if (ubi->ro_mode)

		return -EROFS;

drivers/mtd/ubi/kapi.c

+3 −1
Original line number Diff line number Diff line
@@ -152,6 +152,7 @@ struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode) 
		break;

	}

	get_device(&vol->dev);

	vol->ref_count += 1;

	spin_unlock(&ubi->volumes_lock);



	desc->vol = vol;
@@ -261,10 +262,11 @@ void ubi_close_volume(struct ubi_volume_desc *desc) 
	case UBI_EXCLUSIVE:

		vol->exclusive = 0;

	}

	vol->ref_count -= 1;

	spin_unlock(&vol->ubi->volumes_lock);



	kfree(desc);

	put_device(&vol->dev);

	kfree(desc);

	module_put(THIS_MODULE);

}

EXPORT_SYMBOL_GPL(ubi_close_volume);

drivers/mtd/ubi/ubi.h

+11 −11
Original line number Diff line number Diff line
@@ -140,10 +140,10 @@ struct ubi_volume_desc; 
 * @cdev: character device object to create character device

 * @ubi: reference to the UBI device description object

 * @vol_id: volume ID

 * @ref_count: volume reference count

 * @readers: number of users holding this volume in read-only mode

 * @writers: number of users holding this volume in read-write mode

 * @exclusive: whether somebody holds this volume in exclusive mode

 * @removed: if the volume was removed

 * @checked: if this static volume was checked

 *

 * @reserved_pebs: how many physical eraseblocks are reserved for this volume
@@ -185,10 +185,10 @@ struct ubi_volume { 
	struct cdev cdev;

	struct ubi_device *ubi;

	int vol_id;

	int ref_count;

	int readers;

	int writers;

	int exclusive;

	int removed;

	int checked;



	int reserved_pebs;
@@ -242,9 +242,9 @@ struct ubi_wl_entry; 
 * @vol_count: number of volumes in this UBI device

 * @volumes: volumes of this UBI device

 * @volumes_lock: protects @volumes, @rsvd_pebs, @avail_pebs, beb_rsvd_pebs,

 * @beb_rsvd_level, @bad_peb_count, @good_peb_count, @vol_count, @vol->readers,

 * @vol->writers, @vol->exclusive, @vol->removed, @vol->mapping and

 * @vol->eba_tbl.

 *                @beb_rsvd_level, @bad_peb_count, @good_peb_count, @vol_count,

 *                @vol->readers, @vol->writers, @vol->exclusive,

 *                @vol->ref_count, @vol->mapping and @vol->eba_tbl.

 *

 * @rsvd_pebs: count of reserved physical eraseblocks

 * @avail_pebs: count of available physical eraseblocks

drivers/mtd/ubi/vmt.c

+58 −30
Original line number Diff line number Diff line
@@ -63,21 +63,24 @@ static struct device_attribute attr_vol_upd_marker = 
 * B. process 2 removes volume Y;

 * C. process 1 starts reading the /<sysfs>/class/ubi/ubiX_Y/reserved_ebs file;

 *

 * What we want to do in a situation like that is to return error when the file

 * is read. This is done by means of the 'removed' flag and the 'vol_lock' of

 * the UBI volume description object.

 * In this situation, this function will return %-ENODEV because it will find

 * out that the volume was removed from the @ubi->volumes array.

 */

static ssize_t vol_attribute_show(struct device *dev,

				  struct device_attribute *attr, char *buf)

{

	int ret = -ENODEV;

	int ret;

	struct ubi_volume *vol = container_of(dev, struct ubi_volume, dev);

	struct ubi_device *ubi = vol->ubi;



	spin_lock(&vol->ubi->volumes_lock);

	if (vol->removed) {

		spin_unlock(&vol->ubi->volumes_lock);

		return ret;

	spin_lock(&ubi->volumes_lock);

	if (!ubi->volumes[vol->vol_id]) {

		spin_unlock(&ubi->volumes_lock);

		return -ENODEV;

	}

	/* Take a reference to prevent volume removal */

	vol->ref_count += 1;

	spin_unlock(&ubi->volumes_lock);



	if (attr == &attr_vol_reserved_ebs)

		ret = sprintf(buf, "%d\n", vol->reserved_pebs);
@@ -102,8 +105,13 @@ static ssize_t vol_attribute_show(struct device *dev, 
	else if (attr == &attr_vol_upd_marker)

		ret = sprintf(buf, "%d\n", vol->upd_marker);

	else

		BUG();

	spin_unlock(&vol->ubi->volumes_lock);

		/* This must be a bug */

		ret = -EINVAL;



	spin_lock(&ubi->volumes_lock);

	vol->ref_count -= 1;

	ubi_assert(vol->ref_count >= 0);

	spin_unlock(&ubi->volumes_lock);

	return ret;

}
@@ -179,7 +187,7 @@ static void volume_sysfs_close(struct ubi_volume *vol) 
 * @req: volume creation request

 *

 * This function creates volume described by @req. If @req->vol_id id

 * %UBI_VOL_NUM_AUTO, this function automatically assigne ID to the new volume

 * %UBI_VOL_NUM_AUTO, this function automatically assign ID to the new volume

 * and saves it in @req->vol_id. Returns zero in case of success and a negative

 * error code in case of failure.

 */
@@ -261,7 +269,6 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req) 
	memcpy(vol->name, req->name, vol->name_len + 1);

	vol->exclusive = 1;

	vol->ubi = ubi;

	ubi->volumes[vol_id] = vol;

	spin_unlock(&ubi->volumes_lock);



	/*
@@ -345,6 +352,7 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req) 
	spin_lock(&ubi->volumes_lock);

	ubi->vol_count += 1;

	vol->exclusive = 0;

	ubi->volumes[vol_id] = vol;

	spin_unlock(&ubi->volumes_lock);



	paranoid_check_volumes(ubi);
@@ -353,7 +361,7 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req) 


out_sysfs:

	/*

	 * We have degistered our device, we should not free the volume*

	 * We have registered our device, we should not free the volume*

	 * description object in this function in case of an error - it is

	 * freed by the release function.

	 *
@@ -373,7 +381,6 @@ out_acc: 
	spin_lock(&ubi->volumes_lock);

	ubi->rsvd_pebs -= vol->reserved_pebs;

	ubi->avail_pebs += vol->reserved_pebs;

	ubi->volumes[vol_id] = NULL;

out_unlock:

	spin_unlock(&ubi->volumes_lock);

	mutex_unlock(&ubi->volumes_mutex);
@@ -407,25 +414,32 @@ int ubi_remove_volume(struct ubi_volume_desc *desc) 
		return -EROFS;



	mutex_lock(&ubi->volumes_mutex);

	spin_lock(&ubi->volumes_lock);

	if (vol->ref_count > 1) {

		/*

		 * The volume is busy, probably someone is reading one of its

		 * sysfs files.

		 */

		err = -EBUSY;

		goto out_unlock;

	}

	ubi->volumes[vol_id] = NULL;

	spin_unlock(&ubi->volumes_lock);



	err = ubi_destroy_gluebi(vol);

	if (err)

		goto out;

		goto out_err;



	err = ubi_change_vtbl_record(ubi, vol_id, NULL);

	if (err)

		goto out;

		goto out_err;



	for (i = 0; i < vol->reserved_pebs; i++) {

		err = ubi_eba_unmap_leb(ubi, vol, i);

		if (err)

			goto out;

			goto out_err;

	}



	spin_lock(&ubi->volumes_lock);

	vol->removed = 1;

	ubi->volumes[vol_id] = NULL;

	spin_unlock(&ubi->volumes_lock);



	kfree(vol->eba_tbl);

	vol->eba_tbl = NULL;

	cdev_del(&vol->cdev);
@@ -447,7 +461,15 @@ int ubi_remove_volume(struct ubi_volume_desc *desc) 
	spin_unlock(&ubi->volumes_lock);



	paranoid_check_volumes(ubi);

out:

	mutex_unlock(&ubi->volumes_mutex);

	return 0;



out_err:

	ubi_err("cannot remove volume %d, error %d", vol_id, err);

	spin_lock(&ubi->volumes_lock);

	ubi->volumes[vol_id] = vol;

out_unlock:

	spin_unlock(&ubi->volumes_lock);

	mutex_unlock(&ubi->volumes_mutex);

	return err;

}
@@ -494,8 +516,17 @@ int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs) 
	for (i = 0; i < reserved_pebs; i++)

		new_mapping[i] = UBI_LEB_UNMAPPED;



	/* Reserve physical eraseblocks */

	mutex_lock(&ubi->volumes_mutex);

	spin_lock(&ubi->volumes_lock);

	if (vol->ref_count > 1) {

		spin_unlock(&ubi->volumes_lock);

		err = -EBUSY;

		goto out_free;

	}

	spin_unlock(&ubi->volumes_lock);





	/* Reserve physical eraseblocks */

	pebs = reserved_pebs - vol->reserved_pebs;

	if (pebs > 0) {

		spin_lock(&ubi->volumes_lock);
@@ -577,8 +608,8 @@ out_free: 
 * @ubi: UBI device description object

 * @vol: volume description object

 *

 * This function adds an existin volume and initializes all its data

 * structures. Returnes zero in case of success and a negative error code in

 * This function adds an existing volume and initializes all its data

 * structures. Returns zero in case of success and a negative error code in

 * case of failure.

 */

int ubi_add_volume(struct ubi_device *ubi, struct ubi_volume *vol)
@@ -588,7 +619,6 @@ int ubi_add_volume(struct ubi_device *ubi, struct ubi_volume *vol) 


	dbg_msg("add volume %d", vol_id);

	ubi_dbg_dump_vol_info(vol);

	ubi_assert(vol);



	/* Register character device for the volume */

	cdev_init(&vol->cdev, &ubi_vol_cdev_operations);
@@ -645,11 +675,9 @@ void ubi_free_volume(struct ubi_device *ubi, struct ubi_volume *vol) 
	int err;



	dbg_msg("free volume %d", vol->vol_id);

	ubi_assert(vol);



	vol->removed = 1;

	err = ubi_destroy_gluebi(vol);

	ubi->volumes[vol->vol_id] = NULL;

	err = ubi_destroy_gluebi(vol);

	cdev_del(&vol->cdev);

	volume_sysfs_close(vol);

}

drivers/mtd/ubi/vtbl.c

+2 −0
Original line number Diff line number Diff line
@@ -565,6 +565,7 @@ static int init_volumes(struct ubi_device *ubi, const struct ubi_scan_info *si, 
		vol->last_eb_bytes = sv->last_data_size;

	}



	/* And add the layout volume */

	vol = kzalloc(sizeof(struct ubi_volume), GFP_KERNEL);

	if (!vol)

		return -ENOMEM;
@@ -580,6 +581,7 @@ static int init_volumes(struct ubi_device *ubi, const struct ubi_scan_info *si, 
	vol->used_bytes =

		(long long)vol->used_ebs * (ubi->leb_size - vol->data_pad);

	vol->vol_id = UBI_LAYOUT_VOL_ID;

	vol->ref_count = 1;



	ubi_assert(!ubi->volumes[i]);

	ubi->volumes[vol_id2idx(ubi, vol->vol_id)] = vol;

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