[RFC] UBI volume re-name
Artem Bityutskiy
dedekind at infradead.org
Mon Jul 14 06:05:51 EDT 2008
Hi,
here is implementation of the volume re-name ioctl suggested
by Richard Titmuss. I think it was quite nice idea which allows
users to upgrade UBI volumes atomically:
1. Suppose we want to update volumes A and B atomically.
2. Create temporary volumes A1 and B1
3. Put new contents to volumes A1 and B1
4. Atomically rename A1->A and A->A1, B1->B and B->B1.
5. Now A and B have new contents
6. Remove A1 and B1.
Of course volume id of A1 and B1 would change, but if the
volumes are only referred by name, then it'll be fine.
>From b285d9230c753890e9f57c43174559e4d1122c11 Mon Sep 17 00:00:00 2001
From: Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
Date: Sun, 13 Jul 2008 21:47:47 +0300
Subject: [PATCH] UBI: implement multiple volumes rename
Quite useful ioctl which allows to make atomic system upgrades.
The idea belongs to Richard Titmuss <richard_titmuss at logitech.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
---
drivers/mtd/ubi/cdev.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++++
drivers/mtd/ubi/ubi.h | 5 ++-
drivers/mtd/ubi/vmt.c | 30 +++++++++++++++
drivers/mtd/ubi/vtbl.c | 46 +++++++++++++++++++++++
include/mtd/ubi-user.h | 42 +++++++++++++++++++++
5 files changed, 217 insertions(+), 1 deletions(-)
diff --git a/drivers/mtd/ubi/cdev.c b/drivers/mtd/ubi/cdev.c
index 333c98e..b29c362 100644
--- a/drivers/mtd/ubi/cdev.c
+++ b/drivers/mtd/ubi/cdev.c
@@ -599,6 +599,75 @@ static int verify_rsvol_req(const struct ubi_device *ubi,
return 0;
}
+/**
+ * rename_volumes - rename UBI volumes.
+ * @ubi: UBI device description object
+ * @req: volumes re-name request
+ *
+ * This is a helper function for the volume re-name IOCTL which validates the
+ * the request, opens the volume and calls corresponding volumes management
+ * function. Returns zero in case of success and a negative error code in case
+ * of failure.
+ */
+static int rename_volumes(struct ubi_device *ubi,
+ struct ubi_rnvol_req *req)
+{
+ int i, n, err;
+ struct ubi_volume_desc *desc[UBI_MAX_RNVOL];
+
+ if (req->count < 0 || req->count > UBI_MAX_RNVOL)
+ return -EINVAL;
+
+ /* Validate volume IDs and names in the request */
+ for (i = 0; i < req->count; i++) {
+ if (req->vols[i].vol_id < 0 ||
+ req->vols[i].vol_id >= ubi->vtbl_slots)
+ return -EINVAL;
+ if (req->vols[i].name_len < 0)
+ return -EINVAL;
+ if (req->vols[i].name_len > UBI_VOL_NAME_MAX)
+ return -ENAMETOOLONG;
+ req->vols[i].name[req->vols[i].name_len] = '\0';
+ n = strlen(req->vols[i].name);
+ if (n != req->vols[i].name_len)
+ err = -EINVAL;
+ }
+
+ /* Make sure volume IDs and names are unique */
+ for (i = 0; i < req->count - 1; i++) {
+ for (n = i + 1; n < req->count; n++) {
+ if (req->vols[i].vol_id == req->vols[n].vol_id) {
+ dbg_err("duplicated volume id %d",
+ req->vols[i].vol_id);
+ return -EINVAL;
+ }
+ if (!strcmp(req->vols[i].name, req->vols[n].name)) {
+ dbg_err("duplicated volume name %s",
+ req->vols[i].name);
+ return -EINVAL;
+ }
+ }
+ }
+
+ /* Open all involeved volumes in exclusive mode */
+ for (i = 0; i < req->count; i++) {
+ desc[i] = ubi_open_volume(ubi->ubi_num, req->vols[i].vol_id,
+ UBI_EXCLUSIVE);
+ if (IS_ERR(desc[i])) {
+ err = PTR_ERR(desc[i]);
+ goto out;
+ }
+ }
+
+ i = req->count;
+ err = ubi_rename_volumes(ubi, req);
+
+out:
+ for (n = 0; n < i; n++)
+ ubi_close_volume(desc[n]);
+ return err;
+}
+
static int ubi_cdev_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
@@ -711,6 +780,32 @@ static int ubi_cdev_ioctl(struct inode *inode, struct file *file,
break;
}
+ /* Re-name volumes command */
+ case UBI_IOCRNVOL:
+ {
+ struct ubi_rnvol_req *req;
+
+ dbg_msg("re-name volumes");
+ req = kmalloc(sizeof(struct ubi_rnvol_req), GFP_KERNEL);
+ if (!req) {
+ err = -ENOMEM;
+ break;
+ };
+
+ err = copy_from_user(req, argp, sizeof(struct ubi_rnvol_req));
+ if (err) {
+ err = -EFAULT;
+ kfree(req);
+ break;
+ }
+
+ mutex_lock(&ubi->volumes_mutex);
+ err = rename_volumes(ubi, req);
+ mutex_unlock(&ubi->volumes_mutex);
+ kfree(req);
+ break;
+ }
+
default:
err = -ENOTTY;
break;
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index 940f6b7..e41f508 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -273,7 +273,7 @@ struct ubi_wl_entry;
* @vtbl_size: size of the volume table in bytes
* @vtbl: in-RAM volume table copy
* @volumes_mutex: protects on-flash volume table and serializes volume
- * changes, like creation, deletion, update, resize
+ * changes, like creation, deletion, update, re-size and re-name
*
* @max_ec: current highest erase counter value
* @mean_ec: current mean erase counter value
@@ -427,12 +427,15 @@ extern struct mutex ubi_devices_mutex;
/* vtbl.c */
int ubi_change_vtbl_record(struct ubi_device *ubi, int idx,
struct ubi_vtbl_record *vtbl_rec);
+int ubi_vtbl_rename_volumes(struct ubi_device *ubi,
+ const struct ubi_rnvol_req *req);
int ubi_read_volume_table(struct ubi_device *ubi, struct ubi_scan_info *si);
/* vmt.c */
int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req);
int ubi_remove_volume(struct ubi_volume_desc *desc);
int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs);
+int ubi_rename_volumes(struct ubi_device *ubi, const struct ubi_rnvol_req *req);
int ubi_add_volume(struct ubi_device *ubi, struct ubi_volume *vol);
void ubi_free_volume(struct ubi_device *ubi, struct ubi_volume *vol);
diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c
index bfa7c5d..03a6042 100644
--- a/drivers/mtd/ubi/vmt.c
+++ b/drivers/mtd/ubi/vmt.c
@@ -602,6 +602,36 @@ out_free:
}
/**
+ * ubi_vtbl_rename_volumes - re-name UBI volumes.
+ * @req: volumes re-name request
+ *
+ * This function re-names multiple volumes specified in @req. Returns zero in
+ * case of success and a negative error code in case of failure.
+ */
+int ubi_rename_volumes(struct ubi_device *ubi, const struct ubi_rnvol_req *req)
+{
+ int i, err;
+
+ err = ubi_vtbl_rename_volumes(ubi, req);
+ if (err)
+ return err;
+
+ spin_lock(&ubi->volumes_lock);
+ for (i = 0; i < req->count; i++) {
+ int vol_id = req->vols[i].vol_id;
+ int name_len = req->vols[i].name_len;
+ const char *name = req->vols[i].name;
+ struct ubi_volume *vol = ubi->volumes[vol_id];
+
+ vol->name_len = name_len;
+ memcpy(vol->name, name, name_len + 1);
+ }
+ spin_unlock(&ubi->volumes_lock);
+
+ return 0;
+}
+
+/**
* ubi_add_volume - add volume.
* @ubi: UBI device description object
* @vol: volume description object
diff --git a/drivers/mtd/ubi/vtbl.c b/drivers/mtd/ubi/vtbl.c
index d9af11a..8629574 100644
--- a/drivers/mtd/ubi/vtbl.c
+++ b/drivers/mtd/ubi/vtbl.c
@@ -115,6 +115,52 @@ int ubi_change_vtbl_record(struct ubi_device *ubi, int idx,
}
/**
+ * ubi_vtbl_rename_volumes - rename UBI volumes in the volume table.
+ * @ubi: UBI device description object
+ * @req: volumes re-name request
+ *
+ * This function re-names multiple volumes specified in @req in the volume
+ * table. Returns zero in case of success and a negative error code in case of
+ * failure.
+ */
+int ubi_vtbl_rename_volumes(struct ubi_device *ubi,
+ const struct ubi_rnvol_req *req)
+{
+ int i, err;
+ struct ubi_volume *layout_vol;
+
+ for (i = 0; i < req->count; i++) {
+ uint32_t crc;
+ int vol_id = req->vols[i].vol_id;
+ int name_len = req->vols[i].name_len;
+ const char *name = req->vols[i].name;
+ struct ubi_vtbl_record *vtbl_rec = &ubi->vtbl[vol_id];
+
+ vtbl_rec->name_len = cpu_to_be16(name_len);
+ memset(vtbl_rec->name, 0, UBI_VOL_NAME_MAX + 1);
+ memcpy(vtbl_rec->name, name, name_len);
+ crc = crc32(UBI_CRC32_INIT, vtbl_rec,
+ UBI_VTBL_RECORD_SIZE_CRC);
+ vtbl_rec->crc = cpu_to_be32(crc);
+ }
+
+ layout_vol = ubi->volumes[vol_id2idx(ubi, UBI_LAYOUT_VOLUME_ID)];
+ for (i = 0; i < UBI_LAYOUT_VOLUME_EBS; i++) {
+ err = ubi_eba_unmap_leb(ubi, layout_vol, i);
+ if (err)
+ return err;
+
+ err = ubi_eba_write_leb(ubi, layout_vol, i, ubi->vtbl, 0,
+ ubi->vtbl_size, UBI_LONGTERM);
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
+
+/**
* vtbl_check - check if volume table is not corrupted and contains sensible
* data.
* @ubi: UBI device description object
diff --git a/include/mtd/ubi-user.h b/include/mtd/ubi-user.h
index a7421f1..bd93b57 100644
--- a/include/mtd/ubi-user.h
+++ b/include/mtd/ubi-user.h
@@ -58,6 +58,13 @@
* device should be used. A &struct ubi_rsvol_req object has to be properly
* filled and a pointer to it has to be passed to the IOCTL.
*
+ * UBI volumes re-name
+ * ~~~~~~~~~~~~~~~~~~~
+ *
+ * To rename several volumes atomically at one go, the %UBI_IOCRNVOL command
+ * of the UBI character device should be used. A &struct ubi_rnvol_req object
+ * has to be properly filled and a pointer to it has to be passed to the IOCTL.
+ *
* UBI volume update
* ~~~~~~~~~~~~~~~~~
*
@@ -104,6 +111,8 @@
#define UBI_IOCRMVOL _IOW(UBI_IOC_MAGIC, 1, int32_t)
/* Re-size an UBI volume */
#define UBI_IOCRSVOL _IOW(UBI_IOC_MAGIC, 2, struct ubi_rsvol_req)
+/* Re-name volumes */
+#define UBI_IOCRNVOL _IOW(UBI_IOC_MAGIC, 3, struct ubi_rnvol_req)
/* IOCTL commands of the UBI control character device */
@@ -128,6 +137,9 @@
/* Maximum MTD device name length supported by UBI */
#define MAX_UBI_MTD_NAME_LEN 127
+/* Maximum amount of UBI volumes that can be renamed at one go */
+#define UBI_MAX_RNVOL 32
+
/*
* UBI data type hint constants.
*
@@ -251,6 +263,36 @@ struct ubi_rsvol_req {
} __attribute__ ((packed));
/**
+ * struct ubi_rnvol_req - volumes rename request.
+ * @count: count of volumes to rename
+ * @padding1: reserved for future, not used, has to be zeroed
+ * @vol_id: ID of the volume to rename
+ * @name_len: name length
+ * @padding2: reserved for future, not used, has to be zeroed
+ * @name: new volume name
+ *
+ * UBI allows to rename up to %32 volumes at one go. The count of volumes to
+ * rename is specified in the @count field. The ID of the volumes to rename
+ * and the new names are specified in the @vol_id and @name fields.
+ *
+ * The UBI volume rename operation is atomic, which means that should power cut
+ * happen, the volumes will have either old name or new name. So the possible
+ * use-cases of this command is atomic upgrade. Indeed, to upgrade, say, volumes
+ * A and B one may create temporary volumes A1 and B1 with the new contents,
+ * then atomically rename A1->A and A->A1, B1->B and B->B1.
+ */
+struct ubi_rnvol_req {
+ int32_t count;
+ uint8_t padding1[12];
+ struct {
+ int32_t vol_id;
+ int16_t name_len;
+ uint8_t padding2[2];
+ char name[UBI_MAX_VOLUME_NAME + 1];
+ } vols[UBI_MAX_RNVOL];
+} __attribute__ ((packed));
+
+/**
* struct ubi_leb_change_req - a data structure used in atomic logical
* eraseblock change requests.
* @lnum: logical eraseblock number to change
--
1.5.4.1
--
Best regards,
Artem Bityutskiy (Битюцкий Артём)
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