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UBI: introduce volume refcounting

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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: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
This commit is contained in:
Artem Bityutskiy 2007-12-17 15:42:57 +02:00
parent db6e5770ef
commit d05c77a816
5 changed files with 84 additions and 42 deletions
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10
drivers/mtd/ubi/eba.c
View File

@ -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;

4
drivers/mtd/ubi/kapi.c
View File

@ -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);

22
drivers/mtd/ubi/ubi.h
View File

@ -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
@ -156,7 +156,7 @@ struct ubi_volume_desc;
* @corrupted: non-zero if the volume is corrupted (static volumes only)
* @alignment: volume alignment
* @data_pad: how many bytes are not used at the end of physical eraseblocks to
* satisfy the requested alignment
* satisfy the requested alignment
* @name_len: volume name length
* @name: volume name
*
@ -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
@ -273,11 +273,11 @@ struct ubi_wl_entry;
* @prot.pnum: protection tree indexed by physical eraseblock numbers
* @prot.aec: protection tree indexed by absolute erase counter value
* @wl_lock: protects the @used, @free, @prot, @lookuptbl, @abs_ec, @move_from,
* @move_to, @move_to_put @erase_pending, @wl_scheduled, and @works
* fields
* @move_to, @move_to_put @erase_pending, @wl_scheduled, and @works
* fields
* @wl_scheduled: non-zero if the wear-leveling was scheduled
* @lookuptbl: a table to quickly find a &struct ubi_wl_entry object for any
* physical eraseblock
* physical eraseblock
* @abs_ec: absolute erase counter
* @move_from: physical eraseblock from where the data is being moved
* @move_to: physical eraseblock where the data is being moved to
@ -308,13 +308,13 @@ struct ubi_wl_entry;
* @hdrs_min_io_size
* @vid_hdr_shift: contains @vid_hdr_offset - @vid_hdr_aloffset
* @bad_allowed: whether the MTD device admits of bad physical eraseblocks or
* not
* not
* @mtd: MTD device descriptor
*
* @peb_buf1: a buffer of PEB size used for different purposes
* @peb_buf2: another buffer of PEB size used for different purposes
* @buf_mutex: proptects @peb_buf1 and @peb_buf2
* @dbg_peb_buf: buffer of PEB size used for debugging
* @dbg_peb_buf: buffer of PEB size used for debugging
* @dbg_buf_mutex: proptects @dbg_peb_buf
*/
struct ubi_device {

88
drivers/mtd/ubi/vmt.c
View File

@ -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 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req)
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 @@ int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs)
* @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);
}

2
drivers/mtd/ubi/vtbl.c
View File

@ -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;