From: Artem Bityutskiy Date: Mon, 17 Dec 2007 13:42:57 +0000 (+0200) Subject: UBI: introduce volume refcounting X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=d05c77a816974c09f8c7e8f48e5b9f7b59dafdf3;p=GitHub%2FLineageOS%2Fandroid_kernel_samsung_universal7580.git 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: Artem Bityutskiy --- diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c index 2ff34923e51..84f7dc9fd3a 100644 --- a/drivers/mtd/ubi/eba.c +++ b/drivers/mtd/ubi/eba.c @@ -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; diff --git a/drivers/mtd/ubi/kapi.c b/drivers/mtd/ubi/kapi.c index 9c283768319..780c273ff45 100644 --- a/drivers/mtd/ubi/kapi.c +++ b/drivers/mtd/ubi/kapi.c @@ -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); diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h index 69cbee3be7a..f782d5aa849 100644 --- a/drivers/mtd/ubi/ubi.h +++ b/drivers/mtd/ubi/ubi.h @@ -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 { diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c index 3d6ac029c17..18ef1e1da49 100644 --- a/drivers/mtd/ubi/vmt.c +++ b/drivers/mtd/ubi/vmt.c @@ -63,21 +63,24 @@ static struct device_attribute attr_vol_upd_marker = * B. process 2 removes volume Y; * C. process 1 starts reading the //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); } diff --git a/drivers/mtd/ubi/vtbl.c b/drivers/mtd/ubi/vtbl.c index 5879fdb3e6d..a37dc7a213b 100644 --- a/drivers/mtd/ubi/vtbl.c +++ b/drivers/mtd/ubi/vtbl.c @@ -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;