diff options
author | Christoph Hellwig <hch@lst.de> | 2020-11-26 18:43:37 +0100 |
---|---|---|
committer | Jens Axboe <axboe@kernel.dk> | 2020-12-01 14:53:40 -0700 |
commit | a782483cc1f875355690625d8253a232f2581418 (patch) | |
tree | 492d3bf67cdd2535afd826dde93aa35dcfb42180 | |
parent | e6cb53827ed60019bbbc5cf189dd204b3b0e8121 (diff) | |
download | lwn-a782483cc1f875355690625d8253a232f2581418.tar.gz lwn-a782483cc1f875355690625d8253a232f2581418.zip |
block: remove the nr_sects field in struct hd_struct
Now that the hd_struct always has a block device attached to it, there is
no need for having two size field that just get out of sync.
Additionally the field in hd_struct did not use proper serialization,
possibly allowing for torn writes. By only using the block_device field
this problem also gets fixed.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Coly Li <colyli@suse.de> [bcache]
Acked-by: Chao Yu <yuchao0@huawei.com> [f2fs]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r-- | block/bio.c | 4 | ||||
-rw-r--r-- | block/blk-core.c | 2 | ||||
-rw-r--r-- | block/blk.h | 53 | ||||
-rw-r--r-- | block/genhd.c | 59 | ||||
-rw-r--r-- | block/partitions/core.c | 17 | ||||
-rw-r--r-- | drivers/block/loop.c | 1 | ||||
-rw-r--r-- | drivers/block/nbd.c | 2 | ||||
-rw-r--r-- | drivers/block/xen-blkback/common.h | 4 | ||||
-rw-r--r-- | drivers/md/bcache/super.c | 2 | ||||
-rw-r--r-- | drivers/s390/block/dasd_ioctl.c | 4 | ||||
-rw-r--r-- | drivers/target/target_core_pscsi.c | 5 | ||||
-rw-r--r-- | fs/block_dev.c | 73 | ||||
-rw-r--r-- | fs/f2fs/super.c | 2 | ||||
-rw-r--r-- | fs/pstore/blk.c | 2 | ||||
-rw-r--r-- | include/linux/genhd.h | 29 | ||||
-rw-r--r-- | kernel/trace/blktrace.c | 2 |
16 files changed, 67 insertions, 194 deletions
diff --git a/block/bio.c b/block/bio.c index fa01bef35bb1..669bb47a3198 100644 --- a/block/bio.c +++ b/block/bio.c @@ -613,8 +613,8 @@ void guard_bio_eod(struct bio *bio) rcu_read_lock(); part = __disk_get_part(bio->bi_disk, bio->bi_partno); if (part) - maxsector = part_nr_sects_read(part); - else + maxsector = bdev_nr_sectors(part->bdev); + else maxsector = get_capacity(bio->bi_disk); rcu_read_unlock(); diff --git a/block/blk-core.c b/block/blk-core.c index 2db8bda43b6e..988f45094a38 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -755,7 +755,7 @@ static inline int blk_partition_remap(struct bio *bio) goto out; if (bio_sectors(bio)) { - if (bio_check_eod(bio, part_nr_sects_read(p))) + if (bio_check_eod(bio, bdev_nr_sectors(p->bdev))) goto out; bio->bi_iter.bi_sector += p->start_sect; trace_block_bio_remap(bio->bi_disk->queue, bio, part_devt(p), diff --git a/block/blk.h b/block/blk.h index c4839abcfa27..09cee7024fb4 100644 --- a/block/blk.h +++ b/block/blk.h @@ -387,59 +387,6 @@ static inline void hd_free_part(struct hd_struct *part) percpu_ref_exit(&part->ref); } -/* - * Any access of part->nr_sects which is not protected by partition - * bd_mutex or gendisk bdev bd_mutex, should be done using this - * accessor function. - * - * Code written along the lines of i_size_read() and i_size_write(). - * CONFIG_PREEMPTION case optimizes the case of UP kernel with preemption - * on. - */ -static inline sector_t part_nr_sects_read(struct hd_struct *part) -{ -#if BITS_PER_LONG==32 && defined(CONFIG_SMP) - sector_t nr_sects; - unsigned seq; - do { - seq = read_seqcount_begin(&part->nr_sects_seq); - nr_sects = part->nr_sects; - } while (read_seqcount_retry(&part->nr_sects_seq, seq)); - return nr_sects; -#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION) - sector_t nr_sects; - - preempt_disable(); - nr_sects = part->nr_sects; - preempt_enable(); - return nr_sects; -#else - return part->nr_sects; -#endif -} - -/* - * Should be called with mutex lock held (typically bd_mutex) of partition - * to provide mutual exlusion among writers otherwise seqcount might be - * left in wrong state leaving the readers spinning infinitely. - */ -static inline void part_nr_sects_write(struct hd_struct *part, sector_t size) -{ -#if BITS_PER_LONG==32 && defined(CONFIG_SMP) - preempt_disable(); - write_seqcount_begin(&part->nr_sects_seq); - part->nr_sects = size; - write_seqcount_end(&part->nr_sects_seq); - preempt_enable(); -#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION) - preempt_disable(); - part->nr_sects = size; - preempt_enable(); -#else - part->nr_sects = size; -#endif -} - int bio_add_hw_page(struct request_queue *q, struct bio *bio, struct page *page, unsigned int len, unsigned int offset, unsigned int max_sectors, bool *same_page); diff --git a/block/genhd.c b/block/genhd.c index bf8fa82f135f..c65f485b9db5 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -40,6 +40,16 @@ static void disk_add_events(struct gendisk *disk); static void disk_del_events(struct gendisk *disk); static void disk_release_events(struct gendisk *disk); +void set_capacity(struct gendisk *disk, sector_t sectors) +{ + struct block_device *bdev = disk->part0.bdev; + + spin_lock(&bdev->bd_size_lock); + i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT); + spin_unlock(&bdev->bd_size_lock); +} +EXPORT_SYMBOL(set_capacity); + /* * Set disk capacity and notify if the size is not currently zero and will not * be set to zero. Returns true if a uevent was sent, otherwise false. @@ -47,18 +57,30 @@ static void disk_release_events(struct gendisk *disk); bool set_capacity_and_notify(struct gendisk *disk, sector_t size) { sector_t capacity = get_capacity(disk); + char *envp[] = { "RESIZE=1", NULL }; set_capacity(disk, size); - revalidate_disk_size(disk, true); - if (capacity != size && capacity != 0 && size != 0) { - char *envp[] = { "RESIZE=1", NULL }; + /* + * Only print a message and send a uevent if the gendisk is user visible + * and alive. This avoids spamming the log and udev when setting the + * initial capacity during probing. + */ + if (size == capacity || + (disk->flags & (GENHD_FL_UP | GENHD_FL_HIDDEN)) != GENHD_FL_UP) + return false; - kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp); - return true; - } + pr_info("%s: detected capacity change from %lld to %lld\n", + disk->disk_name, size, capacity); - return false; + /* + * Historically we did not send a uevent for changes to/from an empty + * device. + */ + if (!capacity || !size) + return false; + kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp); + return true; } EXPORT_SYMBOL_GPL(set_capacity_and_notify); @@ -247,7 +269,7 @@ struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter) part = rcu_dereference(ptbl->part[piter->idx]); if (!part) continue; - if (!part_nr_sects_read(part) && + if (!bdev_nr_sectors(part->bdev) && !(piter->flags & DISK_PITER_INCL_EMPTY) && !(piter->flags & DISK_PITER_INCL_EMPTY_PART0 && piter->idx == 0)) @@ -284,7 +306,7 @@ EXPORT_SYMBOL_GPL(disk_part_iter_exit); static inline int sector_in_part(struct hd_struct *part, sector_t sector) { return part->start_sect <= sector && - sector < part->start_sect + part_nr_sects_read(part); + sector < part->start_sect + bdev_nr_sectors(part->bdev); } /** @@ -986,8 +1008,8 @@ void __init printk_all_partitions(void) printk("%s%s %10llu %s %s", is_part0 ? "" : " ", bdevt_str(part_devt(part), devt_buf), - (unsigned long long)part_nr_sects_read(part) >> 1 - , disk_name(disk, part->partno, name_buf), + bdev_nr_sectors(part->bdev) >> 1, + disk_name(disk, part->partno, name_buf), part->info ? part->info->uuid : ""); if (is_part0) { if (dev->parent && dev->parent->driver) @@ -1079,7 +1101,7 @@ static int show_partition(struct seq_file *seqf, void *v) while ((part = disk_part_iter_next(&piter))) seq_printf(seqf, "%4d %7d %10llu %s\n", MAJOR(part_devt(part)), MINOR(part_devt(part)), - (unsigned long long)part_nr_sects_read(part) >> 1, + bdev_nr_sectors(part->bdev) >> 1, disk_name(sgp, part->partno, buf)); disk_part_iter_exit(&piter); @@ -1161,8 +1183,7 @@ ssize_t part_size_show(struct device *dev, { struct hd_struct *p = dev_to_part(dev); - return sprintf(buf, "%llu\n", - (unsigned long long)part_nr_sects_read(p)); + return sprintf(buf, "%llu\n", bdev_nr_sectors(p->bdev)); } ssize_t part_stat_show(struct device *dev, @@ -1618,16 +1639,6 @@ struct gendisk *__alloc_disk_node(int minors, int node_id) ptbl = rcu_dereference_protected(disk->part_tbl, 1); rcu_assign_pointer(ptbl->part[0], &disk->part0); - /* - * set_capacity() and get_capacity() currently don't use - * seqcounter to read/update the part0->nr_sects. Still init - * the counter as we can read the sectors in IO submission - * patch using seqence counters. - * - * TODO: Ideally set_capacity() and get_capacity() should be - * converted to make use of bd_mutex and sequence counters. - */ - hd_sects_seq_init(&disk->part0); if (hd_ref_init(&disk->part0)) goto out_free_bdstats; diff --git a/block/partitions/core.c b/block/partitions/core.c index 696bd9ff63c6..bcfa8215bd5e 100644 --- a/block/partitions/core.c +++ b/block/partitions/core.c @@ -85,6 +85,13 @@ static int (*check_part[])(struct parsed_partitions *) = { NULL }; +static void bdev_set_nr_sectors(struct block_device *bdev, sector_t sectors) +{ + spin_lock(&bdev->bd_size_lock); + i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT); + spin_unlock(&bdev->bd_size_lock); +} + static struct parsed_partitions *allocate_partitions(struct gendisk *hd) { struct parsed_partitions *state; @@ -295,7 +302,7 @@ static void hd_struct_free_work(struct work_struct *work) put_device(disk_to_dev(disk)); part->start_sect = 0; - part->nr_sects = 0; + bdev_set_nr_sectors(part->bdev, 0); part_stat_set_all(part, 0); put_device(part_to_dev(part)); } @@ -412,11 +419,10 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno, goto out_free_stats; p->bdev = bdev; - hd_sects_seq_init(p); pdev = part_to_dev(p); p->start_sect = start; - p->nr_sects = len; + bdev_set_nr_sectors(bdev, len); p->partno = partno; p->policy = get_disk_ro(disk); @@ -509,7 +515,7 @@ static bool partition_overlaps(struct gendisk *disk, sector_t start, disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY); while ((part = disk_part_iter_next(&piter))) { if (part->partno == skip_partno || - start >= part->start_sect + part->nr_sects || + start >= part->start_sect + bdev_nr_sectors(part->bdev) || start + length <= part->start_sect) continue; overlap = true; @@ -600,8 +606,7 @@ int bdev_resize_partition(struct block_device *bdev, int partno, if (partition_overlaps(bdev->bd_disk, start, length, partno)) goto out_unlock; - part_nr_sects_write(part, length); - bd_set_nr_sectors(bdevp, length); + bdev_set_nr_sectors(bdevp, length); ret = 0; out_unlock: diff --git a/drivers/block/loop.c b/drivers/block/loop.c index d643c67be6ac..d2ce1ddc192d 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1241,7 +1241,6 @@ static int __loop_clr_fd(struct loop_device *lo, bool release) set_capacity(lo->lo_disk, 0); loop_sysfs_exit(lo); if (bdev) { - bd_set_nr_sectors(bdev, 0); /* let user-space know about this change */ kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); } diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 45b0423ef2c5..014683968ce1 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -1132,7 +1132,7 @@ static void nbd_bdev_reset(struct block_device *bdev) { if (bdev->bd_openers > 1) return; - bd_set_nr_sectors(bdev, 0); + set_capacity(bdev->bd_disk, 0); } static void nbd_parse_flags(struct nbd_device *nbd) diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h index c6ea5d38c509..0762db247b41 100644 --- a/drivers/block/xen-blkback/common.h +++ b/drivers/block/xen-blkback/common.h @@ -358,9 +358,7 @@ struct pending_req { }; -#define vbd_sz(_v) ((_v)->bdev->bd_part ? \ - (_v)->bdev->bd_part->nr_sects : \ - get_capacity((_v)->bdev->bd_disk)) +#define vbd_sz(_v) bdev_nr_sectors((_v)->bdev) #define xen_blkif_get(_b) (atomic_inc(&(_b)->refcnt)) #define xen_blkif_put(_b) \ diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c index c55d3c58a7ef..04fa40868fbe 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -1408,7 +1408,7 @@ static int cached_dev_init(struct cached_dev *dc, unsigned int block_size) q->limits.raid_partial_stripes_expensive; ret = bcache_device_init(&dc->disk, block_size, - dc->bdev->bd_part->nr_sects - dc->sb.data_offset, + bdev_nr_sectors(dc->bdev) - dc->sb.data_offset, dc->bdev, &bcache_cached_ops); if (ret) return ret; diff --git a/drivers/s390/block/dasd_ioctl.c b/drivers/s390/block/dasd_ioctl.c index 3359559517bf..304eba1acf16 100644 --- a/drivers/s390/block/dasd_ioctl.c +++ b/drivers/s390/block/dasd_ioctl.c @@ -54,8 +54,6 @@ dasd_ioctl_enable(struct block_device *bdev) return -ENODEV; dasd_enable_device(base); - /* Formatting the dasd device can change the capacity. */ - bd_set_nr_sectors(bdev, get_capacity(base->block->gdp)); dasd_put_device(base); return 0; } @@ -88,7 +86,7 @@ dasd_ioctl_disable(struct block_device *bdev) * Set i_size to zero, since read, write, etc. check against this * value. */ - bd_set_nr_sectors(bdev, 0); + set_capacity(bdev->bd_disk, 0); dasd_put_device(base); return 0; } diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c index 4e37fa9b409d..7994f27e4527 100644 --- a/drivers/target/target_core_pscsi.c +++ b/drivers/target/target_core_pscsi.c @@ -1029,9 +1029,8 @@ static sector_t pscsi_get_blocks(struct se_device *dev) { struct pscsi_dev_virt *pdv = PSCSI_DEV(dev); - if (pdv->pdv_bd && pdv->pdv_bd->bd_part) - return pdv->pdv_bd->bd_part->nr_sects; - + if (pdv->pdv_bd) + return bdev_nr_sectors(pdv->pdv_bd); return 0; } diff --git a/fs/block_dev.c b/fs/block_dev.c index a5b6955a841f..31ee5a857f71 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1208,70 +1208,6 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk) EXPORT_SYMBOL_GPL(bd_unlink_disk_holder); #endif -/** - * check_disk_size_change - checks for disk size change and adjusts bdev size. - * @disk: struct gendisk to check - * @bdev: struct bdev to adjust. - * @verbose: if %true log a message about a size change if there is any - * - * This routine checks to see if the bdev size does not match the disk size - * and adjusts it if it differs. When shrinking the bdev size, its all caches - * are freed. - */ -static void check_disk_size_change(struct gendisk *disk, - struct block_device *bdev, bool verbose) -{ - loff_t disk_size, bdev_size; - - spin_lock(&bdev->bd_size_lock); - disk_size = (loff_t)get_capacity(disk) << 9; - bdev_size = i_size_read(bdev->bd_inode); - if (disk_size != bdev_size) { - if (verbose) { - printk(KERN_INFO - "%s: detected capacity change from %lld to %lld\n", - disk->disk_name, bdev_size, disk_size); - } - i_size_write(bdev->bd_inode, disk_size); - } - spin_unlock(&bdev->bd_size_lock); -} - -/** - * revalidate_disk_size - checks for disk size change and adjusts bdev size. - * @disk: struct gendisk to check - * @verbose: if %true log a message about a size change if there is any - * - * This routine checks to see if the bdev size does not match the disk size - * and adjusts it if it differs. When shrinking the bdev size, its all caches - * are freed. - */ -void revalidate_disk_size(struct gendisk *disk, bool verbose) -{ - struct block_device *bdev; - - /* - * Hidden disks don't have associated bdev so there's no point in - * revalidating them. - */ - if (disk->flags & GENHD_FL_HIDDEN) - return; - - bdev = bdget_disk(disk, 0); - if (bdev) { - check_disk_size_change(disk, bdev, verbose); - bdput(bdev); - } -} - -void bd_set_nr_sectors(struct block_device *bdev, sector_t sectors) -{ - spin_lock(&bdev->bd_size_lock); - i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT); - spin_unlock(&bdev->bd_size_lock); -} -EXPORT_SYMBOL(bd_set_nr_sectors); - static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part); int bdev_disk_changed(struct block_device *bdev, bool invalidate) @@ -1305,8 +1241,6 @@ rescan: disk->fops->revalidate_disk(disk); } - check_disk_size_change(disk, bdev, !invalidate); - if (get_capacity(disk)) { ret = blk_add_partitions(disk, bdev); if (ret == -EAGAIN) @@ -1349,10 +1283,8 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode) if (disk->fops->open) ret = disk->fops->open(bdev, mode); - if (!ret) { - bd_set_nr_sectors(bdev, get_capacity(disk)); + if (!ret) set_init_blocksize(bdev); - } /* * If the device is invalidated, rescan partition @@ -1381,13 +1313,12 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode) bdev->bd_part = disk_get_part(disk, bdev->bd_partno); if (!(disk->flags & GENHD_FL_UP) || - !bdev->bd_part || !bdev->bd_part->nr_sects) { + !bdev->bd_part || !bdev_nr_sectors(bdev)) { __blkdev_put(whole, mode, 1); bdput(whole); ret = -ENXIO; goto out_clear; } - bd_set_nr_sectors(bdev, bdev->bd_part->nr_sects); set_init_blocksize(bdev); } diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 00eff2f51807..d4e7fab352ba 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -3151,7 +3151,7 @@ static int f2fs_report_zone_cb(struct blk_zone *zone, unsigned int idx, static int init_blkz_info(struct f2fs_sb_info *sbi, int devi) { struct block_device *bdev = FDEV(devi).bdev; - sector_t nr_sectors = bdev->bd_part->nr_sects; + sector_t nr_sectors = bdev_nr_sectors(bdev); struct f2fs_report_zones_args rep_zone_arg; int ret; diff --git a/fs/pstore/blk.c b/fs/pstore/blk.c index fcd5563dde06..777a26f7bbe2 100644 --- a/fs/pstore/blk.c +++ b/fs/pstore/blk.c @@ -245,7 +245,7 @@ static struct block_device *psblk_get_bdev(void *holder, return bdev; } - nr_sects = part_nr_sects_read(bdev->bd_part); + nr_sects = bdev_nr_sectors(bdev); if (!nr_sects) { pr_err("not enough space for '%s'\n", blkdev); blkdev_put(bdev, mode); diff --git a/include/linux/genhd.h b/include/linux/genhd.h index 6ba91ee54cb2..30d4785b7df8 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -52,15 +52,6 @@ struct partition_meta_info { struct hd_struct { sector_t start_sect; - /* - * nr_sects is protected by sequence counter. One might extend a - * partition while IO is happening to it and update of nr_sects - * can be non-atomic on 32bit machines with 64bit sector_t. - */ - sector_t nr_sects; -#if BITS_PER_LONG==32 && defined(CONFIG_SMP) - seqcount_t nr_sects_seq; -#endif unsigned long stamp; struct disk_stats __percpu *dkstats; struct percpu_ref ref; @@ -254,13 +245,6 @@ static inline void disk_put_part(struct hd_struct *part) put_device(part_to_dev(part)); } -static inline void hd_sects_seq_init(struct hd_struct *p) -{ -#if BITS_PER_LONG==32 && defined(CONFIG_SMP) - seqcount_init(&p->nr_sects_seq); -#endif -} - /* * Smarter partition iterator without context limits. */ @@ -318,13 +302,15 @@ static inline sector_t get_start_sect(struct block_device *bdev) { return bdev->bd_part->start_sect; } -static inline sector_t get_capacity(struct gendisk *disk) + +static inline sector_t bdev_nr_sectors(struct block_device *bdev) { - return disk->part0.nr_sects; + return i_size_read(bdev->bd_inode) >> 9; } -static inline void set_capacity(struct gendisk *disk, sector_t size) + +static inline sector_t get_capacity(struct gendisk *disk) { - disk->part0.nr_sects = size; + return bdev_nr_sectors(disk->part0.bdev); } int bdev_disk_changed(struct block_device *bdev, bool invalidate); @@ -358,10 +344,9 @@ int __register_blkdev(unsigned int major, const char *name, __register_blkdev(major, name, NULL) void unregister_blkdev(unsigned int major, const char *name); -void revalidate_disk_size(struct gendisk *disk, bool verbose); bool bdev_check_media_change(struct block_device *bdev); int __invalidate_device(struct block_device *bdev, bool kill_dirty); -void bd_set_nr_sectors(struct block_device *bdev, sector_t sectors); +void set_capacity(struct gendisk *disk, sector_t size); /* for drivers/char/raw.c: */ int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long); diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index f1022945e346..7076d588a50d 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -465,7 +465,7 @@ static void blk_trace_setup_lba(struct blk_trace *bt, if (part) { bt->start_lba = part->start_sect; - bt->end_lba = part->start_sect + part->nr_sects; + bt->end_lba = part->start_sect + bdev_nr_sectors(bdev); } else { bt->start_lba = 0; bt->end_lba = -1ULL; |