X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=drivers%2Fblock%2Floop.c;h=ddae80825899ae0459bff4a8109d8fc3468868c3;hb=8be741b0ac8e8857fb64da269e81da8a131377bb;hp=af6d7274a7cc9a28c84d5bf7a4dfba1b6fdf0789;hpb=73285082745045bcd64333c1fbaa88f8490f2626;p=safe%2Fjmp%2Flinux-2.6 diff --git a/drivers/block/loop.c b/drivers/block/loop.c index af6d727..ddae808 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -29,7 +29,7 @@ * * Maximum number of loop devices when compiled-in now selectable by passing * max_loop=<1-255> to the kernel on boot. - * Erik I. Bolsø, , Oct 31, 1999 + * Erik I. Bolsø, , Oct 31, 1999 * * Completely rewrite request handling to be make_request_fn style and * non blocking, pushing work to a helper thread. Lots of fixes from @@ -40,8 +40,7 @@ * Heinz Mauelshagen , Feb 2002 * * Support for falling back on the write file operation when the address space - * operations prepare_write and/or commit_write are not available on the - * backing filesystem. + * operations write_begin is not available on the backing filesystem. * Anton Altaparmakov, 16 Feb 2005 * * Still To Fix: @@ -68,18 +67,23 @@ #include #include #include +#include #include #include /* for invalidate_bdev() */ #include #include #include #include +#include #include static LIST_HEAD(loop_devices); static DEFINE_MUTEX(loop_devices_mutex); +static int max_part; +static int part_shift; + /* * Transfer functions */ @@ -202,14 +206,13 @@ lo_do_transfer(struct loop_device *lo, int cmd, * do_lo_send_aops - helper for writing data to a loop device * * This is the fast version for backing filesystems which implement the address - * space operations prepare_write and commit_write. + * space operations write_begin and write_end. */ static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec, - int bsize, loff_t pos, struct page *page) + loff_t pos, struct page *unused) { struct file *file = lo->lo_backing_file; /* kudos to NFsckingS */ struct address_space *mapping = file->f_mapping; - const struct address_space_operations *aops = mapping->a_ops; pgoff_t index; unsigned offset, bv_offs; int len, ret; @@ -221,67 +224,45 @@ static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec, len = bvec->bv_len; while (len > 0) { sector_t IV; - unsigned size; + unsigned size, copied; int transfer_result; + struct page *page; + void *fsdata; IV = ((sector_t)index << (PAGE_CACHE_SHIFT - 9))+(offset >> 9); size = PAGE_CACHE_SIZE - offset; if (size > len) size = len; - page = grab_cache_page(mapping, index); - if (unlikely(!page)) + + ret = pagecache_write_begin(file, mapping, pos, size, 0, + &page, &fsdata); + if (ret) goto fail; - ret = aops->prepare_write(file, page, offset, - offset + size); - if (unlikely(ret)) { - if (ret == AOP_TRUNCATED_PAGE) { - page_cache_release(page); - continue; - } - goto unlock; - } + transfer_result = lo_do_transfer(lo, WRITE, page, offset, bvec->bv_page, bv_offs, size, IV); - if (unlikely(transfer_result)) { - char *kaddr; - - /* - * The transfer failed, but we still write the data to - * keep prepare/commit calls balanced. - */ - printk(KERN_ERR "loop: transfer error block %llu\n", - (unsigned long long)index); - kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr + offset, 0, size); - kunmap_atomic(kaddr, KM_USER0); - } - flush_dcache_page(page); - ret = aops->commit_write(file, page, offset, - offset + size); - if (unlikely(ret)) { - if (ret == AOP_TRUNCATED_PAGE) { - page_cache_release(page); - continue; - } - goto unlock; - } + copied = size; if (unlikely(transfer_result)) - goto unlock; - bv_offs += size; - len -= size; + copied = 0; + + ret = pagecache_write_end(file, mapping, pos, size, copied, + page, fsdata); + if (ret < 0 || ret != copied) + goto fail; + + if (unlikely(transfer_result)) + goto fail; + + bv_offs += copied; + len -= copied; offset = 0; index++; - pos += size; - unlock_page(page); - page_cache_release(page); + pos += copied; } ret = 0; out: mutex_unlock(&mapping->host->i_mutex); return ret; -unlock: - unlock_page(page); - page_cache_release(page); fail: ret = -1; goto out; @@ -315,12 +296,12 @@ static int __do_lo_send_write(struct file *file, * do_lo_send_direct_write - helper for writing data to a loop device * * This is the fast, non-transforming version for backing filesystems which do - * not implement the address space operations prepare_write and commit_write. + * not implement the address space operations write_begin and write_end. * It uses the write file operation which should be present on all writeable * filesystems. */ static int do_lo_send_direct_write(struct loop_device *lo, - struct bio_vec *bvec, int bsize, loff_t pos, struct page *page) + struct bio_vec *bvec, loff_t pos, struct page *page) { ssize_t bw = __do_lo_send_write(lo->lo_backing_file, kmap(bvec->bv_page) + bvec->bv_offset, @@ -334,7 +315,7 @@ static int do_lo_send_direct_write(struct loop_device *lo, * do_lo_send_write - helper for writing data to a loop device * * This is the slow, transforming version for filesystems which do not - * implement the address space operations prepare_write and commit_write. It + * implement the address space operations write_begin and write_end. It * uses the write file operation which should be present on all writeable * filesystems. * @@ -344,7 +325,7 @@ static int do_lo_send_direct_write(struct loop_device *lo, * destination pages of the backing file. */ static int do_lo_send_write(struct loop_device *lo, struct bio_vec *bvec, - int bsize, loff_t pos, struct page *page) + loff_t pos, struct page *page) { int ret = lo_do_transfer(lo, WRITE, page, 0, bvec->bv_page, bvec->bv_offset, bvec->bv_len, pos >> 9); @@ -359,10 +340,9 @@ static int do_lo_send_write(struct loop_device *lo, struct bio_vec *bvec, return ret; } -static int lo_send(struct loop_device *lo, struct bio *bio, int bsize, - loff_t pos) +static int lo_send(struct loop_device *lo, struct bio *bio, loff_t pos) { - int (*do_lo_send)(struct loop_device *, struct bio_vec *, int, loff_t, + int (*do_lo_send)(struct loop_device *, struct bio_vec *, loff_t, struct page *page); struct bio_vec *bvec; struct page *page = NULL; @@ -380,7 +360,7 @@ static int lo_send(struct loop_device *lo, struct bio *bio, int bsize, } } bio_for_each_segment(bvec, bio, i) { - ret = do_lo_send(lo, bvec, bsize, pos, page); + ret = do_lo_send(lo, bvec, pos, page); if (ret < 0) break; pos += bvec->bv_len; @@ -405,50 +385,72 @@ struct lo_read_data { }; static int -lo_read_actor(read_descriptor_t *desc, struct page *page, - unsigned long offset, unsigned long size) +lo_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf, + struct splice_desc *sd) { - unsigned long count = desc->count; - struct lo_read_data *p = desc->arg.data; + struct lo_read_data *p = sd->u.data; struct loop_device *lo = p->lo; + struct page *page = buf->page; sector_t IV; + int size, ret; - IV = ((sector_t) page->index << (PAGE_CACHE_SHIFT - 9))+(offset >> 9); + ret = buf->ops->confirm(pipe, buf); + if (unlikely(ret)) + return ret; - if (size > count) - size = count; + IV = ((sector_t) page->index << (PAGE_CACHE_SHIFT - 9)) + + (buf->offset >> 9); + size = sd->len; + if (size > p->bsize) + size = p->bsize; - if (lo_do_transfer(lo, READ, page, offset, p->page, p->offset, size, IV)) { - size = 0; + if (lo_do_transfer(lo, READ, page, buf->offset, p->page, p->offset, size, IV)) { printk(KERN_ERR "loop: transfer error block %ld\n", page->index); - desc->error = -EINVAL; + size = -EINVAL; } flush_dcache_page(p->page); - desc->count = count - size; - desc->written += size; - p->offset += size; + if (size > 0) + p->offset += size; + return size; } static int +lo_direct_splice_actor(struct pipe_inode_info *pipe, struct splice_desc *sd) +{ + return __splice_from_pipe(pipe, sd, lo_splice_actor); +} + +static int do_lo_receive(struct loop_device *lo, struct bio_vec *bvec, int bsize, loff_t pos) { struct lo_read_data cookie; + struct splice_desc sd; struct file *file; - int retval; + long retval; cookie.lo = lo; cookie.page = bvec->bv_page; cookie.offset = bvec->bv_offset; cookie.bsize = bsize; + + sd.len = 0; + sd.total_len = bvec->bv_len; + sd.flags = 0; + sd.pos = pos; + sd.u.data = &cookie; + file = lo->lo_backing_file; - retval = file->f_op->sendfile(file, &pos, bvec->bv_len, - lo_read_actor, &cookie); - return (retval < 0)? retval: 0; + retval = splice_direct_to_actor(file, &sd, lo_direct_splice_actor); + + if (retval < 0) + return retval; + + return 0; } static int @@ -472,10 +474,35 @@ static int do_bio_filebacked(struct loop_device *lo, struct bio *bio) int ret; pos = ((loff_t) bio->bi_sector << 9) + lo->lo_offset; - if (bio_rw(bio) == WRITE) - ret = lo_send(lo, bio, lo->lo_blocksize, pos); - else + + if (bio_rw(bio) == WRITE) { + int barrier = bio_barrier(bio); + struct file *file = lo->lo_backing_file; + + if (barrier) { + if (unlikely(!file->f_op->fsync)) { + ret = -EOPNOTSUPP; + goto out; + } + + ret = vfs_fsync(file, file->f_path.dentry, 0); + if (unlikely(ret)) { + ret = -EIO; + goto out; + } + } + + ret = lo_send(lo, bio, pos); + + if (barrier && !ret) { + ret = vfs_fsync(file, file->f_path.dentry, 0); + if (unlikely(ret)) + ret = -EIO; + } + } else ret = lo_receive(lo, bio, lo->lo_blocksize, pos); + +out: return ret; } @@ -508,7 +535,7 @@ static struct bio *loop_get_bio(struct loop_device *lo) return bio; } -static int loop_make_request(request_queue_t *q, struct bio *old_bio) +static int loop_make_request(struct request_queue *q, struct bio *old_bio) { struct loop_device *lo = q->queuedata; int rw = bio_rw(old_bio); @@ -530,18 +557,18 @@ static int loop_make_request(request_queue_t *q, struct bio *old_bio) out: spin_unlock_irq(&lo->lo_lock); - bio_io_error(old_bio, old_bio->bi_size); + bio_io_error(old_bio); return 0; } /* * kick off io on the underlying address space */ -static void loop_unplug(request_queue_t *q) +static void loop_unplug(struct request_queue *q) { struct loop_device *lo = q->queuedata; - clear_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags); + queue_flag_clear_unlocked(QUEUE_FLAG_PLUGGED, q); blk_run_address_space(lo->lo_backing_file->f_mapping); } @@ -559,7 +586,7 @@ static inline void loop_handle_bio(struct loop_device *lo, struct bio *bio) bio_put(bio); } else { int ret = do_bio_filebacked(lo, bio); - bio_endio(bio, bio->bi_size, ret); + bio_endio(bio, ret); } } @@ -580,13 +607,6 @@ static int loop_thread(void *data) struct loop_device *lo = data; struct bio *bio; - /* - * loop can be used in an encrypted device, - * hence, it mustn't be stopped at all - * because it could be indirectly used during suspension - */ - current->flags |= PF_NOFREEZE; - set_user_nice(current, -20); while (!kthread_should_stop() || lo->lo_bio) { @@ -615,7 +635,7 @@ static int loop_thread(void *data) static int loop_switch(struct loop_device *lo, struct file *file) { struct switch_request w; - struct bio *bio = bio_alloc(GFP_KERNEL, 1); + struct bio *bio = bio_alloc(GFP_KERNEL, 0); if (!bio) return -ENOMEM; init_completion(&w.wait); @@ -628,20 +648,38 @@ static int loop_switch(struct loop_device *lo, struct file *file) } /* + * Helper to flush the IOs in loop, but keeping loop thread running + */ +static int loop_flush(struct loop_device *lo) +{ + /* loop not yet configured, no running thread, nothing to flush */ + if (!lo->lo_thread) + return 0; + + return loop_switch(lo, NULL); +} + +/* * Do the actual switch; called from the BIO completion routine */ static void do_loop_switch(struct loop_device *lo, struct switch_request *p) { struct file *file = p->file; struct file *old_file = lo->lo_backing_file; - struct address_space *mapping = file->f_mapping; + struct address_space *mapping; + + /* if no new file, only flush of queued bios requested */ + if (!file) + goto out; + mapping = file->f_mapping; mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask); lo->lo_backing_file = file; lo->lo_blocksize = S_ISBLK(mapping->host->i_mode) ? mapping->host->i_bdev->bd_block_size : PAGE_SIZE; lo->old_gfp_mask = mapping_gfp_mask(mapping); mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); +out: complete(&p->wait); } @@ -654,8 +692,8 @@ static void do_loop_switch(struct loop_device *lo, struct switch_request *p) * This can only work if the loop device is used read-only, and if the * new backing store is the same size and type as the old backing store. */ -static int loop_change_fd(struct loop_device *lo, struct file *lo_file, - struct block_device *bdev, unsigned int arg) +static int loop_change_fd(struct loop_device *lo, struct block_device *bdev, + unsigned int arg) { struct file *file, *old_file; struct inode *inode; @@ -683,8 +721,8 @@ static int loop_change_fd(struct loop_device *lo, struct file *lo_file, if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode)) goto out_putf; - /* new backing store needs to support loop (eg sendfile) */ - if (!inode->i_fop->sendfile) + /* new backing store needs to support loop (eg splice_read) */ + if (!inode->i_fop->splice_read) goto out_putf; /* size of the new backing store needs to be the same */ @@ -697,6 +735,8 @@ static int loop_change_fd(struct loop_device *lo, struct file *lo_file, goto out_putf; fput(old_file); + if (max_part > 0) + ioctl_by_bdev(bdev, BLKRRPART, 0); return 0; out_putf: @@ -712,7 +752,7 @@ static inline int is_loop_device(struct file *file) return i && S_ISBLK(i->i_mode) && MAJOR(i->i_rdev) == LOOP_MAJOR; } -static int loop_set_fd(struct loop_device *lo, struct file *lo_file, +static int loop_set_fd(struct loop_device *lo, fmode_t mode, struct block_device *bdev, unsigned int arg) { struct file *file, *f; @@ -740,7 +780,7 @@ static int loop_set_fd(struct loop_device *lo, struct file *lo_file, while (is_loop_device(f)) { struct loop_device *l; - if (f->f_mapping->host->i_rdev == lo_file->f_mapping->host->i_rdev) + if (f->f_mapping->host->i_bdev == bdev) goto out_putf; l = f->f_mapping->host->i_bdev->bd_disk->private_data; @@ -764,9 +804,9 @@ static int loop_set_fd(struct loop_device *lo, struct file *lo_file, * If we can't read - sorry. If we only can't write - well, * it's going to be read-only. */ - if (!file->f_op->sendfile) + if (!file->f_op->splice_read) goto out_putf; - if (aops->prepare_write && aops->commit_write) + if (aops->write_begin) lo_flags |= LO_FLAGS_USE_AOPS; if (!(lo_flags & LO_FLAGS_USE_AOPS) && !file->f_op->write) lo_flags |= LO_FLAGS_READ_ONLY; @@ -786,7 +826,7 @@ static int loop_set_fd(struct loop_device *lo, struct file *lo_file, goto out_putf; } - if (!(lo_file->f_mode & FMODE_WRITE)) + if (!(mode & FMODE_WRITE)) lo_flags |= LO_FLAGS_READ_ONLY; set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0); @@ -811,6 +851,9 @@ static int loop_set_fd(struct loop_device *lo, struct file *lo_file, lo->lo_queue->queuedata = lo; lo->lo_queue->unplug_fn = loop_unplug; + if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync) + blk_queue_ordered(lo->lo_queue, QUEUE_ORDERED_DRAIN, NULL); + set_capacity(lo->lo_disk, size); bd_set_size(bdev, size << 9); @@ -824,6 +867,8 @@ static int loop_set_fd(struct loop_device *lo, struct file *lo_file, } lo->lo_state = Lo_bound; wake_up_process(lo->lo_thread); + if (max_part > 0) + ioctl_by_bdev(bdev, BLKRRPART, 0); return 0; out_clr: @@ -901,6 +946,7 @@ static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev) kthread_stop(lo->lo_thread); + lo->lo_queue->unplug_fn = NULL; lo->lo_backing_file = NULL; loop_release_xfer(lo); @@ -916,14 +962,25 @@ static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev) memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE); memset(lo->lo_crypt_name, 0, LO_NAME_SIZE); memset(lo->lo_file_name, 0, LO_NAME_SIZE); - invalidate_bdev(bdev); + if (bdev) + invalidate_bdev(bdev); set_capacity(lo->lo_disk, 0); - bd_set_size(bdev, 0); + if (bdev) + bd_set_size(bdev, 0); mapping_set_gfp_mask(filp->f_mapping, gfp); lo->lo_state = Lo_unbound; - fput(filp); /* This is safe: open() is still holding a reference. */ module_put(THIS_MODULE); + if (max_part > 0) + ioctl_by_bdev(bdev, BLKRRPART, 0); + mutex_unlock(&lo->lo_ctl_mutex); + /* + * Need not hold lo_ctl_mutex to fput backing file. + * Calling fput holding lo_ctl_mutex triggers a circular + * lock dependency possibility warning as fput can take + * bd_mutex which is usually taken before lo_ctl_mutex. + */ + fput(filp); return 0; } @@ -932,8 +989,10 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) { int err; struct loop_func_table *xfer; + uid_t uid = current_uid(); - if (lo->lo_encrypt_key_size && lo->lo_key_owner != current->uid && + if (lo->lo_encrypt_key_size && + lo->lo_key_owner != uid && !capable(CAP_SYS_ADMIN)) return -EPERM; if (lo->lo_state != Lo_bound) @@ -978,13 +1037,17 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) lo->transfer = xfer->transfer; lo->ioctl = xfer->ioctl; + if ((lo->lo_flags & LO_FLAGS_AUTOCLEAR) != + (info->lo_flags & LO_FLAGS_AUTOCLEAR)) + lo->lo_flags ^= LO_FLAGS_AUTOCLEAR; + lo->lo_encrypt_key_size = info->lo_encrypt_key_size; lo->lo_init[0] = info->lo_init[0]; lo->lo_init[1] = info->lo_init[1]; if (info->lo_encrypt_key_size) { memcpy(lo->lo_encrypt_key, info->lo_encrypt_key, info->lo_encrypt_key_size); - lo->lo_key_owner = current->uid; + lo->lo_key_owner = uid; } return 0; @@ -1129,22 +1192,49 @@ loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) { return err; } -static int lo_ioctl(struct inode * inode, struct file * file, +static int loop_set_capacity(struct loop_device *lo, struct block_device *bdev) +{ + int err; + sector_t sec; + loff_t sz; + + err = -ENXIO; + if (unlikely(lo->lo_state != Lo_bound)) + goto out; + err = figure_loop_size(lo); + if (unlikely(err)) + goto out; + sec = get_capacity(lo->lo_disk); + /* the width of sector_t may be narrow for bit-shift */ + sz = sec; + sz <<= 9; + mutex_lock(&bdev->bd_mutex); + bd_set_size(bdev, sz); + mutex_unlock(&bdev->bd_mutex); + + out: + return err; +} + +static int lo_ioctl(struct block_device *bdev, fmode_t mode, unsigned int cmd, unsigned long arg) { - struct loop_device *lo = inode->i_bdev->bd_disk->private_data; + struct loop_device *lo = bdev->bd_disk->private_data; int err; - mutex_lock(&lo->lo_ctl_mutex); + mutex_lock_nested(&lo->lo_ctl_mutex, 1); switch (cmd) { case LOOP_SET_FD: - err = loop_set_fd(lo, file, inode->i_bdev, arg); + err = loop_set_fd(lo, mode, bdev, arg); break; case LOOP_CHANGE_FD: - err = loop_change_fd(lo, file, inode->i_bdev, arg); + err = loop_change_fd(lo, bdev, arg); break; case LOOP_CLR_FD: - err = loop_clr_fd(lo, inode->i_bdev); + /* loop_clr_fd would have unlocked lo_ctl_mutex on success */ + err = loop_clr_fd(lo, bdev); + if (!err) + goto out_unlocked; break; case LOOP_SET_STATUS: err = loop_set_status_old(lo, (struct loop_info __user *) arg); @@ -1158,10 +1248,17 @@ static int lo_ioctl(struct inode * inode, struct file * file, case LOOP_GET_STATUS64: err = loop_get_status64(lo, (struct loop_info64 __user *) arg); break; + case LOOP_SET_CAPACITY: + err = -EPERM; + if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) + err = loop_set_capacity(lo, bdev); + break; default: err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL; } mutex_unlock(&lo->lo_ctl_mutex); + +out_unlocked: return err; } @@ -1284,13 +1381,12 @@ loop_get_status_compat(struct loop_device *lo, return err; } -static long lo_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +static int lo_compat_ioctl(struct block_device *bdev, fmode_t mode, + unsigned int cmd, unsigned long arg) { - struct inode *inode = file->f_path.dentry->d_inode; - struct loop_device *lo = inode->i_bdev->bd_disk->private_data; + struct loop_device *lo = bdev->bd_disk->private_data; int err; - lock_kernel(); switch(cmd) { case LOOP_SET_STATUS: mutex_lock(&lo->lo_ctl_mutex); @@ -1304,59 +1400,63 @@ static long lo_compat_ioctl(struct file *file, unsigned int cmd, unsigned long a lo, (struct compat_loop_info __user *) arg); mutex_unlock(&lo->lo_ctl_mutex); break; + case LOOP_SET_CAPACITY: case LOOP_CLR_FD: case LOOP_GET_STATUS64: case LOOP_SET_STATUS64: arg = (unsigned long) compat_ptr(arg); case LOOP_SET_FD: case LOOP_CHANGE_FD: - err = lo_ioctl(inode, file, cmd, arg); + err = lo_ioctl(bdev, mode, cmd, arg); break; default: err = -ENOIOCTLCMD; break; } - unlock_kernel(); return err; } #endif -static struct loop_device *loop_find_dev(int number) +static int lo_open(struct block_device *bdev, fmode_t mode) { - struct loop_device *lo; - - list_for_each_entry(lo, &loop_devices, lo_list) { - if (lo->lo_number == number) - return lo; - } - return NULL; -} - -static struct loop_device *loop_init_one(int i); -static int lo_open(struct inode *inode, struct file *file) -{ - struct loop_device *lo = inode->i_bdev->bd_disk->private_data; + struct loop_device *lo = bdev->bd_disk->private_data; mutex_lock(&lo->lo_ctl_mutex); lo->lo_refcnt++; mutex_unlock(&lo->lo_ctl_mutex); - mutex_lock(&loop_devices_mutex); - if (!loop_find_dev(lo->lo_number + 1)) - loop_init_one(lo->lo_number + 1); - mutex_unlock(&loop_devices_mutex); - return 0; } -static int lo_release(struct inode *inode, struct file *file) +static int lo_release(struct gendisk *disk, fmode_t mode) { - struct loop_device *lo = inode->i_bdev->bd_disk->private_data; + struct loop_device *lo = disk->private_data; + int err; mutex_lock(&lo->lo_ctl_mutex); - --lo->lo_refcnt; - mutex_unlock(&lo->lo_ctl_mutex); + if (--lo->lo_refcnt) + goto out; + + if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) { + /* + * In autoclear mode, stop the loop thread + * and remove configuration after last close. + */ + err = loop_clr_fd(lo, NULL); + if (!err) + goto out_unlocked; + } else { + /* + * Otherwise keep thread (if running) and config, + * but flush possible ongoing bios in thread. + */ + loop_flush(lo); + } + +out: + mutex_unlock(&lo->lo_ctl_mutex); +out_unlocked: return 0; } @@ -1375,7 +1475,9 @@ static struct block_device_operations lo_fops = { */ static int max_loop; module_param(max_loop, int, 0); -MODULE_PARM_DESC(max_loop, "obsolete, loop device is created on-demand"); +MODULE_PARM_DESC(max_loop, "Maximum number of loop devices"); +module_param(max_part, int, 0); +MODULE_PARM_DESC(max_part, "Maximum number of partitions per loop device"); MODULE_LICENSE("GPL"); MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR); @@ -1415,7 +1517,7 @@ int loop_unregister_transfer(int number) EXPORT_SYMBOL(loop_register_transfer); EXPORT_SYMBOL(loop_unregister_transfer); -static struct loop_device *loop_init_one(int i) +static struct loop_device *loop_alloc(int i) { struct loop_device *lo; struct gendisk *disk; @@ -1428,7 +1530,7 @@ static struct loop_device *loop_init_one(int i) if (!lo->lo_queue) goto out_free_dev; - disk = lo->lo_disk = alloc_disk(1); + disk = lo->lo_disk = alloc_disk(1 << part_shift); if (!disk) goto out_free_queue; @@ -1438,13 +1540,11 @@ static struct loop_device *loop_init_one(int i) init_waitqueue_head(&lo->lo_event); spin_lock_init(&lo->lo_lock); disk->major = LOOP_MAJOR; - disk->first_minor = i; + disk->first_minor = i << part_shift; disk->fops = &lo_fops; disk->private_data = lo; disk->queue = lo->lo_queue; sprintf(disk->disk_name, "loop%d", i); - add_disk(disk); - list_add_tail(&lo->lo_list, &loop_devices); return lo; out_free_queue: @@ -1452,73 +1552,133 @@ out_free_queue: out_free_dev: kfree(lo); out: - return ERR_PTR(-ENOMEM); + return NULL; } -static void loop_del_one(struct loop_device *lo) +static void loop_free(struct loop_device *lo) { - del_gendisk(lo->lo_disk); blk_cleanup_queue(lo->lo_queue); put_disk(lo->lo_disk); list_del(&lo->lo_list); kfree(lo); } +static struct loop_device *loop_init_one(int i) +{ + struct loop_device *lo; + + list_for_each_entry(lo, &loop_devices, lo_list) { + if (lo->lo_number == i) + return lo; + } + + lo = loop_alloc(i); + if (lo) { + add_disk(lo->lo_disk); + list_add_tail(&lo->lo_list, &loop_devices); + } + return lo; +} + +static void loop_del_one(struct loop_device *lo) +{ + del_gendisk(lo->lo_disk); + loop_free(lo); +} + static struct kobject *loop_probe(dev_t dev, int *part, void *data) { - unsigned int number = dev & MINORMASK; struct loop_device *lo; + struct kobject *kobj; mutex_lock(&loop_devices_mutex); - lo = loop_find_dev(number); - if (lo == NULL) - lo = loop_init_one(number); + lo = loop_init_one(dev & MINORMASK); + kobj = lo ? get_disk(lo->lo_disk) : ERR_PTR(-ENOMEM); mutex_unlock(&loop_devices_mutex); *part = 0; - if (IS_ERR(lo)) - return (void *)lo; - else - return &lo->lo_disk->kobj; + return kobj; } static int __init loop_init(void) { - struct loop_device *lo; + int i, nr; + unsigned long range; + struct loop_device *lo, *next; - if (register_blkdev(LOOP_MAJOR, "loop")) - return -EIO; - blk_register_region(MKDEV(LOOP_MAJOR, 0), 1UL << MINORBITS, - THIS_MODULE, loop_probe, NULL, NULL); + /* + * loop module now has a feature to instantiate underlying device + * structure on-demand, provided that there is an access dev node. + * However, this will not work well with user space tool that doesn't + * know about such "feature". In order to not break any existing + * tool, we do the following: + * + * (1) if max_loop is specified, create that many upfront, and this + * also becomes a hard limit. + * (2) if max_loop is not specified, create 8 loop device on module + * load, user can further extend loop device by create dev node + * themselves and have kernel automatically instantiate actual + * device on-demand. + */ - lo = loop_init_one(0); - if (IS_ERR(lo)) - goto out; + part_shift = 0; + if (max_part > 0) + part_shift = fls(max_part); + + if (max_loop > 1UL << (MINORBITS - part_shift)) + return -EINVAL; if (max_loop) { - printk(KERN_INFO "loop: the max_loop option is obsolete " - "and will be removed in March 2008\n"); + nr = max_loop; + range = max_loop; + } else { + nr = 8; + range = 1UL << (MINORBITS - part_shift); + } + if (register_blkdev(LOOP_MAJOR, "loop")) + return -EIO; + + for (i = 0; i < nr; i++) { + lo = loop_alloc(i); + if (!lo) + goto Enomem; + list_add_tail(&lo->lo_list, &loop_devices); } + + /* point of no return */ + + list_for_each_entry(lo, &loop_devices, lo_list) + add_disk(lo->lo_disk); + + blk_register_region(MKDEV(LOOP_MAJOR, 0), range, + THIS_MODULE, loop_probe, NULL, NULL); + printk(KERN_INFO "loop: module loaded\n"); return 0; -out: +Enomem: + printk(KERN_INFO "loop: out of memory\n"); + + list_for_each_entry_safe(lo, next, &loop_devices, lo_list) + loop_free(lo); + unregister_blkdev(LOOP_MAJOR, "loop"); - printk(KERN_ERR "loop: ran out of memory\n"); return -ENOMEM; } static void __exit loop_exit(void) { + unsigned long range; struct loop_device *lo, *next; + range = max_loop ? max_loop : 1UL << (MINORBITS - part_shift); + list_for_each_entry_safe(lo, next, &loop_devices, lo_list) loop_del_one(lo); - blk_unregister_region(MKDEV(LOOP_MAJOR, 0), 1UL << MINORBITS); - if (unregister_blkdev(LOOP_MAJOR, "loop")) - printk(KERN_WARNING "loop: cannot unregister blkdev\n"); + blk_unregister_region(MKDEV(LOOP_MAJOR, 0), range); + unregister_blkdev(LOOP_MAJOR, "loop"); } module_init(loop_init);