1 /*
2 * GPL HEADER START
3 *
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 only,
8 * as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License version 2 for more details (a copy is included
14 * in the LICENSE file that accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License
17 * version 2 along with this program; If not, see
18 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
19 *
20 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
21 * CA 95054 USA or visit www.sun.com if you need additional information or
22 * have any questions.
23 *
24 * GPL HEADER END
25 */
26 /*
27 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
28 * Use is subject to license terms.
29 *
30 * Copyright (c) 2011, 2012, Intel Corporation.
31 */
32 /*
33 * This file is part of Lustre, http://www.lustre.org/
34 * Lustre is a trademark of Sun Microsystems, Inc.
35 */
36
37 /*
38 * linux/drivers/block/loop.c
39 *
40 * Written by Theodore Ts'o, 3/29/93
41 *
42 * Copyright 1993 by Theodore Ts'o. Redistribution of this file is
43 * permitted under the GNU General Public License.
44 *
45 * Modularized and updated for 1.1.16 kernel - Mitch Dsouza 28th May 1994
46 * Adapted for 1.3.59 kernel - Andries Brouwer, 1 Feb 1996
47 *
48 * Fixed do_loop_request() re-entrancy - Vincent.Renardias@waw.com Mar 20, 1997
49 *
50 * Added devfs support - Richard Gooch <rgooch@atnf.csiro.au> 16-Jan-1998
51 *
52 * Handle sparse backing files correctly - Kenn Humborg, Jun 28, 1998
53 *
54 * Loadable modules and other fixes by AK, 1998
55 *
56 * Maximum number of loop devices now dynamic via max_loop module parameter.
57 * Russell Kroll <rkroll@exploits.org> 19990701
58 *
59 * Maximum number of loop devices when compiled-in now selectable by passing
60 * max_loop=<1-255> to the kernel on boot.
61 * Erik I. Bols?, <eriki@himolde.no>, Oct 31, 1999
62 *
63 * Completely rewrite request handling to be make_request_fn style and
64 * non blocking, pushing work to a helper thread. Lots of fixes from
65 * Al Viro too.
66 * Jens Axboe <axboe@suse.de>, Nov 2000
67 *
68 * Support up to 256 loop devices
69 * Heinz Mauelshagen <mge@sistina.com>, Feb 2002
70 *
71 * Support for falling back on the write file operation when the address space
72 * operations prepare_write and/or commit_write are not available on the
73 * backing filesystem.
74 * Anton Altaparmakov, 16 Feb 2005
75 *
76 * Still To Fix:
77 * - Advisory locking is ignored here.
78 * - Should use an own CAP_* category instead of CAP_SYS_ADMIN
79 *
80 */
81
82 #include <linux/module.h>
83
84 #include <linux/sched.h>
85 #include <linux/fs.h>
86 #include <linux/file.h>
87 #include <linux/stat.h>
88 #include <linux/errno.h>
89 #include <linux/major.h>
90 #include <linux/wait.h>
91 #include <linux/blkdev.h>
92 #include <linux/blkpg.h>
93 #include <linux/init.h>
94 #include <linux/swap.h>
95 #include <linux/slab.h>
96 #include <linux/suspend.h>
97 #include <linux/writeback.h>
98 #include <linux/buffer_head.h> /* for invalidate_bdev() */
99 #include <linux/completion.h>
100 #include <linux/highmem.h>
101 #include <linux/gfp.h>
102 #include <linux/pagevec.h>
103
104 #include <asm/uaccess.h>
105
106 #include "../include/lustre_lib.h"
107 #include "../include/lustre_lite.h"
108 #include "llite_internal.h"
109
110 #define LLOOP_MAX_SEGMENTS LNET_MAX_IOV
111
112 /* Possible states of device */
113 enum {
114 LLOOP_UNBOUND,
115 LLOOP_BOUND,
116 LLOOP_RUNDOWN,
117 };
118
119 struct lloop_device {
120 int lo_number;
121 int lo_refcnt;
122 loff_t lo_offset;
123 loff_t lo_sizelimit;
124 int lo_flags;
125 struct file *lo_backing_file;
126 struct block_device *lo_device;
127 unsigned lo_blocksize;
128
129 gfp_t old_gfp_mask;
130
131 spinlock_t lo_lock;
132 struct bio *lo_bio;
133 struct bio *lo_biotail;
134 int lo_state;
135 struct semaphore lo_sem;
136 struct mutex lo_ctl_mutex;
137 atomic_t lo_pending;
138 wait_queue_head_t lo_bh_wait;
139
140 struct request_queue *lo_queue;
141
142 const struct lu_env *lo_env;
143 struct cl_io lo_io;
144 struct ll_dio_pages lo_pvec;
145
146 /* data to handle bio for lustre. */
147 struct lo_request_data {
148 struct page *lrd_pages[LLOOP_MAX_SEGMENTS];
149 loff_t lrd_offsets[LLOOP_MAX_SEGMENTS];
150 } lo_requests[1];
151 };
152
153 /*
154 * Loop flags
155 */
156 enum {
157 LO_FLAGS_READ_ONLY = 1,
158 };
159
160 static int lloop_major;
161 #define MAX_LOOP_DEFAULT 16
162 static int max_loop = MAX_LOOP_DEFAULT;
163 static struct lloop_device *loop_dev;
164 static struct gendisk **disks;
165 static struct mutex lloop_mutex;
166 static void *ll_iocontrol_magic = NULL;
167
get_loop_size(struct lloop_device * lo,struct file * file)168 static loff_t get_loop_size(struct lloop_device *lo, struct file *file)
169 {
170 loff_t size, offset, loopsize;
171
172 /* Compute loopsize in bytes */
173 size = i_size_read(file->f_mapping->host);
174 offset = lo->lo_offset;
175 loopsize = size - offset;
176 if (lo->lo_sizelimit > 0 && lo->lo_sizelimit < loopsize)
177 loopsize = lo->lo_sizelimit;
178
179 /*
180 * Unfortunately, if we want to do I/O on the device,
181 * the number of 512-byte sectors has to fit into a sector_t.
182 */
183 return loopsize >> 9;
184 }
185
do_bio_lustrebacked(struct lloop_device * lo,struct bio * head)186 static int do_bio_lustrebacked(struct lloop_device *lo, struct bio *head)
187 {
188 const struct lu_env *env = lo->lo_env;
189 struct cl_io *io = &lo->lo_io;
190 struct inode *inode = lo->lo_backing_file->f_dentry->d_inode;
191 struct cl_object *obj = ll_i2info(inode)->lli_clob;
192 pgoff_t offset;
193 int ret;
194 int rw;
195 u32 page_count = 0;
196 struct bio_vec bvec;
197 struct bvec_iter iter;
198 struct bio *bio;
199 ssize_t bytes;
200
201 struct ll_dio_pages *pvec = &lo->lo_pvec;
202 struct page **pages = pvec->ldp_pages;
203 loff_t *offsets = pvec->ldp_offsets;
204
205 truncate_inode_pages(inode->i_mapping, 0);
206
207 /* initialize the IO */
208 memset(io, 0, sizeof(*io));
209 io->ci_obj = obj;
210 ret = cl_io_init(env, io, CIT_MISC, obj);
211 if (ret)
212 return io->ci_result;
213 io->ci_lockreq = CILR_NEVER;
214
215 LASSERT(head != NULL);
216 rw = head->bi_rw;
217 for (bio = head; bio != NULL; bio = bio->bi_next) {
218 LASSERT(rw == bio->bi_rw);
219
220 offset = (pgoff_t)(bio->bi_iter.bi_sector << 9) + lo->lo_offset;
221 bio_for_each_segment(bvec, bio, iter) {
222 BUG_ON(bvec.bv_offset != 0);
223 BUG_ON(bvec.bv_len != PAGE_CACHE_SIZE);
224
225 pages[page_count] = bvec.bv_page;
226 offsets[page_count] = offset;
227 page_count++;
228 offset += bvec.bv_len;
229 }
230 LASSERT(page_count <= LLOOP_MAX_SEGMENTS);
231 }
232
233 ll_stats_ops_tally(ll_i2sbi(inode),
234 (rw == WRITE) ? LPROC_LL_BRW_WRITE : LPROC_LL_BRW_READ,
235 page_count);
236
237 pvec->ldp_size = page_count << PAGE_CACHE_SHIFT;
238 pvec->ldp_nr = page_count;
239
240 /* FIXME: in ll_direct_rw_pages, it has to allocate many cl_page{}s to
241 * write those pages into OST. Even worse case is that more pages
242 * would be asked to write out to swap space, and then finally get here
243 * again.
244 * Unfortunately this is NOT easy to fix.
245 * Thoughts on solution:
246 * 0. Define a reserved pool for cl_pages, which could be a list of
247 * pre-allocated cl_pages;
248 * 1. Define a new operation in cl_object_operations{}, says clo_depth,
249 * which measures how many layers for this lustre object. Generally
250 * speaking, the depth would be 2, one for llite, and one for lovsub.
251 * However, for SNS, there will be more since we need additional page
252 * to store parity;
253 * 2. Reserve the # of (page_count * depth) cl_pages from the reserved
254 * pool. Afterwards, the clio would allocate the pages from reserved
255 * pool, this guarantees we needn't allocate the cl_pages from
256 * generic cl_page slab cache.
257 * Of course, if there is NOT enough pages in the pool, we might
258 * be asked to write less pages once, this purely depends on
259 * implementation. Anyway, we should be careful to avoid deadlocking.
260 */
261 mutex_lock(&inode->i_mutex);
262 bytes = ll_direct_rw_pages(env, io, rw, inode, pvec);
263 mutex_unlock(&inode->i_mutex);
264 cl_io_fini(env, io);
265 return (bytes == pvec->ldp_size) ? 0 : (int)bytes;
266 }
267
268 /*
269 * Add bio to back of pending list
270 */
loop_add_bio(struct lloop_device * lo,struct bio * bio)271 static void loop_add_bio(struct lloop_device *lo, struct bio *bio)
272 {
273 unsigned long flags;
274
275 spin_lock_irqsave(&lo->lo_lock, flags);
276 if (lo->lo_biotail) {
277 lo->lo_biotail->bi_next = bio;
278 lo->lo_biotail = bio;
279 } else
280 lo->lo_bio = lo->lo_biotail = bio;
281 spin_unlock_irqrestore(&lo->lo_lock, flags);
282
283 atomic_inc(&lo->lo_pending);
284 if (waitqueue_active(&lo->lo_bh_wait))
285 wake_up(&lo->lo_bh_wait);
286 }
287
288 /*
289 * Grab first pending buffer
290 */
loop_get_bio(struct lloop_device * lo,struct bio ** req)291 static unsigned int loop_get_bio(struct lloop_device *lo, struct bio **req)
292 {
293 struct bio *first;
294 struct bio **bio;
295 unsigned int count = 0;
296 unsigned int page_count = 0;
297 int rw;
298
299 spin_lock_irq(&lo->lo_lock);
300 first = lo->lo_bio;
301 if (unlikely(first == NULL)) {
302 spin_unlock_irq(&lo->lo_lock);
303 return 0;
304 }
305
306 /* TODO: need to split the bio, too bad. */
307 LASSERT(first->bi_vcnt <= LLOOP_MAX_SEGMENTS);
308
309 rw = first->bi_rw;
310 bio = &lo->lo_bio;
311 while (*bio && (*bio)->bi_rw == rw) {
312 CDEBUG(D_INFO, "bio sector %llu size %u count %u vcnt%u \n",
313 (unsigned long long)(*bio)->bi_iter.bi_sector,
314 (*bio)->bi_iter.bi_size,
315 page_count, (*bio)->bi_vcnt);
316 if (page_count + (*bio)->bi_vcnt > LLOOP_MAX_SEGMENTS)
317 break;
318
319
320 page_count += (*bio)->bi_vcnt;
321 count++;
322 bio = &(*bio)->bi_next;
323 }
324 if (*bio) {
325 /* Some of bios can't be mergeable. */
326 lo->lo_bio = *bio;
327 *bio = NULL;
328 } else {
329 /* Hit the end of queue */
330 lo->lo_biotail = NULL;
331 lo->lo_bio = NULL;
332 }
333 *req = first;
334 spin_unlock_irq(&lo->lo_lock);
335 return count;
336 }
337
loop_make_request(struct request_queue * q,struct bio * old_bio)338 static void loop_make_request(struct request_queue *q, struct bio *old_bio)
339 {
340 struct lloop_device *lo = q->queuedata;
341 int rw = bio_rw(old_bio);
342 int inactive;
343
344 if (!lo)
345 goto err;
346
347 CDEBUG(D_INFO, "submit bio sector %llu size %u\n",
348 (unsigned long long)old_bio->bi_iter.bi_sector,
349 old_bio->bi_iter.bi_size);
350
351 spin_lock_irq(&lo->lo_lock);
352 inactive = (lo->lo_state != LLOOP_BOUND);
353 spin_unlock_irq(&lo->lo_lock);
354 if (inactive)
355 goto err;
356
357 if (rw == WRITE) {
358 if (lo->lo_flags & LO_FLAGS_READ_ONLY)
359 goto err;
360 } else if (rw == READA) {
361 rw = READ;
362 } else if (rw != READ) {
363 CERROR("lloop: unknown command (%x)\n", rw);
364 goto err;
365 }
366 loop_add_bio(lo, old_bio);
367 return;
368 err:
369 cfs_bio_io_error(old_bio, old_bio->bi_iter.bi_size);
370 }
371
372
loop_handle_bio(struct lloop_device * lo,struct bio * bio)373 static inline void loop_handle_bio(struct lloop_device *lo, struct bio *bio)
374 {
375 int ret;
376 ret = do_bio_lustrebacked(lo, bio);
377 while (bio) {
378 struct bio *tmp = bio->bi_next;
379 bio->bi_next = NULL;
380 cfs_bio_endio(bio, bio->bi_iter.bi_size, ret);
381 bio = tmp;
382 }
383 }
384
loop_active(struct lloop_device * lo)385 static inline int loop_active(struct lloop_device *lo)
386 {
387 return atomic_read(&lo->lo_pending) ||
388 (lo->lo_state == LLOOP_RUNDOWN);
389 }
390
391 /*
392 * worker thread that handles reads/writes to file backed loop devices,
393 * to avoid blocking in our make_request_fn.
394 */
loop_thread(void * data)395 static int loop_thread(void *data)
396 {
397 struct lloop_device *lo = data;
398 struct bio *bio;
399 unsigned int count;
400 unsigned long times = 0;
401 unsigned long total_count = 0;
402
403 struct lu_env *env;
404 int refcheck;
405 int ret = 0;
406
407 set_user_nice(current, MIN_NICE);
408
409 lo->lo_state = LLOOP_BOUND;
410
411 env = cl_env_get(&refcheck);
412 if (IS_ERR(env)) {
413 ret = PTR_ERR(env);
414 goto out;
415 }
416
417 lo->lo_env = env;
418 memset(&lo->lo_pvec, 0, sizeof(lo->lo_pvec));
419 lo->lo_pvec.ldp_pages = lo->lo_requests[0].lrd_pages;
420 lo->lo_pvec.ldp_offsets = lo->lo_requests[0].lrd_offsets;
421
422 /*
423 * up sem, we are running
424 */
425 up(&lo->lo_sem);
426
427 for (;;) {
428 wait_event(lo->lo_bh_wait, loop_active(lo));
429 if (!atomic_read(&lo->lo_pending)) {
430 int exiting = 0;
431 spin_lock_irq(&lo->lo_lock);
432 exiting = (lo->lo_state == LLOOP_RUNDOWN);
433 spin_unlock_irq(&lo->lo_lock);
434 if (exiting)
435 break;
436 }
437
438 bio = NULL;
439 count = loop_get_bio(lo, &bio);
440 if (!count) {
441 CWARN("lloop(minor: %d): missing bio\n", lo->lo_number);
442 continue;
443 }
444
445 total_count += count;
446 if (total_count < count) { /* overflow */
447 total_count = count;
448 times = 1;
449 } else {
450 times++;
451 }
452 if ((times & 127) == 0) {
453 CDEBUG(D_INFO, "total: %lu, count: %lu, avg: %lu\n",
454 total_count, times, total_count / times);
455 }
456
457 LASSERT(bio != NULL);
458 LASSERT(count <= atomic_read(&lo->lo_pending));
459 loop_handle_bio(lo, bio);
460 atomic_sub(count, &lo->lo_pending);
461 }
462 cl_env_put(env, &refcheck);
463
464 out:
465 up(&lo->lo_sem);
466 return ret;
467 }
468
loop_set_fd(struct lloop_device * lo,struct file * unused,struct block_device * bdev,struct file * file)469 static int loop_set_fd(struct lloop_device *lo, struct file *unused,
470 struct block_device *bdev, struct file *file)
471 {
472 struct inode *inode;
473 struct address_space *mapping;
474 int lo_flags = 0;
475 int error;
476 loff_t size;
477
478 if (!try_module_get(THIS_MODULE))
479 return -ENODEV;
480
481 error = -EBUSY;
482 if (lo->lo_state != LLOOP_UNBOUND)
483 goto out;
484
485 mapping = file->f_mapping;
486 inode = mapping->host;
487
488 error = -EINVAL;
489 if (!S_ISREG(inode->i_mode) || inode->i_sb->s_magic != LL_SUPER_MAGIC)
490 goto out;
491
492 if (!(file->f_mode & FMODE_WRITE))
493 lo_flags |= LO_FLAGS_READ_ONLY;
494
495 size = get_loop_size(lo, file);
496
497 if ((loff_t)(sector_t)size != size) {
498 error = -EFBIG;
499 goto out;
500 }
501
502 /* remove all pages in cache so as dirty pages not to be existent. */
503 truncate_inode_pages(mapping, 0);
504
505 set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0);
506
507 lo->lo_blocksize = PAGE_CACHE_SIZE;
508 lo->lo_device = bdev;
509 lo->lo_flags = lo_flags;
510 lo->lo_backing_file = file;
511 lo->lo_sizelimit = 0;
512 lo->old_gfp_mask = mapping_gfp_mask(mapping);
513 mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
514
515 lo->lo_bio = lo->lo_biotail = NULL;
516
517 /*
518 * set queue make_request_fn, and add limits based on lower level
519 * device
520 */
521 blk_queue_make_request(lo->lo_queue, loop_make_request);
522 lo->lo_queue->queuedata = lo;
523
524 /* queue parameters */
525 CLASSERT(PAGE_CACHE_SIZE < (1 << (sizeof(unsigned short) * 8)));
526 blk_queue_logical_block_size(lo->lo_queue,
527 (unsigned short)PAGE_CACHE_SIZE);
528 blk_queue_max_hw_sectors(lo->lo_queue,
529 LLOOP_MAX_SEGMENTS << (PAGE_CACHE_SHIFT - 9));
530 blk_queue_max_segments(lo->lo_queue, LLOOP_MAX_SEGMENTS);
531
532 set_capacity(disks[lo->lo_number], size);
533 bd_set_size(bdev, size << 9);
534
535 set_blocksize(bdev, lo->lo_blocksize);
536
537 kthread_run(loop_thread, lo, "lloop%d", lo->lo_number);
538 down(&lo->lo_sem);
539 return 0;
540
541 out:
542 /* This is safe: open() is still holding a reference. */
543 module_put(THIS_MODULE);
544 return error;
545 }
546
loop_clr_fd(struct lloop_device * lo,struct block_device * bdev,int count)547 static int loop_clr_fd(struct lloop_device *lo, struct block_device *bdev,
548 int count)
549 {
550 struct file *filp = lo->lo_backing_file;
551 gfp_t gfp = lo->old_gfp_mask;
552
553 if (lo->lo_state != LLOOP_BOUND)
554 return -ENXIO;
555
556 if (lo->lo_refcnt > count) /* we needed one fd for the ioctl */
557 return -EBUSY;
558
559 if (filp == NULL)
560 return -EINVAL;
561
562 spin_lock_irq(&lo->lo_lock);
563 lo->lo_state = LLOOP_RUNDOWN;
564 spin_unlock_irq(&lo->lo_lock);
565 wake_up(&lo->lo_bh_wait);
566
567 down(&lo->lo_sem);
568 lo->lo_backing_file = NULL;
569 lo->lo_device = NULL;
570 lo->lo_offset = 0;
571 lo->lo_sizelimit = 0;
572 lo->lo_flags = 0;
573 invalidate_bdev(bdev);
574 set_capacity(disks[lo->lo_number], 0);
575 bd_set_size(bdev, 0);
576 mapping_set_gfp_mask(filp->f_mapping, gfp);
577 lo->lo_state = LLOOP_UNBOUND;
578 fput(filp);
579 /* This is safe: open() is still holding a reference. */
580 module_put(THIS_MODULE);
581 return 0;
582 }
583
lo_open(struct block_device * bdev,fmode_t mode)584 static int lo_open(struct block_device *bdev, fmode_t mode)
585 {
586 struct lloop_device *lo = bdev->bd_disk->private_data;
587
588 mutex_lock(&lo->lo_ctl_mutex);
589 lo->lo_refcnt++;
590 mutex_unlock(&lo->lo_ctl_mutex);
591
592 return 0;
593 }
594
lo_release(struct gendisk * disk,fmode_t mode)595 static void lo_release(struct gendisk *disk, fmode_t mode)
596 {
597 struct lloop_device *lo = disk->private_data;
598
599 mutex_lock(&lo->lo_ctl_mutex);
600 --lo->lo_refcnt;
601 mutex_unlock(&lo->lo_ctl_mutex);
602 }
603
604 /* lloop device node's ioctl function. */
lo_ioctl(struct block_device * bdev,fmode_t mode,unsigned int cmd,unsigned long arg)605 static int lo_ioctl(struct block_device *bdev, fmode_t mode,
606 unsigned int cmd, unsigned long arg)
607 {
608 struct lloop_device *lo = bdev->bd_disk->private_data;
609 struct inode *inode = NULL;
610 int err = 0;
611
612 mutex_lock(&lloop_mutex);
613 switch (cmd) {
614 case LL_IOC_LLOOP_DETACH: {
615 err = loop_clr_fd(lo, bdev, 2);
616 if (err == 0)
617 blkdev_put(bdev, 0); /* grabbed in LLOOP_ATTACH */
618 break;
619 }
620
621 case LL_IOC_LLOOP_INFO: {
622 struct lu_fid fid;
623
624 if (lo->lo_backing_file == NULL) {
625 err = -ENOENT;
626 break;
627 }
628 if (inode == NULL)
629 inode = lo->lo_backing_file->f_dentry->d_inode;
630 if (lo->lo_state == LLOOP_BOUND)
631 fid = ll_i2info(inode)->lli_fid;
632 else
633 fid_zero(&fid);
634
635 if (copy_to_user((struct lu_fid *)arg, &fid, sizeof(fid)))
636 err = -EFAULT;
637 break;
638 }
639
640 default:
641 err = -EINVAL;
642 break;
643 }
644 mutex_unlock(&lloop_mutex);
645
646 return err;
647 }
648
649 static struct block_device_operations lo_fops = {
650 .owner = THIS_MODULE,
651 .open = lo_open,
652 .release = lo_release,
653 .ioctl = lo_ioctl,
654 };
655
656 /* dynamic iocontrol callback.
657 * This callback is registered in lloop_init and will be called by
658 * ll_iocontrol_call.
659 *
660 * This is a llite regular file ioctl function. It takes the responsibility
661 * of attaching or detaching a file by a lloop's device number.
662 */
lloop_ioctl(struct inode * unused,struct file * file,unsigned int cmd,unsigned long arg,void * magic,int * rcp)663 static enum llioc_iter lloop_ioctl(struct inode *unused, struct file *file,
664 unsigned int cmd, unsigned long arg,
665 void *magic, int *rcp)
666 {
667 struct lloop_device *lo = NULL;
668 struct block_device *bdev = NULL;
669 int err = 0;
670 dev_t dev;
671
672 if (magic != ll_iocontrol_magic)
673 return LLIOC_CONT;
674
675 if (disks == NULL) {
676 err = -ENODEV;
677 goto out1;
678 }
679
680 CWARN("Enter llop_ioctl\n");
681
682 mutex_lock(&lloop_mutex);
683 switch (cmd) {
684 case LL_IOC_LLOOP_ATTACH: {
685 struct lloop_device *lo_free = NULL;
686 int i;
687
688 for (i = 0; i < max_loop; i++, lo = NULL) {
689 lo = &loop_dev[i];
690 if (lo->lo_state == LLOOP_UNBOUND) {
691 if (!lo_free)
692 lo_free = lo;
693 continue;
694 }
695 if (lo->lo_backing_file->f_dentry->d_inode ==
696 file->f_dentry->d_inode)
697 break;
698 }
699 if (lo || !lo_free) {
700 err = -EBUSY;
701 goto out;
702 }
703
704 lo = lo_free;
705 dev = MKDEV(lloop_major, lo->lo_number);
706
707 /* quit if the used pointer is writable */
708 if (put_user((long)old_encode_dev(dev), (long *)arg)) {
709 err = -EFAULT;
710 goto out;
711 }
712
713 bdev = blkdev_get_by_dev(dev, file->f_mode, NULL);
714 if (IS_ERR(bdev)) {
715 err = PTR_ERR(bdev);
716 goto out;
717 }
718
719 get_file(file);
720 err = loop_set_fd(lo, NULL, bdev, file);
721 if (err) {
722 fput(file);
723 blkdev_put(bdev, 0);
724 }
725
726 break;
727 }
728
729 case LL_IOC_LLOOP_DETACH_BYDEV: {
730 int minor;
731
732 dev = old_decode_dev(arg);
733 if (MAJOR(dev) != lloop_major) {
734 err = -EINVAL;
735 goto out;
736 }
737
738 minor = MINOR(dev);
739 if (minor > max_loop - 1) {
740 err = -EINVAL;
741 goto out;
742 }
743
744 lo = &loop_dev[minor];
745 if (lo->lo_state != LLOOP_BOUND) {
746 err = -EINVAL;
747 goto out;
748 }
749
750 bdev = lo->lo_device;
751 err = loop_clr_fd(lo, bdev, 1);
752 if (err == 0)
753 blkdev_put(bdev, 0); /* grabbed in LLOOP_ATTACH */
754
755 break;
756 }
757
758 default:
759 err = -EINVAL;
760 break;
761 }
762
763 out:
764 mutex_unlock(&lloop_mutex);
765 out1:
766 if (rcp)
767 *rcp = err;
768 return LLIOC_STOP;
769 }
770
lloop_init(void)771 static int __init lloop_init(void)
772 {
773 int i;
774 unsigned int cmdlist[] = {
775 LL_IOC_LLOOP_ATTACH,
776 LL_IOC_LLOOP_DETACH_BYDEV,
777 };
778
779 if (max_loop < 1 || max_loop > 256) {
780 max_loop = MAX_LOOP_DEFAULT;
781 CWARN("lloop: invalid max_loop (must be between"
782 " 1 and 256), using default (%u)\n", max_loop);
783 }
784
785 lloop_major = register_blkdev(0, "lloop");
786 if (lloop_major < 0)
787 return -EIO;
788
789 CDEBUG(D_CONFIG, "registered lloop major %d with %u minors\n",
790 lloop_major, max_loop);
791
792 ll_iocontrol_magic = ll_iocontrol_register(lloop_ioctl, 2, cmdlist);
793 if (ll_iocontrol_magic == NULL)
794 goto out_mem1;
795
796 loop_dev = kzalloc(max_loop * sizeof(*loop_dev), GFP_KERNEL);
797 if (!loop_dev)
798 goto out_mem1;
799
800 disks = kzalloc(max_loop * sizeof(*disks), GFP_KERNEL);
801 if (!disks)
802 goto out_mem2;
803
804 for (i = 0; i < max_loop; i++) {
805 disks[i] = alloc_disk(1);
806 if (!disks[i])
807 goto out_mem3;
808 }
809
810 mutex_init(&lloop_mutex);
811
812 for (i = 0; i < max_loop; i++) {
813 struct lloop_device *lo = &loop_dev[i];
814 struct gendisk *disk = disks[i];
815
816 lo->lo_queue = blk_alloc_queue(GFP_KERNEL);
817 if (!lo->lo_queue)
818 goto out_mem4;
819
820 mutex_init(&lo->lo_ctl_mutex);
821 sema_init(&lo->lo_sem, 0);
822 init_waitqueue_head(&lo->lo_bh_wait);
823 lo->lo_number = i;
824 spin_lock_init(&lo->lo_lock);
825 disk->major = lloop_major;
826 disk->first_minor = i;
827 disk->fops = &lo_fops;
828 sprintf(disk->disk_name, "lloop%d", i);
829 disk->private_data = lo;
830 disk->queue = lo->lo_queue;
831 }
832
833 /* We cannot fail after we call this, so another loop!*/
834 for (i = 0; i < max_loop; i++)
835 add_disk(disks[i]);
836 return 0;
837
838 out_mem4:
839 while (i--)
840 blk_cleanup_queue(loop_dev[i].lo_queue);
841 i = max_loop;
842 out_mem3:
843 while (i--)
844 put_disk(disks[i]);
845 OBD_FREE(disks, max_loop * sizeof(*disks));
846 out_mem2:
847 OBD_FREE(loop_dev, max_loop * sizeof(*loop_dev));
848 out_mem1:
849 unregister_blkdev(lloop_major, "lloop");
850 ll_iocontrol_unregister(ll_iocontrol_magic);
851 CERROR("lloop: ran out of memory\n");
852 return -ENOMEM;
853 }
854
lloop_exit(void)855 static void lloop_exit(void)
856 {
857 int i;
858
859 ll_iocontrol_unregister(ll_iocontrol_magic);
860 for (i = 0; i < max_loop; i++) {
861 del_gendisk(disks[i]);
862 blk_cleanup_queue(loop_dev[i].lo_queue);
863 put_disk(disks[i]);
864 }
865
866 unregister_blkdev(lloop_major, "lloop");
867
868 OBD_FREE(disks, max_loop * sizeof(*disks));
869 OBD_FREE(loop_dev, max_loop * sizeof(*loop_dev));
870 }
871
872 module_init(lloop_init);
873 module_exit(lloop_exit);
874
875 module_param(max_loop, int, 0444);
876 MODULE_PARM_DESC(max_loop, "maximum of lloop_device");
877 MODULE_AUTHOR("Sun Microsystems, Inc. <http://www.lustre.org/>");
878 MODULE_DESCRIPTION("Lustre virtual block device");
879 MODULE_LICENSE("GPL");
880