aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorGreg Kroah-Hartman <gregkh@suse.de>2009-10-08 14:32:31 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2009-10-09 16:47:23 -0400
commit999b9da40ea4c9efb31689c08d1d1b7a621ecce0 (patch)
tree2150337bb17a71d6b6a54613ec5b382dae6ea708
parent7d230df37a7c08f01e57e1623e0706b3949751a2 (diff)
Staging: remove cowloop driver
The author has found a number of problems with the current version of this driver in the current kernel, and is reworking it to get things working again. Because of that, it would be better to remove the driver now and add it back in a future kernel release. Cc: H.J. Thomassen <hjt@ATComputing.nl> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat
-rw-r--r--drivers/staging/Kconfig2
-rw-r--r--drivers/staging/Makefile1
-rw-r--r--drivers/staging/cowloop/Kconfig16
-rw-r--r--drivers/staging/cowloop/Makefile1
-rw-r--r--drivers/staging/cowloop/TODO11
-rw-r--r--drivers/staging/cowloop/cowloop.c2842
-rw-r--r--drivers/staging/cowloop/cowloop.h66
7 files changed, 0 insertions, 2939 deletions
diff --git a/drivers/staging/Kconfig b/drivers/staging/Kconfig
index ab64971d3fe7..7df3ba4f1f4d 100644
--- a/drivers/staging/Kconfig
+++ b/drivers/staging/Kconfig
@@ -127,7 +127,5 @@ source "drivers/staging/sep/Kconfig"
127 127
128source "drivers/staging/iio/Kconfig" 128source "drivers/staging/iio/Kconfig"
129 129
130source "drivers/staging/cowloop/Kconfig"
131
132endif # !STAGING_EXCLUDE_BUILD 130endif # !STAGING_EXCLUDE_BUILD
133endif # STAGING 131endif # STAGING
diff --git a/drivers/staging/Makefile b/drivers/staging/Makefile
index baffd0e96474..747571172269 100644
--- a/drivers/staging/Makefile
+++ b/drivers/staging/Makefile
@@ -45,4 +45,3 @@ obj-$(CONFIG_VME_BUS) += vme/
45obj-$(CONFIG_RAR_REGISTER) += rar/ 45obj-$(CONFIG_RAR_REGISTER) += rar/
46obj-$(CONFIG_DX_SEP) += sep/ 46obj-$(CONFIG_DX_SEP) += sep/
47obj-$(CONFIG_IIO) += iio/ 47obj-$(CONFIG_IIO) += iio/
48obj-$(CONFIG_COWLOOP) += cowloop/
diff --git a/drivers/staging/cowloop/Kconfig b/drivers/staging/cowloop/Kconfig
deleted file mode 100644
index 58d2a23bd2c1..000000000000
--- a/drivers/staging/cowloop/Kconfig
+++ /dev/null
@@ -1,16 +0,0 @@
1config COWLOOP
2 tristate "copy-on-write pseudo Block Driver"
3 depends on BLOCK
4 default n
5 ---help---
6 Cowloop is a "copy-on-write" pseudo block driver. It can be
7 stacked on top of a "real" block driver, and catches all write
8 operations on their way from the file systems layer above to
9 the real driver below, effectively shielding the lower driver
10 from those write accesses. The requests are then diverted to
11 an ordinary file, located somewhere else (configurable). Later
12 read requests are checked to see whether they can be serviced
13 by the "real" block driver below, or must be pulled in from
14 the diverted location. More information and userspace tools to
15 use the driver are on the project's website
16 http://www.ATComputing.nl/cowloop/
diff --git a/drivers/staging/cowloop/Makefile b/drivers/staging/cowloop/Makefile
deleted file mode 100644
index 2b6b81a63d21..000000000000
--- a/drivers/staging/cowloop/Makefile
+++ /dev/null
@@ -1 +0,0 @@
1obj-$(CONFIG_COWLOOP) += cowloop.o
diff --git a/drivers/staging/cowloop/TODO b/drivers/staging/cowloop/TODO
deleted file mode 100644
index 9399d1c16e15..000000000000
--- a/drivers/staging/cowloop/TODO
+++ /dev/null
@@ -1,11 +0,0 @@
1TODO:
2 - checkpatch.pl cleanups
3 - run sparse to ensure clean
4 - fix up 32/64bit ioctl issues
5 - move proc file usage to debugfs
6 - audit ioctls
7 - add documentation
8 - get linux-fsdevel to review it
9
10Please send patches to "H.J. Thomassen" <hjt@ATComputing.nl> and
11Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/staging/cowloop/cowloop.c b/drivers/staging/cowloop/cowloop.c
deleted file mode 100644
index a71c743a1196..000000000000
--- a/drivers/staging/cowloop/cowloop.c
+++ /dev/null
@@ -1,2842 +0,0 @@
1/*
2** COWLOOP block device driver (2.6 kernel compliant)
3** =======================================================================
4** Read-write loop-driver with copy-on-write functionality.
5**
6** Synopsis:
7**
8** modprobe cowloop [maxcows=..] [rdofile=..... cowfile=.... [option=r]]
9**
10** Definition of number of configured cowdevices:
11** maxcows= number of configured cowdevices (default: 16)
12** (do not confuse this with MAXCOWS: absolute maximum as compiled)
13**
14** One pair of filenames can be supplied during insmod/modprobe to open
15** the first cowdevice:
16** rdofile= read-only file (or filesystem)
17** cowfile= storage-space for modified blocks of read-only file(system)
18** option=r repair cowfile automatically if it appears to be dirty
19**
20** Other cowdevices can be activated via the command "cowdev"
21** whenever the cowloop-driver is loaded.
22**
23** The read-only file may be of type 'regular' or 'block-device'.
24**
25** The cowfile must be of type 'regular'.
26** If an existing regular file is used as cowfile, its contents will be
27** used again for the current read-only file. When the cowfile has not been
28** closed properly during a previous session (i.e. rmmod cowloop), the
29** cowloop-driver refuses to open it unless the parameter "option=r" is
30** specified.
31**
32** Layout of cowfile:
33**
34** +-----------------------------+
35** | cow head block | MAPUNIT bytes
36** |-----------------------------|
37** | | MAPUNIT bytes
38** |--- ---|
39** | | MAPUNIT bytes
40** |--- ---|
41** | used-block bitmap | MAPUNIT bytes
42** |-----------------------------|
43** | gap to align start-offset |
44** | to 4K multiple |
45** |-----------------------------| <---- start-offset cow blocks
46** | |
47** | written cow blocks | MAPUNIT bytes
48** | ..... |
49**
50** cowhead block:
51** - contains general info about the rdofile which is related
52** to this cowfile
53**
54** used-block bitmap:
55** - contains one bit per block with a size of MAPUNIT bytes
56** - bit-value '1' = block has been written on cow
57** '0' = block unused on cow
58** - total bitmap rounded to multiples of MAPUNIT
59**
60** ============================================================================
61** Author: Gerlof Langeveld - AT Computing (March 2003)
62** Current maintainer: Hendrik-Jan Thomassen - AT Computing (Summer 2006)
63** Email: hjt@ATComputing.nl
64** ----------------------------------------------------------------------------
65** Copyright (C) 2003-2009 AT Consultancy
66**
67** This program is free software; you can redistribute it and/or modify it
68** under the terms of the GNU General Public License as published by the
69** Free Software Foundation; either version 2, or (at your option) any
70** later version.
71**
72** This program is distributed in the hope that it will be useful, but
73** WITHOUT ANY WARRANTY; without even the implied warranty of
74** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
75** See the GNU General Public License for more details.
76**
77** You should have received a copy of the GNU General Public License
78** along with this program; if not, write to the Free Software
79** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
80** ----------------------------------------------------------------------------
81**
82** Major modifications:
83**
84** 200405 Ported to kernel-version 2.6 Hendrik-Jan Thomassen
85** 200405 Added cowhead to cowfile to garantee
86** consistency with read-only file Gerlof Langeveld
87** 200405 Postponed flushing of bitmaps to improve
88** performance. Gerlof Langeveld
89** 200405 Inline recovery for dirty cowfiles. Gerlof Langeveld
90** 200502 Redesign to support more cowdevices. Gerlof Langeveld
91** 200502 Support devices/file > 2 Gbytes. Gerlof Langeveld
92** 200507 Check for free space to expand cowfile. Gerlof Langeveld
93** 200902 Upgrade for kernel 2.6.28 Hendrik-Jan Thomassen
94**
95** Inspired by
96** loop.c by Theodore Ts'o and
97** cloop.c by Paul `Rusty' Russell & Klaus Knopper.
98**
99** Design-considerations:
100**
101** For the first experiments with the cowloop-driver, the request-queue
102** made use of the do_generic_file_read() which worked fine except
103** in combination with the cloop-driver; that combination
104** resulted in a non-interruptible hangup of the system during
105** heavy load. Other experiments using the `make_request' interface also
106** resulted in unpredictable system hangups (with proper use of spinlocks).
107**
108** To overcome these problems, the cowloop-driver starts a kernel-thread
109** for every active cowdevice.
110** All read- and write-request on the read-only file and copy-on-write file
111** are handled in the context of that thread.
112** A scheme has been designed to wakeup the kernel-thread as
113** soon as I/O-requests are available in the request-queue; this thread
114** handles the requests one-by-one by calling the proper read- or
115** write-function related to the open read-only file or copy-on-write file.
116** When all pending requests have been handled, the kernel-thread goes
117** back to sleep-state.
118** This approach requires some additional context-switches; however the
119** performance loss during heavy I/O is less than 3%.
120**
121** -------------------------------------------------------------------------*/
122/* The following is the cowloop package version number. It must be
123 identical to the content of the include-file "version.h" that is
124 used in all supporting utilities: */
125char revision[] = "$Revision: 3.1 $"; /* cowlo_init_module() has
126 assumptions about this string's format */
127
128/* Note that the following numbers are *not* the cowloop package version
129 numbers, but separate revision history numbers to track the
130 modifications of this particular source file: */
131/* $Log: cowloop.c,v $
132**
133** Revision 1.30 2009/02/08 hjt
134** Integrated earlier fixes
135** Upgraded to kernel 2.6.28 (thanks Jerome Poulin)
136**
137** Revision 1.29 2006/12/03 22:12:00 hjt
138** changed 'cowdevlock' from spinlock to semaphore, to avoid
139** "scheduling while atomic". Contributed by Juergen Christ.
140** Added version.h again
141**
142** Revision 1.28 2006/08/16 16:00:00 hjt
143** malloc each individual cowloopdevice struct separately
144**
145** Revision 1.27 2006/03/14 14:57:03 root
146** Removed include version.h
147**
148** Revision 1.26 2005/08/08 11:22:48 root
149** Implement possibility to close a cow file or reopen a cowfile read-only.
150**
151** Revision 1.25 2005/08/03 14:00:39 root
152** Added modinfo info to driver.
153**
154** Revision 1.24 2005/07/21 06:14:53 root
155** Cosmetic changes source code.
156**
157** Revision 1.23 2005/07/20 13:07:32 root
158** Supply ioctl to write watchdog program to react on lack of cowfile space.
159**
160** Revision 1.22 2005/07/20 07:53:34 root
161** Regular verification of free space in filesystem holding the cowfile
162** (give warnings whenever space is almost exhausted).
163** Terminology change: checksum renamed to fingerprint.
164**
165** Revision 1.21 2005/07/19 09:21:52 root
166** Removing maximum limit of 16 Gb per cowdevice.
167**
168** Revision 1.20 2005/07/19 07:50:33 root
169** Minor bugfixes and cosmetic changes.
170**
171** Revision 1.19 2005/06/10 12:29:55 root
172** Removed lock/unlock operation from cowlo_open().
173**
174** Revision 1.18 2005/05/09 12:56:26 root
175** Allow a cowdevice to be open more than once
176** (needed for support of ReiserFS and XFS).
177**
178** Revision 1.17 2005/03/17 14:36:16 root
179** Fixed some license issues.
180**
181** Revision 1.16 2005/03/07 14:42:05 root
182** Only allow one parallel open per cowdevice.
183**
184** Revision 1.15 2005/02/18 11:52:04 gerlof
185** Redesign to support more than one cowdevice > 2 Gb space.
186**
187** Revision 1.14 2004/08/17 14:19:16 gerlof
188** Modified output of /proc/cowloop.
189**
190** Revision 1.13 2004/08/16 07:21:10 gerlof
191** Separate statistical counter for read on rdofile and cowfile.
192**
193** Revision 1.12 2004/08/11 06:52:11 gerlof
194** Modified messages.
195**
196** Revision 1.11 2004/08/11 06:44:11 gerlof
197** Modified log messages.
198**
199** Revision 1.10 2004/08/10 12:27:27 gerlof
200** Cosmetic changes.
201**
202** Revision 1.9 2004/08/09 11:43:37 gerlof
203** Removed double definition of major number (COWMAJOR).
204**
205** Revision 1.8 2004/08/09 08:03:39 gerlof
206** Cleanup of messages.
207**
208** Revision 1.7 2004/05/27 06:37:33 gerlof
209** Modified /proc message.
210**
211** Revision 1.6 2004/05/26 21:23:28 gerlof
212** Modified /proc output.
213**
214** Revision 1.5 2004/05/26 13:23:34 gerlof
215** Support cowsync to force flushing the bitmaps and cowhead.
216**
217** Revision 1.4 2004/05/26 11:11:10 gerlof
218** Updated the comment to the actual situation.
219**
220** Revision 1.3 2004/05/26 10:50:00 gerlof
221** Implemented recovery-option.
222**
223** Revision 1.2 2004/05/25 15:14:41 gerlof
224** Modified bitmap flushing strategy.
225**
226*/
227
228#define COWMAJOR 241
229
230// #define COWDEBUG
231
232#ifdef COWDEBUG
233#define DEBUGP printk
234#define DCOW KERN_ALERT
235#else
236#define DEBUGP(format, x...)
237#endif
238
239#include <linux/types.h>
240#include <linux/autoconf.h>
241#ifndef AUTOCONF_INCLUDED
242#include <linux/config.h>
243#endif
244#include <linux/module.h>
245#include <linux/version.h>
246#include <linux/moduleparam.h>
247#include <linux/init.h>
248#include <linux/errno.h>
249#include <linux/kernel.h>
250#include <linux/major.h>
251#include <linux/sched.h>
252#include <linux/fs.h>
253#include <linux/file.h>
254#include <linux/stat.h>
255#include <linux/vmalloc.h>
256#include <linux/slab.h>
257#include <linux/semaphore.h>
258#include <asm/uaccess.h>
259#include <linux/proc_fs.h>
260#include <linux/blkdev.h>
261#include <linux/buffer_head.h>
262#include <linux/hdreg.h>
263#include <linux/genhd.h>
264#include <linux/statfs.h>
265
266#include "cowloop.h"
267
268MODULE_LICENSE("GPL");
269/* MODULE_AUTHOR("Gerlof Langeveld <gerlof@ATComputing.nl>"); obsolete address */
270MODULE_AUTHOR("Hendrik-Jan Thomassen <hjt@ATComputing.nl>"); /* current maintainer */
271MODULE_DESCRIPTION("Copy-on-write loop driver");
272MODULE_PARM_DESC(maxcows, " Number of configured cowdevices (default 16)");
273MODULE_PARM_DESC(rdofile, " Read-only file for /dev/cow/0");
274MODULE_PARM_DESC(cowfile, " Cowfile for /dev/cow/0");
275MODULE_PARM_DESC(option, " Repair cowfile if inconsistent: option=r");
276
277#define DEVICE_NAME "cow"
278
279#define DFLCOWS 16 /* default cowloop devices */
280
281static int maxcows = DFLCOWS;
282module_param(maxcows, int, 0);
283static char *rdofile = "";
284module_param(rdofile, charp, 0);
285static char *cowfile = "";
286module_param(cowfile, charp, 0);
287static char *option = "";
288module_param(option, charp, 0);
289
290/*
291** per cowdevice several bitmap chunks are allowed of MAPCHUNKSZ each
292**
293** each bitmap chunk can describe MAPCHUNKSZ * 8 * MAPUNIT bytes of data
294** suppose:
295** MAPCHUNKSZ 4096 and MAPUNIT 1024 --> 4096 * 8 * 1024 = 32 Mb per chunk
296*/
297#define MAPCHUNKSZ 4096 /* #bytes per bitmap chunk (do not change) */
298
299#define SPCMINBLK 100 /* space threshold to give warning messages */
300#define SPCDFLINTVL 16 /* once every SPCDFLINTVL writes to cowfile, */
301 /* available space in filesystem is checked */
302
303#define CALCMAP(x) ((x)/(MAPCHUNKSZ*8))
304#define CALCBYTE(x) (((x)%(MAPCHUNKSZ*8))>>3)
305#define CALCBIT(x) ((x)&7)
306
307#define ALLCOW 1
308#define ALLRDO 2
309#define MIXEDUP 3
310
311static char allzeroes[MAPUNIT];
312
313/*
314** administration per cowdevice (pair of cowfile/rdofile)
315*/
316
317/* bit-values for state */
318#define COWDEVOPEN 0x01 /* cowdevice opened */
319#define COWRWCOWOPEN 0x02 /* cowfile opened read-write */
320#define COWRDCOWOPEN 0x04 /* cowfile opened read-only */
321#define COWWATCHDOG 0x08 /* ioctl for watchdog cowfile space active */
322
323#define COWCOWOPEN (COWRWCOWOPEN|COWRDCOWOPEN)
324
325struct cowloop_device
326{
327 /*
328 ** current status
329 */
330 int state; /* bit-values (see above) */
331 int opencnt; /* # opens for cowdevice */
332
333 /*
334 ** open file pointers
335 */
336 struct file *rdofp, *cowfp; /* open file pointers */
337 char *rdoname, *cowname; /* file names */
338
339 /*
340 ** request queue administration
341 */
342 struct request_queue *rqueue;
343 spinlock_t rqlock;
344 struct gendisk *gd;
345
346 /*
347 ** administration about read-only file
348 */
349 unsigned int numblocks; /* # blocks input file in MAPUNIT */
350 unsigned int blocksz; /* minimum unit to access this dev */
351 unsigned long fingerprint; /* fingerprint of current rdofile */
352 struct block_device *belowdev; /* block device below us */
353 struct gendisk *belowgd; /* gendisk for blk dev below us */
354 struct request_queue *belowq; /* req. queue of blk dev below us */
355
356 /*
357 ** bitmap administration to register which blocks are modified
358 */
359 long int mapsize; /* total size of bitmap (bytes) */
360 long int mapremain; /* remaining bytes in last bitmap */
361 int mapcount; /* number of bitmaps in use */
362 char **mapcache; /* area with pointers to bitmaps */
363
364 char *iobuf; /* databuffer of MAPUNIT bytes */
365 struct cowhead *cowhead; /* buffer containing cowhead */
366
367 /*
368 ** administration for interface with the kernel-thread
369 */
370 int pid; /* pid==0: no thread available */
371 struct request *req; /* request to be handled now */
372 wait_queue_head_t waitq; /* wait-Q: thread waits for work */
373 char closedown; /* boolean: thread exit required */
374 char qfilled; /* boolean: I/O request pending */
375 char iobusy; /* boolean: req under treatment */
376
377 /*
378 ** administration to keep track of free space in cowfile filesystem
379 */
380 unsigned long blksize; /* block size of fs (bytes) */
381 unsigned long blktotal; /* recent total space in fs (blocks) */
382 unsigned long blkavail; /* recent free space in fs (blocks) */
383
384 wait_queue_head_t watchq; /* wait-Q: watcher awaits threshold */
385 unsigned long watchthresh; /* threshold of watcher (blocks) */
386
387 /*
388 ** statistical counters
389 */
390 unsigned long rdoreads; /* number of read-actions rdo */
391 unsigned long cowreads; /* number of read-actions cow */
392 unsigned long cowwrites; /* number of write-actions */
393 unsigned long nrcowblocks; /* number of blocks in use on cow */
394};
395
396static struct cowloop_device **cowdevall; /* ptr to ptrs to all cowdevices */
397static struct semaphore cowdevlock; /* generic lock for cowdevs */
398
399static struct gendisk *cowctlgd; /* gendisk control channel */
400static spinlock_t cowctlrqlock; /* for req.q. of ctrl. channel */
401
402/*
403** private directory /proc/cow
404*/
405struct proc_dir_entry *cowlo_procdir;
406
407/*
408** function prototypes
409*/
410static long int cowlo_do_request (struct request *req);
411static void cowlo_sync (void);
412static int cowlo_checkio (struct cowloop_device *, int, loff_t);
413static int cowlo_readmix (struct cowloop_device *, void *, int, loff_t);
414static int cowlo_writemix (struct cowloop_device *, void *, int, loff_t);
415static long int cowlo_readrdo (struct cowloop_device *, void *, int, loff_t);
416static long int cowlo_readcow (struct cowloop_device *, void *, int, loff_t);
417static long int cowlo_readcowraw (struct cowloop_device *, void *, int, loff_t);
418static long int cowlo_writecow (struct cowloop_device *, void *, int, loff_t);
419static long int cowlo_writecowraw(struct cowloop_device *, void *, int, loff_t);
420static int cowlo_ioctl (struct block_device *, fmode_t,
421 unsigned int, unsigned long);
422static int cowlo_makepair (struct cowpair __user *);
423static int cowlo_removepair (unsigned long __user *);
424static int cowlo_watch (struct cowpair __user *);
425static int cowlo_cowctl (unsigned long __user *, int);
426static int cowlo_openpair (char *, char *, int, int);
427static int cowlo_closepair (struct cowloop_device *);
428static int cowlo_openrdo (struct cowloop_device *, char *);
429static int cowlo_opencow (struct cowloop_device *, char *, int);
430static void cowlo_undo_openrdo(struct cowloop_device *);
431static void cowlo_undo_opencow(struct cowloop_device *);
432
433/*****************************************************************************/
434/* System call handling */
435/*****************************************************************************/
436
437/*
438** handle system call open()/mount()
439**
440** returns:
441** 0 - okay
442** < 0 - error value
443*/
444static int cowlo_open(struct block_device *bdev, fmode_t mode)
445{
446 struct inode *inode = bdev->bd_inode;
447
448 if (!inode)
449 return -EINVAL;
450
451 if (imajor(inode) != COWMAJOR) {
452 printk(KERN_WARNING
453 "cowloop - unexpected major %d\n", imajor(inode));
454 return -ENODEV;
455 }
456
457 switch (iminor(inode)) {
458 case COWCTL:
459 DEBUGP(DCOW"cowloop - open %d control\n", COWCTL);
460 break;
461
462 default:
463 DEBUGP(DCOW"cowloop - open minor %d\n", iminor(inode));
464
465 if ( iminor(inode) >= maxcows )
466 return -ENODEV;
467
468 if ( !((cowdevall[iminor(inode)])->state & COWDEVOPEN) )
469 return -ENODEV;
470
471 (cowdevall[iminor(inode)])->opencnt++;
472 }
473
474 return 0;
475}
476
477/*
478** handle system call close()/umount()
479**
480** returns:
481** 0 - okay
482*/
483static int cowlo_release(struct gendisk *gd, fmode_t mode)
484{
485 struct block_device *bdev;
486 struct inode *inode;
487
488 bdev = bdget_disk(gd, 0);
489 inode = bdev->bd_inode;
490 if (!inode)
491 return 0;
492
493 DEBUGP(DCOW"cowloop - release (close) minor %d\n", iminor(inode));
494
495 if ( iminor(inode) != COWCTL)
496 (cowdevall[iminor(inode)])->opencnt--;
497
498 return 0;
499}
500
501/*
502** handle system call ioctl()
503**
504** returns:
505** 0 - okay
506** < 0 - error value
507*/
508static int cowlo_ioctl(struct block_device *bdev, fmode_t mode,
509 unsigned int cmd, unsigned long arg)
510{
511 struct hd_geometry geo;
512 struct inode *inode = bdev->bd_inode;
513
514 DEBUGP(DCOW "cowloop - ioctl cmd %x\n", cmd);
515
516 switch ( iminor(inode) ) {
517
518 /*
519 ** allowed via control device only
520 */
521 case COWCTL:
522 switch (cmd) {
523 /*
524 ** write all bitmap chunks and cowheaders to cowfiles
525 */
526 case COWSYNC:
527 down(&cowdevlock);
528 cowlo_sync();
529 up(&cowdevlock);
530 return 0;
531
532 /*
533 ** open a new cowdevice (pair of rdofile/cowfile)
534 */
535 case COWMKPAIR:
536 return cowlo_makepair((void __user *)arg);
537
538 /*
539 ** close a cowdevice (pair of rdofile/cowfile)
540 */
541 case COWRMPAIR:
542 return cowlo_removepair((void __user *)arg);
543
544 /*
545 ** watch free space of filesystem containing cowfile
546 */
547 case COWWATCH:
548 return cowlo_watch((void __user *)arg);
549
550 /*
551 ** close cowfile for active device
552 */
553 case COWCLOSE:
554 return cowlo_cowctl((void __user *)arg, COWCLOSE);
555
556 /*
557 ** reopen cowfile read-only for active device
558 */
559 case COWRDOPEN:
560 return cowlo_cowctl((void __user *)arg, COWRDOPEN);
561
562 default:
563 return -EINVAL;
564 } /* end of switch on command */
565
566 /*
567 ** allowed for any other cowdevice
568 */
569 default:
570 switch (cmd) {
571 /*
572 ** HDIO_GETGEO must be supported for fdisk, etc
573 */
574 case HDIO_GETGEO:
575 geo.cylinders = 0;
576 geo.heads = 0;
577 geo.sectors = 0;
578
579 if (copy_to_user((void __user *)arg, &geo, sizeof geo))
580 return -EFAULT;
581 return 0;
582
583 default:
584 return -EINVAL;
585 } /* end of switch on ioctl-cmd code parameter */
586 } /* end of switch on minor number */
587}
588
589static struct block_device_operations cowlo_fops =
590{
591 .owner = THIS_MODULE,
592 .open = cowlo_open, /* called upon open */
593 .release = cowlo_release, /* called upon close */
594 .ioctl = cowlo_ioctl, /* called upon ioctl */
595};
596
597/*
598** handle ioctl-command COWMKPAIR:
599** open a new cowdevice (pair of rdofile/cowfile) on-the-fly
600**
601** returns:
602** 0 - okay
603** < 0 - error value
604*/
605static int
606cowlo_makepair(struct cowpair __user *arg)
607{
608 int i, rv=0;
609 struct cowpair cowpair;
610 unsigned char *cowpath;
611 unsigned char *rdopath;
612
613 /*
614 ** retrieve info about pathnames
615 */
616 if ( copy_from_user(&cowpair, arg, sizeof cowpair) )
617 return -EFAULT;
618
619 if ( (MAJOR(cowpair.device) != COWMAJOR) && (cowpair.device != ANYDEV) )
620 return -EINVAL;
621
622 if ( (MINOR(cowpair.device) >= maxcows) && (cowpair.device != ANYDEV) )
623 return -EINVAL;
624
625 /*
626 ** retrieve pathname strings
627 */
628 if ( (cowpair.cowflen > PATH_MAX) || (cowpair.rdoflen > PATH_MAX) )
629 return -ENAMETOOLONG;
630
631 if ( !(cowpath = kmalloc(cowpair.cowflen+1, GFP_KERNEL)) )
632 return -ENOMEM;
633
634 if ( copy_from_user(cowpath, (void __user *)cowpair.cowfile,
635 cowpair.cowflen) ) {
636 kfree(cowpath);
637 return -EFAULT;
638 }
639 *(cowpath+cowpair.cowflen) = 0;
640
641 if ( !(rdopath = kmalloc(cowpair.rdoflen+1, GFP_KERNEL)) ) {
642 kfree(cowpath);
643 return -ENOMEM;
644 }
645
646 if ( copy_from_user(rdopath, (void __user *)cowpair.rdofile,
647 cowpair.rdoflen) ) {
648 kfree(rdopath);
649 kfree(cowpath);
650 return -EFAULT;
651 }
652 *(rdopath+cowpair.rdoflen) = 0;
653
654 /*
655 ** open new cowdevice
656 */
657 if ( cowpair.device == ANYDEV) {
658 /*
659 ** search first unused minor
660 */
661 for (i=0, rv=-EBUSY; i < maxcows; i++) {
662 if ( !((cowdevall[i])->state & COWDEVOPEN) ) {
663 rv = cowlo_openpair(rdopath, cowpath, 0, i);
664 break;
665 }
666 }
667
668 if (rv) { /* open failed? */
669 kfree(rdopath);
670 kfree(cowpath);
671 return rv;
672 }
673
674 /*
675 ** return newly allocated cowdevice to user space
676 */
677 cowpair.device = MKDEV(COWMAJOR, i);
678
679 if ( copy_to_user(arg, &cowpair, sizeof cowpair)) {
680 kfree(rdopath);
681 kfree(cowpath);
682 return -EFAULT;
683 }
684 } else { /* specific minor requested */
685 if ( (rv = cowlo_openpair(rdopath, cowpath, 0,
686 MINOR(cowpair.device)))) {
687 kfree(rdopath);
688 kfree(cowpath);
689 return rv;
690 }
691 }
692
693 return 0;
694}
695
696/*
697** handle ioctl-command COWRMPAIR:
698** deactivate an existing cowdevice (pair of rdofile/cowfile) on-the-fly
699**
700** returns:
701** 0 - okay
702** < 0 - error value
703*/
704static int
705cowlo_removepair(unsigned long __user *arg)
706{
707 unsigned long cowdevice;
708 struct cowloop_device *cowdev;
709
710 /*
711 ** retrieve info about device to be removed
712 */
713 if ( copy_from_user(&cowdevice, arg, sizeof cowdevice))
714 return -EFAULT;
715
716 /*
717 ** verify major-minor number
718 */
719 if ( MAJOR(cowdevice) != COWMAJOR)
720 return -EINVAL;
721
722 if ( MINOR(cowdevice) >= maxcows)
723 return -EINVAL;
724
725 cowdev = cowdevall[MINOR(cowdevice)];
726
727 if ( !(cowdev->state & COWDEVOPEN) )
728 return -ENODEV;
729
730 /*
731 ** synchronize bitmaps and close cowdevice
732 */
733 if (cowdev->state & COWRWCOWOPEN) {
734 down(&cowdevlock);
735 cowlo_sync();
736 up(&cowdevlock);
737 }
738
739 return cowlo_closepair(cowdev);
740}
741
742/*
743** handle ioctl-command COWWATCH:
744** watch the free space of the filesystem containing a cowfile
745** of an open cowdevice
746**
747** returns:
748** 0 - okay
749** < 0 - error value
750*/
751static int
752cowlo_watch(struct cowpair __user *arg)
753{
754 struct cowloop_device *cowdev;
755 struct cowwatch cowwatch;
756
757 /*
758 ** retrieve structure holding info
759 */
760 if ( copy_from_user(&cowwatch, arg, sizeof cowwatch))
761 return -EFAULT;
762
763 /*
764 ** verify if cowdevice exists and is currently open
765 */
766 if ( MINOR(cowwatch.device) >= maxcows)
767 return -EINVAL;
768
769 cowdev = cowdevall[MINOR(cowwatch.device)];
770
771 if ( !(cowdev->state & COWDEVOPEN) )
772 return -ENODEV;
773
774 /*
775 ** if the WATCHWAIT-option is set, wait until the indicated
776 ** threshold is reached (only one waiter allowed)
777 */
778 if (cowwatch.flags & WATCHWAIT) {
779 /*
780 ** check if already another waiter active
781 ** for this cowdevice
782 */
783 if (cowdev->state & COWWATCHDOG)
784 return -EAGAIN;
785
786 cowdev->state |= COWWATCHDOG;
787
788 cowdev->watchthresh = (unsigned long long)
789 cowwatch.threshold /
790 (cowdev->blksize / 1024);
791
792 if (wait_event_interruptible(cowdev->watchq,
793 cowdev->watchthresh >= cowdev->blkavail)) {
794 cowdev->state &= ~COWWATCHDOG;
795 return EINTR;
796 }
797
798 cowdev->state &= ~COWWATCHDOG;
799 }
800
801 cowwatch.totalkb = (unsigned long long)cowdev->blktotal *
802 cowdev->blksize / 1024;
803 cowwatch.availkb = (unsigned long long)cowdev->blkavail *
804 cowdev->blksize / 1024;
805
806 if ( copy_to_user(arg, &cowwatch, sizeof cowwatch))
807 return -EFAULT;
808
809 return 0;
810}
811
812/*
813** handle ioctl-commands COWCLOSE and COWRDOPEN:
814** COWCLOSE - close the cowfile while the cowdevice remains open;
815** this allows an unmount of the filesystem on which
816** the cowfile resides
817** COWRDOPEN - close the cowfile and reopen it for read-only;
818** this allows a remount read-ony of the filesystem
819** on which the cowfile resides
820**
821** returns:
822** 0 - okay
823** < 0 - error value
824*/
825static int
826cowlo_cowctl(unsigned long __user *arg, int cmd)
827{
828 struct cowloop_device *cowdev;
829 unsigned long cowdevice;
830
831 /*
832 ** retrieve info about device to be removed
833 */
834 if ( copy_from_user(&cowdevice, arg, sizeof cowdevice))
835 return -EFAULT;
836
837 /*
838 ** verify major-minor number
839 */
840 if ( MAJOR(cowdevice) != COWMAJOR)
841 return -EINVAL;
842
843 if ( MINOR(cowdevice) >= maxcows)
844 return -EINVAL;
845
846 cowdev = cowdevall[MINOR(cowdevice)];
847
848 if ( !(cowdev->state & COWDEVOPEN) )
849 return -ENODEV;
850
851 /*
852 ** synchronize bitmaps and close cowfile
853 */
854 if (cowdev->state & COWRWCOWOPEN) {
855 down(&cowdevlock);
856 cowlo_sync();
857 up(&cowdevlock);
858 }
859
860 /*
861 ** handle specific ioctl-command
862 */
863 switch (cmd) {
864 case COWRDOPEN:
865 /*
866 ** if the cowfile is still opened read-write
867 */
868 if (cowdev->state & COWRWCOWOPEN) {
869 /*
870 ** close the cowfile
871 */
872 if (cowdev->cowfp)
873 filp_close(cowdev->cowfp, 0);
874
875 cowdev->state &= ~COWRWCOWOPEN;
876
877 /*
878 ** open again for read-only
879 */
880 cowdev->cowfp = filp_open(cowdev->cowname,
881 O_RDONLY|O_LARGEFILE, 0600);
882
883 if ( (cowdev->cowfp == NULL) || IS_ERR(cowdev->cowfp) ) {
884 printk(KERN_ERR
885 "cowloop - failed to reopen cowfile %s\n",
886 cowdev->cowname);
887 return -EINVAL;
888 }
889
890 /*
891 ** mark cowfile open for read-only
892 */
893 cowdev->state |= COWRDCOWOPEN;
894 } else {
895 return -EINVAL;
896 }
897 break;
898
899 case COWCLOSE:
900 /*
901 ** if the cowfile is still open
902 */
903 if (cowdev->state & COWCOWOPEN) {
904 /*
905 ** close the cowfile
906 */
907 if (cowdev->cowfp)
908 filp_close(cowdev->cowfp, 0);
909
910 cowdev->state &= ~COWCOWOPEN;
911 }
912 }
913
914 return 0;
915}
916
917
918/*****************************************************************************/
919/* Handling of I/O-requests for a cowdevice */
920/*****************************************************************************/
921
922/*
923** function to be called by core-kernel to handle the I/O-requests
924** in the queue
925*/
926static void cowlo_request(struct request_queue *q)
927{
928 struct request *req;
929 struct cowloop_device *cowdev;
930
931 DEBUGP(DCOW "cowloop - request function called....\n");
932
933 while((req = blk_peek_request(q)) != NULL) {
934 DEBUGP(DCOW "cowloop - got next request\n");
935
936 if (! blk_fs_request(req)) {
937 /* this is not a normal file system request */
938 __blk_end_request_cur(req, -EIO);
939 continue;
940 }
941 cowdev = req->rq_disk->private_data;
942
943 if (cowdev->iobusy)
944 return;
945 else
946 cowdev->iobusy = 1;
947
948 /*
949 ** when no kernel-thread is available, the request will
950 ** produce an I/O-error
951 */
952 if (!cowdev->pid) {
953 printk(KERN_ERR"cowloop - no thread available\n");
954 __blk_end_request_cur(req, -EIO); /* request failed */
955 cowdev->iobusy = 0;
956 continue;
957 }
958
959 /*
960 ** handle I/O-request in the context of the kernel-thread
961 */
962 cowdev->req = req;
963 cowdev->qfilled = 1;
964
965 wake_up_interruptible_sync(&cowdev->waitq);
966
967 /*
968 ** get out of this function now while the I/O-request is
969 ** under treatment of the kernel-thread; this function
970 ** will be called again after the current I/O-request has
971 ** been finished by the thread
972 */
973 return;
974 }
975}
976
977/*
978** daemon-process (kernel-thread) executes this function
979*/
980static int
981cowlo_daemon(struct cowloop_device *cowdev)
982{
983 int rv;
984 int minor;
985 char myname[16];
986
987 for (minor = 0; minor < maxcows; minor++) {
988 if (cowdev == cowdevall[minor]) break;
989 }
990 sprintf(myname, "cowloopd%d", minor);
991
992 daemonize(myname);
993
994 while (!cowdev->closedown) {
995 /*
996 ** sleep while waiting for an I/O request;
997 ** note that no non-interruptible wait has been used
998 ** because the non-interruptible version of
999 ** a *synchronous* wake_up does not exist (any more)
1000 */
1001 if (wait_event_interruptible(cowdev->waitq, cowdev->qfilled)){
1002 flush_signals(current); /* ignore signal-based wakeup */
1003 continue;
1004 }
1005
1006 if (cowdev->closedown) /* module will be unloaded ? */{
1007 cowdev->pid = 0;
1008 return 0;
1009 }
1010
1011 /*
1012 ** woken up by the I/O-request handler: treat requested I/O
1013 */
1014 cowdev->qfilled = 0;
1015
1016 rv = cowlo_do_request(cowdev->req);
1017
1018 /*
1019 ** reacquire the queue-spinlock for manipulating
1020 ** the request-queue and dequeue the request
1021 */
1022 spin_lock_irq(&cowdev->rqlock);
1023
1024 __blk_end_request_cur(cowdev->req, rv);
1025 cowdev->iobusy = 0;
1026
1027 /*
1028 ** initiate the next request from the queue
1029 */
1030 cowlo_request(cowdev->rqueue);
1031
1032 spin_unlock_irq(&cowdev->rqlock);
1033 }
1034 return 0;
1035}
1036
1037/*
1038** function to be called in the context of the kernel thread
1039** to handle the queued I/O-requests
1040**
1041** returns:
1042** 0 - fail
1043** 1 - success
1044*/
1045static long int
1046cowlo_do_request(struct request *req)
1047{
1048 unsigned long len;
1049 long int rv;
1050 loff_t offset;
1051 struct cowloop_device *cowdev = req->rq_disk->private_data;
1052
1053 /*
1054 ** calculate some variables which are needed later on
1055 */
1056 len = blk_rq_cur_sectors(req) << 9;
1057 offset = (loff_t) blk_rq_pos(req) << 9;
1058
1059 DEBUGP(DCOW"cowloop - req cmd=%d offset=%lld len=%lu addr=%p\n",
1060 *(req->cmd), offset, len, req->buffer);
1061
1062 /*
1063 ** handle READ- or WRITE-request
1064 */
1065 switch (rq_data_dir(req)) {
1066 /**********************************************************/
1067 case READ:
1068 switch ( cowlo_checkio(cowdev, len, offset) ) {
1069 case ALLCOW:
1070 rv = cowlo_readcow(cowdev, req->buffer, len, offset);
1071 break;
1072
1073 case ALLRDO:
1074 rv = cowlo_readrdo(cowdev, req->buffer, len, offset);
1075 break;
1076
1077 case MIXEDUP:
1078 rv = cowlo_readmix(cowdev, req->buffer, len, offset);
1079 break;
1080
1081 default:
1082 rv = 0; /* never happens */
1083 }
1084 break;
1085
1086 /**********************************************************/
1087 case WRITE:
1088 switch ( cowlo_checkio(cowdev, len, offset) ) {
1089 case ALLCOW:
1090 /*
1091 ** straight-forward write will do...
1092 */
1093 DEBUGP(DCOW"cowloop - write straight ");
1094
1095 rv = cowlo_writecow(cowdev, req->buffer, len, offset);
1096 break; /* from switch */
1097
1098 case ALLRDO:
1099 if ( (len & MUMASK) == 0) {
1100 DEBUGP(DCOW"cowloop - write straight ");
1101
1102 rv = cowlo_writecow(cowdev, req->buffer,
1103 len, offset);
1104 break;
1105 }
1106
1107 case MIXEDUP:
1108 rv = cowlo_writemix(cowdev, req->buffer, len, offset);
1109 break;
1110
1111 default:
1112 rv = 0; /* never happens */
1113 }
1114 break;
1115
1116 default:
1117 printk(KERN_ERR
1118 "cowloop - unrecognized command %d\n", *(req->cmd));
1119 rv = 0;
1120 }
1121
1122 return (rv <= 0 ? 0 : 1);
1123}
1124
1125/*
1126** check for a given I/O-request if all underlying blocks
1127** (with size MAPUNIT) are either in the read-only file or in
1128** the cowfile (or a combination of the two)
1129**
1130** returns:
1131** ALLRDO - all underlying blocks in rdofile
1132** ALLCOW - all underlying blocks in cowfile
1133** MIXEDUP - underlying blocks partly in rdofile and partly in cowfile
1134*/
1135static int
1136cowlo_checkio(struct cowloop_device *cowdev, int len, loff_t offset)
1137{
1138 unsigned long mapnum, bytenum, bitnum, blocknr, partlen;
1139 long int totcnt, cowcnt;
1140 char *mc;
1141
1142 /*
1143 ** notice that the requested block might cross
1144 ** a blocksize boundary while one of the concerned
1145 ** blocks resides in the read-only file and another
1146 ** one in the copy-on-write file; in that case the
1147 ** request will be broken up into pieces
1148 */
1149 if ( (len <= MAPUNIT) &&
1150 (MAPUNIT - (offset & MUMASK) <= len) ) {
1151 /*
1152 ** easy situation:
1153 ** requested data-block entirely fits within
1154 ** the mapunit used for the bitmap
1155 ** check if that block is located in rdofile or
1156 ** cowfile
1157 */
1158 blocknr = offset >> MUSHIFT;
1159
1160 mapnum = CALCMAP (blocknr);
1161 bytenum = CALCBYTE(blocknr);
1162 bitnum = CALCBIT (blocknr);
1163
1164 if (*(*(cowdev->mapcache+mapnum)+bytenum)&(1<<bitnum))
1165 return ALLCOW;
1166 else
1167 return ALLRDO;
1168 }
1169
1170 /*
1171 ** less easy situation:
1172 ** the requested data-block does not fit within the mapunit
1173 ** used for the bitmap
1174 ** check if *all* underlying blocks involved reside on the rdofile
1175 ** or the cowfile (so still no breakup required)
1176 */
1177 for (cowcnt=totcnt=0; len > 0; len-=partlen, offset+=partlen, totcnt++){
1178 /*
1179 ** calculate blocknr of involved block
1180 */
1181 blocknr = offset >> MUSHIFT;
1182
1183 /*
1184 ** calculate partial length for this transfer
1185 */
1186 partlen = MAPUNIT - (offset & MUMASK);
1187 if (partlen > len)
1188 partlen = len;
1189
1190 /*
1191 ** is this block located in the cowfile
1192 */
1193 mapnum = CALCMAP (blocknr);
1194 bytenum = CALCBYTE(blocknr);
1195 bitnum = CALCBIT (blocknr);
1196
1197 mc = *(cowdev->mapcache+mapnum);
1198
1199 if (*(mc+bytenum)&(1<<bitnum))
1200 cowcnt++;;
1201
1202 DEBUGP(DCOW
1203 "cowloop - check %lu - map %lu, byte %lu, bit %lu, "
1204 "cowcnt %ld, totcnt %ld %02x %p\n",
1205 blocknr, mapnum, bytenum, bitnum, cowcnt, totcnt,
1206 *(mc+bytenum), mc);
1207 }
1208
1209 if (cowcnt == 0) /* all involved blocks on rdofile? */
1210 return ALLRDO;
1211
1212 if (cowcnt == totcnt) /* all involved blocks on cowfile? */
1213 return ALLCOW;
1214
1215 /*
1216 ** situation somewhat more complicated:
1217 ** involved underlying blocks spread over both files
1218 */
1219 return MIXEDUP;
1220}
1221
1222/*
1223** read requested chunk partly from rdofile and partly from cowfile
1224**
1225** returns:
1226** 0 - fail
1227** 1 - success
1228*/
1229static int
1230cowlo_readmix(struct cowloop_device *cowdev, void *buf, int len, loff_t offset)
1231{
1232 unsigned long mapnum, bytenum, bitnum, blocknr, partlen;
1233 long int rv;
1234 char *mc;
1235
1236 /*
1237 ** complicated approach: breakup required of read-request
1238 */
1239 for (rv=1; len > 0; len-=partlen, buf+=partlen, offset+=partlen) {
1240 /*
1241 ** calculate blocknr of entire block
1242 */
1243 blocknr = offset >> MUSHIFT;
1244
1245 /*
1246 ** calculate partial length for this transfer
1247 */
1248 partlen = MAPUNIT - (offset & MUMASK);
1249 if (partlen > len)
1250 partlen = len;
1251
1252 /*
1253 ** is this block located in the cowfile
1254 */
1255 mapnum = CALCMAP (blocknr);
1256 bytenum = CALCBYTE(blocknr);
1257 bitnum = CALCBIT (blocknr);
1258 mc = *(cowdev->mapcache+mapnum);
1259
1260 if (*(mc+bytenum)&(1<<bitnum)) {
1261 /*
1262 ** read (partial) block from cowfile
1263 */
1264 DEBUGP(DCOW"cowloop - split read "
1265 "cow partlen=%ld off=%lld\n", partlen, offset);
1266
1267 if (cowlo_readcow(cowdev, buf, partlen, offset) <= 0)
1268 rv = 0;
1269 } else {
1270 /*
1271 ** read (partial) block from rdofile
1272 */
1273 DEBUGP(DCOW"cowloop - split read "
1274 "rdo partlen=%ld off=%lld\n", partlen, offset);
1275
1276 if (cowlo_readrdo(cowdev, buf, partlen, offset) <= 0)
1277 rv = 0;
1278 }
1279 }
1280
1281 return rv;
1282}
1283
1284/*
1285** chunk to be written to the cowfile needs pieces to be
1286** read from the rdofile
1287**
1288** returns:
1289** 0 - fail
1290** 1 - success
1291*/
1292static int
1293cowlo_writemix(struct cowloop_device *cowdev, void *buf, int len, loff_t offset)
1294{
1295 unsigned long mapnum, bytenum, bitnum, blocknr, partlen;
1296 long int rv;
1297 char *mc;
1298
1299 /*
1300 ** somewhat more complicated stuff is required:
1301 ** if the request is larger than one underlying
1302 ** block or is spread over two underlying blocks,
1303 ** split the request into pieces; if a block does not
1304 ** start at a block boundary, take care that
1305 ** surrounding data is read first (if needed),
1306 ** fit the new data in and write it as a full block
1307 */
1308 for (rv=1; len > 0; len-=partlen, buf+=partlen, offset+=partlen) {
1309 /*
1310 ** calculate partial length for this transfer
1311 */
1312 partlen = MAPUNIT - (offset & MUMASK);
1313 if (partlen > len)
1314 partlen = len;
1315
1316 /*
1317 ** calculate blocknr of entire block
1318 */
1319 blocknr = offset >> MUSHIFT;
1320
1321 /*
1322 ** has this block been written before?
1323 */
1324 mapnum = CALCMAP (blocknr);
1325 bytenum = CALCBYTE(blocknr);
1326 bitnum = CALCBIT (blocknr);
1327 mc = *(cowdev->mapcache+mapnum);
1328
1329 if (*(mc+bytenum)&(1<<bitnum)) {
1330 /*
1331 ** block has been written before;
1332 ** write transparantly to cowfile
1333 */
1334 DEBUGP(DCOW
1335 "cowloop - splitwr transp\n");
1336
1337 if (cowlo_writecow(cowdev, buf, partlen, offset) <= 0)
1338 rv = 0;
1339 } else {
1340 /*
1341 ** block has never been written before,
1342 ** so read entire block from
1343 ** read-only file first, unless
1344 ** a full block is requested to
1345 ** be written
1346 */
1347 if (partlen < MAPUNIT) {
1348 if (cowlo_readrdo(cowdev, cowdev->iobuf,
1349 MAPUNIT, (loff_t)blocknr << MUSHIFT) <= 0)
1350 rv = 0;
1351 }
1352
1353 /*
1354 ** transfer modified part into
1355 ** the block just read
1356 */
1357 memcpy(cowdev->iobuf + (offset & MUMASK), buf, partlen);
1358
1359 /*
1360 ** write entire block to cowfile
1361 */
1362 DEBUGP(DCOW"cowloop - split "
1363 "partlen=%ld off=%lld\n",
1364 partlen, (loff_t)blocknr << MUSHIFT);
1365
1366 if (cowlo_writecow(cowdev, cowdev->iobuf, MAPUNIT,
1367 (loff_t)blocknr << MUSHIFT) <= 0)
1368 rv = 0;
1369 }
1370 }
1371
1372 return rv;
1373}
1374
1375/*****************************************************************************/
1376/* I/O-support for read-only file and copy-on-write file */
1377/*****************************************************************************/
1378
1379/*
1380** read data from the read-only file
1381**
1382** return-value: similar to user-mode read
1383*/
1384static long int
1385cowlo_readrdo(struct cowloop_device *cowdev, void *buf, int len, loff_t offset)
1386{
1387 long int rv;
1388 mm_segment_t old_fs;
1389 loff_t saveoffset = offset;
1390
1391 DEBUGP(DCOW"cowloop - readrdo called\n");
1392
1393 old_fs = get_fs();
1394 set_fs( get_ds() );
1395 rv = cowdev->rdofp->f_op->read(cowdev->rdofp, buf, len, &offset);
1396 set_fs(old_fs);
1397
1398 if (rv < len) {
1399 printk(KERN_WARNING "cowloop - read-failure %ld on rdofile"
1400 "- offset=%lld len=%d\n",
1401 rv, saveoffset, len);
1402 }
1403
1404 cowdev->rdoreads++;
1405 return rv;
1406}
1407
1408/*
1409** read cowfile from a modified offset, i.e. skipping the bitmap and cowhead
1410**
1411** return-value: similar to user-mode read
1412*/
1413static long int
1414cowlo_readcow(struct cowloop_device *cowdev, void *buf, int len, loff_t offset)
1415{
1416 DEBUGP(DCOW"cowloop - readcow called\n");
1417
1418 offset += cowdev->cowhead->doffset;
1419
1420 return cowlo_readcowraw(cowdev, buf, len, offset);
1421}
1422
1423/*
1424** read cowfile from an absolute offset
1425**
1426** return-value: similar to user-mode read
1427*/
1428static long int
1429cowlo_readcowraw(struct cowloop_device *cowdev,
1430 void *buf, int len, loff_t offset)
1431{
1432 long int rv;
1433 mm_segment_t old_fs;
1434 loff_t saveoffset = offset;
1435
1436 DEBUGP(DCOW"cowloop - readcowraw called\n");
1437
1438 /*
1439 ** be sure that cowfile is opened for read-write
1440 */
1441 if ( !(cowdev->state & COWCOWOPEN) ) {
1442 printk(KERN_WARNING
1443 "cowloop - read request from cowfile refused\n");
1444
1445 return -EBADF;
1446 }
1447
1448 /*
1449 ** issue low level read
1450 */
1451 old_fs = get_fs();
1452 set_fs( get_ds() );
1453 rv = cowdev->cowfp->f_op->read(cowdev->cowfp, buf, len, &offset);
1454 set_fs(old_fs);
1455
1456 if (rv < len) {
1457 printk(KERN_WARNING
1458 "cowloop - read-failure %ld on cowfile"
1459 "- offset=%lld len=%d\n", rv, saveoffset, len);
1460 }
1461
1462 cowdev->cowreads++;
1463 return rv;
1464}
1465
1466/*
1467** write cowfile from a modified offset, i.e. skipping the bitmap and cowhead
1468**
1469** if a block is written for the first time while its contents consists
1470** of binary zeroes only, the concerning bitmap is flushed to the cowfile
1471**
1472** return-value: similar to user-mode write
1473*/
1474static long int
1475cowlo_writecow(struct cowloop_device *cowdev, void *buf, int len, loff_t offset)
1476{
1477 long int rv;
1478 unsigned long mapnum=0, mapbyte=0, mapbit=0, cowblock=0, partlen;
1479 char *tmpptr, *mapptr = NULL;
1480 loff_t tmpoffset, mapoffset = 0;
1481
1482 DEBUGP(DCOW"cowloop - writecow called\n");
1483
1484 /*
1485 ** be sure that cowfile is opened for read-write
1486 */
1487 if ( !(cowdev->state & COWRWCOWOPEN) ) {
1488 printk(KERN_WARNING
1489 "cowloop - Write request to cowfile refused\n");
1490
1491 return -EBADF;
1492 }
1493
1494 /*
1495 ** write the entire block to the cowfile
1496 */
1497 tmpoffset = offset + cowdev->cowhead->doffset;
1498
1499 rv = cowlo_writecowraw(cowdev, buf, len, tmpoffset);
1500
1501 /*
1502 ** verify if enough space available on filesystem holding
1503 ** the cowfile
1504 ** - when the last write failed (might be caused by lack of space)
1505 ** - when a watcher is active (to react adequatly)
1506 ** - when the previous check indicated fs was almost full
1507 ** - with regular intervals
1508 */
1509 if ( (rv <= 0) ||
1510 (cowdev->state & COWWATCHDOG) ||
1511 (cowdev->blkavail / 2 < SPCDFLINTVL) ||
1512 (cowdev->cowwrites % SPCDFLINTVL == 0) ) {
1513 struct kstatfs ks;
1514
1515 if (vfs_statfs(cowdev->cowfp->f_dentry, &ks)==0){
1516 if (ks.f_bavail <= SPCMINBLK) {
1517 switch (ks.f_bavail) {
1518 case 0:
1519 case 1:
1520 case 2:
1521 case 3:
1522 printk(KERN_ALERT
1523 "cowloop - "
1524 "ALERT: cowfile full!\n");
1525 break;
1526
1527 default:
1528 printk(KERN_WARNING
1529 "cowloop - cowfile almost "
1530 "full (only %llu Kb free)\n",
1531 (unsigned long long)
1532 ks.f_bsize * ks.f_bavail /1024);
1533 }
1534 }
1535
1536 cowdev->blktotal = ks.f_blocks;
1537 cowdev->blkavail = ks.f_bavail;
1538
1539 /*
1540 ** wakeup watcher if threshold has been reached
1541 */
1542 if ( (cowdev->state & COWWATCHDOG) &&
1543 (cowdev->watchthresh >= cowdev->blkavail) ) {
1544 wake_up_interruptible(&cowdev->watchq);
1545 }
1546 }
1547 }
1548
1549 if (rv <= 0)
1550 return rv;
1551
1552 DEBUGP(DCOW"cowloop - block written\n");
1553
1554 /*
1555 ** check if block(s) is/are written to the cowfile
1556 ** for the first time; if so, adapt the bitmap
1557 */
1558 for (; len > 0; len-=partlen, offset+=partlen, buf+=partlen) {
1559 /*
1560 ** calculate partial length for this transfer
1561 */
1562 partlen = MAPUNIT - (offset & MUMASK);
1563 if (partlen > len)
1564 partlen = len;
1565
1566 /*
1567 ** calculate bitnr of written chunk of cowblock
1568 */
1569 cowblock = offset >> MUSHIFT;
1570
1571 mapnum = CALCMAP (cowblock);
1572 mapbyte = CALCBYTE(cowblock);
1573 mapbit = CALCBIT (cowblock);
1574
1575 if (*(*(cowdev->mapcache+mapnum)+mapbyte) & (1<<mapbit))
1576 continue; /* already written before */
1577
1578 /*
1579 ** if the block is written for the first time,
1580 ** the corresponding bit should be set in the bitmap
1581 */
1582 *(*(cowdev->mapcache+mapnum)+mapbyte) |= (1<<mapbit);
1583
1584 cowdev->nrcowblocks++;
1585
1586 DEBUGP(DCOW"cowloop - bitupdate blk=%ld map=%ld "
1587 "byte=%ld bit=%ld\n",
1588 cowblock, mapnum, mapbyte, mapbit);
1589
1590 /*
1591 ** check if the cowhead in the cowfile is currently
1592 ** marked clean; if so, mark it dirty and flush it
1593 */
1594 if ( !(cowdev->cowhead->flags &= COWDIRTY)) {
1595 cowdev->cowhead->flags |= COWDIRTY;
1596
1597 cowlo_writecowraw(cowdev, cowdev->cowhead,
1598 MAPUNIT, (loff_t)0);
1599 }
1600
1601 /*
1602 ** if the written datablock contained binary zeroes,
1603 ** the bitmap block should be marked to be flushed to disk
1604 ** (blocks containing all zeroes cannot be recovered by
1605 ** the cowrepair-program later on if cowloop is not properly
1606 ** removed via rmmod)
1607 */
1608 if ( memcmp(buf, allzeroes, partlen) ) /* not all zeroes? */
1609 continue; /* no flush needed */
1610
1611 /*
1612 ** calculate positions of bitmap block to be flushed
1613 ** - pointer of bitmap block in memory
1614 ** - offset of bitmap block in cowfile
1615 */
1616 tmpptr = *(cowdev->mapcache+mapnum) + (mapbyte & (~MUMASK));
1617 tmpoffset = (loff_t) MAPUNIT + mapnum * MAPCHUNKSZ +
1618 (mapbyte & (~MUMASK));
1619
1620 /*
1621 ** flush a bitmap block at the moment that all bits have
1622 ** been set in that block, i.e. at the moment that we
1623 ** switch to another bitmap block
1624 */
1625 if ( (mapoffset != 0) && (mapoffset != tmpoffset) ) {
1626 if (cowlo_writecowraw(cowdev, mapptr, MAPUNIT,
1627 mapoffset) < 0) {
1628 printk(KERN_WARNING
1629 "cowloop - write-failure on bitmap - "
1630 "blk=%ld map=%ld byte=%ld bit=%ld\n",
1631 cowblock, mapnum, mapbyte, mapbit);
1632 }
1633
1634 DEBUGP(DCOW"cowloop - bitmap blk written %lld\n",
1635 mapoffset);
1636 }
1637
1638 /*
1639 ** remember offset in cowfile and offset in memory
1640 ** for bitmap to be flushed; flushing will be done
1641 ** as soon as all updates in this bitmap block have
1642 ** been done
1643 */
1644 mapoffset = tmpoffset;
1645 mapptr = tmpptr;
1646 }
1647
1648 /*
1649 ** any new block written containing binary zeroes?
1650 */
1651 if (mapoffset) {
1652 if (cowlo_writecowraw(cowdev, mapptr, MAPUNIT, mapoffset) < 0) {
1653 printk(KERN_WARNING
1654 "cowloop - write-failure on bitmap - "
1655 "blk=%ld map=%ld byte=%ld bit=%ld\n",
1656 cowblock, mapnum, mapbyte, mapbit);
1657 }
1658
1659 DEBUGP(DCOW"cowloop - bitmap block written %lld\n", mapoffset);
1660 }
1661
1662 return rv;
1663}
1664
1665/*
1666** write cowfile from an absolute offset
1667**
1668** return-value: similar to user-mode write
1669*/
1670static long int
1671cowlo_writecowraw(struct cowloop_device *cowdev,
1672 void *buf, int len, loff_t offset)
1673{
1674 long int rv;
1675 mm_segment_t old_fs;
1676 loff_t saveoffset = offset;
1677
1678 DEBUGP(DCOW"cowloop - writecowraw called\n");
1679
1680 /*
1681 ** be sure that cowfile is opened for read-write
1682 */
1683 if ( !(cowdev->state & COWRWCOWOPEN) ) {
1684 printk(KERN_WARNING
1685 "cowloop - write request to cowfile refused\n");
1686
1687 return -EBADF;
1688 }
1689
1690 /*
1691 ** issue low level write
1692 */
1693 old_fs = get_fs();
1694 set_fs( get_ds() );
1695 rv = cowdev->cowfp->f_op->write(cowdev->cowfp, buf, len, &offset);
1696 set_fs(old_fs);
1697
1698 if (rv < len) {
1699 printk(KERN_WARNING
1700 "cowloop - write-failure %ld on cowfile"
1701 "- offset=%lld len=%d\n", rv, saveoffset, len);
1702 }
1703
1704 cowdev->cowwrites++;
1705 return rv;
1706}
1707
1708
1709/*
1710** readproc-function: called when the corresponding /proc-file is read
1711*/
1712static int
1713cowlo_readproc(char *buf, char **start, off_t pos, int cnt, int *eof, void *p)
1714{
1715 struct cowloop_device *cowdev = p;
1716
1717 revision[sizeof revision - 3] = '\0';
1718
1719 return sprintf(buf,
1720 " cowloop version: %9s\n\n"
1721 " device state: %s%s%s%s\n"
1722 " number of opens: %9d\n"
1723 " pid of thread: %9d\n\n"
1724 " read-only file: %9s\n"
1725 " rdoreads: %9lu\n\n"
1726 "copy-on-write file: %9s\n"
1727 " state cowfile: %9s\n"
1728 " bitmap-blocks: %9lu (of %d bytes)\n"
1729 " cowblocks in use: %9lu (of %d bytes)\n"
1730 " cowreads: %9lu\n"
1731 " cowwrites: %9lu\n",
1732 &revision[11],
1733
1734 cowdev->state & COWDEVOPEN ? "devopen " : "",
1735 cowdev->state & COWRWCOWOPEN ? "cowopenrw " : "",
1736 cowdev->state & COWRDCOWOPEN ? "cowopenro " : "",
1737 cowdev->state & COWWATCHDOG ? "watchdog " : "",
1738
1739 cowdev->opencnt,
1740 cowdev->pid,
1741 cowdev->rdoname,
1742 cowdev->rdoreads,
1743 cowdev->cowname,
1744 cowdev->cowhead->flags & COWDIRTY ? "dirty":"clean",
1745 cowdev->mapsize >> MUSHIFT, MAPUNIT,
1746 cowdev->nrcowblocks, MAPUNIT,
1747 cowdev->cowreads,
1748 cowdev->cowwrites);
1749}
1750
1751/*****************************************************************************/
1752/* Setup and destroy cowdevices */
1753/*****************************************************************************/
1754
1755/*
1756** open and prepare a cowdevice (rdofile and cowfile) and allocate bitmaps
1757**
1758** returns:
1759** 0 - okay
1760** < 0 - error value
1761*/
1762static int
1763cowlo_openpair(char *rdof, char *cowf, int autorecover, int minor)
1764{
1765 long int rv;
1766 struct cowloop_device *cowdev = cowdevall[minor];
1767 struct kstatfs ks;
1768
1769 down(&cowdevlock);
1770
1771 /*
1772 ** requested device exists?
1773 */
1774 if (minor >= maxcows) {
1775 up(&cowdevlock);
1776 return -ENODEV;
1777 }
1778
1779 /*
1780 ** requested device already assigned to cowdevice?
1781 */
1782 if (cowdev->state & COWDEVOPEN) {
1783 up(&cowdevlock);
1784 return -EBUSY;
1785 }
1786
1787 /*
1788 ** initialize administration
1789 */
1790 memset(cowdev, 0, sizeof *cowdev);
1791
1792 spin_lock_init (&cowdev->rqlock);
1793 init_waitqueue_head(&cowdev->waitq);
1794 init_waitqueue_head(&cowdev->watchq);
1795
1796 /*
1797 ** open the read-only file
1798 */
1799 DEBUGP(DCOW"cowloop - call openrdo....\n");
1800
1801 if ( (rv = cowlo_openrdo(cowdev, rdof)) ) {
1802 cowlo_undo_openrdo(cowdev);
1803 up(&cowdevlock);
1804 return rv;
1805 }
1806
1807 /*
1808 ** open the cowfile
1809 */
1810 DEBUGP(DCOW"cowloop - call opencow....\n");
1811
1812 if ( (rv = cowlo_opencow(cowdev, cowf, autorecover)) ) {
1813 cowlo_undo_openrdo(cowdev);
1814 cowlo_undo_opencow(cowdev);
1815 up(&cowdevlock);
1816 return rv;
1817 }
1818
1819 /*
1820 ** administer total and available size of filesystem holding cowfile
1821 */
1822 if (vfs_statfs(cowdev->cowfp->f_dentry, &ks)==0) {
1823 cowdev->blksize = ks.f_bsize;
1824 cowdev->blktotal = ks.f_blocks;
1825 cowdev->blkavail = ks.f_bavail;
1826 } else {
1827 cowdev->blksize = 1024; /* avoid division by zero */
1828 }
1829
1830 /*
1831 ** flush the (recovered) bitmaps and cowhead to the cowfile
1832 */
1833 DEBUGP(DCOW"cowloop - call cowsync....\n");
1834
1835 cowlo_sync();
1836
1837 /*
1838 ** allocate gendisk for the cow device
1839 */
1840 DEBUGP(DCOW"cowloop - alloc disk....\n");
1841
1842 if ((cowdev->gd = alloc_disk(1)) == NULL) {
1843 printk(KERN_WARNING
1844 "cowloop - unable to alloc_disk for cowloop\n");
1845
1846 cowlo_undo_openrdo(cowdev);
1847 cowlo_undo_opencow(cowdev);
1848 up(&cowdevlock);
1849 return -ENOMEM;
1850 }
1851
1852 cowdev->gd->major = COWMAJOR;
1853 cowdev->gd->first_minor = minor;
1854 cowdev->gd->minors = 1;
1855 cowdev->gd->fops = &cowlo_fops;
1856 cowdev->gd->private_data = cowdev;
1857 sprintf(cowdev->gd->disk_name, "%s%d", DEVICE_NAME, minor);
1858
1859 /* in .5 Kb units */
1860 set_capacity(cowdev->gd, (cowdev->numblocks*(MAPUNIT/512)));
1861
1862 DEBUGP(DCOW"cowloop - init request queue....\n");
1863
1864 if ((cowdev->rqueue = blk_init_queue(cowlo_request, &cowdev->rqlock))
1865 == NULL) {
1866 printk(KERN_WARNING
1867 "cowloop - unable to get request queue for cowloop\n");
1868
1869 del_gendisk(cowdev->gd);
1870 cowlo_undo_openrdo(cowdev);
1871 cowlo_undo_opencow(cowdev);
1872 up(&cowdevlock);
1873 return -EINVAL;
1874 }
1875
1876 blk_queue_logical_block_size(cowdev->rqueue, cowdev->blocksz);
1877 cowdev->gd->queue = cowdev->rqueue;
1878
1879 /*
1880 ** start kernel thread to handle requests
1881 */
1882 DEBUGP(DCOW"cowloop - kickoff daemon....\n");
1883
1884 cowdev->pid = kernel_thread((int (*)(void *))cowlo_daemon, cowdev, 0);
1885
1886 /*
1887 ** create a file below directory /proc/cow for this new cowdevice
1888 */
1889 if (cowlo_procdir) {
1890 char tmpname[64];
1891
1892 sprintf(tmpname, "%d", minor);
1893
1894 create_proc_read_entry(tmpname, 0 , cowlo_procdir,
1895 cowlo_readproc, cowdev);
1896 }
1897
1898 cowdev->state |= COWDEVOPEN;
1899
1900 cowdev->rdoname = rdof;
1901 cowdev->cowname = cowf;
1902
1903 /*
1904 ** enable the new disk; this triggers the first request!
1905 */
1906 DEBUGP(DCOW"cowloop - call add_disk....\n");
1907
1908 add_disk(cowdev->gd);
1909
1910 up(&cowdevlock);
1911 return 0;
1912}
1913
1914/*
1915** close a cowdevice (pair of rdofile/cowfile) and release memory
1916**
1917** returns:
1918** 0 - okay
1919** < 0 - error value
1920*/
1921static int
1922cowlo_closepair(struct cowloop_device *cowdev)
1923{
1924 int minor;
1925
1926 down(&cowdevlock);
1927
1928 /*
1929 ** if cowdevice is not activated at all, refuse
1930 */
1931 if ( !(cowdev->state & COWDEVOPEN) ) {
1932 up(&cowdevlock);
1933 return -ENODEV;
1934 }
1935
1936 /*
1937 ** if this cowdevice is still open, refuse
1938 */
1939 if (cowdev->opencnt > 0) {
1940 up(&cowdevlock);
1941 return -EBUSY;
1942 }
1943
1944 up(&cowdevlock);
1945
1946 /*
1947 ** wakeup watcher (if any)
1948 */
1949 if (cowdev->state & COWWATCHDOG) {
1950 cowdev->watchthresh = cowdev->blkavail;
1951 wake_up_interruptible(&cowdev->watchq);
1952 }
1953
1954 /*
1955 ** wakeup kernel-thread to be able to exit
1956 ** and wait until it has exited
1957 */
1958 cowdev->closedown = 1;
1959 cowdev->qfilled = 1;
1960 wake_up_interruptible(&cowdev->waitq);
1961
1962 while (cowdev->pid)
1963 schedule();
1964
1965 del_gendisk(cowdev->gd); /* revert the alloc_disk() */
1966 put_disk(cowdev->gd); /* revert the add_disk() */
1967
1968 if (cowlo_procdir) {
1969 char tmpname[64];
1970
1971 for (minor = 0; minor < maxcows; minor++) {
1972 if (cowdev == cowdevall[minor]) break;
1973 }
1974 sprintf(tmpname, "%d", minor);
1975
1976 remove_proc_entry(tmpname, cowlo_procdir);
1977 }
1978
1979 blk_cleanup_queue(cowdev->rqueue);
1980
1981 /*
1982 ** release memory for filenames if these names have
1983 ** been allocated dynamically
1984 */
1985 if ( (cowdev->cowname) && (cowdev->cowname != cowfile))
1986 kfree(cowdev->cowname);
1987
1988 if ( (cowdev->rdoname) && (cowdev->rdoname != rdofile))
1989 kfree(cowdev->rdoname);
1990
1991 cowlo_undo_openrdo(cowdev);
1992 cowlo_undo_opencow(cowdev);
1993
1994 cowdev->state &= ~COWDEVOPEN;
1995
1996 return 0;
1997}
1998
1999/*
2000** open the read-only file
2001**
2002** returns:
2003** 0 - okay
2004** < 0 - error value
2005*/
2006static int
2007cowlo_openrdo(struct cowloop_device *cowdev, char *rdof)
2008{
2009 struct file *f;
2010 struct inode *inode;
2011 long int i, nrval;
2012
2013 DEBUGP(DCOW"cowloop - openrdo called\n");
2014
2015 /*
2016 ** open the read-only file
2017 */
2018 if(*rdof == '\0') {
2019 printk(KERN_ERR
2020 "cowloop - specify name for read-only file\n\n");
2021 return -EINVAL;
2022 }
2023
2024 f = filp_open(rdof, O_RDONLY|O_LARGEFILE, 0);
2025
2026 if ( (f == NULL) || IS_ERR(f) ) {
2027 printk(KERN_ERR
2028 "cowloop - open of rdofile %s failed\n", rdof);
2029 return -EINVAL;
2030 }
2031
2032 cowdev->rdofp = f;
2033
2034 inode = f->f_dentry->d_inode;
2035
2036 if ( !S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode) ) {
2037 printk(KERN_ERR
2038 "cowloop - %s not regular file or blockdev\n", rdof);
2039 return -EINVAL;
2040 }
2041
2042 DEBUGP(DCOW"cowloop - determine size rdo....\n");
2043
2044 /*
2045 ** determine block-size and total size of read-only file
2046 */
2047 if (S_ISREG(inode->i_mode)) {
2048 /*
2049 ** read-only file is a regular file
2050 */
2051 cowdev->blocksz = 512; /* other value fails */
2052 cowdev->numblocks = inode->i_size >> MUSHIFT;
2053
2054 if (inode->i_size & MUMASK) {
2055 printk(KERN_WARNING
2056 "cowloop - rdofile %s truncated to multiple "
2057 "of %d bytes\n", rdof, MAPUNIT);
2058 }
2059
2060 DEBUGP(DCOW"cowloop - RO=regular: numblocks=%d, blocksz=%d\n",
2061 cowdev->numblocks, cowdev->blocksz);
2062 } else {
2063 /*
2064 ** read-only file is a block device
2065 */
2066 cowdev->belowdev = inode->i_bdev;
2067 cowdev->belowgd = cowdev->belowdev->bd_disk; /* gendisk */
2068
2069 if (cowdev->belowdev->bd_part) {
2070 cowdev->numblocks = cowdev->belowdev->bd_part->nr_sects
2071 / (MAPUNIT/512);
2072 }
2073
2074 if (cowdev->belowgd) {
2075 cowdev->belowq = cowdev->belowgd->queue;
2076
2077 if (cowdev->numblocks == 0) {
2078 cowdev->numblocks = get_capacity(cowdev->belowgd)
2079 / (MAPUNIT/512);
2080 }
2081 }
2082
2083
2084 if (cowdev->belowq)
2085 cowdev->blocksz = queue_logical_block_size(cowdev->belowq);
2086
2087 if (cowdev->blocksz == 0)
2088 cowdev->blocksz = BLOCK_SIZE; /* default 2^10 */
2089
2090 DEBUGP(DCOW"cowloop - numblocks=%d, "
2091 "blocksz=%d, belowgd=%p, belowq=%p\n",
2092 cowdev->numblocks, cowdev->blocksz,
2093 cowdev->belowgd, cowdev->belowq);
2094
2095 DEBUGP(DCOW"cowloop - belowdev.bd_block_size=%d\n",
2096 cowdev->belowdev->bd_block_size);
2097 }
2098
2099 if (cowdev->numblocks == 0) {
2100 printk(KERN_ERR "cowloop - %s has no contents\n", rdof);
2101 return -EINVAL;
2102 }
2103
2104 /*
2105 ** reserve space in memory as generic I/O buffer
2106 */
2107 cowdev->iobuf = kmalloc(MAPUNIT, GFP_KERNEL);
2108
2109 if (!cowdev->iobuf) {
2110 printk(KERN_ERR
2111 "cowloop - cannot get space for buffer %d\n", MAPUNIT);
2112 return -ENOMEM;
2113 }
2114
2115 DEBUGP(DCOW"cowloop - determine fingerprint rdo....\n");
2116
2117 /*
2118 ** determine fingerprint for read-only file
2119 ** calculate fingerprint from first four datablocks
2120 ** which do not contain binary zeroes
2121 */
2122 for (i=0, cowdev->fingerprint=0, nrval=0;
2123 (nrval < 4)&&(i < cowdev->numblocks); i++) {
2124 int j;
2125 unsigned char cs;
2126
2127 /*
2128 ** read next block
2129 */
2130 if (cowlo_readrdo(cowdev, cowdev->iobuf, MAPUNIT,
2131 (loff_t)i << MUSHIFT) < 1)
2132 break;
2133
2134 /*
2135 ** calculate fingerprint by adding all byte-values
2136 */
2137 for (j=0, cs=0; j < MAPUNIT; j++)
2138 cs += *(cowdev->iobuf+j);
2139
2140 if (cs == 0) /* block probably contained zeroes */
2141 continue;
2142
2143 /*
2144 ** shift byte-value to proper place in final fingerprint
2145 */
2146 cowdev->fingerprint |= cs << (nrval*8);
2147 nrval++;
2148 }
2149
2150 return 0;
2151}
2152
2153/*
2154** undo memory allocs and file opens issued so far
2155** related to the read-only file
2156*/
2157static void
2158cowlo_undo_openrdo(struct cowloop_device *cowdev)
2159{
2160 if(cowdev->iobuf);
2161 kfree(cowdev->iobuf);
2162
2163 if (cowdev->rdofp)
2164 filp_close(cowdev->rdofp, 0);
2165}
2166
2167/*
2168** open the cowfile
2169**
2170** returns:
2171** 0 - okay
2172** < 0 - error value
2173*/
2174static int
2175cowlo_opencow(struct cowloop_device *cowdev, char *cowf, int autorecover)
2176{
2177 long int i, rv;
2178 int minor;
2179 unsigned long nb;
2180 struct file *f;
2181 struct inode *inode;
2182 loff_t offset;
2183 struct cowloop_device *cowtmp;
2184
2185 DEBUGP(DCOW"cowloop - opencow called\n");
2186
2187 /*
2188 ** open copy-on-write file (read-write)
2189 */
2190 if (cowf[0] == '\0') {
2191 printk(KERN_ERR
2192 "cowloop - specify name of copy-on-write file\n\n");
2193 return -EINVAL;
2194 }
2195
2196 f = filp_open(cowf, O_RDWR|O_LARGEFILE, 0600);
2197
2198 if ( (f == NULL) || IS_ERR(f) ) {
2199 /*
2200 ** non-existing cowfile: try to create
2201 */
2202 f = filp_open(cowf, O_RDWR|O_CREAT|O_LARGEFILE, 0600);
2203
2204 if ( (f == NULL) || IS_ERR(f) ) {
2205 printk(KERN_ERR
2206 "cowloop - failed to open file %s for read-write\n\n",
2207 cowf);
2208 return -EINVAL;
2209 }
2210 }
2211
2212 cowdev->cowfp = f;
2213
2214 inode = f->f_dentry->d_inode;
2215
2216 if (!S_ISREG(inode->i_mode)) {
2217 printk(KERN_ERR "cowloop - %s is not regular file\n", cowf);
2218 return -EINVAL;
2219 }
2220
2221 /*
2222 ** check if this cowfile is already in use for another cowdevice
2223 */
2224 for (minor = 0; minor < maxcows; minor++) {
2225
2226 cowtmp = cowdevall[minor];
2227
2228 if ( !(cowtmp->state & COWDEVOPEN) )
2229 continue;
2230
2231 if (cowtmp == cowdev)
2232 continue;
2233
2234 if (cowtmp->cowfp->f_dentry->d_inode == f->f_dentry->d_inode) {
2235 printk(KERN_ERR
2236 "cowloop - %s: already in use as cow\n", cowf);
2237 return -EBUSY;
2238 }
2239 }
2240
2241 /*
2242 ** mark cowfile open for read-write
2243 */
2244 cowdev->state |= COWRWCOWOPEN;
2245
2246 /*
2247 ** calculate size (in bytes) for total bitmap in cowfile;
2248 ** when the size of the cowhead block is added, the start-offset
2249 ** for the modified data blocks can be found
2250 */
2251 nb = cowdev->numblocks;
2252
2253 if (nb%8) /* transform #bits to #bytes */
2254 nb+=8; /* rounded if necessary */
2255 nb /= 8;
2256
2257 if (nb & MUMASK) /* round up #bytes to MAPUNIT chunks */
2258 cowdev->mapsize = ( (nb>>MUSHIFT) +1) << MUSHIFT;
2259 else
2260 cowdev->mapsize = nb;
2261
2262 /*
2263 ** reserve space in memory for the cowhead
2264 */
2265 cowdev->cowhead = kmalloc(MAPUNIT, GFP_KERNEL);
2266
2267 if (!cowdev->cowhead) {
2268 printk(KERN_ERR "cowloop - cannot get space for cowhead %d\n",
2269 MAPUNIT);
2270 return -ENOMEM;
2271 }
2272
2273 memset(cowdev->cowhead, 0, MAPUNIT);
2274
2275 DEBUGP(DCOW"cowloop - prepare cowhead....\n");
2276
2277 /*
2278 ** check if the cowfile exists or should be created
2279 */
2280 if (inode->i_size != 0) {
2281 /*
2282 ** existing cowfile: read the cow head
2283 */
2284 if (inode->i_size < MAPUNIT) {
2285 printk(KERN_ERR
2286 "cowloop - existing cowfile %s too small\n",
2287 cowf);
2288 return -EINVAL;
2289 }
2290
2291 cowlo_readcowraw(cowdev, cowdev->cowhead, MAPUNIT, (loff_t) 0);
2292
2293 /*
2294 ** verify if the existing file is really a cowfile
2295 */
2296 if (cowdev->cowhead->magic != COWMAGIC) {
2297 printk(KERN_ERR
2298 "cowloop - cowfile %s has incorrect format\n",
2299 cowf);
2300 return -EINVAL;
2301 }
2302
2303 /*
2304 ** verify the cowhead version of the cowfile
2305 */
2306 if (cowdev->cowhead->version > COWVERSION) {
2307 printk(KERN_ERR
2308 "cowloop - cowfile %s newer than this driver\n",
2309 cowf);
2310 return -EINVAL;
2311 }
2312
2313 /*
2314 ** make sure that this is not a packed cowfile
2315 */
2316 if (cowdev->cowhead->flags & COWPACKED) {
2317 printk(KERN_ERR
2318 "cowloop - packed cowfile %s not accepted\n", cowf);
2319 return -EINVAL;
2320 }
2321
2322 /*
2323 ** verify if the cowfile has been properly closed
2324 */
2325 if (cowdev->cowhead->flags & COWDIRTY) {
2326 /*
2327 ** cowfile was not properly closed;
2328 ** check if automatic recovery is required
2329 ** (actual recovery will be done later on)
2330 */
2331 if (!autorecover) {
2332 printk(KERN_ERR
2333 "cowloop - cowfile %s is dirty "
2334 "(not properly closed by rmmod?)\n",
2335 cowf);
2336 printk(KERN_ERR
2337 "cowloop - run cowrepair or specify "
2338 "'option=r' to recover\n");
2339 return -EINVAL;
2340 }
2341 }
2342
2343 /*
2344 ** verify if the cowfile is really related to this rdofile
2345 */
2346 if (cowdev->cowhead->rdoblocks != cowdev->numblocks) {
2347 printk(KERN_ERR
2348 "cowloop - cowfile %s (size %lld) not related "
2349 "to rdofile (size %lld)\n",
2350 cowf,
2351 (long long)cowdev->cowhead->rdoblocks <<MUSHIFT,
2352 (long long)cowdev->numblocks <<MUSHIFT);
2353 return -EINVAL;
2354 }
2355
2356 if (cowdev->cowhead->rdofingerprint != cowdev->fingerprint) {
2357 printk(KERN_ERR
2358 "cowloop - cowfile %s not related to rdofile "
2359 " (fingerprint err - rdofile modified?)\n", cowf);
2360 return -EINVAL;
2361 }
2362 } else {
2363 /*
2364 ** new cowfile: determine the minimal size (cowhead+bitmap)
2365 */
2366 offset = (loff_t) MAPUNIT + cowdev->mapsize - 1;
2367
2368 if ( cowlo_writecowraw(cowdev, "", 1, offset) < 1) {
2369 printk(KERN_ERR
2370 "cowloop - cannot set cowfile to size %lld\n",
2371 offset+1);
2372 return -EINVAL;
2373 }
2374
2375 /*
2376 ** prepare new cowhead
2377 */
2378 cowdev->cowhead->magic = COWMAGIC;
2379 cowdev->cowhead->version = COWVERSION;
2380 cowdev->cowhead->mapunit = MAPUNIT;
2381 cowdev->cowhead->mapsize = cowdev->mapsize;
2382 cowdev->cowhead->rdoblocks = cowdev->numblocks;
2383 cowdev->cowhead->rdofingerprint = cowdev->fingerprint;
2384 cowdev->cowhead->cowused = 0;
2385
2386 /*
2387 ** calculate start offset of data in cowfile,
2388 ** rounded up to multiple of 4K to avoid
2389 ** unnecessary disk-usage for written datablocks in
2390 ** the sparsed cowfile on e.g. 4K filesystems
2391 */
2392 cowdev->cowhead->doffset =
2393 ((MAPUNIT+cowdev->mapsize+4095)>>12)<<12;
2394 }
2395
2396 cowdev->cowhead->flags = 0;
2397
2398 DEBUGP(DCOW"cowloop - reserve space bitmap....\n");
2399
2400 /*
2401 ** reserve space in memory for the entire bitmap and
2402 ** fill it with the bitmap-data from disk; the entire
2403 ** bitmap is allocated in several chunks because kmalloc
2404 ** has restrictions regarding the allowed size per kmalloc
2405 */
2406 cowdev->mapcount = (cowdev->mapsize+MAPCHUNKSZ-1)/MAPCHUNKSZ;
2407
2408 /*
2409 ** the size of every bitmap chunk will be MAPCHUNKSZ bytes, except for
2410 ** the last bitmap chunk: calculate remaining size for this chunk
2411 */
2412 if (cowdev->mapsize % MAPCHUNKSZ == 0)
2413 cowdev->mapremain = MAPCHUNKSZ;
2414 else
2415 cowdev->mapremain = cowdev->mapsize % MAPCHUNKSZ;
2416
2417 /*
2418 ** allocate space to store all pointers for the bitmap-chunks
2419 ** (initialize area with zeroes to allow proper undo)
2420 */
2421 cowdev->mapcache = kmalloc(cowdev->mapcount * sizeof(char *),
2422 GFP_KERNEL);
2423 if (!cowdev->mapcache) {
2424 printk(KERN_ERR
2425 "cowloop - can not allocate space for bitmap ptrs\n");
2426 return -ENOMEM;
2427 }
2428
2429 memset(cowdev->mapcache, 0, cowdev->mapcount * sizeof(char *));
2430
2431 /*
2432 ** allocate space to store the bitmap-chunks themselves
2433 */
2434 for (i=0; i < cowdev->mapcount; i++) {
2435 if (i < (cowdev->mapcount-1))
2436 *(cowdev->mapcache+i) = kmalloc(MAPCHUNKSZ, GFP_KERNEL);
2437 else
2438 *(cowdev->mapcache+i) = kmalloc(cowdev->mapremain,
2439 GFP_KERNEL);
2440
2441 if (*(cowdev->mapcache+i) == NULL) {
2442 printk(KERN_ERR "cowloop - no space for bitmapchunk %ld"
2443 " totmapsz=%ld, mapcnt=%d mapunit=%d\n",
2444 i, cowdev->mapsize, cowdev->mapcount,
2445 MAPUNIT);
2446 return -ENOMEM;
2447 }
2448 }
2449
2450 DEBUGP(DCOW"cowloop - read bitmap from cow....\n");
2451
2452 /*
2453 ** read the entire bitmap from the cowfile into the in-memory cache;
2454 ** count the number of blocks that are in use already
2455 ** (statistical purposes)
2456 */
2457 for (i=0, offset=MAPUNIT; i < cowdev->mapcount;
2458 i++, offset+=MAPCHUNKSZ) {
2459 unsigned long numbytes;
2460
2461 if (i < (cowdev->mapcount-1))
2462 /*
2463 ** full bitmap chunk
2464 */
2465 numbytes = MAPCHUNKSZ;
2466 else
2467 /*
2468 ** last bitmap chunk: might be partly filled
2469 */
2470 numbytes = cowdev->mapremain;
2471
2472 cowlo_readcowraw(cowdev, *(cowdev->mapcache+i),
2473 numbytes, offset);
2474 }
2475
2476 /*
2477 ** if the cowfile was dirty and automatic recovery is required,
2478 ** reconstruct a proper bitmap in memory now
2479 */
2480 if (cowdev->cowhead->flags & COWDIRTY) {
2481 unsigned long long blocknum;
2482 char databuf[MAPUNIT];
2483 unsigned long mapnum, mapbyte, mapbit;
2484
2485 printk(KERN_NOTICE "cowloop - recover dirty cowfile %s....\n",
2486 cowf);
2487
2488 /*
2489 ** read all data blocks
2490 */
2491 for (blocknum=0, rv=1, offset=0;
2492 cowlo_readcow(cowdev, databuf, MAPUNIT, offset) > 0;
2493 blocknum++, offset += MAPUNIT) {
2494
2495 /*
2496 ** if this datablock contains real data (not binary
2497 ** zeroes), set the corresponding bit in the bitmap
2498 */
2499 if ( memcmp(databuf, allzeroes, MAPUNIT) == 0)
2500 continue;
2501
2502 mapnum = CALCMAP (blocknum);
2503 mapbyte = CALCBYTE(blocknum);
2504 mapbit = CALCBIT (blocknum);
2505
2506 *(*(cowdev->mapcache+mapnum)+mapbyte) |= (1<<mapbit);
2507 }
2508
2509 printk(KERN_NOTICE "cowloop - cowfile recovery completed\n");
2510 }
2511
2512 /*
2513 ** count all bits set in the bitmaps for statistical purposes
2514 */
2515 for (i=0, cowdev->nrcowblocks = 0; i < cowdev->mapcount; i++) {
2516 long numbytes;
2517 char *p;
2518
2519 if (i < (cowdev->mapcount-1))
2520 numbytes = MAPCHUNKSZ;
2521 else
2522 numbytes = cowdev->mapremain;
2523
2524 p = *(cowdev->mapcache+i);
2525
2526 for (numbytes--; numbytes >= 0; numbytes--, p++) {
2527 /*
2528 ** for only eight checks the following construction
2529 ** is faster than a loop-construction
2530 */
2531 if ((*p) & 0x01) cowdev->nrcowblocks++;
2532 if ((*p) & 0x02) cowdev->nrcowblocks++;
2533 if ((*p) & 0x04) cowdev->nrcowblocks++;
2534 if ((*p) & 0x08) cowdev->nrcowblocks++;
2535 if ((*p) & 0x10) cowdev->nrcowblocks++;
2536 if ((*p) & 0x20) cowdev->nrcowblocks++;
2537 if ((*p) & 0x40) cowdev->nrcowblocks++;
2538 if ((*p) & 0x80) cowdev->nrcowblocks++;
2539 }
2540 }
2541
2542 /*
2543 ** consistency-check for number of bits set in bitmap
2544 */
2545 if ( !(cowdev->cowhead->flags & COWDIRTY) &&
2546 (cowdev->cowhead->cowused != cowdev->nrcowblocks) ) {
2547 printk(KERN_ERR "cowloop - inconsistent cowfile admi\n");
2548 return -EINVAL;
2549 }
2550
2551 return 0;
2552}
2553
2554/*
2555** undo memory allocs and file opens issued so far
2556** related to the cowfile
2557*/
2558static void
2559cowlo_undo_opencow(struct cowloop_device *cowdev)
2560{
2561 int i;
2562
2563 if (cowdev->mapcache) {
2564 for (i=0; i < cowdev->mapcount; i++) {
2565 if (*(cowdev->mapcache+i) != NULL)
2566 kfree( *(cowdev->mapcache+i) );
2567 }
2568
2569 kfree(cowdev->mapcache);
2570 }
2571
2572 if (cowdev->cowhead)
2573 kfree(cowdev->cowhead);
2574
2575 if ( (cowdev->state & COWCOWOPEN) && (cowdev->cowfp) )
2576 filp_close(cowdev->cowfp, 0);
2577
2578 /*
2579 ** mark cowfile closed
2580 */
2581 cowdev->state &= ~COWCOWOPEN;
2582}
2583
2584/*
2585** flush the entire bitmap and the cowhead (clean) to the cowfile
2586**
2587** must be called with the cowdevices-lock set
2588*/
2589static void
2590cowlo_sync(void)
2591{
2592 int i, minor;
2593 loff_t offset;
2594 struct cowloop_device *cowdev;
2595
2596 for (minor=0; minor < maxcows; minor++) {
2597 cowdev = cowdevall[minor];
2598 if ( ! (cowdev->state & COWRWCOWOPEN) )
2599 continue;
2600
2601 for (i=0, offset=MAPUNIT; i < cowdev->mapcount;
2602 i++, offset += MAPCHUNKSZ) {
2603 unsigned long numbytes;
2604
2605 if (i < (cowdev->mapcount-1))
2606 /*
2607 ** full bitmap chunk
2608 */
2609 numbytes = MAPCHUNKSZ;
2610 else
2611 /*
2612 ** last bitmap chunk: might be partly filled
2613 */
2614 numbytes = cowdev->mapremain;
2615
2616 DEBUGP(DCOW
2617 "cowloop - flushing bitmap %2d (%3ld Kb)\n",
2618 i, numbytes/1024);
2619
2620 if (cowlo_writecowraw(cowdev, *(cowdev->mapcache+i),
2621 numbytes, offset) < numbytes) {
2622 break;
2623 }
2624 }
2625
2626 /*
2627 ** flush clean up-to-date cowhead to cowfile
2628 */
2629 cowdev->cowhead->cowused = cowdev->nrcowblocks;
2630 cowdev->cowhead->flags &= ~COWDIRTY;
2631
2632 DEBUGP(DCOW "cowloop - flushing cowhead (%3d Kb)\n",
2633 MAPUNIT/1024);
2634
2635 cowlo_writecowraw(cowdev, cowdev->cowhead, MAPUNIT, (loff_t) 0);
2636 }
2637}
2638
2639/*****************************************************************************/
2640/* Module loading/unloading */
2641/*****************************************************************************/
2642
2643/*
2644** called during insmod/modprobe
2645*/
2646static int __init
2647cowlo_init_module(void)
2648{
2649 int rv;
2650 int minor, uptocows;
2651
2652 revision[sizeof revision - 3] = '\0';
2653
2654 printk(KERN_NOTICE "cowloop - (C) 2009 ATComputing.nl - version: %s\n", &revision[11]);
2655 printk(KERN_NOTICE "cowloop - info: www.ATComputing.nl/cowloop\n");
2656
2657 memset(allzeroes, 0, MAPUNIT);
2658
2659 /*
2660 ** Setup administration for all possible cowdevices.
2661 ** Note that their minor numbers go from 0 to MAXCOWS-1 inclusive
2662 ** and minor == MAXCOWS-1 is reserved for the control device.
2663 */
2664 if ((maxcows < 1) || (maxcows > MAXCOWS)) {
2665 printk(KERN_WARNING
2666 "cowloop - maxcows exceeds maximum of %d\n", MAXCOWS);
2667
2668 maxcows = DFLCOWS;
2669 }
2670
2671 /* allocate room for a table with a pointer to each cowloop_device: */
2672 if ( (cowdevall = kmalloc(maxcows * sizeof(struct cowloop_device *),
2673 GFP_KERNEL)) == NULL) {
2674 printk(KERN_WARNING
2675 "cowloop - can not alloc table for %d devs\n", maxcows);
2676 uptocows = 0;
2677 rv = -ENOMEM;
2678 goto error_out;
2679 }
2680 memset(cowdevall, 0, maxcows * sizeof(struct cowloop_device *));
2681 /* then hook an actual cowloop_device struct to each pointer: */
2682 for (minor=0; minor < maxcows; minor++) {
2683 if ((cowdevall[minor] = kmalloc(sizeof(struct cowloop_device),
2684 GFP_KERNEL)) == NULL) {
2685 printk(KERN_WARNING
2686 "cowloop - can not alloc admin-struct for dev no %d\n", minor);
2687
2688 uptocows = minor; /* this is how far we got.... */
2689 rv = -ENOMEM;
2690 goto error_out;
2691 }
2692 memset(cowdevall[minor], 0, sizeof(struct cowloop_device));
2693 }
2694 uptocows = maxcows; /* we got all devices */
2695
2696 sema_init(&cowdevlock, 1);
2697
2698 /*
2699 ** register cowloop module
2700 */
2701 if ( register_blkdev(COWMAJOR, DEVICE_NAME) < 0) {
2702 printk(KERN_WARNING
2703 "cowloop - unable to get major %d for cowloop\n", COWMAJOR);
2704 rv = -EIO;
2705 goto error_out;
2706 }
2707
2708 /*
2709 ** create a directory below /proc to allocate a file
2710 ** for each cowdevice that is allocated later on
2711 */
2712 cowlo_procdir = proc_mkdir("cow", NULL);
2713
2714 /*
2715 ** check if a cowdevice has to be opened during insmod/modprobe;
2716 ** two parameters should be specified then: rdofile= and cowfile=
2717 */
2718 if( (rdofile[0] != '\0') && (cowfile[0] != '\0') ) {
2719 char *po = option;
2720 int wantrecover = 0;
2721
2722 /*
2723 ** check if automatic recovery is wanted
2724 */
2725 while (*po) {
2726 if (*po == 'r') {
2727 wantrecover = 1;
2728 break;
2729 }
2730 po++;
2731 }
2732
2733 /*
2734 ** open new cowdevice with minor number 0
2735 */
2736 if ( (rv = cowlo_openpair(rdofile, cowfile, wantrecover, 0))) {
2737 remove_proc_entry("cow", NULL);
2738 unregister_blkdev(COWMAJOR, DEVICE_NAME);
2739 goto error_out;
2740 }
2741 } else {
2742 /*
2743 ** check if only one parameter has been specified
2744 */
2745 if( (rdofile[0] != '\0') || (cowfile[0] != '\0') ) {
2746 printk(KERN_ERR
2747 "cowloop - only one filename specified\n");
2748 remove_proc_entry("cow", NULL);
2749 unregister_blkdev(COWMAJOR, DEVICE_NAME);
2750 rv = -EINVAL;
2751 goto error_out;
2752 }
2753 }
2754
2755 /*
2756 ** allocate fake disk as control channel to handle the requests
2757 ** to activate and deactivate cowdevices dynamically
2758 */
2759 if (!(cowctlgd = alloc_disk(1))) {
2760 printk(KERN_WARNING
2761 "cowloop - unable to alloc_disk for cowctl\n");
2762
2763 remove_proc_entry("cow", NULL);
2764 (void) cowlo_closepair(cowdevall[0]);
2765 unregister_blkdev(COWMAJOR, DEVICE_NAME);
2766 rv = -ENOMEM;
2767 goto error_out;
2768 }
2769
2770 spin_lock_init(&cowctlrqlock);
2771 cowctlgd->major = COWMAJOR;
2772 cowctlgd->first_minor = COWCTL;
2773 cowctlgd->minors = 1;
2774 cowctlgd->fops = &cowlo_fops;
2775 cowctlgd->private_data = NULL;
2776 /* the device has capacity 0, so there will be no q-requests */
2777 cowctlgd->queue = blk_init_queue(NULL, &cowctlrqlock);
2778 sprintf(cowctlgd->disk_name, "cowctl");
2779 set_capacity(cowctlgd, 0);
2780
2781 add_disk(cowctlgd);
2782
2783 printk(KERN_NOTICE "cowloop - number of configured cowdevices: %d\n",
2784 maxcows);
2785 if (rdofile[0] != '\0') {
2786 printk(KERN_NOTICE "cowloop - initialized on rdofile=%s\n",
2787 rdofile);
2788 } else {
2789 printk(KERN_NOTICE "cowloop - initialized without rdofile yet\n");
2790 }
2791 return 0;
2792
2793error_out:
2794 for (minor=0; minor < uptocows ; minor++) {
2795 kfree(cowdevall[minor]);
2796 }
2797 kfree(cowdevall);
2798 return rv;
2799}
2800
2801/*
2802** called during rmmod
2803*/
2804static void __exit
2805cowlo_cleanup_module(void)
2806{
2807 int minor;
2808
2809 /*
2810 ** flush bitmaps and cowheads to the cowfiles
2811 */
2812 down(&cowdevlock);
2813 cowlo_sync();
2814 up(&cowdevlock);
2815
2816 /*
2817 ** close all cowdevices
2818 */
2819 for (minor=0; minor < maxcows; minor++)
2820 (void) cowlo_closepair(cowdevall[minor]);
2821
2822 unregister_blkdev(COWMAJOR, DEVICE_NAME);
2823
2824 /*
2825 ** get rid of /proc/cow and unregister the driver
2826 */
2827 remove_proc_entry("cow", NULL);
2828
2829 for (minor = 0; minor < maxcows; minor++) {
2830 kfree(cowdevall[minor]);
2831 }
2832 kfree(cowdevall);
2833
2834 del_gendisk(cowctlgd); /* revert the alloc_disk() */
2835 put_disk (cowctlgd); /* revert the add_disk() */
2836 blk_cleanup_queue(cowctlgd->queue); /* cleanup the empty queue */
2837
2838 printk(KERN_NOTICE "cowloop - unloaded\n");
2839}
2840
2841module_init(cowlo_init_module);
2842module_exit(cowlo_cleanup_module);
diff --git a/drivers/staging/cowloop/cowloop.h b/drivers/staging/cowloop/cowloop.h
deleted file mode 100644
index bbd4a35ac667..000000000000
--- a/drivers/staging/cowloop/cowloop.h
+++ /dev/null
@@ -1,66 +0,0 @@
1/*
2** DO NOT MODIFY THESE VALUES (would make old cowfiles unusable)
3*/
4#define MAPUNIT 1024 /* blocksize for bit in bitmap */
5#define MUSHIFT 10 /* bitshift for bit in bitmap */
6#define MUMASK 0x3ff /* bitmask for bit in bitmap */
7
8#define COWMAGIC 0x574f437f /* byte-swapped '7f C O W' */
9#define COWDIRTY 0x01
10#define COWPACKED 0x02
11#define COWVERSION 1
12
13struct cowhead
14{
15 int magic; /* identifies a cowfile */
16 short version; /* version of cowhead */
17 short flags; /* flags indicating status */
18 unsigned long mapunit; /* blocksize per bit in bitmap */
19 unsigned long mapsize; /* total size of bitmap (bytes) */
20 unsigned long doffset; /* start-offset datablocks in cow */
21 unsigned long rdoblocks; /* size of related read-only file */
22 unsigned long rdofingerprint; /* fingerprint of read-only file */
23 unsigned long cowused; /* number of datablocks used in cow */
24};
25
26#define COWDEVDIR "/dev/cow/"
27#define COWDEVICE COWDEVDIR "%ld"
28#define COWCONTROL COWDEVDIR "ctl"
29
30#define MAXCOWS 1024
31#define COWCTL (MAXCOWS-1) /* minor number of /dev/cow/ctl */
32
33#define COWPROCDIR "/proc/cow/"
34#define COWPROCFILE COWPROCDIR "%d"
35
36/*
37** ioctl related stuff
38*/
39#define ANYDEV ((unsigned long)-1)
40
41struct cowpair
42{
43 unsigned char *rdofile; /* pathname of the rdofile */
44 unsigned char *cowfile; /* pathname of the cowfile */
45 unsigned short rdoflen; /* length of rdofile pathname */
46 unsigned short cowflen; /* length of cowfile pathname */
47 unsigned long device; /* requested/returned device number */
48};
49
50struct cowwatch
51{
52 int flags; /* request flags */
53 unsigned long device; /* requested device number */
54 unsigned long threshold; /* continue if free Kb < threshold */
55 unsigned long totalkb; /* ret: total filesystem size (Kb) */
56 unsigned long availkb; /* ret: free filesystem size (Kb) */
57};
58
59#define WATCHWAIT 0x01 /* block until threshold reached */
60
61#define COWSYNC _IO ('C', 1)
62#define COWMKPAIR _IOW ('C', 2, struct cowpair)
63#define COWRMPAIR _IOW ('C', 3, unsigned long)
64#define COWWATCH _IOW ('C', 4, struct cowwatch)
65#define COWCLOSE _IOW ('C', 5, unsigned long)
66#define COWRDOPEN _IOW ('C', 6, unsigned long)
generated by cgit v1.2.2 (git 2.25.0) at 2025-08-15 21:33:00 -0400