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  1. 07 4月, 2009 1 次提交
  3. 01 4月, 2009 1 次提交
    • J
      loop: add ioctl to resize a loop device · 53d66608
      由 J. R. Okajima 提交于 
      Add the ability to 'resize' the loop device on the fly.

One practical application is a loop file with XFS filesystem, already
mounted: You can easily enlarge the file (append some bytes) and then call
ioctl(fd, LOOP_SET_CAPACITY, new); The loop driver will learn about the
new size and you can use xfs_growfs later on, which will allow you to use
full capacity of the loop file without the need to unmount.

Test app:

#include <linux/fs.h>
#include <linux/loop.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#define _GNU_SOURCE
#include <getopt.h>

char *me;

void usage(FILE *f)
{
	fprintf(f, "%s [options] loop_dev [backend_file]\n"
		"-s, --set new_size_in_bytes\n"
		"\twhen backend_file is given, "
		"it will be expanded too while keeping the original contents\n",
		me);
}

struct option opts[] = {
	{
		.name		= "set",
		.has_arg	= 1,
		.flag		= NULL,
		.val		= 's'
	},
	{
		.name		= "help",
		.has_arg	= 0,
		.flag		= NULL,
		.val		= 'h'
	}
};

void err_size(char *name, __u64 old)
{
	fprintf(stderr, "size must be larger than current %s (%llu)\n",
		name, old);
}

int main(int argc, char *argv[])
{
	int fd, err, c, i, bfd;
	ssize_t ssz;
	size_t sz;
	__u64 old, new, append;
	char a[BUFSIZ];
	struct stat st;
	FILE *out;
	char *backend, *dev;

	err = EINVAL;
	out = stderr;
	me = argv[0];
	new = 0;
	while ((c = getopt_long(argc, argv, "s:h", opts, &i)) != -1) {
		switch (c) {
		case 's':
			errno = 0;
			new = strtoull(optarg, NULL, 0);
			if (errno) {
				err = errno;
				perror(argv[i]);
				goto out;
			}
			break;

		case 'h':
			err = 0;
			out = stdout;
			goto err;

		default:
			perror(argv[i]);
			goto err;
		}
	}

	if (optind < argc)
		dev = argv[optind++];
	else
		goto err;

	fd = open(dev, O_RDONLY);
	if (fd < 0) {
		err = errno;
		perror(dev);
		goto out;
	}

	err = ioctl(fd, BLKGETSIZE64, &old);
	if (err) {
		err = errno;
		perror("ioctl BLKGETSIZE64");
		goto out;
	}

	if (!new) {
		printf("%llu\n", old);
		goto out;
	}

	if (new < old) {
		err = EINVAL;
		err_size(dev, old);
		goto out;
	}

	if (optind < argc) {
		backend = argv[optind++];
		bfd = open(backend, O_WRONLY|O_APPEND);
		if (bfd < 0) {
			err = errno;
			perror(backend);
			goto out;
		}
		err = fstat(bfd, &st);
		if (err) {
			err = errno;
			perror(backend);
			goto out;
		}
		if (new < st.st_size) {
			err = EINVAL;
			err_size(backend, st.st_size);
			goto out;
		}
		append = new - st.st_size;
		sz = sizeof(a);
		while (append > 0) {
			if (append < sz)
				sz = append;
			ssz = write(bfd, a, sz);
			if (ssz != sz) {
				err = errno;
				perror(backend);
				goto out;
			}
			append -= sz;
		}
		err = fsync(bfd);
		if (err) {
			err = errno;
			perror(backend);
			goto out;
		}
	}

	err = ioctl(fd, LOOP_SET_CAPACITY, new);
	if (err) {
		err = errno;
		perror("ioctl LOOP_SET_CAPACITY");
	}
	goto out;

 err:
	usage(out);
 out:
	return err;
}
Signed-off-by: NJ. R. Okajima <hooanon05@yahoo.co.jp>
Signed-off-by: NTomas Matejicek <tomas@slax.org>
Cc: <util-linux-ng@vger.kernel.org>
Cc: Karel Zak <kzak@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: <linux-api@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      53d66608
  5. 26 3月, 2009 1 次提交
    • N
      loop: fix circular locking in loop_clr_fd() · f028f3b2
      由 Nikanth Karthikesan 提交于 
      With CONFIG_PROVE_LOCKING enabled

$ losetup /dev/loop0 file
$ losetup -o 32256 /dev/loop1 /dev/loop0

$ losetup -d /dev/loop1
$ losetup -d /dev/loop0

triggers a [ INFO: possible circular locking dependency detected ]

I think this warning is a false positive.

Open/close on a loop device acquires bd_mutex of the device before
acquiring lo_ctl_mutex of the same device. For ioctl(LOOP_CLR_FD) after
acquiring lo_ctl_mutex, fput on the backing_file might acquire the bd_mutex of
a device, if backing file is a device and this is the last reference to the
file being dropped . But it is guaranteed that it is impossible to have a
circular list of backing devices.(say loop2->loop1->loop0->loop2 is not
possible), which guarantees that this can never deadlock.

So this warning should be suppressed. It is very difficult to annotate lockdep
not to warn here in the correct way. A simple way to silence lockdep could be
to mark the lo_ctl_mutex in ioctl to be a sub class, but this might mask some
other real bugs.

@@ -1164,7 +1164,7 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode,
 	struct loop_device *lo = bdev->bd_disk->private_data;
 	int err;

-	mutex_lock(&lo->lo_ctl_mutex);
+	mutex_lock_nested(&lo->lo_ctl_mutex, 1);
 	switch (cmd) {
 	case LOOP_SET_FD:
 		err = loop_set_fd(lo, mode, bdev, arg);

Or actually marking the bd_mutex after lo_ctl_mutex as a sub class could be
a better solution.

Luckily it is easy to avoid calling fput on backing file with lo_ctl_mutex
held, so no lockdep annotation is required.

If you do not like the special handling of the lo_ctl_mutex just for the
LOOP_CLR_FD ioctl in lo_ioctl(), the mutex handling could be moved inside
each of the individual ioctl handlers and I could send you another patch.
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
      f028f3b2
  7. 24 3月, 2009 1 次提交
  9. 05 3月, 2009 1 次提交
  11. 29 12月, 2008 2 次提交
    • M
      loop: Do not call loop_unplug for not configured loop device. · 8ae30b89
      由 Milan Broz 提交于 
      In loop_unplug() function is expected that mapping is set
and lo->lo_backing_file is not NULL.

Unfortunately loop_set_fd() set the request queue unplug function,
but loop_clr_fd() doesn't clear that.

Loop device allows open of non-configured loop in some situations.
If the unplug on request queue is called, loop module oopses because
of missing lo_backing_file.

Simple reproducer:
	losetup /dev/loop0 /xxx
	losetup -d /dev/loop0
	dmsetup create x --table "0 1 linear /dev/loop0 0"

 EIP is at loop_unplug+0x1d/0x3b
 ...
  Call Trace:
   blk_unplug+0x57/0x5e
   dm_table_unplug_all+0x34/0x77 [dm_mod]
   destroy_inode+0x27/0x38
   generic_delete_inode+0xd5/0xd9
   iput+0x4b/0x4e
   dm_resume+0xca/0xfe [dm_mod]
   dev_suspend+0x143/0x165 [dm_mod]
   dm_ctl_ioctl+0x18e/0x1cf [dm_mod]
   dev_suspend+0x0/0x165 [dm_mod]
   dm_ctl_ioctl+0x0/0x1cf [dm_mod]
   vfs_ioctl+0x22/0x69
   do_vfs_ioctl+0x39d/0x3c7
   trace_hardirqs_on+0xb/0xd
   remove_vma+0x50/0x56
   do_munmap+0x21c/0x237
   sys_ioctl+0x2c/0x45
   sysenter_do_call+0x12/0x31

Several reports here
http://www.kerneloops.org/search.php?search=loop_unplug

Fix it by simply clear unplug function together with
removing of backing file.
Signed-off-by: NMilan Broz <mbroz@redhat.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
      8ae30b89
    • M
      loop: Flush possible running bios when loop device is released. · 14f27939
      由 Milan Broz 提交于 
      When there are still queued bios and reference count
drops to zero, loop device must flush all queued bios.

Otherwise it can lead to situation that caller
closes the device, but some bios are still running
and endio() function call later OOpses when uses
unallocated mempool.

This happens for example when running dm-crypt over loop,
here is typical oops backtrace:

 Oops: 0000 [#1] PREEMPT SMP
 EIP is at mempool_free+0x12/0x6b
...
 crypt_dec_pending+0x50/0x54 [dm_crypt]
 crypt_endio+0x9f/0xa7 [dm_crypt]
 crypt_endio+0x0/0xa7 [dm_crypt]
 bio_endio+0x2b/0x2e
 loop_thread+0x37a/0x3b1
 do_lo_send_aops+0x0/0x165
 autoremove_wake_function+0x0/0x33
 loop_thread+0x0/0x3b1
 kthread+0x3b/0x61
 kthread+0x0/0x61
 kernel_thread_helper+0x7/0x10

(But crash is reproducible with different dm targets
running over loop device too.)

Patch fixes it by flushing the bios in release call,
reusing the flush mechanism for switching backing store.
Signed-off-by: NMilan Broz <mbroz@redhat.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
      14f27939
  13. 14 11月, 2008 1 次提交
  15. 31 10月, 2008 1 次提交
  17. 21 10月, 2008 3 次提交
    • A
      [PATCH] kill the unused bsize on the send side of /dev/loop · 511de73f
      由 Al Viro 提交于 
      Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      511de73f
    • A
      [PATCH] switch loop · bb214884
      由 Al Viro 提交于 
      ioctl doesn't need BKL here
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      bb214884
    • A
      [PATCH] beginning of methods conversion · d4430d62
      由 Al Viro 提交于 
      To keep the size of changesets sane we split the switch by drivers;
to keep the damn thing bisectable we do the following:
	1) rename the affected methods, add ones with correct
prototypes, make (few) callers handle both.  That's this changeset.
	2) for each driver convert to new methods.  *ALL* drivers
are converted in this series.
	3) kill the old (renamed) methods.

Note that it _is_ a flagday; all in-tree drivers are converted and by the
end of this series no trace of old methods remain.  The only reason why
we do that this way is to keep the damn thing bisectable and allow per-driver
debugging if anything goes wrong.

New methods:
	open(bdev, mode)
	release(disk, mode)
	ioctl(bdev, mode, cmd, arg)		/* Called without BKL */
	compat_ioctl(bdev, mode, cmd, arg)
	locked_ioctl(bdev, mode, cmd, arg)	/* Called with BKL, legacy */
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      d4430d62
  19. 29 4月, 2008 1 次提交
  21. 21 4月, 2008 1 次提交
    • L
      loop: manage partitions in disk image · 476a4813
      由 Laurent Vivier 提交于 
      This patch allows to use loop device with partitionned disk image.

Original behavior of loop is not modified.

A new parameter is introduced to define how many partition we want to be
able to manage per loop device. This parameter is "max_part".

For instance, to manage 63 partitions / loop device, we will do:
# modprobe loop max_part=63
# ls -l /dev/loop?*
brw-rw---- 1 root disk 7,   0 2008-03-05 14:55 /dev/loop0
brw-rw---- 1 root disk 7,  64 2008-03-05 14:55 /dev/loop1
brw-rw---- 1 root disk 7, 128 2008-03-05 14:55 /dev/loop2
brw-rw---- 1 root disk 7, 192 2008-03-05 14:55 /dev/loop3
brw-rw---- 1 root disk 7, 256 2008-03-05 14:55 /dev/loop4
brw-rw---- 1 root disk 7, 320 2008-03-05 14:55 /dev/loop5
brw-rw---- 1 root disk 7, 384 2008-03-05 14:55 /dev/loop6
brw-rw---- 1 root disk 7, 448 2008-03-05 14:55 /dev/loop7

And to attach a raw partitionned disk image, the original losetup is used:

# losetup -f etch.img
# ls -l /dev/loop?*
brw-rw---- 1 root disk 7,   0 2008-03-05 14:55 /dev/loop0
brw-rw---- 1 root disk 7,   1 2008-03-05 14:57 /dev/loop0p1
brw-rw---- 1 root disk 7,   2 2008-03-05 14:57 /dev/loop0p2
brw-rw---- 1 root disk 7,   5 2008-03-05 14:57 /dev/loop0p5
brw-rw---- 1 root disk 7,  64 2008-03-05 14:55 /dev/loop1
brw-rw---- 1 root disk 7, 128 2008-03-05 14:55 /dev/loop2
brw-rw---- 1 root disk 7, 192 2008-03-05 14:55 /dev/loop3
brw-rw---- 1 root disk 7, 256 2008-03-05 14:55 /dev/loop4
brw-rw---- 1 root disk 7, 320 2008-03-05 14:55 /dev/loop5
brw-rw---- 1 root disk 7, 384 2008-03-05 14:55 /dev/loop6
brw-rw---- 1 root disk 7, 448 2008-03-05 14:55 /dev/loop7
# mount /dev/loop0p1 /mnt
# ls /mnt
bench  cdrom  home        lib         mnt   root     srv  usr
bin    dev    initrd      lost+found  opt   sbin     sys  var
boot   etc    initrd.img  media       proc  selinux  tmp  vmlinuz
# umount /mnt
# losetup -d /dev/loop0

Of course, the same behavior can be done using kpartx on a loop device,
but modifying loop avoids to stack several layers of block device (loop +
device mapper), this is a very light modification (40% of modifications
are to manage the new parameter).
Signed-off-by: NLaurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
      476a4813
  23. 07 2月, 2008 1 次提交
    • D
      Allow auto-destruction of loop devices · 96c58655
      由 David Woodhouse 提交于 
      This allows a flag to be set on loop devices so that when they are
closed for the last time, they'll self-destruct.

In general, so that we can automatically allocate loop devices (as with
losetup -f) and have them disappear when we're done with them.

In particular, right now, so that we can stop relying on the hackish
special-case in umount(8) which kills off loop devices which were set up by
'mount -oloop'.  That means we can stop putting crap in /etc/mtab which
doesn't belong there, which means it can be a symlink to /proc/mounts, which
means yet another writable file on the root filesystem is eliminated and the
'stateless' folks get happier...  and OLPC trac #356 can be closed.

The mount(8) side of that is at
http://marc.info/?l=util-linux-ng&m=119362955431694&w=2

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>
Cc: Bernardo Innocenti <bernie@codewiz.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      96c58655
  25. 11 1月, 2008 1 次提交
  27. 20 10月, 2007 1 次提交
  29. 17 10月, 2007 3 次提交
  31. 10 10月, 2007 1 次提交
  33. 24 7月, 2007 1 次提交
  35. 18 7月, 2007 2 次提交
  37. 10 7月, 2007 3 次提交
  39. 09 6月, 2007 1 次提交
  41. 14 5月, 2007 1 次提交
    • A
      fix deadlock in loop.c · 705962cc
      由 Al Viro 提交于 
      ... doh

Jeremy Fitzhardinge noted that the recent loop.c cleanups worked, but
cause lockdep to complain.

Ouch.  OK, the deadlock is real and yes, I'm an idiot.  Speaking of which,
we probably want to s/lock/pin/ in drivers/base/map.c to avoid such
brainos again.  And yes, this stuff needs clear documentation.  Will try
to put one together once I get some sleep...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      705962cc
  43. 13 5月, 2007 1 次提交
  45. 10 5月, 2007 1 次提交
    • N
      fs: convert core functions to zero_user_page · 01f2705d
      由 Nate Diller 提交于 
      It's very common for file systems to need to zero part or all of a page,
the simplist way is just to use kmap_atomic() and memset().  There's
actually a library function in include/linux/highmem.h that does exactly
that, but it's confusingly named memclear_highpage_flush(), which is
descriptive of *how* it does the work rather than what the *purpose* is.
So this patchset renames the function to zero_user_page(), and calls it
from the various places that currently open code it.

This first patch introduces the new function call, and converts all the
core kernel callsites, both the open-coded ones and the old
memclear_highpage_flush() ones.  Following this patch is a series of
conversions for each file system individually, per AKPM, and finally a
patch deprecating the old call.  The diffstat below shows the entire
patchset.

[akpm@linux-foundation.org: fix a few things]
Signed-off-by: NNate Diller <nate.diller@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      01f2705d
  47. 09 5月, 2007 1 次提交
    • K
      remove artificial software max_loop limit · 73285082
      由 Ken Chen 提交于 
      Remove artificial maximum 256 loop device that can be created due to a
legacy device number limit.  Searching through lkml archive, there are
several instances where users complained about the artificial limit that
the loop driver impose.  There is no reason to have such limit.

This patch rid the limit entirely and make loop device and associated block
queue instantiation on demand.  With on-demand instantiation, it also gives
the benefit of not wasting memory if these devices are not in use (compare
to current implementation that always create 8 loop devices), a net
improvement in both areas.  This version is both tested with creation of
large number of loop devices and is compatible with existing losetup/mount
user land tools.

There are a number of people who worked on this and provided valuable
suggestions, in no particular order, by:

Jens Axboe
Jan Engelhardt
Christoph Hellwig
Thomas M
Signed-off-by: NKen Chen <kenchen@google.com>
Cc: Jan Engelhardt <jengelh@linux01.gwdg.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      73285082
  49. 08 5月, 2007 1 次提交
  51. 09 12月, 2006 1 次提交
  53. 11 10月, 2006 2 次提交
  55. 01 10月, 2006 1 次提交
  57. 30 9月, 2006 2 次提交
  59. 27 9月, 2006 1 次提交