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  1. 23 8月, 2010 1 次提交
    • M
      loop: add some basic read-only sysfs attributes · ee862730
      由 Milan Broz 提交于 
      Create /sys/block/loopX/loop directory and provide these attributes:
 - backing_file
 - autoclear
 - offset
 - sizelimit

This loop directory is present only if loop device is configured.

To be used in util-linux-ng (and possibly elsewhere like udev rules)
where code need to get loop attributes from kernel (and not store
duplicate info in userspace).

Moreover loop ioctls are not even able to provide full backing
file info because of buffer limits.
Signed-off-by: NMilan Broz <mbroz@redhat.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>
      ee862730
  3. 08 8月, 2010 3 次提交
  5. 22 5月, 2010 2 次提交
    • C
      sanitize vfs_fsync calling conventions · 8018ab05
      由 Christoph Hellwig 提交于 
      Now that the last user passing a NULL file pointer is gone we can remove
the redundant dentry argument and associated hacks inside vfs_fsynmc_range.

The next step will be removig the dentry argument from ->fsync, but given
the luck with the last round of method prototype changes I'd rather
defer this until after the main merge window.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      8018ab05
    • D
      generate "change" uevent for loop device · c3473c63
      由 David Zeuthen 提交于 
      Recent udev versions probe loop devices for filesystems meaning that
the /dev/disk hierarchy may contain useful entries such as

 $ ls -l /dev/disk/by-label/Fedora-12-x86_64-Live
 lrwxrwxrwx 1 root root 11 Mar 11 13:41 /dev/disk/by-label/Fedora-12-x86_64-Live -> ../../loop0

Unfortunately, no "change" uevent is generated when the loop device is
detached so the symlink persists. Additionally, no "change" uevent is
guaranteed to be generated when attaching an fd or changing capacity.
For example,  user space could open the loop device O_RDONLY (in fact,
recent util-linux-ng does this) so udev's OPTIONS+="watch" machinery may
not trigger the "change" uevent.

This patch ensures that the "change" uevent is generated in all of
these cases. As a result, the /dev/disk hierarchy works as expected
for loop devices.
Signed-off-by: NDavid Zeuthen <davidz@redhat.com>
Acked-by: NKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      c3473c63
  7. 09 4月, 2010 1 次提交
  9. 30 3月, 2010 1 次提交
    • T
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking... · 5a0e3ad6
      由 Tejun Heo 提交于 
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
      5a0e3ad6
  11. 29 10月, 2009 1 次提交
    • A
      loop: fix NULL dereference if mount fails · cf6e6932
      由 Alexey Dobriyan 提交于 
      Commit bb214884 ("[PATCH] switch loop")
started to pass NULL bdev to ioctl hook.

Steps to reproduce:

	[boot with loop.max_part=1]
	[mount -o loop something so mount fails]

BUG: unable to handle kernel NULL pointer dereference at 00000000000000b8
IP: [<ffffffff811486ee>] blkdev_ioctl+0x2e/0xa30
PGD 0
Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
last sysfs file: /sys/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:35/ACPI0003:00/power_supply/ACAD/online
CPU 0
Modules linked in: zfs nvidia(P) [last unloaded: zfs]
Pid: 15177, comm: mount Tainted: P           2.6.32-rc4-zfs #2 Satellite X200
RIP: 0010:[<ffffffff811486ee>]  [<ffffffff811486ee>] blkdev_ioctl+0x2e/0xa30
RSP: 0018:ffff88003b3d5bb8  EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 000000000000125f RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88003b3d5ce8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 00007ffffffff000
R13: 0000000000000000 R14: ffff880071cef280 R15: 00000000000200da
FS:  00007fd77cfe7740(0000) GS:ffff880001600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00000000000000b8 CR3: 0000000001001000 CR4: 00000000000026f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process mount (pid: 15177, threadinfo ffff88003b3d4000, task ffff88007572f920)
Stack:
 ffff88003b3d5c38 ffffffff812f95f5 ffff88007eeb6600 0000000000000000
<0> 0000000000000000 ffff88003b3d5c18 ffffffff811547d9 ffff88001bf11ef0
<0> 7fffffffffffffff ffff88001bf11ee8 ffff88001bf11ef0 0000000000000000
Call Trace:
 [<ffffffff812f95f5>] ? schedule_timeout+0x1f5/0x250
 [<ffffffff811547d9>] ? rb_insert_color+0x109/0x140
 [<ffffffff812fb754>] ? _spin_unlock_irq+0x14/0x40
 [<ffffffff812f84c6>] ? wait_for_common+0x66/0x170
 [<ffffffff8105a280>] ? default_wake_function+0x0/0x10
 [<ffffffff810f8258>] ioctl_by_bdev+0x38/0x50
 [<ffffffff811d2481>] loop_clr_fd+0x1e1/0x210
 [<ffffffff811d2522>] lo_release+0x72/0x80
 [<ffffffff810f934c>] __blkdev_put+0x1ac/0x1d0
 [<ffffffff810f937b>] blkdev_put+0xb/0x10
 [<ffffffff810f93b9>] blkdev_close+0x39/0x60
 [<ffffffff810ccef3>] __fput+0xd3/0x230
 [<ffffffff810cd06d>] fput+0x1d/0x30
 [<ffffffff810c9680>] filp_close+0x50/0x80
 [<ffffffff81061f11>] put_files_struct+0x81/0x100
 [<ffffffff81061fde>] exit_files+0x4e/0x60
 [<ffffffff81063ec5>] do_exit+0x6b5/0x730
 [<ffffffff8107b279>] ? up_read+0x9/0x10
 [<ffffffff8104c86e>] ? do_page_fault+0x18e/0x2a0
 [<ffffffff81063f81>] do_group_exit+0x41/0xc0
 [<ffffffff81064012>] sys_exit_group+0x12/0x20
 [<ffffffff81030deb>] system_call_fastpath+0x16/0x1b
Code: f8 48 89 e5 48 81 ec 30 01 00 00 48 89 5d d8 4c 89 6d e8 4c 89 65 e0 4c 89 75 f0 4c 89 7d f8 48 89 bd e8 fe ff ff 49 89 cd 89 f3 <49> 8b 88 b8 00 00 00 81 fa 68 12 00 00 0f 84 57 05 00 00 0f 86
RIP  [<ffffffff811486ee>] blkdev_ioctl+0x2e/0xa30
 RSP <ffff88003b3d5bb8>
CR2: 00000000000000b8
---[ end trace c0b4d3c3118d1427 ]---
Fixing recursive fault but reboot is needed!
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      cf6e6932
  13. 22 9月, 2009 1 次提交
  15. 11 9月, 2009 1 次提交
  17. 13 7月, 2009 1 次提交
  19. 11 5月, 2009 1 次提交
  21. 28 4月, 2009 1 次提交
  23. 07 4月, 2009 1 次提交
  25. 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
  27. 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
  29. 24 3月, 2009 1 次提交
  31. 05 3月, 2009 1 次提交
  33. 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
  35. 14 11月, 2008 1 次提交
  37. 31 10月, 2008 1 次提交
  39. 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
  41. 29 4月, 2008 1 次提交
  43. 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
  45. 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
  47. 11 1月, 2008 1 次提交
  49. 20 10月, 2007 1 次提交
  51. 17 10月, 2007 3 次提交
  53. 10 10月, 2007 1 次提交
  55. 24 7月, 2007 1 次提交
  57. 18 7月, 2007 2 次提交
  59. 10 7月, 2007 2 次提交