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Miklos Szeredi 97e7e0f71d [patch 7/7] vfs: mountinfo: show dominating group id
Show peer group ID of nearest dominating group that has intersection
with the mount's namespace.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-23 00:05:09 -04:00
Ram Pai 2d4d4864ac [patch 6/7] vfs: mountinfo: add /proc/<pid>/mountinfo
[mszeredi@suse.cz] rewrite and split big patch into managable chunks

/proc/mounts in its current form lacks important information:

 - propagation state
 - root of mount for bind mounts
 - the st_dev value used within the filesystem
 - identifier for each mount and it's parent

It also suffers from the following problems:

 - not easily extendable
 - ambiguity of mountpoints within a chrooted environment
 - doesn't distinguish between filesystem dependent and independent options
 - doesn't distinguish between per mount and per super block options

This patch introduces /proc/<pid>/mountinfo which attempts to address
all these deficiencies.

Code shared between /proc/<pid>/mounts and /proc/<pid>/mountinfo is
extracted into separate functions.

Thanks to Al Viro for the help in getting the design right.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-23 00:05:03 -04:00
Miklos Szeredi a1a2c409b6 [patch 5/7] vfs: mountinfo: allow using process root
Allow /proc/<pid>/mountinfo to use the root of <pid> to calculate
mountpoints.

 - move definition of 'struct proc_mounts' to <linux/mnt_namespace.h>
 - add the process's namespace and root to this structure
 - pass a pointer to 'struct proc_mounts' into seq_operations

In addition the following cleanups are made:

 - use a common open function for /proc/<pid>/{mounts,mountstat}
 - surround namespace.c part of these proc files with #ifdef CONFIG_PROC_FS
 - make the seq_operations structures const

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-23 00:04:57 -04:00
Miklos Szeredi 719f5d7f0b [patch 4/7] vfs: mountinfo: add mount peer group ID
Add a unique ID to each peer group using the IDR infrastructure.  The
identifiers are reused after the peer group dissolves.

The IDR structures are protected by holding namepspace_sem for write
while allocating or deallocating IDs.

IDs are allocated when a previously unshared vfsmount becomes the
first member of a peer group.  When a new member is added to an
existing group, the ID is copied from one of the old members.

IDs are freed when the last member of a peer group is unshared.

Setting the MNT_SHARED flag on members of a subtree is done as a
separate step, after all the IDs have been allocated.  This way an
allocation failure can be cleaned up easilty, without affecting the
propagation state.

Based on design sketch by Al Viro.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-23 00:04:51 -04:00
Miklos Szeredi 73cd49ecdd [patch 3/7] vfs: mountinfo: add mount ID
Add a unique ID to each vfsmount using the IDR infrastructure.  The
identifiers are reused after the vfsmount is freed.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-23 00:04:45 -04:00
Miklos Szeredi 9d1bc60138 [patch 2/7] vfs: mountinfo: add seq_file_root()
Add a new function:

  seq_file_root()

This is similar to seq_path(), but calculates the path relative to the
given root, instead of current->fs->root.  If the path was unreachable
from root, then modify the root parameter to reflect this.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-23 00:04:38 -04:00
Ram Pai 6092d04818 [patch 1/7] vfs: mountinfo: add dentry_path()
[mszeredi@suse.cz] split big patch into managable chunks

Add the following functions:

  dentry_path()
  seq_dentry()

These are similar to d_path() and seq_path().  But instead of
calculating the path within a mount namespace, they calculate the path
from the root of the filesystem to a given dentry, ignoring mounts
completely.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-23 00:04:32 -04:00
Al Viro 934b25c597 [PATCH] remove unused label in xattr.c (noise from ro-bind)
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-23 00:04:04 -04:00
Linus Torvalds 94bc891b00 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  [PATCH] get rid of __exit_files(), __exit_fs() and __put_fs_struct()
  [PATCH] proc_readfd_common() race fix
  [PATCH] double-free of inode on alloc_file() failure exit in create_write_pipe()
  [PATCH] teach seq_file to discard entries
  [PATCH] umount_tree() will unhash everything itself
  [PATCH] get rid of more nameidata passing in namespace.c
  [PATCH] switch a bunch of LSM hooks from nameidata to path
  [PATCH] lock exclusively in collect_mounts() and drop_collected_mounts()
  [PATCH] move a bunch of declarations to fs/internal.h
2008-04-22 18:28:34 -07:00
Al Viro 9b4f526cdc [PATCH] proc_readfd_common() race fix
Since we drop the rcu_read_lock inside the loop, we can't assume
that files->fdt will remain unchanged (and not freed) between
iterations.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-22 19:55:03 -04:00
Al Viro ed15243717 [PATCH] double-free of inode on alloc_file() failure exit in create_write_pipe()
Duh...  Fortunately, the bug is quite recent (post-2.6.25) and, embarrassingly,
mine ;-/

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-22 19:54:57 -04:00
David Sterba 16abef0e9e fs: use loff_t type instead of long long
Use offset type consistently.

Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-22 15:17:11 -07:00
Linus Torvalds 03b883840c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/dlm
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/dlm:
  dlm: linux/{dlm,dlm_device}.h: cleanup for userspace
  dlm: common max length definitions
  dlm: move plock code from gfs2
  dlm: recover nodes that are removed and re-added
  dlm: save master info after failed no-queue request
  dlm: make dlm_print_rsb() static
  dlm: match signedness between dlm_config_info and cluster_set
2008-04-22 13:44:23 -07:00
Linus Torvalds 62429f4340 Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-udf-2.6
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-udf-2.6: (41 commits)
  udf: use crc_itu_t from lib instead of udf_crc
  udf: Fix compilation warnings when UDF debug is on
  udf: Fix bug in VAT mapping code
  udf: Add read-only support for 2.50 UDF media
  udf: Fix handling of multisession media
  udf: Mount filesystem read-only if it has pseudooverwrite partition
  udf: Handle VAT packed inside inode properly
  udf: Allow loading of VAT inode
  udf: Fix detection of VAT version
  udf: Silence warning about accesses beyond end of device
  udf: Improve anchor block detection
  udf: Cleanup anchor block detection.
  udf: Move processing of virtual partitions
  udf: Move filling of partition descriptor info into a separate function
  udf: Improve error recovery on mount
  udf: Cleanup volume descriptor sequence processing
  udf: fix anchor point detection
  udf: Remove declarations of arrays of size UDF_NAME_LEN (256 bytes)
  udf: Remove checking of existence of filename in udf_add_entry()
  udf: Mark udf_process_sequence() as noinline
  ...
2008-04-22 13:40:47 -07:00
Al Viro 521b5d0c40 [PATCH] teach seq_file to discard entries
Allow ->show() return SEQ_SKIP; that will discard all
output from that element and move on.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-21 23:14:02 -04:00
Al Viro 4e1b36fb48 [PATCH] umount_tree() will unhash everything itself
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-21 23:13:54 -04:00
Al Viro 8c3ee42e80 [PATCH] get rid of more nameidata passing in namespace.c
Further reduction of stack footprint (sys_pivot_root());
lose useless BKL in there, while we are at it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-21 23:13:47 -04:00
Al Viro b5266eb4c8 [PATCH] switch a bunch of LSM hooks from nameidata to path
Namely, ones from namespace.c

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-21 23:13:23 -04:00
Al Viro 1a60a28077 [PATCH] lock exclusively in collect_mounts() and drop_collected_mounts()
Taking namespace_sem shared there isn't worth the trouble, especially with
vfsmount ID allocation about to be added.  That way we know that umount_tree(),
copy_tree() and clone_mnt() are _always_ serialized by namespace_sem.
umount_tree() still needs vfsmount_lock (it manipulates hash chains, among
other things), but that's a separate story.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-21 23:11:09 -04:00
Al Viro 6d59e7f582 [PATCH] move a bunch of declarations to fs/internal.h
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-21 23:11:01 -04:00
Linus Torvalds 8a32272688 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6:
  [SPARC]: Remove SunOS and Solaris binary support.
2008-04-21 17:20:53 -07:00
Linus Torvalds e9b62693ae Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/juhl/trivial
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/juhl/trivial: (24 commits)
  DOC:  A couple corrections and clarifications in USB doc.
  Generate a slightly more informative error msg for bad HZ
  fix typo "is" -> "if" in Makefile
  ext*: spelling fix prefered -> preferred
  DOCUMENTATION:  Use newer DEFINE_SPINLOCK macro in docs.
  KEYS:  Fix the comment to match the file name in rxrpc-type.h.
  RAID: remove trailing space from printk line
  DMA engine: typo fixes
  Remove unused MAX_NODES_SHIFT
  MAINTAINERS: Clarify access to OCFS2 development mailing list.
  V4L: Storage class should be before const qualifier (sn9c102)
  V4L: Storage class should be before const qualifier
  sonypi: Storage class should be before const qualifier
  intel_menlow: Storage class should be before const qualifier
  DVB: Storage class should be before const qualifier
  arm: Storage class should be before const qualifier
  ALSA: Storage class should be before const qualifier
  acpi: Storage class should be before const qualifier
  firmware_sample_driver.c: fix coding style
  MAINTAINERS: Add ati_remote2 driver
  ...

Fixed up trivial conflicts in firmware_sample_driver.c
2008-04-21 16:36:46 -07:00
Linus Torvalds 548453fd10 Merge branch 'for-2.6.26' of git://git.kernel.dk/linux-2.6-block
* 'for-2.6.26' of git://git.kernel.dk/linux-2.6-block:
  block: fix blk_register_queue() return value
  block: fix memory hotplug and bouncing in block layer
  block: replace remaining __FUNCTION__ occurrences
  Kconfig: clean up block/Kconfig help descriptions
  cciss: fix warning oops on rmmod of driver
  cciss: Fix race between disk-adding code and interrupt handler
  block: move the padding adjustment to blk_rq_map_sg
  block: add bio_copy_user_iov support to blk_rq_map_user_iov
  block: convert bio_copy_user to bio_copy_user_iov
  loop: manage partitions in disk image
  cdrom: use kmalloced buffers instead of buffers on stack
  cdrom: make unregister_cdrom() return void
  cdrom: use list_head for cdrom_device_info list
  cdrom: protect cdrom_device_info list by mutex
  cdrom: cleanup hardcoded error-code
  cdrom: remove ifdef CONFIG_SYSCTL
2008-04-21 16:03:40 -07:00
Linus Torvalds e80ab411e5 Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-2.6: (36 commits)
  SCSI: convert struct class_device to struct device
  DRM: remove unused dev_class
  IB: rename "dev" to "srp_dev" in srp_host structure
  IB: convert struct class_device to struct device
  memstick: convert struct class_device to struct device
  driver core: replace remaining __FUNCTION__ occurrences
  sysfs: refill attribute buffer when reading from offset 0
  PM: Remove destroy_suspended_device()
  Firmware: add iSCSI iBFT Support
  PM: Remove legacy PM (fix)
  Kobject: Replace list_for_each() with list_for_each_entry().
  SYSFS: Explicitly include required header file slab.h.
  Driver core: make device_is_registered() work for class devices
  PM: Convert wakeup flag accessors to inline functions
  PM: Make wakeup flags available whenever CONFIG_PM is set
  PM: Fix misuse of wakeup flag accessors in serial core
  Driver core: Call device_pm_add() after bus_add_device() in device_add()
  PM: Handle device registrations during suspend/resume
  block: send disk "change" event for rescan_partitions()
  sysdev: detect multiple driver registrations
  ...

Fixed trivial conflict in include/linux/memory.h due to semaphore header
file change (made irrelevant by the change to mutex).
2008-04-21 15:49:58 -07:00
Benoit Boissinot 1cc8dcf569 ext*: spelling fix prefered -> preferred
Spelling fix: prefered -> preferred

Signed-off-by: Benoit Boissinot <benoit.boissinot@ens-lyon.org>
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
2008-04-21 22:45:55 +00:00
Linus Torvalds 429f731dea Merge branch 'semaphore' of git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc
* 'semaphore' of git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc:
  Deprecate the asm/semaphore.h files in feature-removal-schedule.
  Convert asm/semaphore.h users to linux/semaphore.h
  security: Remove unnecessary inclusions of asm/semaphore.h
  lib: Remove unnecessary inclusions of asm/semaphore.h
  kernel: Remove unnecessary inclusions of asm/semaphore.h
  include: Remove unnecessary inclusions of asm/semaphore.h
  fs: Remove unnecessary inclusions of asm/semaphore.h
  drivers: Remove unnecessary inclusions of asm/semaphore.h
  net: Remove unnecessary inclusions of asm/semaphore.h
  arch: Remove unnecessary inclusions of asm/semaphore.h
2008-04-21 15:41:27 -07:00
Pavel Machek f5264481c8 trivial: small cleanups
These are small cleanups all over the tree.

Trivial style and comment changes to
  fs/select.c, kernel/signal.c, kernel/stop_machine.c & mm/pdflush.c

Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
2008-04-21 22:15:06 +00:00
David S. Miller ec98c6b9b4 [SPARC]: Remove SunOS and Solaris binary support.
As per Documentation/feature-removal-schedule.txt

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-21 15:10:15 -07:00
David Teigland 3d564fa347 dlm: common max length definitions
Add central definitions for max lockspace name length and max resource
name length.  The lack of central definitions has resulted in scattered
private definitions which we can now clean up, including an unused one
in dlm_device.h.

Signed-off-by: David Teigland <teigland@redhat.com>
2008-04-21 11:22:29 -05:00
David Teigland 2402211a83 dlm: move plock code from gfs2
Move the code that handles cluster posix locks from gfs2 into the dlm
so that it can be used by both gfs2 and ocfs2.

Signed-off-by: David Teigland <teigland@redhat.com>
2008-04-21 11:22:28 -05:00
David Teigland d44e0fc704 dlm: recover nodes that are removed and re-added
If a node is removed from a lockspace, and then added back before the
dlm is notified of the removal, the dlm will not detect the removal
and won't clear the old state from the node.  This is fixed by using a
list of added nodes so the membership recovery can detect when a newly
added node is already in the member list.

Signed-off-by: David Teigland <teigland@redhat.com>
2008-04-21 11:18:01 -05:00
David Teigland 761b9d3ffc dlm: save master info after failed no-queue request
When a NOQUEUE request fails, the rsb res_master field is unnecessarily
reset to -1, instead of leaving the valid master setting in place.  We
want to save the looked-up master values while the rsb is on the "toss
list" so that another lookup can be avoided if the rsb is soon reused.
The fix is to simply leave res_master value alone.

Signed-off-by: David Teigland <teigland@redhat.com>
2008-04-21 11:18:01 -05:00
Adrian Bunk 170e19ab29 dlm: make dlm_print_rsb() static
dlm_print_rsb() can now become static.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: David Teigland <teigland@redhat.com>
2008-04-21 11:18:01 -05:00
Harvey Harrison 5416b704ae dlm: match signedness between dlm_config_info and cluster_set
cluster_set is only called from the macro CLUSTER_ATTR which defines read/write
access functions.  Make the signedness match to avoid sparse warnings every time
CLUSTER_ATTR is used (lines 149-159) all of the form:

fs/dlm/config.c:149:1: warning: incorrect type in argument 3 (different signedness)
fs/dlm/config.c:149:1:    expected unsigned int *info_field
fs/dlm/config.c:149:1:    got int extern [toplevel] *<noident>

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: David Teigland <teigland@redhat.com>
2008-04-21 11:18:01 -05:00
FUJITA Tomonori c5dec1c303 block: convert bio_copy_user to bio_copy_user_iov
This patch enables bio_copy_user to take struct sg_iovec (renamed
bio_copy_user_iov). bio_copy_user uses bio_copy_user_iov internally as
bio_map_user uses bio_map_user_iov.

The major changes are:

- adds sg_iovec array to struct bio_map_data

- adds __bio_copy_iov that copy data between bio and
sg_iovec. bio_copy_user_iov and bio_uncopy_user use it.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-04-21 09:50:08 +02:00
Dan Williams 2424b5dd06 sysfs: refill attribute buffer when reading from offset 0
Requiring userspace to close and re-open sysfs attributes has been the
policy since before 2.6.12.  It allows userspace to get a consistent
snapshot of kernel state and consume it with incremental reads and seeks.

Now, if the file position is zero the kernel assumes userspace wants to see
the new value.  The application for this change is to allow a userspace
RAID metadata handler to check the state of an array without causing any
memory allocations.  Thus not causing writeback to a raid array that might
be blocked waiting for userspace to take action.

Cc: Neil Brown <neilb@suse.de>
Acked-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-04-19 19:10:29 -07:00
Robert P. J. Day c6f8773382 SYSFS: Explicitly include required header file slab.h.
After an experimental deletion of the unnecessary inclusion of
<linux/slab.h> from the header file <linux/percpu.h>, the following
files under fs/sysfs were exposed as needing to explicitly include
<linux/slab.h>.

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-04-19 19:10:27 -07:00
Kay Sievers 6bcf19d02a block: send disk "change" event for rescan_partitions()
Userspace likes to get notified that the disk may have changed, when
rescan_partitions() is called after partitioning or media change. It will
make it possible to update the state of the disk with the "change" event,
before the following partition "add" events are handled.

Cc: David Zeuthen <david@fubar.dk>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-04-19 19:10:24 -07:00
Dave Hansen ad775f5a8f [PATCH] r/o bind mounts: debugging for missed calls
There have been a few oopses caused by 'struct file's with NULL f_vfsmnts.
There was also a set of potentially missed mnt_want_write()s from
dentry_open() calls.

This patch provides a very simple debugging framework to catch these kinds of
bugs.  It will WARN_ON() them, but should stop us from having any oopses or
mnt_writer count imbalances.

I'm quite convinced that this is a good thing because it found bugs in the
stuff I was working on as soon as I wrote it.

[hch: made it conditional on a debug option.
      But it's still a little bit too ugly]

[hch: merged forced remount r/o fix from Dave and akpm's fix for the fix]

Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-19 00:29:28 -04:00
Dave Hansen 2e4b7fcd92 [PATCH] r/o bind mounts: honor mount writer counts at remount
Originally from: Herbert Poetzl <herbert@13thfloor.at>

This is the core of the read-only bind mount patch set.

Note that this does _not_ add a "ro" option directly to the bind mount
operation.  If you require such a mount, you must first do the bind, then
follow it up with a 'mount -o remount,ro' operation:

If you wish to have a r/o bind mount of /foo on bar:

	mount --bind /foo /bar
	mount -o remount,ro /bar

Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-19 00:29:27 -04:00
Dave Hansen 3d733633a6 [PATCH] r/o bind mounts: track numbers of writers to mounts
This is the real meat of the entire series.  It actually
implements the tracking of the number of writers to a mount.
However, it causes scalability problems because there can be
hundreds of cpus doing open()/close() on files on the same mnt at
the same time.  Even an atomic_t in the mnt has massive scalaing
problems because the cacheline gets so terribly contended.

This uses a statically-allocated percpu variable.  All want/drop
operations are local to a cpu as long that cpu operates on the same
mount, and there are no writer count imbalances.  Writer count
imbalances happen when a write is taken on one cpu, and released
on another, like when an open/close pair is performed on two

Upon a remount,ro request, all of the data from the percpu
variables is collected (expensive, but very rare) and we determine
if there are any outstanding writers to the mount.

I've written a little benchmark to sit in a loop for a couple of
seconds in several cpus in parallel doing open/write/close loops.

http://sr71.net/~dave/linux/openbench.c

The code in here is a a worst-possible case for this patch.  It
does opens on a _pair_ of files in two different mounts in parallel.
This should cause my code to lose its "operate on the same mount"
optimization completely.  This worst-case scenario causes a 3%
degredation in the benchmark.

I could probably get rid of even this 3%, but it would be more
complex than what I have here, and I think this is getting into
acceptable territory.  In practice, I expect writing more than 3
bytes to a file, as well as disk I/O to mask any effects that this
has.

(To get rid of that 3%, we could have an #defined number of mounts
in the percpu variable.  So, instead of a CPU getting operate only
on percpu data when it accesses only one mount, it could stay on
percpu data when it only accesses N or fewer mounts.)

[AV] merged fix for __clear_mnt_mount() stepping on freed vfsmount

Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-19 00:29:27 -04:00
Dave Hansen 2c463e9548 [PATCH] r/o bind mounts: check mnt instead of superblock directly
If we depend on the inodes for writeability, we will not catch the r/o mounts
when implemented.

This patches uses __mnt_want_write().  It does not guarantee that the mount
will stay writeable after the check.  But, this is OK for one of the checks
because it is just for a printk().

The other two are probably unnecessary and duplicate existing checks in the
VFS.  This won't make them better checks than before, but it will make them
detect r/o mounts.

Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-19 00:29:27 -04:00
Dave Hansen ec82687f29 [PATCH] r/o bind mounts: elevate count for xfs timestamp updates
Elevate the write count during the xfs m/ctime updates.

XFS has to do it's own timestamp updates due to an unfortunate VFS
design limitation, so it will have to track writers by itself aswell.

[hch: split out from the touch_atime patch as it's not related to it at all]

Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-19 00:29:26 -04:00
Dave Hansen 2f676cbc0d [PATCH] r/o bind mounts: make access() use new r/o helper
It is OK to let access() go without using a mnt_want/drop_write() pair because
it doesn't actually do writes to the filesystem, and it is inherently racy
anyway.  This is a rare case when it is OK to use __mnt_is_readonly()
directly.

Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-19 00:29:26 -04:00
Dave Hansen 9ac9b8474c [PATCH] r/o bind mounts: write counts for truncate()
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-19 00:29:25 -04:00
Dave Hansen 2af482a7ed [PATCH] r/o bind mounts: elevate write count for chmod/chown callers
chown/chmod,etc...  don't call permission in the same way that the normal
"open for write" calls do.  They still write to the filesystem, so bump the
write count during these operations.

Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-19 00:29:25 -04:00
Dave Hansen 4a3fd211cc [PATCH] r/o bind mounts: elevate write count for open()s
This is the first really tricky patch in the series.  It elevates the writer
count on a mount each time a non-special file is opened for write.

We used to do this in may_open(), but Miklos pointed out that __dentry_open()
is used as well to create filps.  This will cover even those cases, while a
call in may_open() would not have.

There is also an elevated count around the vfs_create() call in open_namei().
See the comments for more details, but we need this to fix a 'create, remount,
fail r/w open()' race.

Some filesystems forego the use of normal vfs calls to create
struct files.   Make sure that these users elevate the mnt
writer count because they will get __fput(), and we need
to make sure they're balanced.

Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-19 00:29:25 -04:00
Dave Hansen 42a74f206b [PATCH] r/o bind mounts: elevate write count for ioctls()
Some ioctl()s can cause writes to the filesystem.  Take these, and make them
use mnt_want/drop_write() instead.

[AV: updated]

Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-19 00:29:24 -04:00
Dave Hansen 20ddee2c75 [PATCH] r/o bind mounts: write count for file_update_time()
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-19 00:29:24 -04:00
Dave Hansen 74f9fdfa1f [PATCH] r/o bind mounts: elevate write count for do_utimes()
Now includes fix for oops seen by akpm.

"never let a libc developer write your kernel code" - hch

"nor, apparently, a kernel developer" - akpm

Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-19 00:29:24 -04:00