Commit Graph

110 Commits

Author SHA1 Message Date
Ingo Molnar ac6424b981 sched/wait: Rename wait_queue_t => wait_queue_entry_t
Rename:

	wait_queue_t		=>	wait_queue_entry_t

'wait_queue_t' was always a slight misnomer: its name implies that it's a "queue",
but in reality it's a queue *entry*. The 'real' queue is the wait queue head,
which had to carry the name.

Start sorting this out by renaming it to 'wait_queue_entry_t'.

This also allows the real structure name 'struct __wait_queue' to
lose its double underscore and become 'struct wait_queue_entry',
which is the more canonical nomenclature for such data types.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-06-20 12:18:27 +02:00
Jan Kara d8747d642e reiserfs: Make flush bios explicitely sync
Commit b685d3d65a "block: treat REQ_FUA and REQ_PREFLUSH as
synchronous" removed REQ_SYNC flag from WRITE_{FUA|PREFLUSH|...}
definitions.  generic_make_request_checks() however strips REQ_FUA and
REQ_PREFLUSH flags from a bio when the storage doesn't report volatile
write cache and thus write effectively becomes asynchronous which can
lead to performance regressions

Fix the problem by making sure all bios which are synchronous are
properly marked with REQ_SYNC.

Fixes: b685d3d65a
CC: reiserfs-devel@vger.kernel.org
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
2017-05-24 13:35:20 +02:00
Jan Kara 71b0576bdb reiserfs: Make cancel_old_flush() reliable
Currently canceling of delayed work that flushes old data using
cancel_old_flush() does not prevent work from being requeued. Thus
in theory new work can be queued after cancel_old_flush() from
reiserfs_freeze() has run. This will become larger problem once
flush_old_commits() can requeue the work itself.

Fix the problem by recording in sbi->work_queue that flushing work is
canceled and should not be requeued.

Signed-off-by: Jan Kara <jack@suse.cz>
2017-04-05 14:24:16 +02:00
Christoph Hellwig 70fd76140a block,fs: use REQ_* flags directly
Remove the WRITE_* and READ_SYNC wrappers, and just use the flags
directly.  Where applicable this also drops usage of the
bio_set_op_attrs wrapper.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-11-01 09:43:26 -06:00
Mike Christie dfec8a14fc fs: have ll_rw_block users pass in op and flags separately
This has ll_rw_block users pass in the operation and flags separately,
so ll_rw_block can setup the bio op and bi_rw flags on the bio that
is submitted.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-06-07 13:41:38 -06:00
Mike Christie 2a222ca992 fs: have submit_bh users pass in op and flags separately
This has submit_bh users pass in the operation and flags separately,
so submit_bh_wbc can setup the bio op and bi_rw flags on the bio that
is submitted.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-06-07 13:41:38 -06:00
Kirill A. Shutemov ea1754a084 mm, fs: remove remaining PAGE_CACHE_* and page_cache_{get,release} usage
Mostly direct substitution with occasional adjustment or removing
outdated comments.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-04 10:41:08 -07:00
Kirill A. Shutemov 09cbfeaf1a mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.

This promise never materialized.  And unlikely will.

We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE.  And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.

Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.

Let's stop pretending that pages in page cache are special.  They are
not.

The changes are pretty straight-forward:

 - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};

 - page_cache_get() -> get_page();

 - page_cache_release() -> put_page();

This patch contains automated changes generated with coccinelle using
script below.  For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.

The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.

There are few places in the code where coccinelle didn't reach.  I'll
fix them manually in a separate patch.  Comments and documentation also
will be addressed with the separate patch.

virtual patch

@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT

@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE

@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK

@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)

@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)

@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-04 10:41:08 -07:00
Dmitry Monakhov a1c6f05733 fs: use block_device name vsprintf helper
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-01-06 13:03:18 -05:00
Masanari Iida 6774def642 treewide: fix typo in printk and Kconfig
This patch fix spelling typo in printk and Kconfig within
various part of kernel sources.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2014-11-20 14:56:11 +01:00
Fabian Frederick 54cc6cea73 fs/reiserfs/journal.c: fix sparse context imbalance warning
Merge conditional unlock/lock in the same condition to avoid sparse
warning:

  fs/reiserfs/journal.c:703:36: warning: context imbalance in 'add_to_chunk' - unexpected unlock

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-14 02:18:20 +02:00
Jan Kara 01777836c8 reiserfs: Fix use after free in journal teardown
If do_journal_release() races with do_journal_end() which requeues
delayed works for transaction flushing, we can leave work items for
flushing outstanding transactions queued while freeing them. That
results in use after free and possible crash in run_timers_softirq().

Fix the problem by not requeueing works if superblock is being shut down
(MS_ACTIVE not set) and using cancel_delayed_work_sync() in
do_journal_release().

CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
2014-08-12 12:46:30 +02:00
Jeff Mahoney a228bf8f0a reiserfs: cleanup, remove unnecessary parens
The reiserfs code is littered with extra parens in places where the authors
may not have been certain about precedence of & vs ->. This patch cleans them
out.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2014-05-06 23:18:16 +02:00
Jeff Mahoney cf776a7a4d reiserfs: cleanup, remove leading whitespace from labels
This patch moves reiserfs closer to adhering to the style rules by
removing leading whitespace from labels.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2014-05-06 23:18:09 +02:00
Jeff Mahoney b491dd1769 reiserfs: cleanup, remove blocks arg from journal_join
journal_join is always called with a block count of 1. Let's just get
rid of the argument.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2014-05-06 23:11:15 +02:00
Jeff Mahoney 09f1b80ba8 reiserfs: cleanup, remove sb argument from journal_mark_dirty
journal_mark_dirty doesn't need a separate sb argument; It's provided
by the transaction handle.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2014-05-06 23:10:37 +02:00
Jeff Mahoney 58d854265c reiserfs: cleanup, remove sb argument from journal_end
journal_end doesn't need a separate sb argument; it's provided by the
transaction handle.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2014-05-06 23:08:00 +02:00
Jeff Mahoney 706a532338 reiserfs: cleanup, remove nblocks argument from journal_end
journal_end takes a block count argument but doesn't actually use it
for anything. We can remove it.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2014-05-06 23:05:40 +02:00
Jeff Mahoney 098297b27d reiserfs: cleanup, reformat comments to normal kernel style
This patch reformats comments in the reiserfs code to fit in 80 columns and
to follow the style rules.

There is no functional change but it helps make my eyes bleed less.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2014-05-06 22:52:19 +02:00
Jeff Mahoney 797d9016ce reiserfs: use per-fs commit workqueues
The reiserfs write lock hasn't been the BKL for some time. There's no
need to have different file systems queued up on the same workqueue.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2014-05-06 22:44:45 +02:00
Jeff Mahoney 721a769c03 reiserfs: fix race with flush_used_journal_lists and flush_journal_list
There are two locks involved in managing the journal lists. The general
reiserfs_write_lock and the journal->j_flush_mutex.

While flush_journal_list is sleeping to acquire the j_flush_mutex or to
submit a block for write, it will drop the write lock. This allows
another thread to acquire the write lock and ultimately call
flush_used_journal_lists to traverse the list of journal lists and
select one for flushing. It can select the journal_list that has just
had flush_journal_list called on it in the original thread and call it
again with the same journal_list.

The second thread then drops the write lock to acquire j_flush_mutex and
the first thread reacquires it and continues execution and eventually
clears and frees the journal list before dropping j_flush_mutex and
returning.

The second thread acquires j_flush_mutex and ends up operating on a
journal_list that has already been released. If the memory hasn't
been reused, we'll soon after hit a BUG_ON because the transaction id
has already been cleared. If it's been reused, we'll crash in other
fun ways.

Since flush_journal_list will synchronize on j_flush_mutex, we can fix
the race by taking a proper reference in flush_used_journal_lists
and checking to see if it's still valid after the mutex is taken. It's
safe to iterate the list of journal lists and pick a list with
just the write lock as long as a reference is taken on the journal list
before we drop the lock. We already have code to handle whether a
transaction has been flushed already so we can use that to handle the
race and get rid of the trans_id BUG_ON.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2013-09-24 11:24:21 +02:00
Jeff Mahoney 7bc9cc07ee reiserfs: remove useless flush_old_journal_lists
Commit a3172027 introduced test_transaction as a requirement for
flushing old lists -- but it can never return 1 unless the transaction
has already been flushed.

As a result, we have a routine that iterates the j_realblocks list but
doesn't actually do anything. Since it's been this way since 2006 and
the latency numbers were what Chris expected, let's just rip it out.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2013-09-24 11:24:21 +02:00
Jeff Mahoney 278f6679f4 reiserfs: locking, handle nested locks properly
The reiserfs write lock replaced the BKL and uses similar semantics.

Frederic's locking code makes a distinction between when the lock is nested
and when it's being acquired/released, but I don't think that's the right
distinction to make.

The right distinction is between the lock being released at end-of-use and
the lock being released for a schedule. The unlock should return the depth
and the lock should restore it, rather than the other way around as it is now.

This patch implements that and adds a number of places where the lock
should be dropped.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2013-08-08 17:34:46 -04:00
Al Viro 4385bab128 make blkdev_put() return void
same story as with the previous patches - note that return
value of blkdev_close() is lost, since there's nowhere the
caller (__fput()) could return it to.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-05-07 02:16:31 -04:00
Artem Bityutskiy 033369d1af reiserfs: get rid of resierfs_sync_super
This patch stops reiserfs using the VFS 'write_super()' method along with the
s_dirt flag, because they are on their way out.

The whole "superblock write-out" VFS infrastructure is served by the
'sync_supers()' kernel thread, which wakes up every 5 (by default) seconds and
writes out all dirty superblock using the '->write_super()' call-back.  But the
problem with this thread is that it wastes power by waking up the system every
5 seconds, even if there are no diry superblocks, or there are no client
file-systems which would need this (e.g., btrfs does not use
'->write_super()'). So we want to kill it completely and thus, we need to make
file-systems to stop using the '->write_super()' VFS service, and then remove
it together with the kernel thread.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-01 10:37:36 -04:00
Artem Bityutskiy 5c5fd81962 reiserfs: mark the superblock as dirty a bit later
The 'journal_mark_dirty()' function currently first marks the superblock as
dirty by setting 's_dirt' to 1, then does various sanity checks and returns,
then actuall does all the magic with the journal.

This is not an ideal order, though. It makes more sense to first do all the
checks, then do all the internal stuff, and at the end notify the VFS that the
superblock is now dirty.

This patch moves the 's_dirt = 1' assignment from the very beginning of this
function to the very end.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-01 10:37:36 -04:00
Artem Bityutskiy 25729b0e94 reiserfs: clean-up function return type
Turn 'reiserfs_flush_old_commits()' into a void function because the callers
do not cares about what it returns anyway.

We are going to remove the 'sb->s_dirt' field completely and this patch is a
small step towards this direction.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-01 10:37:36 -04:00
David Howells 9ffc93f203 Remove all #inclusions of asm/system.h
Remove all #inclusions of asm/system.h preparatory to splitting and killing
it.  Performed with the following command:

perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *`

Signed-off-by: David Howells <dhowells@redhat.com>
2012-03-28 18:30:03 +01:00
Al Viro f466c6fdb3 move private bits of reiserfs_fs.h to fs/reiserfs/reiserfs.h
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-03-20 21:29:43 -04:00
Frederic Weisbecker 37c69b98d0 reiserfs: don't lock journal_init()
journal_init() doesn't need the lock since no operation on the filesystem
is involved there.  journal_read() and get_list_bitmap() have yet to be
reviewed carefully though before removing the lock there.  Just keep the
it around these two calls for safety.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 16:30:53 -08:00
Davidlohr Bueso b18c1c6e0c reiserfs: delete comments referring to the BKL
Signed-off-by: Davidlohr Bueso <dave@gnu.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 16:30:53 -08:00
Joe Perches 558feb0818 fs: Convert vmalloc/memset to vzalloc
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Alex Elder <aelder@sgi.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-09-15 13:56:28 +02:00
Justin TerAvest 4aede84b33 fixlet: Remove fs_excl from struct task.
fs_excl is a poor man's priority inheritance for filesystems to hint to
the block layer that an operation is important. It was never clearly
specified, not widely adopted, and will not prevent starvation in many
cases (like across cgroups).

fs_excl was introduced with the time sliced CFQ IO scheduler, to
indicate when a process held FS exclusive resources and thus needed
a boost.

It doesn't cover all file systems, and it was never fully complete.
Lets kill it.

Signed-off-by: Justin TerAvest <teravest@google.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-07-12 08:35:10 +02:00
Lucas De Marchi 25985edced Fix common misspellings
Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-03-31 11:26:23 -03:00
Tejun Heo 28aadf5169 reiserfs: make commit_wq use the default concurrency level
The maximum number of concurrent work items queued on commit_wq is
bound by the number of active journals.  Convert to alloc_workqueue()
and use the default concurrency level so that they can be processed in
parallel.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: reiserfs-devel@vger.kernel.org
2011-02-01 11:42:42 +01:00
Linus Torvalds 275220f0fc Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block
* 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block: (43 commits)
  block: ensure that completion error gets properly traced
  blktrace: add missing probe argument to block_bio_complete
  block cfq: don't use atomic_t for cfq_group
  block cfq: don't use atomic_t for cfq_queue
  block: trace event block fix unassigned field
  block: add internal hd part table references
  block: fix accounting bug on cross partition merges
  kref: add kref_test_and_get
  bio-integrity: mark kintegrityd_wq highpri and CPU intensive
  block: make kblockd_workqueue smarter
  Revert "sd: implement sd_check_events()"
  block: Clean up exit_io_context() source code.
  Fix compile warnings due to missing removal of a 'ret' variable
  fs/block: type signature of major_to_index(int) to major_to_index(unsigned)
  block: convert !IS_ERR(p) && p to !IS_ERR_NOR_NULL(p)
  cfq-iosched: don't check cfqg in choose_service_tree()
  fs/splice: Pull buf->ops->confirm() from splice_from_pipe actors
  cdrom: export cdrom_check_events()
  sd: implement sd_check_events()
  sr: implement sr_check_events()
  ...
2011-01-13 10:45:01 -08:00
Arnd Bergmann 451a3c24b0 BKL: remove extraneous #include <smp_lock.h>
The big kernel lock has been removed from all these files at some point,
leaving only the #include.

Remove this too as a cleanup.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-17 08:59:32 -08:00
Tejun Heo d4d7762995 block: clean up blkdev_get() wrappers and their users
After recent blkdev_get() modifications, open_by_devnum() and
open_bdev_exclusive() are simple wrappers around blkdev_get().
Replace them with blkdev_get_by_dev() and blkdev_get_by_path().

blkdev_get_by_dev() is identical to open_by_devnum().
blkdev_get_by_path() is slightly different in that it doesn't
automatically add %FMODE_EXCL to @mode.

All users are converted.  Most conversions are mechanical and don't
introduce any behavior difference.  There are several exceptions.

* btrfs now sets FMODE_EXCL in btrfs_device->mode, so there's no
  reason to OR it explicitly on blkdev_put().

* gfs2, nilfs2 and the generic mount_bdev() now set FMODE_EXCL in
  sb->s_mode.

* With the above changes, sb->s_mode now always should contain
  FMODE_EXCL.  WARN_ON_ONCE() added to kill_block_super() to detect
  errors.

The new blkdev_get_*() functions are with proper docbook comments.
While at it, add function description to blkdev_get() too.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Joern Engel <joern@lazybastard.org>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Jan Kara <jack@suse.cz>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: reiserfs-devel@vger.kernel.org
Cc: xfs-masters@oss.sgi.com
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
2010-11-13 11:55:18 +01:00
Tejun Heo e525fd89d3 block: make blkdev_get/put() handle exclusive access
Over time, block layer has accumulated a set of APIs dealing with bdev
open, close, claim and release.

* blkdev_get/put() are the primary open and close functions.

* bd_claim/release() deal with exclusive open.

* open/close_bdev_exclusive() are combination of open and claim and
  the other way around, respectively.

* bd_link/unlink_disk_holder() to create and remove holder/slave
  symlinks.

* open_by_devnum() wraps bdget() + blkdev_get().

The interface is a bit confusing and the decoupling of open and claim
makes it impossible to properly guarantee exclusive access as
in-kernel open + claim sequence can disturb the existing exclusive
open even before the block layer knows the current open if for another
exclusive access.  Reorganize the interface such that,

* blkdev_get() is extended to include exclusive access management.
  @holder argument is added and, if is @FMODE_EXCL specified, it will
  gain exclusive access atomically w.r.t. other exclusive accesses.

* blkdev_put() is similarly extended.  It now takes @mode argument and
  if @FMODE_EXCL is set, it releases an exclusive access.  Also, when
  the last exclusive claim is released, the holder/slave symlinks are
  removed automatically.

* bd_claim/release() and close_bdev_exclusive() are no longer
  necessary and either made static or removed.

* bd_link_disk_holder() remains the same but bd_unlink_disk_holder()
  is no longer necessary and removed.

* open_bdev_exclusive() becomes a simple wrapper around lookup_bdev()
  and blkdev_get().  It also has an unexpected extra bdev_read_only()
  test which probably should be moved into blkdev_get().

* open_by_devnum() is modified to take @holder argument and pass it to
  blkdev_get().

Most of bdev open/close operations are unified into blkdev_get/put()
and most exclusive accesses are tested atomically at the open time (as
it should).  This cleans up code and removes some, both valid and
invalid, but unnecessary all the same, corner cases.

open_bdev_exclusive() and open_by_devnum() can use further cleanup -
rename to blkdev_get_by_path() and blkdev_get_by_devt() and drop
special features.  Well, let's leave them for another day.

Most conversions are straight-forward.  drbd conversion is a bit more
involved as there was some reordering, but the logic should stay the
same.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Neil Brown <neilb@suse.de>
Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Peter Osterlund <petero2@telia.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <joel.becker@oracle.com>
Cc: Alex Elder <aelder@sgi.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: dm-devel@redhat.com
Cc: drbd-dev@lists.linbit.com
Cc: Leo Chen <leochen@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Cc: Joern Engel <joern@logfs.org>
Cc: reiserfs-devel@vger.kernel.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
2010-11-13 11:55:17 +01:00
Christoph Hellwig 7cd33ad23e reiserfs: replace barriers with explicit flush / FUA usage
Switch to the WRITE_FLUSH_FUA flag for log writes and remove the EOPNOTSUPP
detection for barriers.  Note that reiserfs had a fairly different code
path for barriers before as it wa the only filesystem actually making use
of them.  The new code always uses the old non-barrier codepath and just
sets the WRITE_FLUSH_FUA explicitly for the journal commits.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jan Kara <jack@suse.cz>
Acked-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-09-10 12:35:39 +02:00
Christoph Hellwig 9cb569d601 remove SWRITE* I/O types
These flags aren't real I/O types, but tell ll_rw_block to always
lock the buffer instead of giving up on a failed trylock.

Instead add a new write_dirty_buffer helper that implements this semantic
and use it from the existing SWRITE* callers.  Note that the ll_rw_block
code had a bug where it didn't promote WRITE_SYNC_PLUG properly, which
this patch fixes.

In the ufs code clean up the helper that used to call ll_rw_block
to mirror sync_dirty_buffer, which is the function it implements for
compound buffers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-18 01:09:01 -04:00
Changli Gao b3397ad544 reiserfs: remove unused local `wait'
Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11 08:59:12 -07:00
Tejun Heo 5a0e3ad6af 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: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00
Jeff Mahoney 3f8b5ee332 reiserfs: properly honor read-only devices
The reiserfs journal behaves inconsistently when determining whether to
allow a mount of a read-only device.

This is due to the use of the continue_replay variable to short circuit
the journal scanning.  If it's set, it's assumed that there are
transactions to replay, but there may not be.  If it's unset, it's assumed
that there aren't any, and that may not be the case either.

I've observed two failure cases:
1) Where a clean file system on a read-only device refuses to mount
2) Where a clean file system on a read-only device passes the
   optimization and then tries writing the journal header to update
   the latest mount id.

The former is easily observable by using a freshly created file system on
a read-only loopback device.

This patch moves the check into journal_read_transaction, where it can
bail out before it's about to replay a transaction.  That way it can go
through and skip transactions where appropriate, yet still refuse to mount
a file system with outstanding transactions.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-24 16:31:21 -07:00
Frederic Weisbecker bbec919150 reiserfs: Fix vmalloc call under reiserfs lock
Vmalloc is called to allocate journal->j_cnode_free_list but
we hold the reiserfs lock at this time, which raises a
{RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} lock inversion.

Just drop the reiserfs lock at this time, as it's not even
needed but kept for paranoid reasons.

This fixes:

[ INFO: inconsistent lock state ]
2.6.33-rc5 #1
---------------------------------
inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage.
kswapd0/313 [HC0[0]:SC0[0]:HE1:SE1] takes:
 (&REISERFS_SB(s)->lock){+.+.?.}, at: [<c11118c8>]
reiserfs_write_lock_once+0x28/0x50
{RECLAIM_FS-ON-W} state was registered at:
  [<c104ee32>] mark_held_locks+0x62/0x90
  [<c104eefa>] lockdep_trace_alloc+0x9a/0xc0
  [<c108f7b6>] kmem_cache_alloc+0x26/0xf0
  [<c108621c>] __get_vm_area_node+0x6c/0xf0
  [<c108690e>] __vmalloc_node+0x7e/0xa0
  [<c1086aab>] vmalloc+0x2b/0x30
  [<c110e1fb>] journal_init+0x6cb/0xa10
  [<c10f90a2>] reiserfs_fill_super+0x342/0xb80
  [<c1095665>] get_sb_bdev+0x145/0x180
  [<c10f68e1>] get_super_block+0x21/0x30
  [<c1094520>] vfs_kern_mount+0x40/0xd0
  [<c1094609>] do_kern_mount+0x39/0xd0
  [<c10aaa97>] do_mount+0x2c7/0x6d0
  [<c10aaf06>] sys_mount+0x66/0xa0
  [<c16198a7>] mount_block_root+0xc4/0x245
  [<c1619a81>] mount_root+0x59/0x5f
  [<c1619b98>] prepare_namespace+0x111/0x14b
  [<c1619269>] kernel_init+0xcf/0xdb
  [<c100303a>] kernel_thread_helper+0x6/0x1c
irq event stamp: 63236801
hardirqs last  enabled at (63236801): [<c134e7fa>]
__mutex_unlock_slowpath+0x9a/0x120
hardirqs last disabled at (63236800): [<c134e799>]
__mutex_unlock_slowpath+0x39/0x120
softirqs last  enabled at (63218800): [<c102f451>] __do_softirq+0xc1/0x110
softirqs last disabled at (63218789): [<c102f4ed>] do_softirq+0x4d/0x60

other info that might help us debug this:
2 locks held by kswapd0/313:
 #0:  (shrinker_rwsem){++++..}, at: [<c1074bb4>] shrink_slab+0x24/0x170
 #1:  (&type->s_umount_key#19){++++..}, at: [<c10a2edd>]
shrink_dcache_memory+0xfd/0x1a0

stack backtrace:
Pid: 313, comm: kswapd0 Not tainted 2.6.33-rc5 #1
Call Trace:
 [<c134db2c>] ? printk+0x18/0x1c
 [<c104e7ef>] print_usage_bug+0x15f/0x1a0
 [<c104ebcf>] mark_lock+0x39f/0x5a0
 [<c104d66b>] ? trace_hardirqs_off+0xb/0x10
 [<c1052c50>] ? check_usage_forwards+0x0/0xf0
 [<c1050c24>] __lock_acquire+0x214/0xa70
 [<c10438c5>] ? sched_clock_cpu+0x95/0x110
 [<c10514fa>] lock_acquire+0x7a/0xa0
 [<c11118c8>] ? reiserfs_write_lock_once+0x28/0x50
 [<c134f03f>] mutex_lock_nested+0x5f/0x2b0
 [<c11118c8>] ? reiserfs_write_lock_once+0x28/0x50
 [<c11118c8>] ? reiserfs_write_lock_once+0x28/0x50
 [<c11118c8>] reiserfs_write_lock_once+0x28/0x50
 [<c10f05b0>] reiserfs_delete_inode+0x50/0x140
 [<c10a653f>] ? generic_delete_inode+0x5f/0x150
 [<c10f0560>] ? reiserfs_delete_inode+0x0/0x140
 [<c10a657c>] generic_delete_inode+0x9c/0x150
 [<c10a666d>] generic_drop_inode+0x3d/0x60
 [<c10a5597>] iput+0x47/0x50
 [<c10a2a4f>] dentry_iput+0x6f/0xf0
 [<c10a2af4>] d_kill+0x24/0x50
 [<c10a2d3d>] __shrink_dcache_sb+0x21d/0x2b0
 [<c10a2f0f>] shrink_dcache_memory+0x12f/0x1a0
 [<c1074c9e>] shrink_slab+0x10e/0x170
 [<c1075177>] kswapd+0x477/0x6a0
 [<c1072d10>] ? isolate_pages_global+0x0/0x1b0
 [<c103e160>] ? autoremove_wake_function+0x0/0x40
 [<c1074d00>] ? kswapd+0x0/0x6a0
 [<c103de6c>] kthread+0x6c/0x80
 [<c103de00>] ? kthread+0x0/0x80
 [<c100303a>] kernel_thread_helper+0x6/0x1c

Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Christian Kujau <lists@nerdbynature.de>
Cc: Chris Mason <chris.mason@oracle.com>
2010-01-28 13:43:50 +01:00
Frederic Weisbecker 0523676d3f reiserfs: Relax reiserfs lock while freeing the journal
Keeping the reiserfs lock while freeing the journal on
umount path triggers a lock inversion between bdev->bd_mutex
and the reiserfs lock.

We don't need the reiserfs lock at this stage. The filesystem
is not usable anymore, and there are no more pending commits,
everything got flushed (even this operation was done in parallel
and didn't required the reiserfs lock from the current process).

This fixes the following lockdep report:

=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.32-atom #172
-------------------------------------------------------
umount/3904 is trying to acquire lock:
 (&bdev->bd_mutex){+.+.+.}, at: [<c10de2c2>] __blkdev_put+0x22/0x160

but task is already holding lock:
 (&REISERFS_SB(s)->lock){+.+.+.}, at: [<c1143279>] reiserfs_write_lock+0x29/0x40

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #3 (&REISERFS_SB(s)->lock){+.+.+.}:
       [<c105ea7f>] __lock_acquire+0x11ff/0x19e0
       [<c105f2c8>] lock_acquire+0x68/0x90
       [<c140199b>] mutex_lock_nested+0x5b/0x340
       [<c1143229>] reiserfs_write_lock_once+0x29/0x50
       [<c111c485>] reiserfs_get_block+0x85/0x1620
       [<c10e1040>] do_mpage_readpage+0x1f0/0x6d0
       [<c10e1640>] mpage_readpages+0xc0/0x100
       [<c1119b89>] reiserfs_readpages+0x19/0x20
       [<c108f1ec>] __do_page_cache_readahead+0x1bc/0x260
       [<c108f2b8>] ra_submit+0x28/0x40
       [<c1087e3e>] filemap_fault+0x40e/0x420
       [<c109b5fd>] __do_fault+0x3d/0x430
       [<c109d47e>] handle_mm_fault+0x12e/0x790
       [<c1022a65>] do_page_fault+0x135/0x330
       [<c1403663>] error_code+0x6b/0x70
       [<c10ef9ca>] load_elf_binary+0x82a/0x1a10
       [<c10ba130>] search_binary_handler+0x90/0x1d0
       [<c10bb70f>] do_execve+0x1df/0x250
       [<c1001746>] sys_execve+0x46/0x70
       [<c1002fa5>] syscall_call+0x7/0xb

-> #2 (&mm->mmap_sem){++++++}:
       [<c105ea7f>] __lock_acquire+0x11ff/0x19e0
       [<c105f2c8>] lock_acquire+0x68/0x90
       [<c109b1ab>] might_fault+0x8b/0xb0
       [<c11b8f52>] copy_to_user+0x32/0x70
       [<c10c3b94>] filldir64+0xa4/0xf0
       [<c1109116>] sysfs_readdir+0x116/0x210
       [<c10c3e1d>] vfs_readdir+0x8d/0xb0
       [<c10c3ea9>] sys_getdents64+0x69/0xb0
       [<c1002ec4>] sysenter_do_call+0x12/0x32

-> #1 (sysfs_mutex){+.+.+.}:
       [<c105ea7f>] __lock_acquire+0x11ff/0x19e0
       [<c105f2c8>] lock_acquire+0x68/0x90
       [<c140199b>] mutex_lock_nested+0x5b/0x340
       [<c110951c>] sysfs_addrm_start+0x2c/0xb0
       [<c1109aa0>] create_dir+0x40/0x90
       [<c1109b1b>] sysfs_create_dir+0x2b/0x50
       [<c11b2352>] kobject_add_internal+0xc2/0x1b0
       [<c11b2531>] kobject_add_varg+0x31/0x50
       [<c11b25ac>] kobject_add+0x2c/0x60
       [<c1258294>] device_add+0x94/0x560
       [<c11036ea>] add_partition+0x18a/0x2a0
       [<c110418a>] rescan_partitions+0x33a/0x450
       [<c10de5bf>] __blkdev_get+0x12f/0x2d0
       [<c10de76a>] blkdev_get+0xa/0x10
       [<c11034b8>] register_disk+0x108/0x130
       [<c11a87a9>] add_disk+0xd9/0x130
       [<c12998e5>] sd_probe_async+0x105/0x1d0
       [<c10528af>] async_thread+0xcf/0x230
       [<c104bfd4>] kthread+0x74/0x80
       [<c1003aab>] kernel_thread_helper+0x7/0x3c

-> #0 (&bdev->bd_mutex){+.+.+.}:
       [<c105f176>] __lock_acquire+0x18f6/0x19e0
       [<c105f2c8>] lock_acquire+0x68/0x90
       [<c140199b>] mutex_lock_nested+0x5b/0x340
       [<c10de2c2>] __blkdev_put+0x22/0x160
       [<c10de40a>] blkdev_put+0xa/0x10
       [<c113ce22>] free_journal_ram+0xd2/0x130
       [<c113ea18>] do_journal_release+0x98/0x190
       [<c113eb2a>] journal_release+0xa/0x10
       [<c1128eb6>] reiserfs_put_super+0x36/0x130
       [<c10b776f>] generic_shutdown_super+0x4f/0xe0
       [<c10b7825>] kill_block_super+0x25/0x40
       [<c11255df>] reiserfs_kill_sb+0x7f/0x90
       [<c10b7f4a>] deactivate_super+0x7a/0x90
       [<c10cccd8>] mntput_no_expire+0x98/0xd0
       [<c10ccfcc>] sys_umount+0x4c/0x310
       [<c10cd2a9>] sys_oldumount+0x19/0x20
       [<c1002ec4>] sysenter_do_call+0x12/0x32

other info that might help us debug this:

2 locks held by umount/3904:
 #0:  (&type->s_umount_key#30){+++++.}, at: [<c10b7f45>] deactivate_super+0x75/0x90
 #1:  (&REISERFS_SB(s)->lock){+.+.+.}, at: [<c1143279>] reiserfs_write_lock+0x29/0x40

stack backtrace:
Pid: 3904, comm: umount Not tainted 2.6.32-atom #172
Call Trace:
 [<c13ff903>] ? printk+0x18/0x1a
 [<c105d33a>] print_circular_bug+0xca/0xd0
 [<c105f176>] __lock_acquire+0x18f6/0x19e0
 [<c108b66f>] ? free_pcppages_bulk+0x1f/0x250
 [<c105f2c8>] lock_acquire+0x68/0x90
 [<c10de2c2>] ? __blkdev_put+0x22/0x160
 [<c10de2c2>] ? __blkdev_put+0x22/0x160
 [<c140199b>] mutex_lock_nested+0x5b/0x340
 [<c10de2c2>] ? __blkdev_put+0x22/0x160
 [<c105c932>] ? mark_held_locks+0x62/0x80
 [<c10afe12>] ? kfree+0x92/0xd0
 [<c10de2c2>] __blkdev_put+0x22/0x160
 [<c105cc3b>] ? trace_hardirqs_on+0xb/0x10
 [<c10de40a>] blkdev_put+0xa/0x10
 [<c113ce22>] free_journal_ram+0xd2/0x130
 [<c113ea18>] do_journal_release+0x98/0x190
 [<c113eb2a>] journal_release+0xa/0x10
 [<c1128eb6>] reiserfs_put_super+0x36/0x130
 [<c1050596>] ? up_write+0x16/0x30
 [<c10b776f>] generic_shutdown_super+0x4f/0xe0
 [<c10b7825>] kill_block_super+0x25/0x40
 [<c10f41e0>] ? vfs_quota_off+0x0/0x20
 [<c11255df>] reiserfs_kill_sb+0x7f/0x90
 [<c10b7f4a>] deactivate_super+0x7a/0x90
 [<c10cccd8>] mntput_no_expire+0x98/0xd0
 [<c10ccfcc>] sys_umount+0x4c/0x310
 [<c10cd2a9>] sys_oldumount+0x19/0x20
 [<c1002ec4>] sysenter_do_call+0x12/0x32

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
2010-01-02 01:56:54 +01:00
Frederic Weisbecker 98ea3f50bc reiserfs: Fix remaining in-reclaim-fs <-> reclaim-fs-on locking inversion
Commit 500f5a0bf5
(reiserfs: Fix possible recursive lock) fixed a vmalloc under reiserfs
lock that triggered a lockdep warning because of a
IN-FS-RECLAIM <-> RECLAIM-FS-ON locking dependency inversion.

But this patch has ommitted another vmalloc call in the same path
that allocates the journal. Relax the lock for this one too.

Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
2009-12-29 22:34:59 +01:00
Frederic Weisbecker 48f6ba5e69 kill-the-bkl/reiserfs: fix reiserfs lock to cpu_add_remove_lock dependency
While creating the reiserfs workqueue during the journal
initialization, we are holding the reiserfs lock, but
create_workqueue() also holds the cpu_add_remove_lock, creating
then the following dependency:

- reiserfs lock -> cpu_add_remove_lock

But we also have the following existing dependencies:

- mm->mmap_sem -> reiserfs lock
- cpu_add_remove_lock -> cpu_hotplug.lock -> slub_lock -> sysfs_mutex

The merged dependency chain then becomes:

- mm->mmap_sem -> reiserfs lock -> cpu_add_remove_lock ->
	cpu_hotplug.lock -> slub_lock -> sysfs_mutex

But when we fill a dir entry in sysfs_readir(), we are holding the
sysfs_mutex and we also might fault while copying the directory entry
to the user, leading to the following dependency:

- sysfs_mutex -> mm->mmap_sem

The end result is then a lock inversion between sysfs_mutex and
mm->mmap_sem, as reported in the following lockdep warning:

[ INFO: possible circular locking dependency detected ]
2.6.31-07095-g25a3912 #4
-------------------------------------------------------
udevadm/790 is trying to acquire lock:
 (&mm->mmap_sem){++++++}, at: [<c1098942>] might_fault+0x72/0xc0

but task is already holding lock:
 (sysfs_mutex){+.+.+.}, at: [<c110813c>] sysfs_readdir+0x7c/0x260

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #5 (sysfs_mutex){+.+.+.}:
      [...]

-> #4 (slub_lock){+++++.}:
      [...]

-> #3 (cpu_hotplug.lock){+.+.+.}:
      [...]

-> #2 (cpu_add_remove_lock){+.+.+.}:
      [...]

-> #1 (&REISERFS_SB(s)->lock){+.+.+.}:
      [...]

-> #0 (&mm->mmap_sem){++++++}:
      [...]

This can be fixed by relaxing the reiserfs lock while creating the
workqueue.
This is fine to relax the lock here, we just keep it around to pass
through reiserfs lock checks and for paranoid reasons.

Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Tested-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Laurent Riffard <laurent.riffard@free.fr>
2009-10-05 16:31:37 +02:00
Frederic Weisbecker 193be0ee17 kill-the-bkl/reiserfs: Fix induced mm->mmap_sem to sysfs_mutex dependency
Alexander Beregalov reported the following warning:

	=======================================================
	[ INFO: possible circular locking dependency detected ]
	2.6.31-03149-gdcc030a #1
	-------------------------------------------------------
	udevadm/716 is trying to acquire lock:
	 (&mm->mmap_sem){++++++}, at: [<c107249a>] might_fault+0x4a/0xa0

	but task is already holding lock:
	 (sysfs_mutex){+.+.+.}, at: [<c10cb9aa>] sysfs_readdir+0x5a/0x200

	which lock already depends on the new lock.

	the existing dependency chain (in reverse order) is:

	-> #3 (sysfs_mutex){+.+.+.}:
	       [...]

	-> #2 (&bdev->bd_mutex){+.+.+.}:
	       [...]

	-> #1 (&REISERFS_SB(s)->lock){+.+.+.}:
	       [...]

	-> #0 (&mm->mmap_sem){++++++}:
	       [...]

On reiserfs mount path, we take the reiserfs lock and while
initializing the journal, we open the device, taking the
bdev->bd_mutex. Then rescan_partition() may signal the change
to sysfs.

We have then the following dependency:

	reiserfs_lock -> bd_mutex -> sysfs_mutex

Later, while entering reiserfs_readpage() after a pagefault in an
mmaped reiserfs file, we are holding the mm->mmap_sem, and we are going
to take the reiserfs lock too.
We have then the following dependency:

	mm->mmap_sem -> reiserfs_lock

which, expanded with the previous dependency gives us:

	mm->mmap_sem -> reiserfs_lock -> bd_mutex -> sysfs_mutex

Now while entering the sysfs readdir path, we are holding the
sysfs_mutex. And when we copy a directory entry to the user buffer, we
might fault and then take the mm->mmap_sem lock. Which leads to the
circular locking dependency reported.

We can fix that by relaxing the reiserfs lock during the call to
journal_init_dev(), which is the place where we open the mounted
device.

This is fine to relax the lock here because we are in the begining of
the reiserfs mount path and there is nothing to protect at this time,
the journal is not intialized.
We just keep this lock around for paranoid reasons.

Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Tested-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Laurent Riffard <laurent.riffard@free.fr>
2009-09-17 05:31:37 +02:00
Frederic Weisbecker c72e05756b kill-the-bkl/reiserfs: acquire the inode mutex safely
While searching a pathname, an inode mutex can be acquired
in do_lookup() which calls reiserfs_lookup() which in turn
acquires the write lock.

On the other side reiserfs_fill_super() can acquire the write_lock
and then call reiserfs_lookup_privroot() which can acquire an
inode mutex (the root of the mount point).

So we theoretically risk an AB - BA lock inversion that could lead
to a deadlock.

As for other lock dependencies found since the bkl to mutex
conversion, the fix is to use reiserfs_mutex_lock_safe() which
drops the lock dependency to the write lock.

[ Impact: fix a possible deadlock with reiserfs ]

Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-09-14 07:18:24 +02:00