Commit Graph

485 Commits

Author SHA1 Message Date
Steven Whitehouse
0820ab517e [GFS2] Use slab operations for all gfs2_bufdata allocations
The old revoke structure was allocated using kalloc/kfree but
there is a slab cache for gfs2_bufdata, so we should use that
now that the structures have been converted.

This is part two of the patch series to merge the revoke
and gfs2_bufdata structures.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:56:10 +01:00
Steven Whitehouse
82e86087bb [GFS2] Replace revoke structure with bufdata structure
Both the revoke structure and the bufdata structure are quite similar.
They are basically small tags which are put on lists. In addition to
which the revoke structure is always allocated when there is a bufdata
structure which is (or can be) freed. As such it should be possible to
reduce the number of frees and allocations by using the same structure
for both purposes.

This patch is the first step along that path. It replaces existing uses
of the revoke structure with the bufdata structure.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:56:07 +01:00
Bob Peterson
8475487bef [GFS2] Fix ordering of dirty/journal for ordered buffer unstuffing
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:56:05 +01:00
Steven Whitehouse
d7b616e252 [GFS2] Clean up ordered write code
The following patch removes the ordered write processing from
databuf_lo_before_commit() and moves it to log.c. This has the effect of
greatly simplyfying databuf_lo_before_commit() and well as potentially
making the ordered write code more efficient.

As a side effect of this, its now possible to remove ordered buffers
from the ordered buffer list at any time, so we now make use of this in
invalidatepage and releasepage to ensure timely release of these
buffers.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:56:03 +01:00
Steven Whitehouse
9b9107a5a8 [GFS2] Move pin/unpin into lops.c, clean up locking
gfs2_pin and gfs2_unpin are only used in lops.c, despite being
defined in meta_io.c, so this patch moves them into lops.c and
makes them static. At the same time, its possible to clean up
the locking in the buf and databuf _lo_add() functions so that
we only need to grab the spinlock once. Also we have to move
lock_buffer() around the _lo_add() functions since we can't
do that in gfs2_pin() any more since we hold the spinlock
for the duration of that function.

As a result, the code shrinks by 12 lines and we do far fewer
operations when adding buffers to the log. It also makes the
code somewhat easier to read & understand.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:56:00 +01:00
Steven Whitehouse
eaf965270f [GFS2] Don't mark jdata dirty in gfs2_unstuffer_page()
Journaled data is marked dirty by gfs2_unpin and should not be marked
dirty here.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:55:58 +01:00
Steven Whitehouse
1e1a3d03e9 [GFS2] Introduce gfs2_remove_from_ail
This collects together the operations required to remove a gfs2_bufdata
from the ail lists. Its only called from two places to start with, but
expect to see more of this function in future.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:55:55 +01:00
Steven Whitehouse
8497a46e17 [GFS2] Correct lock ordering in unlink
This patch corrects the lock ordering in unlink to be the same as
that in the rest of GFS2, i.e. parent -> child -> rgrp.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:55:53 +01:00
Wendy Cheng
e9bd2b3baf [GFS2] fix inode meta data corruption
Fix a nasty inode meta data corruption issue by keeping the buffer head in
icache array. This buffer needs to stay in memory until journal flush occurs
Otherwise, gfs2_meta_inode_buffer could do a disk read before the inode hits
disk. It ends up with meta data corruptions. The buffer will be released as
part of the existing journal flush logic.

Signed-off-by: S. Wendy Cheng <wcheng@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:55:51 +01:00
Benjamin Marzinski
c4f68a130f [GFS2] delay glock demote for a minimum hold time
When a lot of IO, with some distributed mmap IO, is run on a GFS2 filesystem in
a cluster, it will deadlock. The reason is that do_no_page() will repeatedly
call gfs2_sharewrite_nopage(), because each node keeps giving up the glock
too early, and is forced to call unmap_mapping_range(). This bumps the
mapping->truncate_count sequence count, forcing do_no_page() to retry. This
patch institutes a minimum glock hold time a tenth a second.  This insures
that even in heavy contention cases, the node has enough time to get some
useful work done before it gives up the glock.

A second issue is that when gfs2_glock_dq() is called from within a page fault
to demote a lock, and the associated page needs to be written out, it will
try to acqire a lock on it, but it has already been locked at a higher level.
This patch puts makes gfs2_glock_dq() use the work queue as well, to avoid this
issue. This is the same patch as Steve Whitehouse originally proposed to fix
this issue, execpt that gfs2_glock_dq() now grabs a reference to the glock
before it queues up the work on it.

Signed-off-by: Benjamin E. Marzinski <bmarzins@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:55:48 +01:00
Abhijith Das
d1e2777d4f [GFS2] panic after can't parse mount arguments
When you try to mount gfs2 with -o garbage, the mount fails and the gfs2
superblock is deallocated and becomes NULL. The vfs comes around later
on and calls gfs2_kill_sb. At this point the hidden gfs2 superblock
pointer (sb->s_fs_info) is NULL and dereferencing it through
gfs2_meta_syncfs causes the panic. (the other function call to
gfs2_delete_debugfs_file() succeeds because this function already checks
for a NULL pointer)

Signed-off-by: Abhijith Das <adas@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:55:46 +01:00
Bob Peterson
ec217e0ece [GFS2] Patch to protect sd_log_num_jdata
This is a patch to GFS2 to protect sd_log_num_jdata with the
gfs2_log_lock.  Without this patch, there is a timing window
where you can get hit the following assert from function
gfs2_log_flush():

gfs2_assert_withdraw(sdp,
			sdp->sd_log_num_buf + sdp->sd_log_num_jdata ==
			sdp->sd_log_commited_buf +
			sdp->sd_log_commited_databuf);

I've tested it on my roth cluster and it fixes the problem.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:55:43 +01:00
Abhijith Das
a947e03356 [GFS2] Wendy's dump lockname in hex & fix glock dump
With this patch, gfs2 glockdump through the debugfs filesystem will only
dump glocks for the specified filesystem instead of all glocks. Also, to
aid debugging, the glock number is dumped in hex instead of decimal.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: S. Wendy Cheng <wcheng@redhat.com>
Signed-off-by: Abhijith Das <adas@redhat.com>
2007-10-10 08:55:41 +01:00
Wendy Cheng
a13b8c5f23 [GFS2] Reduce truncate IO traffic
Current GFS2 setattr call unconditionally invokes do_shrink even the
requested size and actual file size are equal. This has generated large
amount of extra IOs found during NFS benchmark runs. This patch moves
the relevant logic out of shrink code path. Since setattr is a system
call, the time stamps update is still required.

Signed-off-by: S. Wendy Cheng <wcheng@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:55:36 +01:00
Benjamin Marzinski
9a5ad13856 [GFS2] Add NULL entry to token table
match_token() was returning garbage data instead of a fail value. This data
happened to match a valid option id for an option that required an argument (in
this case, lockproto=%s) For match_token() to correctly fail if the option
doesn't match any of the tokens, the token table must end with a NULL entry.
This patch adds the NULL entry.

Signed-off-by: Benjamin E. Marzinski <bmarzins@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:55:34 +01:00
Steven Whitehouse
382e6e256b [GFS2] Add a missing gfs2_trans_add_bh()
This was missing from the dir_split_leaf() function although in
most cases its not a problem due to other functions having
already previously called gfs2_trans_add_bh. This makes certain
that it is correct.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Wendy Cheng <wcheng@redhat.com>
2007-10-10 08:55:32 +01:00
Steven Whitehouse
bb3b0e3df5 [GFS2] Clean up invalidatepage/releasepage
This patch fixes some bugs relating to journaled data files by cleaning
up the gfs2_invalidatepage() and gfs2_releasepage() functions. We now
never block during gfs2_releasepage(), instead we always either release
or refuse to release depending on the status of the buffers.

This fixes Red Hat bugzillas #248969 and #252392.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Bob Peterson <rpeterso@redhat.com>
2007-10-10 08:55:29 +01:00
Abhijith Das
2d9a4bbf6d [GFS2] Fix quota do_list operation hang
This is the filesystem part of the patches to fix this bz. There are
additional userland patches (gfs2_quota, libgfs2) for the complete
solution. This patch adds a new field qu_ll_next to the gfs2_quota
structure. This field allows us to create linked lists of quotas in the
ondisk quota inode. Instead of scanning through the entire sparse quota
file for valid quotas, we can now simply walk through the user and group
quota linked lists to perform the do_list operation.

Signed-off-by: Abhijith Das <adas@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:55:27 +01:00
Denis Cheng
34eaae398e [GFS2] fixed a NULL pointer assignment BUG
Signed-off-by: Denis Cheng <crquan@gmail.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:55:24 +01:00
Abhijith Das
0fd5355470 [GFS2] Force unstuff of hidden quota inode
This patch forcibly unstuffs (if stuffed) the hidden quota inode at the
first availble opportunity. In any practical scenario the quota inode
won't be stuffed, so this is ok to do. Unstuffing the quota inode allows
us to ignore the case of a stuffed quota inode in gfs2_adjust_quota().

Signed-off-by: Abhijith Das <adas@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:55:22 +01:00
Denis Cheng
5d35e31f43 [GFS2] better code for translating characters
the original code could work, but I think this code could work better.

Signed-off-by: Denis Cheng <crquan@gmail.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:55:20 +01:00
Denis Cheng
2d3ba1ea97 [GFS2] unneeded typecast
sb->s_fs_info is a void pointer, thus the type cast is not needed.

Signed-off-by: Denis Cheng <crquan@gmail.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:55:17 +01:00
Denis Cheng
adb4ec13cd [GFS2] use list_for_each_entry instead
Signed-off-by: Denis Cheng <crquan@gmail.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:55:15 +01:00
Bob Peterson
75be73a824 [GFS2] Ensure journal file cache is flushed after recovery
This is for bugzilla bug #248176: GFS2: invalid metadata block

Patches 1 thru 3 were accepted upstream, but there were problems
with 4 and 5.  Those issues have been resolved and now the recovery
tests are passing without errors.  This code has gone through
41 * 3 successful gfs2 recovery tests before it hit an
unrelated (openais) problem.  I'm continuing to test it.

This is a complete rewrite of patch 5 for bug #248176, written by
Steve Whitehouse.  This is referred to in the bugzilla record as
"new 6" and "a different solution".

The problem was that the journal inodes, although protected by
a glock, were not synched with the other nodes because they don't
use the inode glock synch operations (i.e. no "glops" were defined).
Therefore, journal recovery on a journal-recovering node were causing
the blocks to get out of sync with the node that was actually trying
to use that journal as it comes back up from a reboot.

There are two possible solutions: (1) To make the journals use the
normal inode glock sync operations, or (2) To make the journal
operations take effect immediately (i.e. no caching).  Although
option 1 works, it turns out to be a lot more code.  Steve opted
for option 2, which is much simpler and therefore less prone to
regression errors.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

--
2007-10-10 08:55:12 +01:00
Bob Peterson
5f3eae7546 [GFS2] invalid metadata block - REVISED
This is for bugzilla bug #248176: GFS2: invalid metadata block

Patches 1 thru 3 were accepted upstream, but there were problems
with 4 and 5.  Those issues have been resolved and now the recovery
tests are passing without errors.  This code has gone through
41 * 3 successful gfs2 recovery tests before it hit an
unrelated (openais) problem.

This is a complete rewrite of patch 4 for bug #248176.

Part of the problem was that inodes were being recycled
before their buffers were flushed to the journal logs.
Another problem was that the clone bitmaps were being
searched for deleted inodes to recycle, but only the
"real" bitmaps should be searched for that purpose.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:55:10 +01:00
Steven Whitehouse
8fbbfd214c [GFS2] Reduce number of gfs2_scand processes to one
We only need a single gfs2_scand process rather than the one
per filesystem which we had previously. As a result the parameter
determining the frequency of gfs2_scand runs becomes a module
parameter rather than a mount parameter as it was before.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:55:08 +01:00
Denis Cheng
ca5a939b33 [GFS2] use the declaration of gfs2_dops in the header file instead
Signed-off-by: Denis Cheng <crquan@gmail.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:55:05 +01:00
Denis Cheng
4ef290025c [GFS2] mark struct *_operations const
these struct *_operations are all method tables, thus should be const.

Signed-off-by: Denis Cheng <crquan@gmail.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:55:03 +01:00
Bob Peterson
0f8468c8be [GFS2] Detach buf data during in-place writeback
This is patch 5 of 5 for bug #248176

Metadata corruption was occurring because page references weren't
being removed in all cases.  I previously added a function called
detach_bufdata, but I discovered there already WAS a function out
there to do the job.  It's called gfs2_meta_cache_flush.  So I added
a call to that to remove the page references.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:55:01 +01:00
Denis Cheng
cee23c79d0 [GFS2] use an temp variable to reduce a spin_unlock
this is more clear.

Signed-off-by: Denis Cheng <crquan@gmail.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:54:58 +01:00
Bob Peterson
6760bdcd03 [GFS2] Prevent infinite loop in try_rgrp_unlink()
This is patch three of five for bug #248176.

The try_rgrp_unlink code in rgrp.c had an infinite loop.  This was
caused because the bitmap function rgblk_search can return a block
less than the "goal" block, in which case it was looping.  The fix is
to make it always march forward as needed.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:54:56 +01:00
Bob Peterson
693ddeabbb [GFS2] Revert part of earlier log.c changes
This is patch 2 of 5 for bug #248176.

The list_move code previously concocted in log.c for bug #238162
(see https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=238162#c23)
never runs as bh can now never be NULL at this point.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:54:53 +01:00
Bob Peterson
905d2aefa9 [GFS2] Move some code inside the log lock
This is the first of five patches for bug #248176:

There were still some critical variables being manipulated outside
the log_lock spinlock.  That usually resulted in a hang.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:54:51 +01:00
Steven Whitehouse
7b08fc6201 [GFS2] Fix an oops in glock dumping
This fixes an oops which was occurring during glock dumping due to the
seq file code not taking a reference to the glock. Also this fixes a
memory leak which occurred in certain cases, in turn preventing the
filesystem from unmounting.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:54:49 +01:00
Steve French
afd0942d98 [GFS2] GFS2 not checking pointer on create when running under nfsd
When looking at an unrelated problem, I noticed that nfsd does not
set nameidata pointer on create (ie nd is NULL).  This should
cause an oops in some cases in which when NFSd is mounted over GFS2.

Signed-off-by: Steve French <sfrench@us.ibm.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:54:46 +01:00
Jesper Juhl
aa0481e58a [GFS2] Clean up duplicate includes in fs/gfs2/
This patch cleans up duplicate includes in
	fs/gfs2/

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:54:44 +01:00
Josef Whiter
26caee5bc6 [GFS2] Fix calculation of demote state
If a glock is in the exclusive state and a request for demote to
deferred has been received, then further requests for demote to
shared are being ignored. This patch fixes that by ensuring that
we demote to unlocked in that case.

Signed-off-by: Josef Whiter <jwhiter@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:54:42 +01:00
Steven Whitehouse
87124e581b [GFS2] Fix two races relating to glock callbacks
One of the races relates to referencing a variable while not holding
its protecting spinlock. The patch simply moves the test inside the
spin lock. The other races occurs when a demote to unlocked request
occurs during the time a demote to shared request is already running.
This of course only happens in the case that the lock was in the
exclusive mode to start with. The patch adds a check to see if another
demote request has occurred in the mean time and if it has, then it
performs a second demote.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:54:39 +01:00
Steven Whitehouse
d18c4d687d [GFS2] Revert remounting w/o acl option leaves acls enabled
This reverts commit 569a7b6c2e. The
code was correct originally. The default setting for ACLs after a
remount should be to be the same as before the remount.

Signed-off-by: Abhijith Das <adas@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-08-14 10:34:40 +01:00
Steven Whitehouse
b9af7ca6d3 [GFS2] Fix setting of inherit jdata attr
Due to a mix up between the jdata attribute and inherit jdata attribute
it has not been possible to set the inherit jdata attribute on
directories. This is now fixed and the ioctl will report the inherit
jdata attribute for directories rather than the jdata attribute as it
did previously. This stems from our need to have the one bit in the
ioctl attr flags mean two different things according to whether the
underlying inode is a directory or not.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-08-14 10:34:11 +01:00
Steven Whitehouse
a867bb28c1 [GFS2] Fix incorrect error path in prepare_write()
The error path in prepare_write() was incorrect in the (very rare) event
that the transaction fails to start. The following prevents a NULL
pointer dereference,

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-08-14 10:33:44 +01:00
Steven Whitehouse
6eefaf61f6 [GFS2] Fix incorrect return code in rgrp.c
The following patch fixes a bug where 0 was being used as a return code
to indicate "nothing to do" when in fact 0 was a valid block location
which might be returned by the function.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-08-14 10:33:15 +01:00
Bob Peterson
24c7387333 [GFS2] soft lockup in rgblk_search
This patch seems to fix the problem described in bugzilla bug 246114.
It was written by Steve Whitehouse with some tweaking by me.

The code was looping in the relatively new section of code designed to
search for and reuse unlinked inodes.  In cases where it was finding an
appropriate inode to reuse, it was looping around and finding the same
block over and over because a "<=" check should have been a "<" when
comparing the goal block to the last unlinked block found.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-08-14 10:32:43 +01:00
Bob Peterson
bdcb88562c [GFS2] soft lockup detected in databuf_lo_before_commit
This is part 2 of the patch for bug #245832, part 1 of which is already
in the git tree.

The problem was that sdp->sd_log_num_databuf was not always being
protected by the gfs2_log_lock spinlock, but the sd_log_le_databuf
(which it is supposed to reflect) was protected.  That meant there
was a timing window during which gfs2_log_flush called
databuf_lo_before_commit and the count didn't match what was
really on the linked list in that window.  So when it ran out of
items on the linked list, it decremented total_dbuf from 0 to -1 and
thus never left the "while(total_dbuf)" loop.

The solution is to protect the variable sdp->sd_log_num_databuf so
that the value will always match the contents of the linked list,
and therefore the number will never go negative, and therefore, the
loop will be exited properly.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-08-14 10:32:04 +01:00
Christoph Hellwig
0af1a45046 rename setlease to generic_setlease
Make it a little more clear that this is the default implementation for
the setleast operation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Acked-by: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-31 15:39:43 -07:00
Paul Mundt
20c2df83d2 mm: Remove slab destructors from kmem_cache_create().
Slab destructors were no longer supported after Christoph's
c59def9f22 change. They've been
BUGs for both slab and slub, and slob never supported them
either.

This rips out support for the dtor pointer from kmem_cache_create()
completely and fixes up every single callsite in the kernel (there were
about 224, not including the slab allocator definitions themselves,
or the documentation references).

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-07-20 10:11:58 +09:00
Nick Piggin
83c54070ee mm: fault feedback #2
This patch completes Linus's wish that the fault return codes be made into
bit flags, which I agree makes everything nicer.  This requires requires
all handle_mm_fault callers to be modified (possibly the modifications
should go further and do things like fault accounting in handle_mm_fault --
however that would be for another patch).

[akpm@linux-foundation.org: fix alpha build]
[akpm@linux-foundation.org: fix s390 build]
[akpm@linux-foundation.org: fix sparc build]
[akpm@linux-foundation.org: fix sparc64 build]
[akpm@linux-foundation.org: fix ia64 build]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ian Molton <spyro@f2s.com>
Cc: Bryan Wu <bryan.wu@analog.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Greg Ungerer <gerg@uclinux.org>
Cc: Matthew Wilcox <willy@debian.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Richard Curnow <rc@rc0.org.uk>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp>
Cc: Chris Zankel <chris@zankel.net>
Acked-by: Kyle McMartin <kyle@mcmartin.ca>
Acked-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
[ Still apparently needs some ARM and PPC loving - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19 10:04:41 -07:00
Nick Piggin
d0217ac04c mm: fault feedback #1
Change ->fault prototype.  We now return an int, which contains
VM_FAULT_xxx code in the low byte, and FAULT_RET_xxx code in the next byte.
 FAULT_RET_ code tells the VM whether a page was found, whether it has been
locked, and potentially other things.  This is not quite the way he wanted
it yet, but that's changed in the next patch (which requires changes to
arch code).

This means we no longer set VM_CAN_INVALIDATE in the vma in order to say
that a page is locked which requires filemap_nopage to go away (because we
can no longer remain backward compatible without that flag), but we were
going to do that anyway.

struct fault_data is renamed to struct vm_fault as Linus asked. address
is now a void __user * that we should firmly encourage drivers not to use
without really good reason.

The page is now returned via a page pointer in the vm_fault struct.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19 10:04:41 -07:00
Nick Piggin
54cb8821de mm: merge populate and nopage into fault (fixes nonlinear)
Nonlinear mappings are (AFAIKS) simply a virtual memory concept that encodes
the virtual address -> file offset differently from linear mappings.

->populate is a layering violation because the filesystem/pagecache code
should need to know anything about the virtual memory mapping.  The hitch here
is that the ->nopage handler didn't pass down enough information (ie.  pgoff).
 But it is more logical to pass pgoff rather than have the ->nopage function
calculate it itself anyway (because that's a similar layering violation).

Having the populate handler install the pte itself is likewise a nasty thing
to be doing.

This patch introduces a new fault handler that replaces ->nopage and
->populate and (later) ->nopfn.  Most of the old mechanism is still in place
so there is a lot of duplication and nice cleanups that can be removed if
everyone switches over.

The rationale for doing this in the first place is that nonlinear mappings are
subject to the pagefault vs invalidate/truncate race too, and it seemed stupid
to duplicate the synchronisation logic rather than just consolidate the two.

After this patch, MAP_NONBLOCK no longer sets up ptes for pages present in
pagecache.  Seems like a fringe functionality anyway.

NOPAGE_REFAULT is removed.  This should be implemented with ->fault, and no
users have hit mainline yet.

[akpm@linux-foundation.org: cleanup]
[randy.dunlap@oracle.com: doc. fixes for readahead]
[akpm@linux-foundation.org: build fix]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Mark Fasheh <mark.fasheh@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19 10:04:41 -07:00
Nick Piggin
d00806b183 mm: fix fault vs invalidate race for linear mappings
Fix the race between invalidate_inode_pages and do_no_page.

Andrea Arcangeli identified a subtle race between invalidation of pages from
pagecache with userspace mappings, and do_no_page.

The issue is that invalidation has to shoot down all mappings to the page,
before it can be discarded from the pagecache.  Between shooting down ptes to
a particular page, and actually dropping the struct page from the pagecache,
do_no_page from any process might fault on that page and establish a new
mapping to the page just before it gets discarded from the pagecache.

The most common case where such invalidation is used is in file truncation.
This case was catered for by doing a sort of open-coded seqlock between the
file's i_size, and its truncate_count.

Truncation will decrease i_size, then increment truncate_count before
unmapping userspace pages; do_no_page will read truncate_count, then find the
page if it is within i_size, and then check truncate_count under the page
table lock and back out and retry if it had subsequently been changed (ptl
will serialise against unmapping, and ensure a potentially updated
truncate_count is actually visible).

Complexity and documentation issues aside, the locking protocol fails in the
case where we would like to invalidate pagecache inside i_size.  do_no_page
can come in anytime and filemap_nopage is not aware of the invalidation in
progress (as it is when it is outside i_size).  The end result is that
dangling (->mapping == NULL) pages that appear to be from a particular file
may be mapped into userspace with nonsense data.  Valid mappings to the same
place will see a different page.

Andrea implemented two working fixes, one using a real seqlock, another using
a page->flags bit.  He also proposed using the page lock in do_no_page, but
that was initially considered too heavyweight.  However, it is not a global or
per-file lock, and the page cacheline is modified in do_no_page to increment
_count and _mapcount anyway, so a further modification should not be a large
performance hit.  Scalability is not an issue.

This patch implements this latter approach.  ->nopage implementations return
with the page locked if it is possible for their underlying file to be
invalidated (in that case, they must set a special vm_flags bit to indicate
so).  do_no_page only unlocks the page after setting up the mapping
completely.  invalidation is excluded because it holds the page lock during
invalidation of each page (and ensures that the page is not mapped while
holding the lock).

This also allows significant simplifications in do_no_page, because we have
the page locked in the right place in the pagecache from the start.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19 10:04:41 -07:00