Commit Graph

25873 Commits

Author SHA1 Message Date
Dave Jones
4edc2ca388 Btrfs: fix use-after-free in __btrfs_end_transaction
49b25e0540 introduced a use-after-free bug
that caused spurious -EIO's to be returned.

Do the check before we free the transaction.

Cc: David Sterba <dsterba@suse.cz>
Cc: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-04-12 16:03:56 -04:00
Tsutomu Itoh
e627ee7bcd Btrfs: check return value of bio_alloc() properly
bio_alloc() has the possibility of returning NULL.
So, it is necessary to check the return value.

Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-04-12 16:03:56 -04:00
Ilya Dryomov
c6664b42c4 Btrfs: remove lock assert from get_restripe_target()
This fixes a regression introduced by fc67c450.  spin_is_locked() always
returns 0 on UP kernels, which caused assert in get_restripe_target() to
be fired on every call from btrfs_reduce_alloc_profile() on UP systems.
Remove it completely for now, it's not clear if it's going to be needed
in future.

Reported-by: Bobby Powers <bobbypowers@gmail.com>
Reported-by: Mitch Harder <mitch.harder@sabayonlinux.org>
Tested-by: Mitch Harder <mitch.harder@sabayonlinux.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-04-12 16:03:56 -04:00
Liu Bo
b89203f74b Btrfs: fix eof while discarding extents
We miscalculate the length of extents we're discarding, and it leads to
an eof of device.

Reported-by: Daniel Blueman <daniel@quora.org>
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-04-12 16:03:56 -04:00
Chris Mason
d95603b262 Btrfs: fix uninit variable in repair_eb_io_failure
We'd have to be passing bogus extent buffers for this uninit variable to
actually be used, but set it to zero just in case.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-04-12 15:55:15 -04:00
Chris Mason
8e62c2de6e Revert "Btrfs: increase the global block reserve estimates"
This reverts commit 5500cdbe14.

We've had a number of complaints of early enospc that bisect down
to this patch.  We'll hae to fix the reservations differently.

CC: stable@kernel.org
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-04-12 13:46:48 -04:00
Chris Mason
bc3f116fec Btrfs: update the checks for mixed block groups with big metadata blocks
Dave Sterba had put in patches to look for mixed data/metadata groups
with metadata bigger than 4KB.  But these ended up in the wrong place
and it wasn't testing the feature flag correctly.

This updates the tests to make sure our sizes are matching

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-29 17:02:47 -04:00
Liu Bo
e1f041e14c Btrfs: update to the right index of defragment
When we use autodefrag, we forget to update the index which indicates
the last page we've dirty.  And we'll set dirty flags on a same set of
pages again and again.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-29 09:57:45 -04:00
Liu Bo
66c2689226 Btrfs: do not bother to defrag an extent if it is a big real extent
$ mkfs.btrfs /dev/sdb7
$ mount /dev/sdb7 /mnt/btrfs/ -oautodefrag
$ dd if=/dev/zero of=/mnt/btrfs/foobar bs=4k count=10 oflag=direct 2>/dev/null
$ filefrag -v /mnt/btrfs/foobar
Filesystem type is: 9123683e
File size of /mnt/btrfs/foobar is 40960 (10 blocks, blocksize 4096)
 ext logical physical expected length flags
   0       0     3072              10 eof
/mnt/btrfs/foobar: 1 extent found

Now we have a big real extent [0, 40960), but autodefrag will still defrag it.

$ sync
$ filefrag -v /mnt/btrfs/foobar
Filesystem type is: 9123683e
File size of /mnt/btrfs/foobar is 40960 (10 blocks, blocksize 4096)
 ext logical physical expected length flags
   0       0     3082              10 eof
/mnt/btrfs/foobar: 1 extent found

So if we already find a big real extent, we're ok about that, just skip it.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-29 09:57:45 -04:00
Liu Bo
17ce6ef8d7 Btrfs: add a check to decide if we should defrag the range
If our file's layout is as follows:
| hole | data1 | hole | data2 |

we do not need to defrag this file, because this file has holes and
cannot be merged into one extent.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-29 09:57:45 -04:00
Liu Bo
4cb13e5d6e Btrfs: fix recursive defragment with autodefrag option
$ mkfs.btrfs disk
$ mount disk /mnt -o autodefrag
$ dd if=/dev/zero of=/mnt/foobar bs=4k count=10 2>/dev/null && sync
$ for i in `seq 9 -2 0`; do dd if=/dev/zero of=/mnt/foobar bs=4k count=1 \
  seek=$i conv=notrunc 2> /dev/null; done && sync

then we'll get to defrag "foobar" again and again.
So does option "-o autodefrag,compress".

Reasons:
When the cleaner kthread gets to fetch inodes from the defrag tree and defrag
them, it will dirty pages and submit them, this will comes to another DATA COW
where the processing inode will be inserted to the defrag tree again.

This patch sets a rule for COW code, i.e. insert an inode when we're really
going to make some defragments.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-29 09:57:45 -04:00
Liu Bo
1f12bd0632 Btrfs: fix the mismatch of page->mapping
commit 600a45e1d5
(Btrfs: fix deadlock on page lock when doing auto-defragment)
fixes the deadlock on page, but it also introduces another bug.

A page may have been truncated after unlock & lock.
So we need to find it again to get the right one.

And since we've held i_mutex lock, inode size remains unchanged and
we can drop isize overflow checks.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-29 09:57:44 -04:00
Liu Bo
ecb8bea87d Btrfs: fix race between direct io and autodefrag
The bug is from running xfstests 209 with autodefrag.

The race is as follows:
       t1                       t2(autodefrag)
   direct IO
     invalidate pagecache
     dio(old data)             add_inode_defrag
     invalidate pagecache
   endio

   direct IO
     invalidate pagecache
                                run_defrag
                                  readpage(old data)
                                  set page dirty (old data)
     dio(new data, rewrite)
     invalidate pagecache (*)
     endio

t2(autodefrag) will get old data into pagecache via readpage and set
pagecache dirty.  Meanwhile, invalidate pagecache(*) will fail due to
dirty flags in pages.  So the old data may be flushed into disk by
flush thread, which will lead to data loss.

And so does the case of user defragment progs.

The patch fixes this race by holding i_mutex when we readpage and set page dirty.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-29 09:57:44 -04:00
Liu Bo
15d1ff8111 Btrfs: fix deadlock during allocating chunks
This deadlock comes from xfstests 251.

We'll hold the chunk_mutex throughout the whole of a chunk allocation.
But if we find that we've used up system chunk space, we need to allocate a
new system chunk, but this will lead to a recursion of chunk allocation and end
up with a deadlock on chunk_mutex.
So instead we need to allocate the system chunk first if we find we're in ENOSPC.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-29 09:57:44 -04:00
Liu Bo
2bcc0328c3 Btrfs: show useful info in space reservation tracepoint
o For space info, the type of space info is useful for debug.
o For transaction handle, its transid is useful.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-29 09:57:44 -04:00
Chris Mason
7ca4be45a0 Btrfs: don't use crc items bigger than 4KB
With the big metadata blocks, we can have crc items
that are much bigger than a page.  There are a few
places that we try to kmalloc memory to hold the
items during a split.

Items bigger than 4KB don't really have a huge benefit
in efficiency, but they do trigger larger order allocations.
This commits changes the csums to make sure they stay under
4KB.  This is not a format change, just a #define to limit
huge items.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-28 20:34:10 -04:00
Chris Mason
3c4bb26b21 Btrfs: flush out and clean up any block device pages during mount
Btrfs puts the filesystem metadata into its own address space, and
somehow the block device address space isn't getting onto disk properly
before a mount.  The end result is that a loop of mkfs and mounting the
filesystem will sometimes find stale or incorrect data.

This commit should fix it by sprinkling fdatawrites and invalidate_bdev
calls around.  This is a short term measure to make sure it is fixed.
The block devices really should be flushed and cleaned up higher in the
stack.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-28 20:33:58 -04:00
Chris Mason
98961a7e43 Merge git://git.jan-o-sch.net/btrfs-unstable into for-linus
Conflicts:
	fs/btrfs/transaction.c

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-28 20:33:40 -04:00
Chris Mason
1c691b330a Merge branch 'for-chris' of git://github.com/idryomov/btrfs-unstable into for-linus 2012-03-28 20:32:46 -04:00
Chris Mason
1d4284bd6e Merge branch 'error-handling' into for-linus
Conflicts:
	fs/btrfs/ctree.c
	fs/btrfs/disk-io.c
	fs/btrfs/extent-tree.c
	fs/btrfs/extent_io.c
	fs/btrfs/extent_io.h
	fs/btrfs/inode.c
	fs/btrfs/scrub.c

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-28 20:31:37 -04:00
David Sterba
65139ed992 btrfs: disallow unequal data/metadata blocksize for mixed block groups
With support for bigger metadata blocks, we must avoid mounting a
filesystem with different block size for mixed block groups, this causes
corruption (found by xfstests/083).

Signed-off-by: David Sterba <dsterba@suse.cz>
2012-03-28 20:30:28 -04:00
David Sterba
fcd1f065da Btrfs: enhance superblock sanity checks
Validate checksum algorithm during mount and prevent BUG_ON later in
btrfs_super_csum_size.

Signed-off-by: David Sterba <dsterba@suse.cz>
2012-03-28 20:30:28 -04:00
Stefan Behrens
b5d67f64f9 Btrfs: change scrub to support big blocks
Scrub used to be coded for nodesize == leafsize == sectorsize == PAGE_SIZE.
This is now changed to support sizes for nodesize and leafsize which are
N * PAGE_SIZE.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-27 14:21:27 -04:00
Stefan Behrens
1623edebee Btrfs: minor cleanup in scrub
Just a minor cleanup commit in preparation for the big block changes.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-27 14:21:26 -04:00
Stefan Behrens
94598ba8d8 Btrfs: introduce common define for max number of mirrors
Readahead already has a define for the max number of mirrors. Scrub
needs such a define now, the rest of the code will need something
like this soon. Therefore the define was added to ctree.h and removed
from the readahead code.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-27 14:21:26 -04:00
Ilya Dryomov
213e64da90 Btrfs: fix infinite loop in btrfs_shrink_device()
If relocate of block group 0 fails with ENOSPC we end up infinitely
looping because key.offset -= 1 statement in that case brings us back to
where we started.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-03-27 17:09:18 +03:00
Ilya Dryomov
5eb56d2520 Btrfs: fix memory leak in resolver code
init_ipath() allocates btrfs_data_container which is never freed.  Free
it in free_ipath() and nuke the comment for init_data_container() - we
can safely free it with kfree().

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-03-27 17:09:18 +03:00
Ilya Dryomov
e4837f8f3b Btrfs: allow dup for data chunks in mixed mode
Generally we don't allow dup for data, but mixed chunks are special and
people seem to think this has its use cases.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-03-27 17:09:17 +03:00
Ilya Dryomov
6728b198de Btrfs: validate target profiles only if we are going to use them
Do not run sanity checks on all target profiles unless they all will be
used.  This came up because alloc_profile_is_valid() is now more strict
than it used to be.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-03-27 17:09:17 +03:00
Ilya Dryomov
4a5e98f5d6 Btrfs: improve the logic in btrfs_can_relocate()
Currently if we don't have enough space allocated we go ahead and loop
though devices in the hopes of finding enough space for a chunk of the
*same* type as the one we are trying to relocate.  The problem with that
is that if we are trying to restripe the chunk its target type can be
more relaxed than the current one (eg require less devices or less
space).  So, when restriping, run checks against the target profile
instead of the current one.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-03-27 17:09:17 +03:00
Ilya Dryomov
7738a53a3a Btrfs: add __get_block_group_index() helper
Add __get_block_group_index() helper to be able to derive block group
index from an arbitary set of flags.  Implement get_block_group_index()
in terms of it.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-03-27 17:09:17 +03:00
Ilya Dryomov
fc67c45083 Btrfs: add get_restripe_target() helper
Add get_restripe_target() helper and switch everybody to use it.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-03-27 17:09:17 +03:00
Ilya Dryomov
0c460c0d70 Btrfs: move alloc_profile_is_valid() to volumes.c
Header file is not a good place to define functions.  This also moves a
call to alloc_profile_is_valid() down the stack and removes a redundant
check from __btrfs_alloc_chunk() - alloc_profile_is_valid() takes it
into account.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-03-27 17:09:17 +03:00
Ilya Dryomov
e8920a640b Btrfs: make profile_is_valid() check more strict
"0" is a valid value for an on-disk chunk profile, but it is not a valid
extended profile.  (We have a separate bit for single chunks in extended
case)

Also rename it to alloc_profile_is_valid() for clarity.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-03-27 17:09:17 +03:00
Ilya Dryomov
899c81eac8 Btrfs: add wrappers for working with alloc profiles
Add functions to abstract the conversion between chunk and extended
allocation profile formats and switch everybody to use them.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-03-27 17:09:16 +03:00
Ilya Dryomov
e3176ca276 Btrfs: stop silently switching single chunks to raid0 on balance
This has been causing a lot of confusion for quite a while now and a lot
of users were surprised by this (some of them were even stuck in a
ENOSPC situation which they couldn't easily get out of).  The addition
of restriper gives users a clear choice between raid0 and drive concat
setup so there's absolutely no excuse for us to keep doing this.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-03-27 17:09:16 +03:00
Jan Schmidt
7a3ae2f8c8 Btrfs: fix regression in scrub path resolving
In commit 4692cf58 we introduced new backref walking code for btrfs. This
assumes we're searching live roots, which requires a transaction context.
While scrubbing, however, we must not join a transaction because this could
deadlock with the commit path. Additionally, what scrub really wants to do
is resolving a logical address in the commit root it's currently checking.

This patch adds support for logical to path resolving on commit roots and
makes scrub use that.

Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-03-27 14:51:21 +02:00
Jan Schmidt
103e976616 Btrfs: check return value of btrfs_cow_block()
The two helper functions commit_cowonly_roots() and
create_pending_snapshot() failed to check the return value from
btrfs_cow_block(), which could at least in theory fail with -ENOSPC from
btrfs_alloc_free_block(). This commit adds the missing checks.

Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-03-27 14:51:20 +02:00
Jan Schmidt
e565d4b962 Btrfs: actually call btrfs_init_lockdep
btrfs_init_lockdep only makes our lockdep class names look prettier, thus
it did never hurt we forgot to actually call it. This turns our lockdep
identifier strings from lockdep auto-set #[id] into really pretty
"btrfs-fs-01" or "btrfs-csum-03".

Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-03-27 14:51:17 +02:00
Josef Bacik
ea46679408 Btrfs: deal with read errors on extent buffers differently
Since we need to read and write extent buffers in their entirety we can't use
the normal bio_readpage_error stuff since it only works on a per page basis.  So
instead make it so that if we see an io error in endio we just mark the eb as
having an IO error and then in btree_read_extent_buffer_pages we will manually
try other mirrors and then overwrite the bad mirror if we find a good copy.
This works with larger than page size blocks.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-26 21:57:36 -04:00
Chris Mason
f3f266ab1b Btrfs: don't use threaded IO completion helpers for metadata writes
The metadata write IO completion code is now simple enough that we
don't need the threaded helpers anymore.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-26 17:04:24 -04:00
Chris Mason
f7c79f30cb Btrfs: adjust the write_lock_level as we unlock
btrfs_search_slot sometimes needs write locks on high levels of
the tree.  It remembers the highest level that needs a write lock
and will use that for all future searches through the tree in a given
call.

But, very often we'll just cow the top level or the level below and we
won't really need write locks on the root again after that.  This patch
changes things to adjust the write lock requirement as it unlocks
levels.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-26 17:04:24 -04:00
Chris Mason
a098d8e8ee Btrfs: loop waiting on writeback
lock_extent_buffer_for_io needs to loop around and make sure the
writeback bits are not set.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-26 17:04:23 -04:00
Chris Mason
cfed81a04e Btrfs: add the ability to cache a pointer into the eb
This cuts down on the CPU time used by map_private_extent_buffer

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-26 17:04:23 -04:00
Josef Bacik
0b32f4bbb4 Btrfs: ensure an entire eb is written at once
This patch simplifies how we track our extent buffers.  Previously we could exit
writepages with only having written half of an extent buffer, which meant we had
to track the state of the pages and the state of the extent buffers differently.
Now we only read in entire extent buffers and write out entire extent buffers,
this allows us to simply set bits in our bflags to indicate the state of the eb
and we no longer have to do things like track uptodate with our iotree.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-26 17:04:23 -04:00
Josef Bacik
5df4235ea1 Btrfs: introduce mark_extent_buffer_accessed
Because an eb can have multiple pages we need to make sure that all pages within
the eb are markes as accessed, since releasepage can be called against any page
in the eb.  This will keep us from possibly evicting hot eb's when we're doing
larger than pagesize eb's.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
2012-03-26 16:51:09 -04:00
Josef Bacik
3083ee2e18 Btrfs: introduce free_extent_buffer_stale
Because btrfs cow's we can end up with extent buffers that are no longer
necessary just sitting around in memory.  So instead of evicting these pages, we
could end up evicting things we actually care about.  Thus we have
free_extent_buffer_stale for use when we are freeing tree blocks.  This will
make it so that the ref for the eb being in the radix tree is dropped as soon as
possible and then is freed when the refcount hits 0 instead of waiting to be
released by releasepage.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
2012-03-26 16:51:08 -04:00
Josef Bacik
115391d231 Btrfs: only use the existing eb if it's count isn't 0
We can run into a problem where we find an eb for our existing page already on
the radix tree but it has a ref count of 0.  It hasn't yet been removed by RCU
yet so this can cause issues where we will use the EB after free.  So do
atomic_inc_not_zero on the exists->refs and if it is zero just do
synchronize_rcu() and try again.  We won't have to worry about new allocators
coming in since they will block on the page lock at this point.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
2012-03-26 16:51:08 -04:00
Josef Bacik
4f2de97ace Btrfs: set page->private to the eb
We spend a lot of time looking up extent buffers from pages when we could just
store the pointer to the eb the page is associated with in page->private.  This
patch does just that, and it makes things a little simpler and reduces a bit of
CPU overhead involved with doing metadata IO.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
2012-03-26 16:51:07 -04:00
Chris Mason
727011e07c Btrfs: allow metadata blocks larger than the page size
A few years ago the btrfs code to support blocks lager than
the page size was disabled to fix a few corner cases in the
page cache handling.  This fixes the code to properly support
large metadata blocks again.

Since current kernels will crash early and often with larger
metadata blocks, this adds an incompat bit so that older kernels
can't mount it.

This also does away with different blocksizes for nodes and leaves.
You get a single block size for all tree blocks.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-26 16:50:37 -04:00
Josef Bacik
81c9ad237c Btrfs: remove search_start and search_end from find_free_extent and callers
We have been passing nothing but (u64)-1 to find_free_extent for search_end in
all of the callers, so it's completely useless, and we've always been passing 0
in as search_start, so just remove them as function arguments and move
search_start into find_free_extent.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
2012-03-26 14:42:51 -04:00
Josef Bacik
285ff5af6c Btrfs: remove the ideal caching code
This is a relic from before we had the disk space cache and it was to make
bootup times when you had btrfs as root not be so damned slow.  Now that we have
the disk space cache this isn't a problem anymore and really having this code
casues uneeded fragmentation and complexity, so just remove it.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
2012-03-26 14:42:51 -04:00
Jan Kara
914b20070b btrfs: Fix busyloop in transaction_kthread()
When a filesystem got aborted due do error, transaction_kthread() will
busyloop.  Fix it by going to sleep in that case as well. Maybe we should
just stop transaction_kthread() when filesystem is aborted but that would be
more complex.

Signed-off-by: Jan Kara <jack@suse.cz>
2012-03-22 11:53:11 +01:00
Jeff Mahoney
79787eaab4 btrfs: replace many BUG_ONs with proper error handling
btrfs currently handles most errors with BUG_ON. This patch is a work-in-
 progress but aims to handle most errors other than internal logic
 errors and ENOMEM more gracefully.

 This iteration prevents most crashes but can run into lockups with
 the page lock on occasion when the timing "works out."

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22 11:52:54 +01:00
Jeff Mahoney
49b25e0540 btrfs: enhance transaction abort infrastructure
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22 01:45:40 +01:00
Jeff Mahoney
4da3511342 btrfs: add varargs to btrfs_error
btrfs currently handles most errors with BUG_ON. This patch is a work-in-
 progress but aims to handle most errors other than internal logic
 errors and ENOMEM more gracefully.

 This iteration prevents most crashes but can run into lockups with
 the page lock on occasion when the timing "works out."

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22 01:45:40 +01:00
Mark Fasheh
3acd395317 btrfs: Remove BUG_ON from __finish_chunk_alloc()
btrfs_alloc_chunk() unconditionally BUGs on any error returned from
__finish_chunk_alloc() so there's no need for two BUG_ON lines. Remove the
one from __finish_chunk_alloc().

Signed-off-by: Mark Fasheh <mfasheh@suse.de>
2012-03-22 01:45:39 +01:00
Mark Fasheh
1dd4602fa7 btrfs: Remove BUG_ON from __btrfs_alloc_chunk()
We BUG_ON() error from add_extent_mapping(), but that error looks pretty
easy to bubble back up - as far as I can tell there have not been any
permanent modifications to fs state at that point.

Signed-off-by: Mark Fasheh <mfasheh@suse.de>
2012-03-22 01:45:39 +01:00
Mark Fasheh
2cdcecbc15 btrfs: Don't BUG_ON insert errors in btrfs_alloc_dev_extent()
The only caller of btrfs_alloc_dev_extent() is __btrfs_alloc_chunk() which
already bugs on any error returned. We can remove the BUG_ON's in
btrfs_alloc_dev_extent() then since __btrfs_alloc_chunk() will "catch" them
anyway.

Signed-off-by: Mark Fasheh <mfasheh@suse.de>
2012-03-22 01:45:38 +01:00
Mark Fasheh
305a26af5b btrfs: Go readonly on tree errors in balance_level
balace_level() seems to deal with missing tree nodes by BUG_ON(). Instead,
we can easily just set the file system readonly and bubble -EROFS back up
the stack.

Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2012-03-22 01:45:38 +01:00
Mark Fasheh
b68dc2a93e btrfs: Don't BUG_ON errors from update_ref_for_cow()
__btrfs_cow_block(), the only caller of update_ref_for_cow() will BUG_ON()
any error return.  Instead, we can go read-only fs as update_ref_for_cow()
manipulates disk data in a way which doesn't look like it's easily rolled
back.

Signed-off-by: Mark Fasheh <mfasheh@suse.de>
2012-03-22 01:45:38 +01:00
Mark Fasheh
e5df957328 btrfs: Go readonly on bad extent refs in update_ref_for_cow()
update_ref_for_cow() will BUG_ON() after it's call to
btrfs_lookup_extent_info() if no existing references are found.  Since refs
are computed directly from disk, this should be treated as a corruption
instead of a logic error.

Signed-off-by: Mark Fasheh <mfasheh@suse.de>
2012-03-22 01:45:37 +01:00
Mark Fasheh
4ed1d16e94 btrfs: Don't BUG_ON errors in __finish_chunk_alloc()
All callers of __finish_chunk_alloc() BUG_ON() return value, so it's trivial
for us to always bubble up any errors caught in __finish_chunk_alloc() to be
caught there.

Signed-off-by: Mark Fasheh <mfasheh@suse.de>
2012-03-22 01:45:37 +01:00
Mark Fasheh
0678b61851 btrfs: Don't BUG_ON kzalloc error in btrfs_lookup_csums_range()
Unfortunately it isn't enough to just exit here - the kzalloc() happens in a
loop and the allocated items are added to a linked list whose head is passed
in from the caller.

To fix the BUG_ON() and also provide the semantic that the list passed in is
only modified on success, I create function-local temporary list that we add
items too. If no error is met, that list is spliced to the callers at the
end of the function. Otherwise the list will be walked and all items freed
before the error value is returned.

I did a simple test on this patch by forcing an error at the kzalloc() point
and verifying that when this hits (git clone seemed to exercise this), the
function throws the proper error. Unfortunately but predictably, we later
hit a BUG_ON(ret) type line that still hasn't been fixed up ;)

Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2012-03-22 01:45:37 +01:00
Mark Fasheh
be1a5564fd btrfs: Don't BUG_ON() errors in update_ref_for_cow()
The only caller of update_ref_for_cow() is __btrfs_cow_block() which was
originally ignoring any return values. update_ref_for_cow() however doesn't
look like a candidate to become a void function - there are a few places
where errors can occur.

So instead I changed update_ref_for_cow() to bubble all errors up (instead
of BUG_ON). __btrfs_cow_block() was then updated to catch and BUG_ON() any
errors from update_ref_for_cow(). The end effect is that we have no change
in behavior, but about 8 different places where a BUG_ON(ret) was removed.

Obviously a future patch will have to address the BUG_ON() in
__btrfs_cow_block().

Signed-off-by: Mark Fasheh <mfasheh@suse.de>
2012-03-22 01:45:36 +01:00
Mark Fasheh
ce598979be btrfs: Don't BUG_ON errors from btrfs_create_subvol_root()
This is called from only one place - create_subvol() which passes errors
safely back out to it's caller, btrfs_mksubvol where they are handled.

Additionally, btrfs_create_subvol_root() itself bug's needlessly from error
return of btrfs_update_inode(). Since create_subvol() was fixed to catch
errors we can bubble this one up too.

Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2012-03-22 01:45:36 +01:00
Jeff Mahoney
2c536799f1 btrfs: btrfs_drop_snapshot should return int
Commit cb1b69f4 (Btrfs: forced readonly when btrfs_drop_snapshot() fails)
made btrfs_drop_snapshot return void because there were no callers checking
the return value. That is the wrong order to handle error propogation since
the caller will have no idea that an error has occured and continue on
as if nothing went wrong.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22 01:45:36 +01:00
Jeff Mahoney
3fbe5c02ae btrfs: split extent_state ops
set_extent_bit can do exclusive locking but only when called by lock_extent*,

 Drop the exclusive bits argument except when called by lock_extent.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22 01:45:35 +01:00
Jeff Mahoney
d0082371cf btrfs: drop gfp_t from lock_extent
lock_extent and unlock_extent are always called with GFP_NOFS, drop the
 argument and use GFP_NOFS consistently.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22 01:45:35 +01:00
Jeff Mahoney
143bede527 btrfs: return void in functions without error conditions
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22 01:45:34 +01:00
Jeff Mahoney
ffd7b33944 btrfs: __add_reloc_root error push-up
This patch pushes kmalloc errors up to the caller and BUGs in the caller.

The BUG_ON for duplicate reloc tree root insertion is replaced with a
panic explaining the issue.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22 01:45:34 +01:00
Jeff Mahoney
355808c296 btrfs: ->submit_bio_hook error push-up
This pushes failures from the submit_bio_hook callbacks,
btrfs_submit_bio_hook and btree_submit_bio_hook into the callers, including
callers of submit_one_bio where it catches the failures with BUG_ON.

It also pushes up through the ->readpage_io_failed_hook to
end_bio_extent_writepage where the error is already caught with BUG_ON.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22 01:45:34 +01:00
Jeff Mahoney
3444a97255 btrfs: Factor out tree->ops->merge_bio_hook call
In submit_extent_page, there's a visually noisy if statement that, in
the midst of other conditions, does the tree dependency for tree->ops
and tree->ops->merge_bio_hook before calling it, and then another
condition afterwards. If an error is returned from merge_bio_hook,
there's no way to catch it. It's considered a routine "1" return
value instead of a failure.

This patch factors out the dependency check into a new local merge_bio
routine and BUG's on an error. The if statement is less noisy as a side-
effect.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22 01:45:33 +01:00
Jeff Mahoney
0417341e6b btrfs: Simplify btrfs_submit_bio_hook
btrfs_submit_bio_hook currently calls btrfs_bio_wq_end_io in either case
of an if statement that determines one of the arguments.

This patch moves the function call outside of the if statement and uses it
to only determine the different argument. This allows us to catch an
error in one place in a more visually obvious way.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22 01:45:33 +01:00
Jeff Mahoney
b45a9d8b48 btrfs: btrfs_update_root error push-up
btrfs_update_root BUG's when it can't alloc a path, yet it can recover
from a search error. This patch returns -ENOMEM instead.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22 01:45:33 +01:00
Jeff Mahoney
200a5c1767 btrfs: find_and_setup_root error push-up
find_and_setup_root BUGs when it encounters an error from
btrfs_find_last_root, which can occur if a path can't be allocated.

This patch pushes it up to its callers where it is already handled.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22 01:45:32 +01:00
Jeff Mahoney
6763af84a6 btrfs: Remove set bits return from clear_extent_bit
There is only one caller of clear_extent_bit that checks the return value
and it only checks if it's negative. Since there are no users of the
returned bits functionality of clear_extent_bit, stop returning it
and avoid complicating error handling.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22 01:45:32 +01:00
Jeff Mahoney
538042801a btrfs: avoid NULL deref in btrfs_reserve_extent with DEBUG_ENOSPC
__find_space_info can return NULL but we don't check it before calling
 dump_space_info().

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22 01:45:32 +01:00
Jeff Mahoney
d5c13f927f btrfs: clean_tree_block should panic on observed memory corruption and return void
The only error condition in clean_tree_block is an accounting bug.
 Returning without modifying dirty_metadata_bytes and as if the cleaning
 as been performed may cause problems later so it should panic instead.

 It should probably be a BUG_ON but we have btrfs_panic now.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22 01:45:31 +01:00
Jeff Mahoney
d16cb050e5 btrfs: Simplify btrfs_insert_root
btrfs_insert_root is just a wrapper for btrfs_insert_item. Just return
the error directly.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22 01:45:31 +01:00
Jeff Mahoney
cddcd80018 btrfs: Fix kfree of member instead of structure
Correctness fix: The kfree calls in the add_delayed_* functions free
the node that's passed into it, but the node is a member of another
structure. It works because it's always the first member of the
containing structure, but it should really be using the containing
structure itself.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22 01:45:30 +01:00
Jeff Mahoney
43c04fb1b8 btrfs: Panic on bad rbtree operations
The ordered data and relocation trees have BUG_ONs to protect against
bad tree operations.

This patch replaces them with a panic that will report the problem.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22 01:45:30 +01:00
Jeff Mahoney
c2d904e086 btrfs: Catch locking failures in {set,clear,convert}_extent_bit
The *_state functions can only return 0 or -EEXIST. This patch addresses
the cases where those functions returning -EEXIST represent a locking
failure. It handles them by panicking with an appropriate error message.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22 01:45:30 +01:00
Jeff Mahoney
8c34293001 btrfs: Add btrfs_panic()
As part of the effort to eliminate BUG_ON as an error handling
technique, we need to determine which errors are actual logic errors,
which are on-disk corruption, and which are normal runtime errors
e.g. -ENOMEM.

Annotating these error cases is helpful to understand and report them.

This patch adds a btrfs_panic() routine that will either panic
or BUG depending on the new -ofatal_errors={panic,bug} mount option.
Since there are still so many BUG_ONs, it defaults to BUG for now but I
expect that to change once the error handling effort has made
significant progress.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22 01:45:29 +01:00
Jason Baron
93dc6107a7 Don't limit non-nested epoll paths
Commit 28d82dc1c4 ("epoll: limit paths") that I did to limit the
number of possible wakeup paths in epoll is causing a few applications
to longer work (dovecot for one).

The original patch is really about limiting the amount of epoll nesting
(since epoll fds can be attached to other fds). Thus, we probably can
allow an unlimited number of paths of depth 1. My current patch limits
it at 1000. And enforce the limits on paths that have a greater depth.

This is captured in: https://bugzilla.redhat.com/show_bug.cgi?id=681578

Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-18 12:25:04 -07:00
Linus Torvalds
cb1ecf25a8 Merge branch 'akpm' (more patches from Andrew)
Merge some more email patches from Andrew Morton:
 "A couple of nilfs fixes"

* emailed from Andrew Morton <akpm@linux-foundation.org>:
  nilfs2: fix NULL pointer dereference in nilfs_load_super_block()
  nilfs2: clamp ns_r_segments_percentage to [1, 99]
2012-03-16 17:14:55 -07:00
Ryusuke Konishi
d7178c79d9 nilfs2: fix NULL pointer dereference in nilfs_load_super_block()
According to the report from Slicky Devil, nilfs caused kernel oops at
nilfs_load_super_block function during mount after he shrank the
partition without resizing the filesystem:

 BUG: unable to handle kernel NULL pointer dereference at 00000048
 IP: [<d0d7a08e>] nilfs_load_super_block+0x17e/0x280 [nilfs2]
 *pde = 00000000
 Oops: 0000 [#1] PREEMPT SMP
 ...
 Call Trace:
  [<d0d7a87b>] init_nilfs+0x4b/0x2e0 [nilfs2]
  [<d0d6f707>] nilfs_mount+0x447/0x5b0 [nilfs2]
  [<c0226636>] mount_fs+0x36/0x180
  [<c023d961>] vfs_kern_mount+0x51/0xa0
  [<c023ddae>] do_kern_mount+0x3e/0xe0
  [<c023f189>] do_mount+0x169/0x700
  [<c023fa9b>] sys_mount+0x6b/0xa0
  [<c04abd1f>] sysenter_do_call+0x12/0x28
 Code: 53 18 8b 43 20 89 4b 18 8b 4b 24 89 53 1c 89 43 24 89 4b 20 8b 43
 20 c7 43 2c 00 00 00 00 23 75 e8 8b 50 68 89 53 28 8b 54 b3 20 <8b> 72
 48 8b 7a 4c 8b 55 08 89 b3 84 00 00 00 89 bb 88 00 00 00
 EIP: [<d0d7a08e>] nilfs_load_super_block+0x17e/0x280 [nilfs2] SS:ESP 0068:ca9bbdcc
 CR2: 0000000000000048

This turned out due to a defect in an error path which runs if the
calculated location of the secondary super block was invalid.

This patch fixes it and eliminates the reported oops.

Reported-by: Slicky Devil <slicky.dvl@gmail.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Tested-by: Slicky Devil <slicky.dvl@gmail.com>
Cc: <stable@vger.kernel.org>	[2.6.30+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-16 17:14:44 -07:00
Haogang Chen
3d777a6406 nilfs2: clamp ns_r_segments_percentage to [1, 99]
ns_r_segments_percentage is read from the disk.  Bogus or malicious
value could cause integer overflow and malfunction due to meaningless
disk usage calculation.  This patch reports error when mounting such
bogus volumes.

Signed-off-by: Haogang Chen <haogangchen@gmail.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-16 17:14:44 -07:00
Anton Blanchard
c017386352 afs: Remote abort can cause BUG in rxrpc code
When writing files to afs I sometimes hit a BUG:

kernel BUG at fs/afs/rxrpc.c:179!

With a backtrace of:

	afs_free_call
	afs_make_call
	afs_fs_store_data
	afs_vnode_store_data
	afs_write_back_from_locked_page
	afs_writepages_region
	afs_writepages

The cause is:

	ASSERT(skb_queue_empty(&call->rx_queue));

Looking at a tcpdump of the session the abort happens because we
are exceeding our disk quota:

	rx abort fs reply store-data error diskquota exceeded (32)

So the abort error is valid. We hit the BUG because we haven't
freed all the resources for the call.

By freeing any skbs in call->rx_queue before calling afs_free_call
we avoid hitting leaking memory and avoid hitting the BUG.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-16 17:01:41 -07:00
Anton Blanchard
2c724fb927 afs: Read of file returns EBADMSG
A read of a large file on an afs mount failed:

# cat junk.file > /dev/null
cat: junk.file: Bad message

Looking at the trace, call->offset wrapped since it is only an
unsigned short. In afs_extract_data:

        _enter("{%u},{%zu},%d,,%zu", call->offset, len, last, count);
...

        if (call->offset < count) {
                if (last) {
                        _leave(" = -EBADMSG [%d < %zu]", call->offset, count);
                        return -EBADMSG;
                }

Which matches the trace:

[cat   ] ==> afs_extract_data({65132},{524},1,,65536)
[cat   ] <== afs_extract_data() = -EBADMSG [0 < 65536]

call->offset went from 65132 to 0. Fix this by making call->offset an
unsigned int.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-16 17:01:41 -07:00
Linus Torvalds
f1cbd03f5e Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe:
 "Been sitting on this for a while, but lets get this out the door.
  This fixes various important bugs for 3.3 final, along with a few more
  trivial ones.  Please pull!"

* 'for-linus' of git://git.kernel.dk/linux-block:
  block: fix ioc leak in put_io_context
  block, sx8: fix pointer math issue getting fw version
  Block: use a freezable workqueue for disk-event polling
  drivers/block/DAC960: fix -Wuninitialized warning
  drivers/block/DAC960: fix DAC960_V2_IOCTL_Opcode_T -Wenum-compare warning
  block: fix __blkdev_get and add_disk race condition
  block: Fix setting bio flags in drivers (sd_dif/floppy)
  block: Fix NULL pointer dereference in sd_revalidate_disk
  block: exit_io_context() should call elevator_exit_icq_fn()
  block: simplify ioc_release_fn()
  block: replace icq->changed with icq->flags
2012-03-14 17:16:45 -07:00
Linus Torvalds
8e8bb96d24 Merge git://git.samba.org/sfrench/cifs-2.6
Pull CIFS fixes from Steve French.

* git://git.samba.org/sfrench/cifs-2.6:
  CIFS: Do not kmalloc under the flocks spinlock
  cifs: possible memory leak in xattr.
2012-03-13 17:03:53 -07:00
Al Viro
310fa7a367 restore smp_mb() in unlock_new_inode()
wait_on_inode() doesn't have ->i_lock

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-03-10 17:07:28 -05:00
Miklos Szeredi
7f6c7e62fc vfs: fix return value from do_last()
complete_walk() returns either ECHILD or ESTALE.  do_last() turns this into
ECHILD unconditionally.  If not in RCU mode, this error will reach userspace
which is complete nonsense.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-03-10 17:05:30 -05:00
Miklos Szeredi
097b180ca0 vfs: fix double put after complete_walk()
complete_walk() already puts nd->path, no need to do it again at cleanup time.

This would result in Oopses if triggered, apparently the codepath is not too
well exercised.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-03-10 17:05:30 -05:00
Jan Kara
f6940fe909 udf: Fix deadlock in udf_release_file()
udf_release_file() can be called from munmap() path with mmap_sem held.  Thus
we cannot take i_mutex there because that ranks above mmap_sem. Luckily,
i_mutex is not needed in udf_release_file() anymore since protection by
i_data_sem is enough to protect from races with write and truncate.

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Reviewed-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-03-10 16:05:38 -05:00
Tyler Hicks
978d6d8c45 vfs: Correctly set the dir i_mutex lockdep class
9a7aa12f39 introduced additional logic around setting the i_mutex
lockdep class for directory inodes. The idea was that some filesystems
may want their own special lockdep class for different directory
inodes and calling unlock_new_inode() should not clobber one of
those special classes.

I believe that the added conditional, around the *negated* return value
of lockdep_match_class(), caused directory inodes to be placed in the
wrong lockdep class.

inode_init_always() sets the i_mutex lockdep class with i_mutex_key for
all inodes. If the filesystem did not change the class during inode
initialization, then the conditional mentioned above was false and the
directory inode was incorrectly left in the non-directory lockdep class.
If the filesystem did set a special lockdep class, then the conditional
mentioned above was true and that class was clobbered with
i_mutex_dir_key.

This patch removes the negation from the conditional so that the i_mutex
lockdep class is properly set for directory inodes. Special classes are
preserved and directory inodes with unmodified classes are set with
i_mutex_dir_key.

Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-03-10 16:05:38 -05:00
Al Viro
c7b2855505 aio: fix the "too late munmap()" race
Current code has put_ioctx() called asynchronously from aio_fput_routine();
that's done *after* we have killed the request that used to pin ioctx,
so there's nothing to stop io_destroy() waiting in wait_for_all_aios()
from progressing.  As the result, we can end up with async call of
put_ioctx() being the last one and possibly happening during exit_mmap()
or elf_core_dump(), neither of which expects stray munmap() being done
to them...

We do need to prevent _freeing_ ioctx until aio_fput_routine() is done
with that, but that's all we care about - neither io_destroy() nor
exit_aio() will progress past wait_for_all_aios() until aio_fput_routine()
does really_put_req(), so the ioctx teardown won't be done until then
and we don't care about the contents of ioctx past that point.

Since actual freeing of these suckers is RCU-delayed, we don't need to
bump ioctx refcount when request goes into list for async removal.
All we need is rcu_read_lock held just over the ->ctx_lock-protected
area in aio_fput_routine().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Acked-by: Benjamin LaHaise <bcrl@kvack.org>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-09 18:59:59 -08:00
Al Viro
86b62a2cb4 aio: fix io_setup/io_destroy race
Have ioctx_alloc() return an extra reference, so that caller would drop it
on success and not bother with re-grabbing it on failure exit.  The current
code is obviously broken - io_destroy() from another thread that managed
to guess the address io_setup() would've returned would free ioctx right
under us; gets especially interesting if aio_context_t * we pass to
io_setup() points to PROT_READ mapping, so put_user() fails and we end
up doing io_destroy() on kioctx another thread has just got freed...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Benjamin LaHaise <bcrl@kvack.org>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-09 18:59:59 -08:00
Linus Torvalds
86e0600833 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs updates from Chris Mason:
 "I have two additional and btrfs fixes in my for-linus branch.  One is
  a casting error that leads to memory corruption on i386 during scrub,
  and the other fixes a corner case in the backref walking code (also
  triggered by scrub)."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: fix casting error in scrub reada code
  btrfs: fix locking issues in find_parent_nodes()
2012-03-09 18:09:18 -08:00