Commit Graph

21477 Commits (57df216bd8c8813a79a6a618e3d2ec937d532b86)

Author SHA1 Message Date
Huang Weiyi 57df216bd8 nfs4: remove duplicated #include
Remove duplicated #include('s) in
  fs/nfs/nfs4proc.c

Signed-off-by: Huang Weiyi <weiyi.huang@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-03-11 15:18:37 -05:00
Trond Myklebust f9feab1e18 NFSv4: nfs4_state_mark_reclaim_nograce() should be static
There are no more external users of nfs4_state_mark_reclaim_nograce() or
nfs4_state_mark_reclaim_reboot(), so mark them as static.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-03-11 15:18:36 -05:00
Trond Myklebust ecac799a5e NFSv4: Fix the setlk error handler
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-03-11 15:18:36 -05:00
Trond Myklebust b4410c2f7f NFSv4.1: Fix the handling of the SEQUENCE status bits
We want SEQUENCE status bits to be handled by the state manager in order
to avoid threading issues.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-03-11 15:18:35 -05:00
Trond Myklebust 0400a6b0cb NFSv4/4.1: Fix nfs4_schedule_state_recovery abuses
nfs4_schedule_state_recovery() should only be used when we need to force
the state manager to check the lease. If we just want to start the
state manager in order to handle a state recovery situation, we should be
using nfs4_schedule_state_manager().

This patch fixes the abuses of nfs4_schedule_state_recovery() by replacing
its use with a set of helper functions that do the right thing.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-03-11 15:18:22 -05:00
Andy Adamson c34c32ea97 NFSv4.1 reclaim complete must wait for completion
Signed-off-by: Andy Adamson <andros@netapp.com>
[Trond: fix whitespace errors]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-03-10 15:05:01 -05:00
Andy Adamson 114f64b5f2 NFSv4: remove duplicate clientid in struct nfs_client
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-03-10 15:05:00 -05:00
Ricardo Labiaga 7d6d63d642 NFSv4.1: Retry CREATE_SESSION on NFS4ERR_DELAY
Fix bug where we currently retry the EXCHANGEID call again, eventhough
we already have a valid clientid.  Instead, delay and retry the CREATE_SESSION
call.

Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-03-10 15:04:59 -05:00
Frank Filz 3fa0b4e201 (try3-resend) Fix nfs_compat_user_ino64 so it doesn't cause problems if bit 31 or 63 are set in fileid
The problem was use of an int32, which when converted to a uint64
is sign extended resulting in a fileid that doesn't fit in 32 bits
even though the intent of the function is to fit the fileid into
32 bits.

Signed-off-by: Frank Filz <ffilzlnx@us.ibm.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
[Trond: Added an include for compat.h]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-03-10 15:04:58 -05:00
Jovi Zhang 43b7c3f051 nfs: fix compilation warning
this commit fix compilation warning as following:
linux-2.6/fs/nfs/nfs4proc.c:3265: warning: comparison of distinct pointer types lacks a cast

Signed-off-by: Jovi Zhang <bookjovi@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-03-10 15:04:56 -05:00
Stanislav Fomichev b9f810570d nfs: add kmalloc return value check in decode_and_add_ds
add kmalloc return value check in decode_and_add_ds

Signed-off-by: Stanislav Fomichev <kernel@fomichev.me>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-03-10 15:04:55 -05:00
Jeff Layton d2224e7afb nfs: close NFSv4 COMMIT vs. CLOSE race
I've been adding in more artificial delays in the NFSv4 commit and close
codepaths to uncover races. The kernel I'm testing has the patch to
close the race in __rpc_wait_for_completion_task that's in Trond's
cthon2011 branch. The reproducer I've been using does this in a loop:

	mkdir("DIR");
	fd = open("DIR/FILE", O_WRONLY|O_CREAT|O_EXCL, 0644);
	write(fd, "abcdefg", 7);
	close(fd);
	unlink("DIR/FILE");
	rmdir("DIR");

The above reproducer shouldn't result in any silly-renaming. However,
when I add a "msleep(100)" just after the nfs_commit_clear_lock call in
nfs_commit_release, I can almost always force one to occur. If I can
force it to occur with that, then it can happen without that delay
given the right timing.

nfs_commit_inode waits for the NFS_INO_COMMIT bit to clear when called
with FLUSH_SYNC set. nfs_commit_rpcsetup on the other hand does not wait
for the task to complete before putting its reference to it, so the last
reference get put in rpc_release task and gets queued to a workqueue.

In this situation, the last open context reference may be put by the
COMMIT release instead of the close() syscall. The close() syscall
returns too quickly and the unlink runs while the d_count is still
high since the COMMIT release hasn't put its dentry reference yet.

Fix this by having rpc_commit_rpcsetup wait for the RPC call to complete
before putting the task reference when FLUSH_SYNC is set. With this, the
last reference is put by the process that's initiating the FLUSH_SYNC
commit and the race is closed.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-03-10 15:04:53 -05:00
Trond Myklebust bf294b41ce SUNRPC: Close a race in __rpc_wait_for_completion_task()
Although they run as rpciod background tasks, under normal operation
(i.e. no SIGKILL), functions like nfs_sillyrename(), nfs4_proc_unlck()
and nfs4_do_close() want to be fully synchronous. This means that when we
exit, we want all references to the rpc_task to be gone, and we want
any dentry references etc. held by that task to be released.

For this reason these functions call __rpc_wait_for_completion_task(),
followed by rpc_put_task() in the expectation that the latter will be
releasing the last reference to the rpc_task, and thus ensuring that the
callback_ops->rpc_release() has been called synchronously.

This patch fixes a race which exists due to the fact that
rpciod calls rpc_complete_task() (in order to wake up the callers of
__rpc_wait_for_completion_task()) and then subsequently calls
rpc_put_task() without ensuring that these two steps are done atomically.

In order to avoid adding new spin locks, the patch uses the existing
waitqueue spin lock to order the rpc_task reference count releases between
the waiting process and rpciod.
The common case where nobody is waiting for completion is optimised for by
checking if the RPC_TASK_ASYNC flag is cleared and/or if the rpc_task
reference count is 1: in those cases we drop trying to grab the spin lock,
and immediately free up the rpc_task.

Those few processes that need to put the rpc_task from inside an
asynchronous context and that do not care about ordering are given a new
helper: rpc_put_task_async().

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-03-10 15:04:52 -05:00
Linus Torvalds fb62c00a6d Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  ceph: no .snap inside of snapped namespace
  libceph: fix msgr standby handling
  libceph: fix msgr keepalive flag
  libceph: fix msgr backoff
  libceph: retry after authorization failure
  libceph: fix handling of short returns from get_user_pages
  ceph: do not clear I_COMPLETE from d_release
  ceph: do not set I_COMPLETE
  Revert "ceph: keep reference to parent inode on ceph_dentry"
2011-03-05 10:43:22 -08:00
Neil Horman e9e3d724e2 nfs4: Ensure that ACL pages sent over NFS were not allocated from the slab (v3)
The "bad_page()" page allocator sanity check was reported recently (call
chain as follows):

  bad_page+0x69/0x91
  free_hot_cold_page+0x81/0x144
  skb_release_data+0x5f/0x98
  __kfree_skb+0x11/0x1a
  tcp_ack+0x6a3/0x1868
  tcp_rcv_established+0x7a6/0x8b9
  tcp_v4_do_rcv+0x2a/0x2fa
  tcp_v4_rcv+0x9a2/0x9f6
  do_timer+0x2df/0x52c
  ip_local_deliver+0x19d/0x263
  ip_rcv+0x539/0x57c
  netif_receive_skb+0x470/0x49f
  :virtio_net:virtnet_poll+0x46b/0x5c5
  net_rx_action+0xac/0x1b3
  __do_softirq+0x89/0x133
  call_softirq+0x1c/0x28
  do_softirq+0x2c/0x7d
  do_IRQ+0xec/0xf5
  default_idle+0x0/0x50
  ret_from_intr+0x0/0xa
  default_idle+0x29/0x50
  cpu_idle+0x95/0xb8
  start_kernel+0x220/0x225
  _sinittext+0x22f/0x236

It occurs because an skb with a fraglist was freed from the tcp
retransmit queue when it was acked, but a page on that fraglist had
PG_Slab set (indicating it was allocated from the Slab allocator (which
means the free path above can't safely free it via put_page.

We tracked this back to an nfsv4 setacl operation, in which the nfs code
attempted to fill convert the passed in buffer to an array of pages in
__nfs4_proc_set_acl, which gets used by the skb->frags list in
xs_sendpages.  __nfs4_proc_set_acl just converts each page in the buffer
to a page struct via virt_to_page, but the vfs allocates the buffer via
kmalloc, meaning the PG_slab bit is set.  We can't create a buffer with
kmalloc and free it later in the tcp ack path with put_page, so we need
to either:

1) ensure that when we create the list of pages, no page struct has
   PG_Slab set

 or

2) not use a page list to send this data

Given that these buffers can be multiple pages and arbitrarily sized, I
think (1) is the right way to go.  I've written the below patch to
allocate a page from the buddy allocator directly and copy the data over
to it.  This ensures that we have a put_page free-able page for every
entry that winds up on an skb frag list, so it can be safely freed when
the frame is acked.  We do a put page on each entry after the
rpc_call_sync call so as to drop our own reference count to the page,
leaving only the ref count taken by tcp_sendpages.  This way the data
will be properly freed when the ack comes in

Successfully tested by myself to solve the above oops.

Note, as this is the result of a setacl operation that exceeded a page
of data, I think this amounts to a local DOS triggerable by an
uprivlidged user, so I'm CCing security on this as well.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Trond Myklebust <Trond.Myklebust@netapp.com>
CC: security@kernel.org
CC: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-04 17:28:52 -08:00
Sage Weil 455cec0abf ceph: no .snap inside of snapped namespace
Otherwise you can do things like

# mkdir .snap/foo
# cd .snap/foo/.snap
# ls
<badness>

Signed-off-by: Sage Weil <sage@newdream.net>
2011-03-04 12:25:09 -08:00
Linus Torvalds 8336026942 Merge branch 'i_nlink' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'i_nlink' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  hfs: fix rename() over non-empty directory
  udf: fix i_nlink limit
  fix reiserfs mkdir() breakage
  exofs: i_nlink races in rename()
  nilfs2: i_nlink races in rename()
  minix: i_nlink races in rename()
  ufs: i_nlink races in rename()
  sysv: i_nlink races in rename()
2011-03-03 15:37:59 -08:00
Linus Torvalds 4c7fd114c6 Merge branch 'for-linus' of git://oss.sgi.com/xfs/xfs
* 'for-linus' of git://oss.sgi.com/xfs/xfs:
  xfs: zero proper structure size for geometry calls
2011-03-03 12:44:22 -08:00
Linus Torvalds c640e13f8e Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ryusuke/nilfs2
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ryusuke/nilfs2:
  nilfs2: fix regression that i-flag is not set on changeless checkpoints
2011-03-03 12:42:48 -08:00
Sage Weil 16a8b70a5a ceph: do not clear I_COMPLETE from d_release
First, this was racy anyway: d_release isn't called until well after the
dentry is unhashed.  Second, this runs afoul of the recent dcache change
that clears d_parent prior to calling d_release (949854d0), causing a NULL
pointer dereference.

Signed-off-by: Sage Weil <sage@newdream.net>
2011-03-03 10:09:52 -08:00
Sage Weil b545cc1505 ceph: do not set I_COMPLETE
Do not set the I_COMPLETE flag on directories until we resolve races with
dcache pruning.

Signed-off-by: Sage Weil <sage@newdream.net>
2011-03-03 10:09:51 -08:00
Sage Weil 9bde178d05 Revert "ceph: keep reference to parent inode on ceph_dentry"
This reverts commit 97d79b403e.

This fails to account for d_parent changes due to rename or disconnected
dentries due to submounts or NFS reexports.

Signed-off-by: Sage Weil <sage@newdream.net>
2011-03-03 10:09:50 -08:00
Al Viro 69102e9b4b hfs: fix rename() over non-empty directory
merge hfs_unlink() and hfs_rmdir(), while we are at it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-03 01:28:40 -05:00
Al Viro 810c1b2e48 udf: fix i_nlink limit
(256 << sizeof(x)) - 1 is not the maximal possible value of x...
In reality, the maximal allowed value for UDF FileLinkCount is
65535.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-03 01:28:40 -05:00
Al Viro 99890a3be1 fix reiserfs mkdir() breakage
if directory has so many subdirectories that its link count is set
to 1 (i.e. "can't tell accurately") and reiserfs_new_inode() fails,
we shouldn't decrement the parent's link count in cleanup path;
that's what DEC_DIR_INODE_NLINK() is for.  As it is, we end up
with parent suddenly getting zero i_nlink, with very unpleasant
effects.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-03 01:28:40 -05:00
Al Viro babfe56046 exofs: i_nlink races in rename()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-03 01:28:17 -05:00
Al Viro 30eb43d314 nilfs2: i_nlink races in rename()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-03 01:28:17 -05:00
Al Viro 6f88049caf minix: i_nlink races in rename()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-03 01:28:16 -05:00
Al Viro 37750cdda3 ufs: i_nlink races in rename()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-03 01:28:16 -05:00
Al Viro 4787d45fa7 sysv: i_nlink races in rename()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-03 01:28:16 -05:00
Linus Torvalds f7d222ea2a Merge branch 'devicetree/merge' of git://git.secretlab.ca/git/linux-2.6
* 'devicetree/merge' of git://git.secretlab.ca/git/linux-2.6:
  of/promtree: allow DT device matching by fixing 'name' brokenness (v5)
  x86: OLPC: have prom_early_alloc BUG rather than return NULL
  of/flattree: Drop an uninteresting message to pr_debug level
  of: Add missing of_address.h to xilinx ehci driver
2011-03-02 20:01:57 -08:00
Paul Bolle 8aaccf7fa2 of/flattree: Drop an uninteresting message to pr_debug level
This message looks like an error (which it isn't) when booting with a
flattened device tree.  Remove the message from normal kernel builds.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2011-03-02 13:45:18 -07:00
Josh Hunt e8a80c6f76 ext2: Fix link count corruption under heavy link+rename load
vfs_rename_other() does not lock renamed inode with i_mutex. Thus changing
i_nlink in a non-atomic manner (which happens in ext2_rename()) can corrupt
it as reported and analyzed by Josh.

In fact, there is no good reason to mess with i_nlink of the moved file.
We did it presumably to simulate linking into the new directory and unlinking
from an old one. But the practical effect of this is disputable because fsck
can possibly treat file as being properly linked into both directories without
writing any error which is confusing. So we just stop increment-decrement
games with i_nlink which also fixes the corruption.

CC: stable@kernel.org
CC: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Josh Hunt <johunt@akamai.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2011-03-02 11:03:52 +01:00
Alex Elder af24ee9ea8 xfs: zero proper structure size for geometry calls
Commit 493f3358cb added this call to
xfs_fs_geometry() in order to avoid passing kernel stack data back
to user space:

+       memset(geo, 0, sizeof(*geo));

Unfortunately, one of the callers of that function passes the
address of a smaller data type, cast to fit the type that
xfs_fs_geometry() requires.  As a result, this can happen:

Kernel panic - not syncing: stack-protector: Kernel stack is corrupted
in: f87aca93

Pid: 262, comm: xfs_fsr Not tainted 2.6.38-rc6-493f3358cb2+ #1
Call Trace:

[<c12991ac>] ? panic+0x50/0x150
[<c102ed71>] ? __stack_chk_fail+0x10/0x18
[<f87aca93>] ? xfs_ioc_fsgeometry_v1+0x56/0x5d [xfs]

Fix this by fixing that one caller to pass the right type and then
copy out the subset it is interested in.

Note: This patch is an alternative to one originally proposed by
Eric Sandeen.

Reported-by: Jeffrey Hundstad <jeffrey.hundstad@mnsu.edu>
Signed-off-by: Alex Elder <aelder@sgi.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Tested-by: Jeffrey Hundstad <jeffrey.hundstad@mnsu.edu>
2011-03-01 21:21:13 -06:00
Ryusuke Konishi 72746ac643 nilfs2: fix regression that i-flag is not set on changeless checkpoints
According to the report from Jiro SEKIBA titled "regression in
2.6.37?"  (Message-Id: <8739n8vs1f.wl%jir@sekiba.com>), on 2.6.37 and
later kernels, lscp command no longer displays "i" flag on checkpoints
that snapshot operations or garbage collection created.

This is a regression of nilfs2 checkpointing function, and it's
critical since it broke behavior of a part of nilfs2 applications.
For instance, snapshot manager of TimeBrowse gets to create
meaningless snapshots continuously; snapshot creation triggers another
checkpoint, but applications cannot distinguish whether the new
checkpoint contains meaningful changes or not without the i-flag.

This patch fixes the regression and brings that application behavior
back to normal.

Reported-by: Jiro SEKIBA <jir@unicus.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Tested-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Tested-by: Jiro SEKIBA <jir@unicus.jp>
Cc: stable <stable@kernel.org>  [2.6.37]
2011-03-02 09:55:18 +09:00
Randy Dunlap e6eb5ce1b2 fs/block_dev.c: fix new kernel-doc warning
Fix new kernel-doc warning in fs/block_dev.c:

Warning(fs/block_dev.c:937): No description found for parameter 'kill_dirty'

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-28 18:08:31 -08:00
Linus Torvalds 58da94f013 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: fix truncate after open
  fuse: fix hang of single threaded fuseblk filesystem
2011-02-28 17:53:04 -08:00
Linus Torvalds 158a5d61f7 Merge branch 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2:
  ocfs2: Check heartbeat mode for kernel stacks only
  Ocfs2/refcounttree: Fix a bug for refcounttree to writeback clusters in a right number.
  ocfs2: Fix estimate of necessary credits for mkdir
2011-02-28 17:52:47 -08:00
Jan Kara 7137c6bd45 aio: fix race between io_destroy() and io_submit()
A race can occur when io_submit() races with io_destroy():

 CPU1						CPU2
io_submit()
  do_io_submit()
    ...
    ctx = lookup_ioctx(ctx_id);
						io_destroy()
    Now do_io_submit() holds the last reference to ctx.
    ...
    queue new AIO
    put_ioctx(ctx) - frees ctx with active AIOs

We solve this issue by checking whether ctx is being destroyed in AIO
submission path after adding new AIO to ctx.  Then we are guaranteed that
either io_destroy() waits for new AIO or we see that ctx is being
destroyed and bail out.

Cc: Nick Piggin <npiggin@kernel.dk>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-25 15:07:37 -08:00
Nick Piggin 3bd9a5d734 aio: fix rcu ioctx lookup
aio-dio-invalidate-failure GPFs in aio_put_req from io_submit.

lookup_ioctx doesn't implement the rcu lookup pattern properly.
rcu_read_lock does not prevent refcount going to zero, so we might take
a refcount on a zero count ioctx.

Fix the bug by atomically testing for zero refcount before incrementing.

[jack@suse.cz: added comment into the code]
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-25 15:07:37 -08:00
Timo Warns 294f6cf486 ldm: corrupted partition table can cause kernel oops
The kernel automatically evaluates partition tables of storage devices.
The code for evaluating LDM partitions (in fs/partitions/ldm.c) contains
a bug that causes a kernel oops on certain corrupted LDM partitions.  A
kernel subsystem seems to crash, because, after the oops, the kernel no
longer recognizes newly connected storage devices.

The patch changes ldm_parse_vmdb() to Validate the value of vblk_size.

Signed-off-by: Timo Warns <warns@pre-sense.de>
Cc: Eugene Teo <eugeneteo@kernel.sg>
Acked-by: Richard Russon <ldm@flatcap.org>
Cc: Harvey Harrison <harvey.harrison@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-25 15:07:36 -08:00
Davide Libenzi 22bacca48a epoll: prevent creating circular epoll structures
In several places, an epoll fd can call another file's ->f_op->poll()
method with ep->mtx held.  This is in general unsafe, because that other
file could itself be an epoll fd that contains the original epoll fd.

The code defends against this possibility in its own ->poll() method using
ep_call_nested, but there are several other unsafe calls to ->poll
elsewhere that can be made to deadlock.  For example, the following simple
program causes the call in ep_insert recursively call the original fd's
->poll, leading to deadlock:

 #include <unistd.h>
 #include <sys/epoll.h>

 int main(void) {
     int e1, e2, p[2];
     struct epoll_event evt = {
         .events = EPOLLIN
     };

     e1 = epoll_create(1);
     e2 = epoll_create(2);
     pipe(p);

     epoll_ctl(e2, EPOLL_CTL_ADD, e1, &evt);
     epoll_ctl(e1, EPOLL_CTL_ADD, p[0], &evt);
     write(p[1], p, sizeof p);
     epoll_ctl(e1, EPOLL_CTL_ADD, e2, &evt);

     return 0;
 }

On insertion, check whether the inserted file is itself a struct epoll,
and if so, do a recursive walk to detect whether inserting this file would
create a loop of epoll structures, which could lead to deadlock.

[nelhage@ksplice.com: Use epmutex to serialize concurrent inserts]
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Nelson Elhage <nelhage@ksplice.com>
Reported-by: Nelson Elhage <nelhage@ksplice.com>
Tested-by: Nelson Elhage <nelhage@ksplice.com>
Cc: <stable@kernel.org>		[2.6.34+, possibly earlier]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-25 15:07:36 -08:00
Linus Torvalds 4660ba63f1 Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
  Btrfs: fix fiemap bugs with delalloc
  Btrfs: set FMODE_EXCL in btrfs_device->mode
  Btrfs: make btrfs_rm_device() fail gracefully
  Btrfs: Avoid accessing unmapped kernel address
  Btrfs: Fix BTRFS_IOC_SUBVOL_SETFLAGS ioctl
  Btrfs: allow balance to explicitly allocate chunks as it relocates
  Btrfs: put ENOSPC debugging under a mount option
2011-02-25 14:03:39 -08:00
Linus Torvalds 638691a7a4 Merge branch 'for-linus' of git://neil.brown.name/md
* 'for-linus' of git://neil.brown.name/md:
  md: Fix - again - partition detection when array becomes active
  Fix over-zealous flush_disk when changing device size.
  md: avoid spinlock problem in blk_throtl_exit
  md: correctly handle probe of an 'mdp' device.
  md: don't set_capacity before array is active.
  md: Fix raid1->raid0 takeover
2011-02-25 11:13:26 -08:00
Anton Blanchard f129ccc923 afs: Fix oops in afs_unlink_writeback
I'm seeing the following oops when testing afs:

  Unable to handle kernel paging request for data at address 0x00000008
  ...
  NIP [c0000000003393b0] .afs_unlink_writeback+0x38/0xc0
  LR [c00000000033987c] .afs_put_writeback+0x98/0xec
  Call Trace:
  [c00000000345f600] [c00000000033987c] .afs_put_writeback+0x98/0xec
  [c00000000345f690] [c00000000033ae80] .afs_write_begin+0x6a4/0x75c
  [c00000000345f790] [c00000000012b77c] .generic_file_buffered_write+0x148/0x320
  [c00000000345f8d0] [c00000000012e1b8] .__generic_file_aio_write+0x37c/0x3e4
  [c00000000345f9d0] [c00000000012e2a8] .generic_file_aio_write+0x88/0xfc
  [c00000000345fa90] [c0000000003390a8] .afs_file_write+0x10c/0x178
  [c00000000345fb40] [c000000000188788] .do_sync_write+0xc4/0x128
  [c00000000345fcc0] [c000000000189658] .vfs_write+0xe8/0x1d8
  [c00000000345fd70] [c000000000189884] .SyS_write+0x68/0xb0
  [c00000000345fe30] [c000000000008564] syscall_exit+0x0/0x40

afs_write_begin hits an error and calls afs_unlink_writeback. In there
we do list_del_init on an uninitialised list.

The patch below initialises ->link when creating the afs_writeback struct.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-25 11:12:37 -08:00
Miklos Szeredi 8d56addd70 fuse: fix truncate after open
Commit e1181ee6 "vfs: pass struct file to do_truncate on O_TRUNC
opens" broke the behavior of open(O_TRUNC|O_RDONLY) in fuse.  Fuse
assumed that when called from open, a truncate() will be done, not an
ftruncate().

Fix by restoring the old behavior, based on the ATTR_OPEN flag.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2011-02-25 14:44:58 +01:00
Miklos Szeredi 5a18ec176c fuse: fix hang of single threaded fuseblk filesystem
Single threaded NTFS-3G could get stuck if a delayed RELEASE reply
triggered a DESTROY request via path_put().

Fix this by

 a) making RELEASE requests synchronous, whenever possible, on fuseblk
 filesystems

 b) if not possible (triggered by an asynchronous read/write) then do
 the path_put() in a separate thread with schedule_work().

Reported-by: Oliver Neukum <oneukum@suse.de>
Cc: stable@kernel.org
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2011-02-25 14:44:58 +01:00
Tejun Heo e7407d1619 block: bd_link_disk_holder() should hold on to holder_dir
The new implementation of bd_link_disk_holder() added by 49731baa41
(block: restore multiple bd_link_disk_holder() support) didn't get an
extra reference for the holder_dir kobject of the slave bdev; however,
bdev kills holder_dir on removal, not release, so if the slave bdev is
removed while there are holder links, the holder_dir will be destroyed
while there still are holder links, which leads to oops later when
bd_unlink_disk_order() tries to remove those links.

Make bd_link_disk_holder() grab an extra reference for the slave's
holder_dir and put it in bd_unlink_disk_holder().

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: "Hawrylewicz Czarnowski, Przemyslaw" <przemyslaw.hawrylewicz.czarnowski@intel.com>
Tested-by: "Hawrylewicz Czarnowski, Przemyslaw" <przemyslaw.hawrylewicz.czarnowski@intel.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-24 08:55:55 -08:00
J. R. Okajima bf9faa2aa3 Unlock vfsmount_lock in do_umount
By the commit
	b3e19d9 2011-01-07 fs: scale mntget/mntput
vfsmount_lock was introduced around testing mnt_count.
Fix the mis-typed 'unlock'

Signed-off-by: J. R. Okajima <hooanon05@yahoo.co.jp>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-02-24 02:10:57 -05:00
NeilBrown 93b270f76e Fix over-zealous flush_disk when changing device size.
There are two cases when we call flush_disk.
In one, the device has disappeared (check_disk_change) so any
data will hold becomes irrelevant.
In the oter, the device has changed size (check_disk_size_change)
so data we hold may be irrelevant.

In both cases it makes sense to discard any 'clean' buffers,
so they will be read back from the device if needed.

In the former case it makes sense to discard 'dirty' buffers
as there will never be anywhere safe to write the data.  In the
second case it *does*not* make sense to discard dirty buffers
as that will lead to file system corruption when you simply enlarge
the containing devices.

flush_disk calls __invalidate_devices.
__invalidate_device calls both invalidate_inodes and invalidate_bdev.

invalidate_inodes *does* discard I_DIRTY inodes and this does lead
to fs corruption.

invalidate_bev *does*not* discard dirty pages, but I don't really care
about that at present.

So this patch adds a flag to __invalidate_device (calling it
__invalidate_device2) to indicate whether dirty buffers should be
killed, and this is passed to invalidate_inodes which can choose to
skip dirty inodes.

flusk_disk then passes true from check_disk_change and false from
check_disk_size_change.

dm avoids tripping over this problem by calling i_size_write directly
rathher than using check_disk_size_change.

md does use check_disk_size_change and so is affected.

This regression was introduced by commit 608aeef17a which causes
check_disk_size_change to call flush_disk, so it is suitable for any
kernel since 2.6.27.

Cc: stable@kernel.org
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Cc: Andrew Patterson <andrew.patterson@hp.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: NeilBrown <neilb@suse.de>
2011-02-24 17:25:47 +11:00