An open file description (struct file) in a given process can be
associated with two different lock owners.
It can have a Posix lock owner which will be different in each process
that has a fd on the file.
It can have a Flock owner which will be the same in all processes.
When searching for a lock stateid to use, we need to consider both of these
owners
So add a new "flock_owner" to the "nfs_open_context" (of which there
is one for each open file description).
This flock_owner does not need to be reference-counted as there is a
1-1 relation between 'struct file' and nfs open contexts,
and it will never be part of a list of contexts. So there is no need
for a 'flock_context' - just the owner is enough.
The io_count included in the (Posix) lock_context provides no
guarantee that all read-aheads that could use the state have
completed, so not supporting it for flock locks in not a serious
problem. Synchronization between flock and read-ahead can be added
later if needed.
When creating an open_context for a non-openning create call, we don't have
a 'struct file' to pass in, so the lock context gets initialized with
a NULL owner, but this will never be used.
The flock_owner is not used at all in this patch, that will come later.
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
We're not holding any locks, so both nfs_wb_all() and inode_dio_wait()
are unenforcible and have livelock potential. Just limit ourselves to
flushing out the data.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
We need to ensure that any writes to the destination file are serialised
with the copy, meaning that the writeback has to occur under the inode lock.
Also relax the writeback requirement on the source, and rely on the
stateid checking to tell us if the source rebooted. Add the helper
nfs_filemap_write_and_wait_range() to call pnfs_sync_inode() as
is appropriate for pNFS servers that may need a layoutcommit.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
This adds the copy_range file_ops function pointer used by the
sys_copy_range() function call. This patch only implements sync copies,
so if an async copy happens we decode the stateid and ignore it.
Signed-off-by: Anna Schumaker <bjschuma@netapp.com>
(badly behaved) dentry code in various file systems. These have been
reviewed by Al and the respective file system mtinainers and are going
through the ext4 tree for convenience.
This also has a few ext4 encryption bug fixes that were discovered in
Android testing (yes, we will need to get these sync'ed up with the
fs/crypto code; I'll take care of that). It also has some bug fixes
and a change to ignore the legacy quota options to allow for xfstests
regression testing of ext4's internal quota feature and to be more
consistent with how xfs handles this case.
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Merge tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 bugfixes from Ted Ts'o:
"These changes contains a fix for overlayfs interacting with some
(badly behaved) dentry code in various file systems. These have been
reviewed by Al and the respective file system mtinainers and are going
through the ext4 tree for convenience.
This also has a few ext4 encryption bug fixes that were discovered in
Android testing (yes, we will need to get these sync'ed up with the
fs/crypto code; I'll take care of that). It also has some bug fixes
and a change to ignore the legacy quota options to allow for xfstests
regression testing of ext4's internal quota feature and to be more
consistent with how xfs handles this case"
* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: ignore quota mount options if the quota feature is enabled
ext4 crypto: fix some error handling
ext4: avoid calling dquot_get_next_id() if quota is not enabled
ext4: retry block allocation for failed DIO and DAX writes
ext4: add lockdep annotations for i_data_sem
ext4: allow readdir()'s of large empty directories to be interrupted
btrfs: fix crash/invalid memory access on fsync when using overlayfs
ext4 crypto: use dget_parent() in ext4_d_revalidate()
ext4: use file_dentry()
ext4: use dget_parent() in ext4_file_open()
nfs: use file_dentry()
fs: add file_dentry()
ext4 crypto: don't let data integrity writebacks fail with ENOMEM
ext4: check if in-inode xattr is corrupted in ext4_expand_extra_isize_ea()
NFS may be used as lower layer of overlayfs and accessing f_path.dentry can
lead to a crash.
Fix by replacing direct access of file->f_path.dentry with the
file_dentry() accessor, which will always return a native object.
Fixes: 4bacc9c923 ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Tested-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Acked-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: <stable@vger.kernel.org> # v4.2
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
The only difference to nfs_file_fsync is the call to pnfs_sync_inode. But
pnfs_sync_inode is just an inline that calls a pNFS layout driver method
if CONFIG_PNFS is designed, and thus can be called just fine from the core
NFS module.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).
Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The btrfs clone ioctls are now adopted by other file systems, with NFS
and CIFS already having support for them, and XFS being under active
development. To avoid growth of various slightly incompatible
implementations, add one to the VFS. Note that clones are different from
file copies in several ways:
- they are atomic vs other writers
- they support whole file clones
- they support 64-bit legth clones
- they do not allow partial success (aka short writes)
- clones are expected to be a fast metadata operation
Because of that it would be rather cumbersome to try to piggyback them on
top of the recent clone_file_range infrastructure. The converse isn't
true and the clone_file_range system call could try clone file range as
a first attempt to copy, something that further patches will enable.
Based on earlier work from Peng Tao.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The NFS CLONE_RANGE defintion was wrong and thus never worked. Fix this
by simply using the btrfs ioctl defintion.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Originally CLONE didn't allow for intra-file clones, but we recently
updated the spec to support this feature which is also supported by
local Linux file systems.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Without this for example 64-bit binaries on typical amd64 distributions
would not be able to use ioctls on NFS. For now this only affects clones.
Additionally ->compat_ioctl is defined even for non-compat builds, so
get rid of the pointless ifdef.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
It follows btrfs BTRFS_IOC_CLONE_RANGE lead on ioctl number and
arguments.
Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
draft-ietf-nfsv4-minorversion2-38.txt says:
Both cl_src_offset and
cl_dst_offset must be aligned to the clone block size Section 12.2.1.
The number of bytes to be cloned must be a multiple of the clone
block size, except in the case in which cl_src_offset plus the number
of bytes to be cloned is equal to the source file size.
Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
It can be called by user space to CLONE two files.
Follow btrfs lead and define NFS_IOC_CLONE same as BTRFS_IOC_CLONE.
Thus we don't mess up userspace with too many ioctls.
Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
The NFSv4 delegation spec allows the server to tell a client to limit how
much data it cache after the file is closed. In return, the server
guarantees enough free space to avoid ENOSPC situations, etc.
Prior to this patch, we assumed we could always cache aggressively after
close. Unfortunately, this causes problems with servers that set the
limit to 0 and therefore do not offer any ENOSPC guarantees.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Check opened, only update it when non-NULL.
It's not needs define an unused value for the opened
when calling _nfs4_do_open.
v3, same as v2.
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Commit 9597c13b forbade opens with O_APPEND|O_DIRECT for NFSv4:
nfs: verify open flags before allowing an atomic open
Currently, you can open a NFSv4 file with O_APPEND|O_DIRECT, but cannot
fcntl(F_SETFL,...) with those flags. This flag combination is explicitly
forbidden on NFSv3 opens, and it seems like it should also be on NFSv4.
However, you can still open a file with O_DIRECT|O_APPEND if there exists a
cached dentry for the file because nfs4_file_open() is used instead of
nfs_atomic_open() and the check is bypassed. Add the check in
nfs4_file_open() as well.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Highlights include:
Stable patches:
- Fix a regression in /proc/self/mountstats
- Fix the pNFS flexfiles O_DIRECT support
- Fix high load average due to callback thread sleeping
Bugfixes:
- Various patches to fix the pNFS layoutcommit support
- Do not cache pNFS deviceids unless server notifications are enabled
- Fix a SUNRPC transport reconnection regression
- make debugfs file creation failure non-fatal in SUNRPC
- Another fix for circular directory warnings on NFSv4 "junctioned" mountpoints
- Fix locking around NFSv4.2 fallocate() support
- Truncating NFSv4 file opens should also sync O_DIRECT writes
- Prevent infinite loop in rpcrdma_ep_create()
Features:
- Various improvements to the RDMA transport code's handling of memory
registration
- Various code cleanups
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Merge tag 'nfs-for-4.1-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs
Pull NFS client updates from Trond Myklebust:
"Another set of mainly bugfixes and a couple of cleanups. No new
functionality in this round.
Highlights include:
Stable patches:
- Fix a regression in /proc/self/mountstats
- Fix the pNFS flexfiles O_DIRECT support
- Fix high load average due to callback thread sleeping
Bugfixes:
- Various patches to fix the pNFS layoutcommit support
- Do not cache pNFS deviceids unless server notifications are enabled
- Fix a SUNRPC transport reconnection regression
- make debugfs file creation failure non-fatal in SUNRPC
- Another fix for circular directory warnings on NFSv4 "junctioned"
mountpoints
- Fix locking around NFSv4.2 fallocate() support
- Truncating NFSv4 file opens should also sync O_DIRECT writes
- Prevent infinite loop in rpcrdma_ep_create()
Features:
- Various improvements to the RDMA transport code's handling of
memory registration
- Various code cleanups"
* tag 'nfs-for-4.1-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (55 commits)
fs/nfs: fix new compiler warning about boolean in switch
nfs: Remove unneeded casts in nfs
NFS: Don't attempt to decode missing directory entries
Revert "nfs: replace nfs_add_stats with nfs_inc_stats when add one"
NFS: Rename idmap.c to nfs4idmap.c
NFS: Move nfs_idmap.h into fs/nfs/
NFS: Remove CONFIG_NFS_V4 checks from nfs_idmap.h
NFS: Add a stub for GETDEVICELIST
nfs: remove WARN_ON_ONCE from nfs_direct_good_bytes
nfs: fix DIO good bytes calculation
nfs: Fetch MOUNTED_ON_FILEID when updating an inode
sunrpc: make debugfs file creation failure non-fatal
nfs: fix high load average due to callback thread sleeping
NFS: Reduce time spent holding the i_mutex during fallocate()
NFS: Don't zap caches on fallocate()
xprtrdma: Make rpcrdma_{un}map_one() into inline functions
xprtrdma: Handle non-SEND completions via a callout
xprtrdma: Add "open" memreg op
xprtrdma: Add "destroy MRs" memreg op
xprtrdma: Add "reset MRs" memreg op
...
At the very least, we should not be taking the i_mutex until after
checking if the server even supports ALLOCATE or DEALLOCATE, allowing
v4.0 or v4.1 to exit without potentially waiting on a lock.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
This patch adds a GETATTR to the end of ALLOCATE and DEALLOCATE
operations so we can set the updated inode size and change attribute
directly. DEALLOCATE will still need to release pagecache pages, so
nfs42_proc_deallocate() now calls truncate_pagecache_range() before
contacting the server.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
that's the bulk of filesystem drivers dealing with inodes of their own
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
All places outside of core VFS that checked ->read and ->write for being NULL or
called the methods directly are gone now, so NULL {read,write} with non-NULL
{read,write}_iter will do the right thing in all cases.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The LAYOUTCOMMIT operation means different things to different layout types.
For blocks and objects, it is both a data and metadata consistency operation.
For files and flexfiles, it is only a metadata consistency operation.
This patch separates out the 2 cases, allowing the files/flexfiles layout
drivers to optimise away the data consistency calls to layoutcommit.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
If the caller does not specify the O_SYNC flag, then it is legitimate
to return from O_DIRECT without doing a pNFS layoutcommit operation.
However if the file is opened O_DIRECT|O_SYNC then we'd better get it
right.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
This patch adds support for using the NFS v4.2 operation DEALLOCATE to
punch holes in a file.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
This patch adds support for using the NFS v4.2 operation ALLOCATE to
preallocate data in a file.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Highlights include:
Stable fixes:
- Fix an uninitialised pointer Oops in the writeback error path
- Fix a bogus warning (and early exit from the loop) in nfs_generic_pgio
Features:
- Add NFSv4.2 SEEK feature and client support for lseek(SEEK_HOLE/SEEK_DATA)
Other fixes:
- pnfs: replace broken pnfs_put_lseg_async
- Remove dead prototype for nfs4_insert_deviceid_node
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Merge tag 'nfs-for-3.18-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs
Pull NFS client updates from Trond Myklebust:
"Highlights include:
Stable fixes:
- fix an uninitialised pointer Oops in the writeback error path
- fix a bogus warning (and early exit from the loop) in nfs_generic_pgio()
Features:
- Add NFSv4.2 SEEK feature and client support for lseek(SEEK_HOLE/SEEK_DATA)
Other fixes:
- pnfs: replace broken pnfs_put_lseg_async
- Remove dead prototype for nfs4_insert_deviceid_node"
* tag 'nfs-for-3.18-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
NFS: Fix a bogus warning in nfs_generic_pgio
NFS: Fix an uninitialised pointer Oops in the writeback error path
NFSv4.1/pnfs: replace broken pnfs_put_lseg_async
NFSv4: Remove dead prototype for nfs4_insert_deviceid_node()
NFS: Implement SEEK
The SEEK operation is used when an application makes an lseek call with
either the SEEK_HOLE or SEEK_DATA flags set. I fall back on
nfs_file_llseek() if the server does not have SEEK support.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
GFS2 and NFS have setlease routines that always just return -EINVAL.
Turn that into a generic routine that can live in fs/libfs.c.
Cc: <linux-nfs@vger.kernel.org>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: <cluster-devel@redhat.com>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Acked-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Pull vfs updates from Al Viro:
"This the bunch that sat in -next + lock_parent() fix. This is the
minimal set; there's more pending stuff.
In particular, I really hope to get acct.c fixes merged this cycle -
we need that to deal sanely with delayed-mntput stuff. In the next
pile, hopefully - that series is fairly short and localized
(kernel/acct.c, fs/super.c and fs/namespace.c). In this pile: more
iov_iter work. Most of prereqs for ->splice_write with sane locking
order are there and Kent's dio rewrite would also fit nicely on top of
this pile"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (70 commits)
lock_parent: don't step on stale ->d_parent of all-but-freed one
kill generic_file_splice_write()
ceph: switch to iter_file_splice_write()
shmem: switch to iter_file_splice_write()
nfs: switch to iter_splice_write_file()
fs/splice.c: remove unneeded exports
ocfs2: switch to iter_file_splice_write()
->splice_write() via ->write_iter()
bio_vec-backed iov_iter
optimize copy_page_{to,from}_iter()
bury generic_file_aio_{read,write}
lustre: get rid of messing with iovecs
ceph: switch to ->write_iter()
ceph_sync_direct_write: stop poking into iov_iter guts
ceph_sync_read: stop poking into iov_iter guts
new helper: copy_page_from_iter()
fuse: switch to ->write_iter()
btrfs: switch to ->write_iter()
ocfs2: switch to ->write_iter()
xfs: switch to ->write_iter()
...
"fdatasync() is similar to fsync(), but does not flush modified metadata
unless that metadata is needed in order to allow a subsequent data
retrieval to be correctly handled."
We absolutely need to commit the layouts to be able to retrieve the data
in case either the client, the server or the storage subsystem go down.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Pull vfs updates from Al Viro:
"All kinds of stuff this time around; some more notable parts:
- RCU'd vfsmounts handling
- new primitives for coredump handling
- files_lock is gone
- Bruce's delegations handling series
- exportfs fixes
plus misc stuff all over the place"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (101 commits)
ecryptfs: ->f_op is never NULL
locks: break delegations on any attribute modification
locks: break delegations on link
locks: break delegations on rename
locks: helper functions for delegation breaking
locks: break delegations on unlink
namei: minor vfs_unlink cleanup
locks: implement delegations
locks: introduce new FL_DELEG lock flag
vfs: take i_mutex on renamed file
vfs: rename I_MUTEX_QUOTA now that it's not used for quotas
vfs: don't use PARENT/CHILD lock classes for non-directories
vfs: pull ext4's double-i_mutex-locking into common code
exportfs: fix quadratic behavior in filehandle lookup
exportfs: better variable name
exportfs: move most of reconnect_path to helper function
exportfs: eliminate unused "noprogress" counter
exportfs: stop retrying once we race with rename/remove
exportfs: clear DISCONNECTED on all parents sooner
exportfs: more detailed comment for path_reconnect
...
Pull fs-cache fixes from David Howells:
Can you pull these commits to fix an issue with NFS whereby caching can be
enabled on a file that is open for writing by subsequently opening it for
reading. This can be made to crash by opening it for writing again if you're
quick enough.
The gist of the patchset is that the cookie should be acquired at inode
creation only and subsequently enabled and disabled as appropriate (which
dispenses with the backing objects when they're not needed).
The extra synchronisation that NFS does can then be dispensed with as it is
thenceforth managed by FS-Cache.
Could you send these on to Linus?
This likely will need fixing also in CIFS and 9P also once the FS-Cache
changes are upstream. AFS and Ceph are probably safe.
* 'fscache' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
NFS: Use i_writecount to control whether to get an fscache cookie in nfs_open()
FS-Cache: Provide the ability to enable/disable cookies
FS-Cache: Add use/unuse/wake cookie wrappers
Use i_writecount to control whether to get an fscache cookie in nfs_open() as
NFS does not do write caching yet. I *think* this is the cause of a problem
encountered by Mark Moseley whereby __fscache_uncache_page() gets a NULL
pointer dereference because cookie->def is NULL:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
IP: [<ffffffff812a1903>] __fscache_uncache_page+0x23/0x160
PGD 0
Thread overran stack, or stack corrupted
Oops: 0000 [#1] SMP
Modules linked in: ...
CPU: 7 PID: 18993 Comm: php Not tainted 3.11.1 #1
Hardware name: Dell Inc. PowerEdge R420/072XWF, BIOS 1.3.5 08/21/2012
task: ffff8804203460c0 ti: ffff880420346640
RIP: 0010:[<ffffffff812a1903>] __fscache_uncache_page+0x23/0x160
RSP: 0018:ffff8801053af878 EFLAGS: 00210286
RAX: 0000000000000000 RBX: ffff8800be2f8780 RCX: ffff88022ffae5e8
RDX: 0000000000004c66 RSI: ffffea00055ff440 RDI: ffff8800be2f8780
RBP: ffff8801053af898 R08: 0000000000000001 R09: 0000000000000003
R10: 0000000000000000 R11: 0000000000000000 R12: ffffea00055ff440
R13: 0000000000001000 R14: ffff8800c50be538 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88042fc60000(0063) knlGS:00000000e439c700
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000000000010 CR3: 0000000001d8f000 CR4: 00000000000607f0
Stack:
...
Call Trace:
[<ffffffff81365a72>] __nfs_fscache_invalidate_page+0x42/0x70
[<ffffffff813553d5>] nfs_invalidate_page+0x75/0x90
[<ffffffff811b8f5e>] truncate_inode_page+0x8e/0x90
[<ffffffff811b90ad>] truncate_inode_pages_range.part.12+0x14d/0x620
[<ffffffff81d6387d>] ? __mutex_lock_slowpath+0x1fd/0x2e0
[<ffffffff811b95d3>] truncate_inode_pages_range+0x53/0x70
[<ffffffff811b969d>] truncate_inode_pages+0x2d/0x40
[<ffffffff811b96ff>] truncate_pagecache+0x4f/0x70
[<ffffffff81356840>] nfs_setattr_update_inode+0xa0/0x120
[<ffffffff81368de4>] nfs3_proc_setattr+0xc4/0xe0
[<ffffffff81357f78>] nfs_setattr+0xc8/0x150
[<ffffffff8122d95b>] notify_change+0x1cb/0x390
[<ffffffff8120a55b>] do_truncate+0x7b/0xc0
[<ffffffff8121f96c>] do_last+0xa4c/0xfd0
[<ffffffff8121ffbc>] path_openat+0xcc/0x670
[<ffffffff81220a0e>] do_filp_open+0x4e/0xb0
[<ffffffff8120ba1f>] do_sys_open+0x13f/0x2b0
[<ffffffff8126aaf6>] compat_SyS_open+0x36/0x50
[<ffffffff81d7204c>] sysenter_dispatch+0x7/0x24
The code at the instruction pointer was disassembled:
> (gdb) disas __fscache_uncache_page
> Dump of assembler code for function __fscache_uncache_page:
> ...
> 0xffffffff812a18ff <+31>: mov 0x48(%rbx),%rax
> 0xffffffff812a1903 <+35>: cmpb $0x0,0x10(%rax)
> 0xffffffff812a1907 <+39>: je 0xffffffff812a19cd <__fscache_uncache_page+237>
These instructions make up:
ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
That cmpb is the faulting instruction (%rax is 0). So cookie->def is NULL -
which presumably means that the cookie has already been at least partway
through __fscache_relinquish_cookie().
What I think may be happening is something like a three-way race on the same
file:
PROCESS 1 PROCESS 2 PROCESS 3
=============== =============== ===============
open(O_TRUNC|O_WRONLY)
open(O_RDONLY)
open(O_WRONLY)
-->nfs_open()
-->nfs_fscache_set_inode_cookie()
nfs_fscache_inode_lock()
nfs_fscache_disable_inode_cookie()
__fscache_relinquish_cookie()
nfs_inode->fscache = NULL
<--nfs_fscache_set_inode_cookie()
-->nfs_open()
-->nfs_fscache_set_inode_cookie()
nfs_fscache_inode_lock()
nfs_fscache_enable_inode_cookie()
__fscache_acquire_cookie()
nfs_inode->fscache = cookie
<--nfs_fscache_set_inode_cookie()
<--nfs_open()
-->nfs_setattr()
...
...
-->nfs_invalidate_page()
-->__nfs_fscache_invalidate_page()
cookie = nfsi->fscache
-->nfs_open()
-->nfs_fscache_set_inode_cookie()
nfs_fscache_inode_lock()
nfs_fscache_disable_inode_cookie()
-->__fscache_relinquish_cookie()
-->__fscache_uncache_page(cookie)
<crash>
<--__fscache_relinquish_cookie()
nfs_inode->fscache = NULL
<--nfs_fscache_set_inode_cookie()
What is needed is something to prevent process #2 from reacquiring the cookie
- and I think checking i_writecount should do the trick.
It's also possible to have a two-way race on this if the file is opened
O_TRUNC|O_RDONLY instead.
Reported-by: Mark Moseley <moseleymark@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Determine if we've created a new file by examining the directory change
attribute and/or the O_EXCL flag.
This fixes a regression when doing a non-exclusive create of a new file.
If the FILE_CREATED flag is not set, the atomic_open() command will
perform full file access permissions checks instead of just checking
for MAY_OPEN.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This is to ensure that we don't clear the NFS_CONTEXT_RESEND_WRITES
flag while there are still writes that haven't been resent.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
