Prevent filesystem freezes while handling the write page fault.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

We want to ensure that we write the cached data to the server, but
don't require it be synced to disk. If the server reboots, we will
get a stateid error, which will cause us to retry anyway.
Signed-off-by: NTrond 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: NTrond Myklebust <trond.myklebust@primarydata.com>

When punching holes in a file, we want to ensure the operation is
serialised w.r.t. other writes, meaning that we want to call
nfs_sync_inode() while holding the inode lock.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

When retrieving stat() information, NFS unfortunately does require us to
sync writes to disk in order to ensure that mtime and ctime are up to
date. However we shouldn't have to ensure that those writes are persisted.

Relaxing that requirement does mean that we may see an mtime/ctime change
if the server reboots and forces us to replay all writes.

The exception to this rule are pNFS clients that are required to send
layoutcommit, however that is dealt with by the call to pnfs_sync_inode()
in _nfs_revalidate_inode().
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

A file that is open for O_DIRECT is by definition not obeying
close-to-open cache consistency semantics, so let's not cache
the attributes too aggressively either.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Clean up...
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

We're now waiting immediately after taking the locks, so waiting
in fsync() and write_begin() is either redundant or potentially
subject to livelock (if not holding the lock).
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

There is only one caller that sets the "write" argument to true,
so just move the call to nfs_zap_mapping() and get rid of the
now redundant argument.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Allow dio requests to be scheduled in parallel, but ensuring that they
do not conflict with buffered I/O.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Preparation for the patch that de-serialises O_DIRECT reads and
writes.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

On success, the RPC callbacks will ensure that we make the appropriate calls
to nfs_writeback_update_inode()
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

We should not be interested in looking at the value of the stable field,
since that could take any value.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Cleanup...
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If we need to update the cached attributes, then we'd better make
sure that we also layoutcommit first. Otherwise, the server may have stale
attributes.

Prior to this patch, the revalidation code tried to "fix" this problem by
simply disabling attributes that would be affected by the layoutcommit.
That approach breaks nfs_writeback_check_extend(), leading to a file size
corruption.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

So ensure that we mark the layout for commit once the write is done,
and then ensure that the commit to ds is finished before sending
layoutcommit.

Note that by doing this, we're able to optimise away the commit
for the case of servers that don't need layoutcommit in order to
return updated attributes.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Let's just have one place where we check ff_layout_need_layoutcommit().
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

We should always do a layoutcommit after commit to DS, except if
the layout segment we're using has set FF_FLAGS_NO_LAYOUTCOMMIT.

Fixes: d67ae825 ("pnfs/flexfiles: Add the FlexFile Layout Driver")
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

According to the errata
https://www.rfc-editor.org/errata_search.php?rfc=5661&eid=2751
we should always send layout commit after a commit to DS.

Fixes: bc7d4b8f ("nfs/filelayout: set layoutcommit...")
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

While COMMIT has the potential to free up a lot of memory that is being
taken by unstable writes, it isn't guaranteed to free up this particular
page. Also, calling fsync() on the server is expensive and so we want to
do it in a more controlled fashion, rather than have it triggered at
random by the VM.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Commits are no longer required to be serialised.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

It is almost always better to wait for more so that we can issue a
bulk commit.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

filemap_datawrite() and friends already deal just fine with livelock.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Unless the user is using file locking, we must assume close-to-open
cache consistency when the file is open for writing. Adjust the
caching algorithm so that it does not clear the cache on out-of-order
writes and/or attribute revalidations.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If an attribute revalidation fails, then we already know that we'll
zap the access cache. If, OTOH, the inode isn't changing, there should
be no need to eject access calls just because they are old.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If there were outstanding writes then chalk up the unexpected change
attribute on the server to them.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

This prevents users from triggering a stack overflow through a recursive
invocation of pagefault handling that involves mapping procfs files into
virtual memory.
Signed-off-by: NJann Horn <jannh@google.com>
Acked-by: NTyler Hicks <tyhicks@canonical.com>
Cc: stable@vger.kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This prevents stacking filesystems (ecryptfs and overlayfs) from using
procfs as lower filesystem.  There is too much magic going on inside
procfs, and there is no good reason to stack stuff on top of procfs.

(For example, procfs does access checks in VFS open handlers, and
ecryptfs by design calls open handlers from a kernel thread that doesn't
drop privileges or so.)
Signed-off-by: NJann Horn <jannh@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The offset in the core file used to be tracked with ->written field of
the coredump_params structure. The field was retired in favour of
file->f_pos.

However, ->f_pos is not maintained for pipes which leads to breakage.

Restore explicit tracking of the offset in coredump_params. Introduce
->pos field for this purpose since ->written was already reused.

Fixes: a0083939 ("get rid of coredump_params->written").
Reported-by: NZbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
Signed-off-by: NMateusz Guzik <mguzik@redhat.com>
Reviewed-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

open("/foo/no_such_file", O_RDONLY | O_CREAT) on should fail with
EACCES when /foo is not writable; failing with ENOENT is obviously
wrong.  That got broken by a braino introduced when moving the
creat_error logics from atomic_open() to lookup_open().  Easy to
fix, fortunately.
Spotted-by: N"Yan, Zheng" <ukernel@gmail.com>
Tested-by: N"Yan, Zheng" <ukernel@gmail.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Ascend-to-parent logics in d_walk() depends on all encountered child
dentries not getting freed without an RCU delay.  Unfortunately, in
quite a few cases it is not true, with hard-to-hit oopsable race as
the result.

Fortunately, the fix is simiple; right now the rule is "if it ever
been hashed, freeing must be delayed" and changing it to "if it
ever had a parent, freeing must be delayed" closes that hole and
covers all cases the old rule used to cover.  Moreover, pipes and
sockets remain _not_ covered, so we do not introduce RCU delay in
the cases which are the reason for having that delay conditional
in the first place.

Cc: stable@vger.kernel.org # v3.2+ (and watch out for __d_materialise_dentry())
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

MNT_LOCKED implies on a child mount implies the child is locked to the
parent.  So while looping through the children the children should be
tested (not their parent).

Typically an unshare of a mount namespace locks all mounts together
making both the parent and the slave as locked but there are a few
corner cases where other things work.

Cc: stable@vger.kernel.org
Fixes: ceeb0e5d ("vfs: Ignore unlocked mounts in fs_fully_visible")
Reported-by: NSeth Forshee <seth.forshee@canonical.com>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

Add this trivial missing error handling.

Cc: stable@vger.kernel.org
Fixes: 1b852bce ("mnt: Refactor the logic for mounting sysfs and proc in a user namespace")
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

In __test_eb_bitmaps(), we write random data to a bitmap. Then copy
the bitmap to another bitmap that resides inside an extent buffer.
Later we verify the values of corresponding bits in the bitmap and the
bitmap inside the extent buffer. However, extent_buffer_test_bit()
reads in byte granularity while test_bit() reads in unsigned long
granularity. Hence we end up comparing wrong bits on big-endian
systems such as ppc64. This commit fixes the issue by reading the
bitmap in byte granularity.
Reviewed-by: NJosef Bacik <jbacik@fb.com>
Reviewed-by: NChandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: NFeifei Xu <xufeifei@linux.vnet.ibm.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

With 64K sectorsize, 1G sized block group cannot span across bitmaps.
To execute test_bitmaps() function, this commit allocates
"BITS_PER_BITMAP * sectorsize + PAGE_SIZE" sized block group.
Reviewed-by: NJosef Bacik <jbacik@fb.com>
Reviewed-by: NChandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: NFeifei Xu <xufeifei@linux.vnet.ibm.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This commit replaces numerical constants with appropriate
preprocessor macros.
Reviewed-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: NFeifei Xu <xufeifei@linux.vnet.ibm.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

To test all possible sectorsizes, this commit adds a sectorsize
array. This commit executes the tests for all possible sectorsizes and
nodesizes.
Reviewed-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: NFeifei Xu <xufeifei@linux.vnet.ibm.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

On ppc64, PAGE_SIZE is 64k which is same as BTRFS_MAX_METADATA_BLOCKSIZE.
In such a scenario, we will never be able to have an extent buffer
containing more than one page. Hence in such cases this commit does not
execute the page straddling tests.
Reviewed-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NFeifei Xu <xufeifei@linux.vnet.ibm.com>
Signed-off-by: NChandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>