sparse says:

    fs/ufs/inode.c:1195:6: warning: symbol 'ufs_truncate_blocks' was not declared. Should it be static?

Note that the forward declaration in the file is already marked static.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

If you have a process that has set itself to be non-dumpable, and it
then undergoes exec(2), any CLOEXEC file descriptors it has open are
"exposed" during a race window between the dumpable flags of the process
being reset for exec(2) and CLOEXEC being applied to the file
descriptors. This can be exploited by a process by attempting to access
/proc/<pid>/fd/... during this window, without requiring CAP_SYS_PTRACE.

The race in question is after set_dumpable has been (for get_link,
though the trace is basically the same for readlink):

[vfs]
-> proc_pid_link_inode_operations.get_link
   -> proc_pid_get_link
      -> proc_fd_access_allowed
         -> ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);

Which will return 0, during the race window and CLOEXEC file descriptors
will still be open during this window because do_close_on_exec has not
been called yet. As a result, the ordering of these calls should be
reversed to avoid this race window.

This is of particular concern to container runtimes, where joining a
PID namespace with file descriptors referring to the host filesystem
can result in security issues (since PRCTL_SET_DUMPABLE doesn't protect
against access of CLOEXEC file descriptors -- file descriptors which may
reference filesystem objects the container shouldn't have access to).

Cc: dev@opencontainers.org
Cc: <stable@vger.kernel.org> # v3.2+
Reported-by: NMichael Crosby <crosbymichael@gmail.com>
Signed-off-by: NAleksa Sarai <asarai@suse.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

If kernfs file is empty on a first read, successive read operations
using the same file descriptor will return no data, even when data is
available. Default kernfs 'seq_next' implementation advances iterator
position even when next object is not there. Kernfs 'seq_start' for
following requests will not return iterator as position is already on
the second object.

This defect doesn't allow to monitor badblocks sysfs files from MD raid.
They are initially empty but if data appears at some stage, userspace is
not able to read it.
Signed-off-by: NTomasz Majchrzak <tomasz.majchrzak@intel.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Strengthen the checking of pos/len vs. i_size, clarify the return values
for the clone prep function, and remove pointless code.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... and fix the minor buglet in compat io_submit() - native one
kills ioctx as cleanup when put_user() fails.  Get rid of
bogus compat_... in !CONFIG_AIO case, while we are at it - they
should simply fail with ENOSYS, same as for native counterparts.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Implement mandatory export_operations, so it is possible to export befs via
nfs.
Signed-off-by: NLuis de Bethencourt <luisbg@osg.samsung.com>

Removing all trailing whitespaces in befs.

I was skeptic about tainting the history with this, but whitespace changes
can be ignored by using 'git blame -w' and 'git log -w'.
Signed-off-by: NLuis de Bethencourt <luisbg@osg.samsung.com>

No idea why some comments have signatures. These predate git. Removing them
since they add noise and no information.
Signed-off-by: NLuis de Bethencourt <luisbg@osg.samsung.com>

Fixing checkpatch.pl issues in befs header files:
WARNING: Missing a blank line after declarations
+       befs_inode_addr iaddr;
+       iaddr.allocation_group = blockno >> BEFS_SB(sb)->ag_shift;

WARNING: space prohibited between function name and open parenthesis '('
+       return BEFS_SB(sb)->block_size / sizeof (befs_disk_inode_addr);

ERROR: "foo * bar" should be "foo *bar"
+                   const char *key, befs_off_t * value);

ERROR: Macros with complex values should be enclosed in parentheses
+#define PACKED __attribute__ ((__packed__))
Signed-off-by: NLuis de Bethencourt <luisbg@osg.samsung.com>

Fix the following type of checkpatch.pl issues:
WARNING: line over 80 characters
+static struct dentry *befs_lookup(struct inode *, struct dentry *, unsigned int);

ERROR: code indent should use tabs where possible
+        if (!bi)$

WARNING: please, no spaces at the start of a line
+        if (!bi)$

WARNING: labels should not be indented
+      unacquire_bh:

WARNING: space prohibited between function name and open parenthesis '('
+                                             sizeof (struct befs_inode_info),

WARNING: braces {} are not necessary for single statement blocks
+       if (!*out) {
+               return -ENOMEM;
+       }

WARNING: Block comments use a trailing */ on a separate line
+        * in special cases */

WARNING: Missing a blank line after declarations
+               int token;
+               if (!*p)

ERROR: do not use assignment in if condition
+       if (!(bh = sb_bread(sb, sb_block))) {

ERROR: space prohibited after that open parenthesis '('
+       if( befs_sb->num_blocks > ~((sector_t)0) ) {

ERROR: space prohibited before that close parenthesis ')'
+       if( befs_sb->num_blocks > ~((sector_t)0) ) {

ERROR: space required before the open parenthesis '('
+       if( befs_sb->num_blocks > ~((sector_t)0) ) {
Signed-off-by: NLuis de Bethencourt <luisbg@osg.samsung.com>

Signed-off-by: NLuis de Bethencourt <luisbg@osg.samsung.com>

Fixing the two following checkpatch.pl issues:
ERROR: trailing whitespace
+ * Based on portions of file.c and inode.c $

WARNING: labels should not be indented
+      error:
Signed-off-by: NLuis de Bethencourt <luisbg@osg.samsung.com>

Fixing the following checkpatch.pl errors and warning:
ERROR: trailing whitespace
+ * $

WARNING: Block comments use * on subsequent lines
+/*
+       Validates the correctness of the befs inode

ERROR: "foo * bar" should be "foo *bar"
+befs_check_inode(struct super_block *sb, befs_inode * raw_inode,
Signed-off-by: NLuis de Bethencourt <luisbg@osg.samsung.com>

Fix all checkpatch.pl errors and warnings in debug.c:
ERROR: trailing whitespace
+ * $

WARNING: Missing a blank line after declarations
+       va_list args;
+       va_start(args, fmt);

ERROR: "foo * bar" should be "foo *bar"
+befs_dump_inode(const struct super_block *sb, befs_inode * inode)

ERROR: "foo * bar" should be "foo *bar"
+befs_dump_super_block(const struct super_block *sb, befs_super_block * sup)

ERROR: "foo * bar" should be "foo *bar"
+befs_dump_small_data(const struct super_block *sb, befs_small_data * sd)

WARNING: line over 80 characters
+befs_dump_index_entry(const struct super_block *sb, befs_disk_btree_super * super)

ERROR: "foo * bar" should be "foo *bar"
+befs_dump_index_entry(const struct super_block *sb, befs_disk_btree_super * super)

ERROR: "foo * bar" should be "foo *bar"
+befs_dump_index_node(const struct super_block *sb, befs_btree_nodehead * node)
Signed-off-by: NLuis de Bethencourt <luisbg@osg.samsung.com>

Commit 8924feff ("splice: lift pipe_lock out of splice_to_pipe()")
caused a regression when there were no more readers left on a pipe that
was being spliced into: rather than the expected SIGPIPE and -EPIPE
return value, the writer would end up waiting forever for space to free
up (which obviously was not going to happen with no readers around).

Fixes: 8924feff ("splice: lift pipe_lock out of splice_to_pipe()")
Reported-and-tested-by: NAndreas Schwab <schwab@linux-m68k.org>
Debugged-by: NAl Viro <viro@zeniv.linux.org.uk>
Cc: stable@kernel.org   # v4.9
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If our DELEGRETURN RPC call is rejected with an EACCES call, then we should
remove the GETATTR call from the compound RPC and retry.
This could potentially happen when there is a conflict between an
ACL denying attribute reads and our use of SP4_MACH_CRED.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If our CLOSE RPC call is rejected with an EACCES call, then we should
remove the GETATTR call from the compound RPC and retry.
This could potentially happen when there is a conflict between an
ACL denying attribute reads and our use of SP4_MACH_CRED.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

In order to benefit from the DENY share lock protection, we should
put the GETATTR operation before the CLOSE. Otherwise, we might race
with a Windows machine that thinks it is now safe to modify the file.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If we're downgrading from a READ+WRITE mode to a READ-only mode, then
ask for cache consistency attributes so that we avoid the revalidation
in nfs_close_context()

Fixes: 3947b74d ("NFSv4: Don't request a GETATTR on open_downgrade.")
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The NFS_INO_REVAL_FORCED flag now really only has meaning for the
case when we've just been handed a delegation for a file that was already
cached, and we're unsure about that cache.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If the client holds no more writeable open state, and does not hold a
write delegation, then send a layoutreturn as part of the OPEN_DOWNGRADE.

We do this only for writes, since some layout drivers may require you to
also hold a read layout if you are doing a R/W workload.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

While we do not need to return the RW layout when downgrading from a
read/write open state to read-only, we might want to do so in order
to reduce the burden on the metadataserver so that it does not need
to check for changed data when responding to GETATTR requests.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

When an NFS4ERR_BAD_SEQID is received the open-owner is removed from
the ->state_owners rbtree so that it will no longer be used.

If any stateids attached to this open-owner are still in use, and if a
request using one gets an NFS4ERR_BAD_STATEID reply, this can for bad.

The state is marked as needing recovery and the nfs4_state_manager()
is scheduled to clean up.  nfs4_state_manager() finds states to be
recovered by walking the state_owners rbtree.  As the open-owner is
not in the rbtree, the bad state is not found so nfs4_state_manager()
completes having done nothing.  The request is then retried, with a
predicatable result (indefinite retries).

If the stateid is for a delegation, this open_owner will be used
to open files when the delegation is returned.  For that to work,
a new open-owner needs to be presented to the server.

This patch changes NFS4ERR_BAD_SEQID handling to leave the open-owner
in the rbtree but updates the 'create_time' so it looks like a new
open-owner.  With this the indefinite retries no longer happen.
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If a file has both flock locks and OFD locks, then it is possible that
two different nfs4 lock states could apply to file accesses from a
single process.

It is not possible to know, efficiently, which one is "correct".
Presumably the state which represents a lock that covers the region
undergoing IO would be the "correct" one to use, but finding that has
a non-trivial cost and would provide miniscule value.

Currently we just return whichever is first in the list, which could
result in inconsistent behaviour if an application ever put it self in
this position.  As consistent behaviour is preferable (when perfectly
correct behaviour is not available), change the search to return a
consistent result in this circumstance.
Specifically: if there is both a flock and OFD lock state, always return
the flock one.
Reviewed-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Various places assume that if nfs4_fl_prepare_ds() turns a non-NULL 'ds',
then ds->ds_clp will also be non-NULL.

This is not necessasrily true in the case when the process received a fatal signal
while nfs4_pnfs_ds_connect is waiting in nfs4_wait_ds_connect().
In that case ->ds_clp may not be set, and the devid may not recently have been marked
unavailable.

So add a test for ds_clp == NULL and return NULL in that case.

Fixes: c23266d5 ("NFS4.1 Fix data server connection race")
Signed-off-by: NNeilBrown <neilb@suse.com>
Acked-by: NOlga Kornievskaia <aglo@umich.edu>
Acked-by: NAdamson, Andy <William.Adamson@netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Instead of marking a device inactive, remove it from the cache entirely.

Flexfiles has a way to report errors back to the server, so we don't want
to stop devices from being tried again for 120 seconds.
Signed-off-by: NWeston Andros Adamson <dros@primarydata.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

It can be made static.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

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

The access cache needs to check whether or not the mode bits, ownership,
or ACL has changed or the cache has timed out.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Just like in nfs_check_verifier(), we want to use
nfs_mapping_need_revalidate_inode() to check our knowledge of the
change attribute is up to date.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Consolidate the open-coded checking of NFS_I(inode)->cache_validity
into a couple of helper functions.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If we're holding a delegation, we can skip sending the close-to-open
GETATTR until we're returning that delegation.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

DELEGRETURN will always carry a reference to the inode except when
the latter is being freed, so let's ensure that we always use that
inode information to ensure close-to-open cache consistency, even
when the DELEGRETURN call is asynchronous.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If we successfully updated the change attribute, we should timestamp the
cache. While we do know that the other attributes are not completely up
to date, we have the NFS_INO_INVALID_ATTR flag that let us know that,
so it is valid to say that the cache has not timed out.
We can also clear NFS_INO_REVAL_PAGECACHE, since our change attribute
is now known to be valid.

Conversely, if the change attribute did not match, we should make sure to
also revalidate the access and ACL caches.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

dquot_disable() was warning when sb_has_quota_loaded() was true when
invalidating page cache for quota files. The thinking behind this
warning was that we must have raced with somebody else turning quotas on
and this should not happen because all places modifying quota state must
hold s_umount exclusively now. However sb_has_quota_loaded() can be also
true at this point when we are just suspending quotas on remount
read-only. Just restore the behavior to situation before commit
c3b00446 ("quota: Remove dqonoff_mutex") which introduced the
warning.

The code in dquot_disable() can be further simplified with the new
locking of quota state changes however let's leave that to a separate
commit that can get more testing exposure.

Fixes: c3b00446Signed-off-by: NJan Kara <jack@suse.cz>

Make sure that clone_mnt() never returns a mount with MNT_SHARED in
flags, but without a valid ->mnt_group_id.  That allows to demystify
do_make_slave() quite a bit, among other things.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

not for CL_PRIVATE clone_mnt()
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Hadn't been true for quite a while
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

If kcalloc() failed, the return value of ovl_fill_super() is -EINVAL,
not -ENOMEM. So this patch sets this value to -ENOMEM before calling
kcalloc(), and sets it back to -EINVAL after calling kcalloc().
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

FWIW, there's a bit of abuse of struct kstat in overlayfs object
creation paths - for one thing, it ends up with a very small subset
of struct kstat (mode + rdev), for another it also needs link in
case of symlinks and ends up passing it separately.

IMO it would be better to introduce a separate object for that.

In principle, we might even lift that thing into general API and switch
 ->mkdir()/->mknod()/->symlink() to identical calling conventions.  Hell
knows, perhaps ->create() as well...
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>