linux-toradex.git/include/linux/exportfs.h, branch v6.6-rc5

exportfs: add explicit flag to request non-decodeable file handles

2023-05-22T16:08:37+00:00

So far, all callers of exportfs_encode_inode_fh(), except for fsnotify's
show_mark_fhandle(), check that filesystem can decode file handles, but
we would like to add more callers that do not require a file handle that
can be decoded.

Introduce a flag to explicitly request a file handle that may not to be
decoded later and a wrapper exportfs_encode_fid() that sets this flag
and convert show_mark_fhandle() to use the new wrapper.

This will be used to allow adding fanotify support to filesystems that
do not support NFS export.

Acked-by: Jeff Layton 
Acked-by: Chuck Lever 
Signed-off-by: Amir Goldstein 
Signed-off-by: Jan Kara 
Message-Id: <20230502124817.3070545-3-amir73il@gmail.com>

exportfs: change connectable argument to bit flags

2023-05-22T16:08:37+00:00

Convert the bool connectable arguemnt into a bit flags argument and
define the EXPORT_FS_CONNECTABLE flag as a requested property of the
file handle.

We are going to add a flag for requesting non-decodeable file handles.

Acked-by: Jeff Layton 
Acked-by: Chuck Lever 
Signed-off-by: Amir Goldstein 
Signed-off-by: Jan Kara 
Message-Id: <20230502124817.3070545-2-amir73il@gmail.com>

nfsd: allow reaping files still under writeback

2023-04-26T13:04:59+00:00

On most filesystems, there is no reason to delay reaping an nfsd_file
just because its underlying inode is still under writeback. nfsd just
relies on client activity or the local flusher threads to do writeback.

The main exception is NFS, which flushes all of its dirty data on last
close. Add a new EXPORT_OP_FLUSH_ON_CLOSE flag to allow filesystems to
signal that they do this, and only skip closing files under writeback on
such filesystems.

Also, remove a redundant NULL file pointer check in
nfsd_file_check_writeback, and clean up nfs's export op flag
definitions.

Signed-off-by: Jeff Layton 
Acked-by: Anna Schumaker 
Signed-off-by: Chuck Lever

Merge tag 'flex-array-transformations-6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux

2023-02-25T20:53:42+00:00

Pull flexible-array updates from Gustavo Silva:
 "Transform zero-length arrays, in unions, into flexible arrays"

* tag 'flex-array-transformations-6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux:
  bcache: Replace zero-length arrays with DECLARE_FLEX_ARRAY() helper
  mm/memremap: Replace zero-length array with DECLARE_FLEX_ARRAY() helper
  exportfs: Replace zero-length array with DECLARE_FLEX_ARRAY() helper

nfsd: remove fetch_iversion export operation

2023-01-26T12:00:06+00:00

Now that the i_version counter is reported in struct kstat, there is no
need for this export operation.

Acked-by: Chuck Lever 
Reviewed-by: NeilBrown 
Signed-off-by: Jeff Layton

exportfs: Replace zero-length array with DECLARE_FLEX_ARRAY() helper

2023-01-05T22:15:18+00:00

Zero-length arrays are deprecated and we are moving towards adopting
C99 flexible-array members instead. So, replace zero-length array
declaration in struct fid with the new DECLARE_FLEX_ARRAY()
helper macro.

This helper allows for a flexible-array member in a union.

Link: https://github.com/KSPP/linux/issues/21
Link: https://github.com/KSPP/linux/issues/193
Link: https://github.com/KSPP/linux/issues/197
Link: https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
Reviewed-by: Kees Cook 
Signed-off-by: Gustavo A. R. Silva

nfs: block notification on fs with its own ->lock

2022-01-08T19:42:01+00:00

NFSv4.1 supports an optional lock notification feature which notifies
the client when a lock comes available.  (Normally NFSv4 clients just
poll for locks if necessary.)  To make that work, we need to request a
blocking lock from the filesystem.

We turned that off for NFS in commit f657f8eef3ff ("nfs: don't atempt
blocking locks on nfs reexports") [sic] because it actually blocks the
nfsd thread while waiting for the lock.

Thanks to Vasily Averin for pointing out that NFS isn't the only
filesystem with that problem.

Any filesystem that leaves ->lock NULL will use posix_lock_file(), which
does the right thing.  Simplest is just to assume that any filesystem
that defines its own ->lock is not safe to request a blocking lock from.

So, this patch mostly reverts commit f657f8eef3ff ("nfs: don't atempt
blocking locks on nfs reexports") [sic] and commit b840be2f00c0 ("lockd:
don't attempt blocking locks on nfs reexports"), and instead uses a
check of ->lock (Vasily's suggestion) to decide whether to support
blocking lock notifications on a given filesystem.  Also add a little
documentation.

Perhaps someday we could add back an export flag later to allow
filesystems with "good" ->lock methods to support blocking lock
notifications.

Reported-by: Vasily Averin 
Signed-off-by: J. Bruce Fields 
[ cel: Description rewritten to address checkpatch nits ]
[ cel: Fixed warning when SUNRPC debugging is disabled ]
[ cel: Fixed NULL check ]
Signed-off-by: Chuck Lever 
Reviewed-by: Vasily Averin

nfs: don't atempt blocking locks on nfs reexports

2021-08-26T19:32:10+00:00

NFS implements blocking locks by blocking inside its lock method.  In
the reexport case, this blocks the nfs server thread, which could lead
to deadlocks since an nfs server thread might be required to unlock the
conflicting lock.  It also causes a crash, since the nfs server thread
assumes it can free the lock when its lm_notify lock callback is called.

Ideal would be to make the nfs lock method return without blocking in
this case, but for now it works just not to attempt blocking locks.  The
difference is just that the original client will have to poll (as it
does in the v4.0 case) instead of getting a callback when the lock's
available.

Signed-off-by: J. Bruce Fields 
Acked-by: Anna Schumaker 
Signed-off-by: Chuck Lever

nfs: use change attribute for NFS re-exports

2021-01-30T16:47:12+00:00

When exporting NFS, we may as well use the real change attribute
returned by the original server instead of faking up a change attribute
from the ctime.

Note we can't do that by setting I_VERSION--that would also turn on the
logic in iversion.h which treats the lower bit specially, and that
doesn't make sense for NFS.

So instead we define a new export operation for filesystems like NFS
that want to manage the change attribute themselves.

Signed-off-by: J. Bruce Fields 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Chuck Lever

nfsd: Record NFSv4 pre/post-op attributes as non-atomic

2020-12-09T14:39:38+00:00

For the case of NFSv4, specify to the client that the pre/post-op
attributes were not recorded atomically with the main operation.

Signed-off-by: Trond Myklebust 
Signed-off-by: Chuck Lever