The current code in pnfs_destroy_all_layouts() assumes that removing
the layout from the server->layouts list is sufficient to make it
invisible to other processes. This ignores the fact that most
users access the layout through the nfs_inode->layout...
There is further breakage due to lack of reference counting of the
layouts, meaning that the whole thing Oopses at the drop of a hat.

The code in initiate_bulk_draining() is almost correct, and can be
used as a model for pnfs_destroy_all_layouts(), so move that
code to pnfs.c, and refactor the code to allow us to choose between
a single filesystem bulk recall, and a recall of all layouts.
Also note that initiate_bulk_draining() currently calls iput() while
holding locks. Fix that too.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

The layout will be set unusable if LAYOUTGET fails. Is it reasonable to
increase the refcount iff LAYOUTGET fails the first time?
Signed-off-by: NYanchuan Nian <ycnian@gmail.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org [>= 3.7]

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The new layout pointer in pnfs_find_alloc_layout() may be NULL because of
out of memory. we must do some check work, otherwise pnfs_free_layout_hdr()
will go wrong because it can not deal with a NULL pointer.
Signed-off-by: NYanchuan Nian <ycnian@gmail.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

For buffer read, use offst-to-isize.

For direct read, use dreq->bytes_left.
Signed-off-by: NPeng Tao <tao.peng@emc.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

For buffer write, block layout client scan inode mapping to find
next hole and use offset-to-hole as layoutget length. Object
layout client uses offset-to-isize as layoutget length.

For direct write, both block layout and object layout use dreq->bytes_left.
Signed-off-by: NPeng Tao <tao.peng@emc.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Split it into two functions, one which checks if layoutgets are blocked,
and one which checks if the layout stateid has expired.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Clamp the layout barrier sequence id to the current sequence id
minus the maximum number of outstanding layoutget requests.

Also ensure that we correctly initialise lo->plh_barrier if there are
no layout segments associated to this layout header.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

...and fix a bug in pnfs_set_layout_stateid.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

...and add a helper function.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If the list of layout segments is empty, we must unconditionally set
the layout stateid.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Failure of the layoutreturn allocation fails is not a good reason to
mark the pnfs_layout_hdr as having failed a layoutget or i/o. Just
exit cleanly.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

It serves no purpose that the test for whether or not we have valid
layout segments doesn't already serve.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Once all the affected layout segments have been freed up, clear the
NFS_LAYOUT_BULK_RECALL flag so that we can reuse the pnfs_layout_hdr
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We already have a mechanism for blocking LAYOUTGET by means of the
plh_block_lgets counter. The only "service" that NFS_LAYOUT_DESTROYED
provides at this point is to block layoutget once the layout segment
list is empty, which basically means that you have to wait until
the pnfs_layout_hdr is destroyed before you can do pNFS on that file
again.

This patch enables the reuse of the pnfs_layout_hdr if the layout
segment list is empty.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

...and ditto for pnfs_free_layout_hdr()
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

These are all in static declared functions that are called only once.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Ensure that the reference count for pnfs_layout_hdr reverts to the
original value after a call to pnfs_layout_remove_lseg().

Note that the caller is expected to hold a reference to the struct
pnfs_layout_hdr.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

There is no longer a need to use pnfs_free_lseg_list(). Just call
pnfs_free_lseg() directly.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Move the code into pnfs_free_layout_hdr(), and add checks to
get_layout_by_fh_locked to ensure that they don't reference a layout
that is being freed.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

None of the existing pNFS layout drivers seem to require the inode
to be locked while they free the layout header.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Each layout segment already holds a reference to the pnfs_layout_hdr,
so there is no need to hold an extra reference that is released once
the last layout segment is freed.

Ensure that pnfs_find_alloc_layout() always returns a reference
to the pnfs_layout_hdr, which will be matched by the final call to
pnfs_put_layout_hdr() in pnfs_update_layout().
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The latter name is more descriptive of the actual function.
Also rename pnfs_insert_layout to pnfs_layout_insert_lseg.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Instead of resetting the inode MDS threshold counters when we mark
the layout for destruction, do it as part of freeing the layout.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If we sleep after dropping the inode->i_lock, then we are no longer
atomic with respect to the rpc_wake_up() call in pnfs_layout_remove_lseg().
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If pnfs_layout_io_test_failed() authorises a retry of the failed layoutgets,
we should clear the existing layout segments so that we start afresh. Do
this in pnfs_layout_io_set_failed().
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We want to cache the pnfs_layout_hdr after a layoutget or i/o
failure so that pnfs_update_layout() can find it and know when
it is time to retry.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If we exit after the call to pnfs_find_alloc_layout(), we have to ensure
that we put the struct pnfs_layout_hdr.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If we had to fall back to read/write through MDS, then assume that we should
retry pNFS after a suitable timeout period.
The following patch sets a timeout of 2 minutes.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

...and make them local to the pnfs.c file.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Dereferencing nfsi->layout in order to read plh_flags without holding
a spin lock is bug prone. Furthermore, the dprintk() tells you nothing
about whether or not the call succeeded.
Replace it with something that tells you about whether or not a valid
layout segment was returned for the inode in question.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Ensure that we do return errors from nfs4_proc_layoutget() and that we
don't mark the layout as having failed if the error was due to a
signal or resource problem on the client side.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

we have encountered a bug whereby reading a lot of files (copying
fedora's /bin) from a pNFS mount and hitting Ctrl+C in the middle caused
a general protection fault in xdr_shrink_bufhead. this function is
called when decoding the response from LAYOUTGET. the decoding is done
by a worker thread, and the caller of LAYOUTGET waits for the worker
thread to complete.

hitting Ctrl+C caused the synchronous wait to end and the next thing the
caller does is to free the pages, so when the worker thread calls
xdr_shrink_bufhead, the pages are gone. therefore, the cleanup of these
pages has been moved to nfs4_layoutget_release.
Signed-off-by: NIdan Kedar <idank@tonian.com>
Signed-off-by: NBenny Halevy <bhalevy@tonian.com>
Cc: stable@vger.kernel.org
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This patch exports symbols needed by the v4 module.  In addition, I also
switch over to using IS_ENABLED() to check if CONFIG_NFS_V4 or
CONFIG_NFS_V4_MODULE are set.

The module (nfs4.ko) will be created in the same directory as nfs.ko and
will be automatically loaded the first time you try to mount over NFS v4.
Signed-off-by: NBryan Schumaker <bjschuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>