Function rename to ensure that the functionality of nfs_unlock_request()
mirrors that of nfs_lock_request(). Then let nfs_unlock_and_release_request()
do the work of what used to be called nfs_unlock_request()...
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Fred Isaman <iisaman@netapp.com>
We only have two places where we need to grab a reference when trying
to lock the nfs_page. We're better off making that explicit.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Fred Isaman <iisaman@netapp.com>
We have to unlock the nfs_page before we call nfs_end_page_writeback
to avoid races with functions that expect the page to be unlocked
when PG_locked and PG_writeback are not set.
The problem is that nfs_unlock_request also releases the nfs_page,
causing a deadlock if the release of the nfs_open_context
triggers an iput() while the PG_writeback flag is still set...
The solution is to separate the unlocking and release of the nfs_page,
so that we can do the former before nfs_end_page_writeback and the
latter after.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Fred Isaman <iisaman@netapp.com>
Factors out the code that will need to change when directio
starts using these code paths. This will allow directio to use
the generic pagein and flush routines
Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Decouple nfs_pgio_header and nfs_read_data, and have (possibly
multiple) nfs_read_datas each take a refcount on nfs_pgio_header.
For the moment keeps nfs_read_header as a way to preallocate a single
nfs_read_data with the nfs_pgio_header. The code doesn't need this,
and would be prettier without, but given the amount of churn I am
already introducing I didn't want to play with tuning new mempools.
This also fixes bug in pnfs_ld_handle_read_error. In the case of
desc->pg_bsize < PAGE_CACHE_SIZE, the pages list was empty, causing
replay attempt to do nothing.
Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Move more pnfs-isms out of the generic commit code.
Bugfixes:
- filelayout_scan_commit_lists doesn't need to get/put the lseg.
In fact since it is run under the inode->i_lock, the lseg_put()
can deadlock.
- Ensure that we distinguish between what needs to be done for
commit-to-data server and what needs to be done for commit-to-MDS
using the new flag PG_COMMIT_TO_DS. Otherwise we may end up calling
put_lseg() on a bucket for a struct nfs_page that got written
through the MDS.
- Fix a case where we were using list_del() on an nfs_page->wb_list
instead of list_del_init().
- filelayout_initiate_commit needs to call filelayout_commit_release
on error instead of the mds_ops->rpc_release(). Otherwise it won't
clear the commit lock.
Cleanups:
- Let the files layout manage the commit lists for the pNFS case.
Don't expose stuff like pnfs_choose_commit_list, and the fact
that the commit buckets hold references to the layout segment
in common code.
- Cast out the put_lseg() calls for the struct nfs_read/write_data->lseg
into the pNFS layer from whence they came.
- Let the pNFS layer manage the NFS_INO_PNFS_COMMIT bit.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Fred Isaman <iisaman@netapp.com>
The radix tree is only being used to compile lists of reqs needing commit.
It is simpler to just put the reqs directly into a list.
Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Don't rely on the PageError flag to tell us if one of the partial reads of
the page failed. Instead, replace that with a dedicated flag in the
struct nfs_page.
Then clean out redundant uses of the PageError flag: the VM no longer
checks it for reads.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
...and ensure that we recoalese to take into account differences in
differences in block sizes when falling back to write through the MDS.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
...and ensure that we recoalese to take into account differences in
block sizes when falling back to read through the MDS.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If an attempt to do pNFS fails, and we have to fall back to writing through
the MDS, then we may want to re-coalesce the requests that we already have
since the block size for the MDS read/writes may be different to that of
the DS read/writes.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
We need to ensure that the layouts are set up before we can decide to
coalesce requests. To do so, we want to further split up the struct
nfs_pageio_descriptor operations into an initialisation callback, a
coalescing test callback, and a 'do i/o' callback.
This patch cleans up the existing callback methods before adding the
'initialisation' callback.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Otherwise we end up overflowing the rpc buffer size on the receive end.
Signed-off-by: Benny Halevy <benny@tonian.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Now that the inode scalability patches have been merged, it is no longer
safe to call igrab() under the inode->i_lock.
Now that we no longer call nfs_clear_request() until the nfs_page is
being freed, we know that we are always holding a reference to the
nfs_open_context, which again holds a reference to the path, and so
the inode cannot be freed until the last nfs_page has been removed
from the radix tree and freed.
We can therefore skip the igrab()/iput() altogether.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
We create three major hooks for the pnfs code.
pnfs_mark_request_commit() is called during writeback_done from
nfs_mark_request_commit, which gives the driver an opportunity to
claim it wants control over commiting a particular req.
pnfs_choose_commit_list() is called from nfs_scan_list
to choose which list a given req should be added to, based on
where we intend to send it for COMMIT. It is up to the driver
to have preallocated list headers for each destination it may need.
pnfs_commit_list() is how the driver actually takes control, it is
used instead of nfs_commit_list().
In order to pass information between the above functions, we create
a union in nfs_page to hold a lseg (which is possible because the req is
not on any list while in transition), and add some flags to indicate
if we need to use the pnfs code.
Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If we're only doing a single write, and there are no other unstable
writes being queued up, we might want to just flip to using a stable
write RPC call.
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This will make it possible to clear the lseg pointer in the same
function as it is put, instead of in the caller nfs_pageio_doio().
Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
