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NFSv4.1: Clean ups and bugfixes for the pNFS read/writeback/commit code

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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>
This commit is contained in:
Trond Myklebust
2012-03-15 17:16:40 -04:00
parent 95a13f7b33
commit 8dd3775889
7 changed files with 184 additions and 98 deletions
Download Patch File Download Diff File Expand all files Collapse all files

82
fs/nfs/nfs4filelayout.c
View File

@@ -224,6 +224,7 @@ static void filelayout_read_release(void *data)
{
struct nfs_read_data *rdata = (struct nfs_read_data *)data;
put_lseg(rdata->lseg);
rdata->mds_ops->rpc_release(data);
}
@@ -310,6 +311,7 @@ static void filelayout_write_release(void *data)
{
struct nfs_write_data *wdata = (struct nfs_write_data *)data;
put_lseg(wdata->lseg);
wdata->mds_ops->rpc_release(data);
}
@@ -320,6 +322,7 @@ static void filelayout_commit_release(void *data)
nfs_commit_release_pages(wdata);
if (atomic_dec_and_test(&NFS_I(wdata->inode)->commits_outstanding))
nfs_commit_clear_lock(NFS_I(wdata->inode));
put_lseg(wdata->lseg);
nfs_commitdata_release(wdata);
}
@@ -779,11 +782,16 @@ static u32 select_bucket_index(struct nfs4_filelayout_segment *fl, u32 j)
/* The generic layer is about to remove the req from the commit list.
* If this will make the bucket empty, it will need to put the lseg reference.
* Note inode lock is held, so we can't do the put here.
*/
static struct pnfs_layout_segment *
filelayout_remove_commit_req(struct nfs_page *req)
static void
filelayout_clear_request_commit(struct nfs_page *req)
{
struct pnfs_layout_segment *freeme = NULL;
struct inode *inode = req->wb_context->dentry->d_inode;
spin_lock(&inode->i_lock);
if (!test_and_clear_bit(PG_COMMIT_TO_DS, &req->wb_flags))
goto out;
if (list_is_singular(&req->wb_list)) {
struct inode *inode = req->wb_context->dentry->d_inode;
struct pnfs_layout_segment *lseg;
@@ -792,11 +800,16 @@ filelayout_remove_commit_req(struct nfs_page *req)
* since there is only one relevant lseg...
*/
list_for_each_entry(lseg, &NFS_I(inode)->layout->plh_segs, pls_list) {
if (lseg->pls_range.iomode == IOMODE_RW)
return lseg;
if (lseg->pls_range.iomode == IOMODE_RW) {
freeme = lseg;
break;
}
}
}
return NULL;
out:
nfs_request_remove_commit_list(req);
spin_unlock(&inode->i_lock);
put_lseg(freeme);
}
static struct list_head *
@@ -829,9 +842,20 @@ filelayout_choose_commit_list(struct nfs_page *req,
*/
get_lseg(lseg);
}
set_bit(PG_COMMIT_TO_DS, &req->wb_flags);
return list;
}
static void
filelayout_mark_request_commit(struct nfs_page *req,
struct pnfs_layout_segment *lseg)
{
struct list_head *list;
list = filelayout_choose_commit_list(req, lseg);
nfs_request_add_commit_list(req, list);
}
static u32 calc_ds_index_from_commit(struct pnfs_layout_segment *lseg, u32 i)
{
struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);
@@ -872,7 +896,7 @@ static int filelayout_initiate_commit(struct nfs_write_data *data, int how)
set_bit(lo_fail_bit(IOMODE_RW), &lseg->pls_layout->plh_flags);
set_bit(lo_fail_bit(IOMODE_READ), &lseg->pls_layout->plh_flags);
prepare_to_resend_writes(data);
data->mds_ops->rpc_release(data);
filelayout_commit_release(data);
return -EAGAIN;
}
dprintk("%s ino %lu, how %d\n", __func__, data->inode->i_ino, how);
@@ -895,7 +919,7 @@ find_only_write_lseg_locked(struct inode *inode)
list_for_each_entry(lseg, &NFS_I(inode)->layout->plh_segs, pls_list)
if (lseg->pls_range.iomode == IOMODE_RW)
return get_lseg(lseg);
return lseg;
return NULL;
}
@@ -905,10 +929,33 @@ static struct pnfs_layout_segment *find_only_write_lseg(struct inode *inode)
spin_lock(&inode->i_lock);
rv = find_only_write_lseg_locked(inode);
if (rv)
get_lseg(rv);
spin_unlock(&inode->i_lock);
return rv;
}
static int
filelayout_scan_ds_commit_list(struct nfs4_fl_commit_bucket *bucket, int max)
{
struct list_head *src = &bucket->written;
struct list_head *dst = &bucket->committing;
struct nfs_page *req, *tmp;
int ret = 0;
list_for_each_entry_safe(req, tmp, src, wb_list) {
if (!nfs_lock_request(req))
continue;
nfs_request_remove_commit_list(req);
clear_bit(PG_COMMIT_TO_DS, &req->wb_flags);
nfs_list_add_request(req, dst);
ret++;
if (ret == max)
break;
}
return ret;
}
/* Move reqs from written to committing lists, returning count of number moved.
* Note called with i_lock held.
*/
@@ -920,21 +967,16 @@ static int filelayout_scan_commit_lists(struct inode *inode, int max)
lseg = find_only_write_lseg_locked(inode);
if (!lseg)
return 0;
goto out_done;
fl = FILELAYOUT_LSEG(lseg);
if (fl->commit_through_mds)
goto out_put;
for (i = 0; i < fl->number_of_buckets; i++) {
if (list_empty(&fl->commit_buckets[i].written))
continue;
cnt = nfs_scan_commit_list(&fl->commit_buckets[i].written,
&fl->commit_buckets[i].committing,
max);
goto out_done;
for (i = 0; i < fl->number_of_buckets && max != 0; i++) {
cnt = filelayout_scan_ds_commit_list(&fl->commit_buckets[i], max);
max -= cnt;
rv += cnt;
}
out_put:
put_lseg(lseg);
out_done:
return rv;
}
@@ -1033,8 +1075,8 @@ static struct pnfs_layoutdriver_type filelayout_type = {
.free_lseg = filelayout_free_lseg,
.pg_read_ops = &filelayout_pg_read_ops,
.pg_write_ops = &filelayout_pg_write_ops,
.choose_commit_list = filelayout_choose_commit_list,
.remove_commit_req = filelayout_remove_commit_req,
.mark_request_commit = filelayout_mark_request_commit,
.clear_request_commit = filelayout_clear_request_commit,
.scan_commit_lists = filelayout_scan_commit_lists,
.commit_pagelist = filelayout_commit_pagelist,
.read_pagelist = filelayout_read_pagelist,