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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

126
fs/nfs/write.c
View File

@@ -100,7 +100,6 @@ void nfs_writedata_free(struct nfs_write_data *p)
void nfs_writedata_release(struct nfs_write_data *wdata)
{
put_lseg(wdata->lseg);
put_nfs_open_context(wdata->args.context);
nfs_writedata_free(wdata);
}
@@ -393,8 +392,6 @@ static void nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
spin_unlock(&inode->i_lock);
}
static struct pnfs_layout_segment *nfs_clear_request_commit(struct nfs_page *req);
/*
* Remove a write request from an inode
*/
@@ -402,18 +399,15 @@ static void nfs_inode_remove_request(struct nfs_page *req)
{
struct inode *inode = req->wb_context->dentry->d_inode;
struct nfs_inode *nfsi = NFS_I(inode);
struct pnfs_layout_segment *lseg;
BUG_ON (!NFS_WBACK_BUSY(req));
spin_lock(&inode->i_lock);
lseg = nfs_clear_request_commit(req);
set_page_private(req->wb_page, 0);
ClearPagePrivate(req->wb_page);
clear_bit(PG_MAPPED, &req->wb_flags);
nfsi->npages--;
spin_unlock(&inode->i_lock);
put_lseg(lseg);
nfs_release_request(req);
}
@@ -424,6 +418,57 @@ nfs_mark_request_dirty(struct nfs_page *req)
}
#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
/**
* nfs_request_add_commit_list - add request to a commit list
* @req: pointer to a struct nfs_page
* @head: commit list head
*
* This sets the PG_CLEAN bit, updates the inode global count of
* number of outstanding requests requiring a commit as well as
* the MM page stats.
*
* The caller must _not_ hold the inode->i_lock, but must be
* holding the nfs_page lock.
*/
void
nfs_request_add_commit_list(struct nfs_page *req, struct list_head *head)
{
struct inode *inode = req->wb_context->dentry->d_inode;
set_bit(PG_CLEAN, &(req)->wb_flags);
spin_lock(&inode->i_lock);
nfs_list_add_request(req, head);
NFS_I(inode)->ncommit++;
spin_unlock(&inode->i_lock);
inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
inc_bdi_stat(req->wb_page->mapping->backing_dev_info, BDI_RECLAIMABLE);
__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
}
EXPORT_SYMBOL_GPL(nfs_request_add_commit_list);
/**
* nfs_request_remove_commit_list - Remove request from a commit list
* @req: pointer to a nfs_page
*
* This clears the PG_CLEAN bit, and updates the inode global count of
* number of outstanding requests requiring a commit
* It does not update the MM page stats.
*
* The caller _must_ hold the inode->i_lock and the nfs_page lock.
*/
void
nfs_request_remove_commit_list(struct nfs_page *req)
{
struct inode *inode = req->wb_context->dentry->d_inode;
if (!test_and_clear_bit(PG_CLEAN, &(req)->wb_flags))
return;
nfs_list_remove_request(req);
NFS_I(inode)->ncommit--;
}
EXPORT_SYMBOL_GPL(nfs_request_remove_commit_list);
/*
* Add a request to the inode's commit list.
*/
@@ -431,18 +476,10 @@ static void
nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg)
{
struct inode *inode = req->wb_context->dentry->d_inode;
struct nfs_inode *nfsi = NFS_I(inode);
struct list_head *clist;
clist = pnfs_choose_commit_list(req, lseg);
spin_lock(&inode->i_lock);
set_bit(PG_CLEAN, &(req)->wb_flags);
nfs_list_add_request(req, clist);
nfsi->ncommit++;
spin_unlock(&inode->i_lock);
inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
inc_bdi_stat(req->wb_page->mapping->backing_dev_info, BDI_RECLAIMABLE);
__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
if (pnfs_mark_request_commit(req, lseg))
return;
nfs_request_add_commit_list(req, &NFS_I(inode)->commit_list);
}
static void
@@ -452,18 +489,19 @@ nfs_clear_page_commit(struct page *page)
dec_bdi_stat(page->mapping->backing_dev_info, BDI_RECLAIMABLE);
}
static struct pnfs_layout_segment *
static void
nfs_clear_request_commit(struct nfs_page *req)
{
struct pnfs_layout_segment *lseg = NULL;
if (test_bit(PG_CLEAN, &req->wb_flags)) {
struct inode *inode = req->wb_context->dentry->d_inode;
if (test_and_clear_bit(PG_CLEAN, &(req)->wb_flags)) {
if (!pnfs_clear_request_commit(req)) {
spin_lock(&inode->i_lock);
nfs_request_remove_commit_list(req);
spin_unlock(&inode->i_lock);
}
nfs_clear_page_commit(req->wb_page);
lseg = pnfs_clear_request_commit(req);
NFS_I(req->wb_context->dentry->d_inode)->ncommit--;
list_del(&req->wb_list);
}
return lseg;
}
static inline
@@ -490,15 +528,14 @@ int nfs_reschedule_unstable_write(struct nfs_page *req,
return 0;
}
#else
static inline void
static void
nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg)
{
}
static inline struct pnfs_layout_segment *
static void
nfs_clear_request_commit(struct nfs_page *req)
{
return NULL;
}
static inline
@@ -523,25 +560,23 @@ nfs_need_commit(struct nfs_inode *nfsi)
}
/* i_lock held by caller */
int
static int
nfs_scan_commit_list(struct list_head *src, struct list_head *dst, int max)
{
struct nfs_page *req, *tmp;
int ret = 0;
list_for_each_entry_safe(req, tmp, src, wb_list) {
if (nfs_lock_request_dontget(req)) {
kref_get(&req->wb_kref);
list_move_tail(&req->wb_list, dst);
clear_bit(PG_CLEAN, &(req)->wb_flags);
ret++;
if (ret == max)
break;
}
if (!nfs_lock_request(req))
continue;
nfs_request_remove_commit_list(req);
nfs_list_add_request(req, dst);
ret++;
if (ret == max)
break;
}
return ret;
}
EXPORT_SYMBOL_GPL(nfs_scan_commit_list);
/*
* nfs_scan_commit - Scan an inode for commit requests
@@ -559,14 +594,12 @@ nfs_scan_commit(struct inode *inode, struct list_head *dst)
spin_lock(&inode->i_lock);
if (nfsi->ncommit > 0) {
const int max = INT_MAX;
int pnfs_ret;
ret = nfs_scan_commit_list(&nfsi->commit_list, dst, INT_MAX);
pnfs_ret = pnfs_scan_commit_lists(inode, INT_MAX - ret);
if (pnfs_ret) {
ret += pnfs_ret;
set_bit(NFS_INO_PNFS_COMMIT, &nfsi->flags);
}
ret = nfs_scan_commit_list(&nfsi->commit_list, dst, max);
pnfs_ret = pnfs_scan_commit_lists(inode, max - ret);
ret += pnfs_ret;
nfsi->ncommit -= ret;
}
spin_unlock(&inode->i_lock);
@@ -601,7 +634,6 @@ static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
unsigned int rqend;
unsigned int end;
int error;
struct pnfs_layout_segment *lseg = NULL;
if (!PagePrivate(page))
return NULL;
@@ -637,8 +669,6 @@ static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
spin_lock(&inode->i_lock);
}
lseg = nfs_clear_request_commit(req);
/* Okay, the request matches. Update the region */
if (offset < req->wb_offset) {
req->wb_offset = offset;
@@ -650,7 +680,7 @@ static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
req->wb_bytes = rqend - req->wb_offset;
out_unlock:
spin_unlock(&inode->i_lock);
put_lseg(lseg);
nfs_clear_request_commit(req);
return req;
out_flushme:
spin_unlock(&inode->i_lock);
@@ -1337,7 +1367,6 @@ void nfs_commitdata_release(void *data)
{
struct nfs_write_data *wdata = data;
put_lseg(wdata->lseg);
put_nfs_open_context(wdata->args.context);
nfs_commit_free(wdata);
}
@@ -1647,6 +1676,7 @@ int nfs_wb_page_cancel(struct inode *inode, struct page *page)
if (req == NULL)
break;
if (nfs_lock_request_dontget(req)) {
nfs_clear_request_commit(req);
nfs_inode_remove_request(req);
/*
* In case nfs_inode_remove_request has marked the