@@ -454,15 +454,23 @@ nfs_create_request(struct nfs_open_context *ctx, struct page *page,
}
static struct nfs_page *
-nfs_create_subreq(struct nfs_page *req, struct nfs_page *last,
- unsigned int pgbase, unsigned int offset,
+nfs_create_subreq(struct nfs_page *req,
+ unsigned int pgbase,
+ unsigned int offset,
unsigned int count)
{
+ struct nfs_page *last;
struct nfs_page *ret;
ret = __nfs_create_request(req->wb_lock_context, req->wb_page,
pgbase, offset, count);
if (!IS_ERR(ret)) {
+ /* find the last request */
+ for (last = req->wb_head;
+ last->wb_this_page != req->wb_head;
+ last = last->wb_this_page)
+ ;
+
nfs_lock_request(ret);
ret->wb_index = req->wb_index;
nfs_page_group_init(ret, last);
@@ -988,7 +996,7 @@ static bool nfs_match_lock_context(const struct nfs_lock_context *l1,
}
/**
- * nfs_can_coalesce_requests - test two requests for compatibility
+ * nfs_coalesce_size - test two requests for compatibility
* @prev: pointer to nfs_page
* @req: pointer to nfs_page
* @pgio: pointer to nfs_pagio_descriptor
@@ -997,41 +1005,36 @@ static bool nfs_match_lock_context(const struct nfs_lock_context *l1,
* page data area they describe is contiguous, and that their RPC
* credentials, NFSv4 open state, and lockowners are the same.
*
- * Return 'true' if this is the case, else return 'false'.
+ * Returns size of the request that can be coalesced
*/
-static bool nfs_can_coalesce_requests(struct nfs_page *prev,
+static unsigned int nfs_coalesce_size(struct nfs_page *prev,
struct nfs_page *req,
struct nfs_pageio_descriptor *pgio)
{
- size_t size;
struct file_lock_context *flctx;
if (prev) {
if (!nfs_match_open_context(nfs_req_openctx(req), nfs_req_openctx(prev)))
- return false;
+ return 0;
flctx = d_inode(nfs_req_openctx(req)->dentry)->i_flctx;
if (flctx != NULL &&
!(list_empty_careful(&flctx->flc_posix) &&
list_empty_careful(&flctx->flc_flock)) &&
!nfs_match_lock_context(req->wb_lock_context,
prev->wb_lock_context))
- return false;
+ return 0;
if (req_offset(req) != req_offset(prev) + prev->wb_bytes)
- return false;
+ return 0;
if (req->wb_page == prev->wb_page) {
if (req->wb_pgbase != prev->wb_pgbase + prev->wb_bytes)
- return false;
+ return 0;
} else {
if (req->wb_pgbase != 0 ||
prev->wb_pgbase + prev->wb_bytes != PAGE_SIZE)
- return false;
+ return 0;
}
}
- size = pgio->pg_ops->pg_test(pgio, prev, req);
- WARN_ON_ONCE(size > req->wb_bytes);
- if (size && size < req->wb_bytes)
- req->wb_bytes = size;
- return size > 0;
+ return pgio->pg_ops->pg_test(pgio, prev, req);
}
/**
@@ -1039,15 +1042,16 @@ static bool nfs_can_coalesce_requests(struct nfs_page *prev,
* @desc: destination io descriptor
* @req: request
*
- * Returns true if the request 'req' was successfully coalesced into the
- * existing list of pages 'desc'.
+ * If the request 'req' was successfully coalesced into the existing list
+ * of pages 'desc', it returns the size of req.
*/
-static int nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc,
- struct nfs_page *req)
+static unsigned int
+nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc,
+ struct nfs_page *req)
{
struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
-
struct nfs_page *prev = NULL;
+ unsigned int size;
if (mirror->pg_count != 0) {
prev = nfs_list_entry(mirror->pg_list.prev);
@@ -1067,11 +1071,12 @@ static int nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc,
return 0;
}
- if (!nfs_can_coalesce_requests(prev, req, desc))
- return 0;
+ size = nfs_coalesce_size(prev, req, desc);
+ if (size < req->wb_bytes)
+ return size;
nfs_list_move_request(req, &mirror->pg_list);
mirror->pg_count += req->wb_bytes;
- return 1;
+ return req->wb_bytes;
}
/*
@@ -1111,7 +1116,8 @@ nfs_pageio_cleanup_request(struct nfs_pageio_descriptor *desc,
* @req: request
*
* This may split a request into subrequests which are all part of the
- * same page group.
+ * same page group. If so, it will submit @req as the last one, to ensure
+ * the pointer to @req is still valid in case of failure.
*
* Returns true if the request 'req' was successfully coalesced into the
* existing list of pages 'desc'.
@@ -1120,51 +1126,50 @@ static int __nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
struct nfs_page *req)
{
struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
-
struct nfs_page *subreq;
- unsigned int bytes_left = 0;
- unsigned int offset, pgbase;
+ unsigned int size, subreq_size;
nfs_page_group_lock(req);
subreq = req;
- bytes_left = subreq->wb_bytes;
- offset = subreq->wb_offset;
- pgbase = subreq->wb_pgbase;
-
- do {
- if (!nfs_pageio_do_add_request(desc, subreq)) {
- /* make sure pg_test call(s) did nothing */
- WARN_ON_ONCE(subreq->wb_bytes != bytes_left);
- WARN_ON_ONCE(subreq->wb_offset != offset);
- WARN_ON_ONCE(subreq->wb_pgbase != pgbase);
-
+ subreq_size = subreq->wb_bytes;
+ for(;;) {
+ size = nfs_pageio_do_add_request(desc, subreq);
+ if (size == subreq_size) {
+ /* We successfully submitted a request */
+ if (subreq == req)
+ break;
+ req->wb_pgbase += size;
+ req->wb_bytes -= size;
+ req->wb_offset += size;
+ subreq_size = req->wb_bytes;
+ subreq = req;
+ continue;
+ }
+ if (WARN_ON_ONCE(subreq != req)) {
+ nfs_page_group_unlock(req);
+ nfs_pageio_cleanup_request(desc, subreq);
+ subreq = req;
+ subreq_size = req->wb_bytes;
+ nfs_page_group_lock(req);
+ }
+ if (!size) {
+ /* Can't coalesce any more, so do I/O */
nfs_page_group_unlock(req);
desc->pg_moreio = 1;
nfs_pageio_doio(desc);
if (desc->pg_error < 0 || mirror->pg_recoalesce)
- goto out_cleanup_subreq;
+ return 0;
/* retry add_request for this subreq */
nfs_page_group_lock(req);
continue;
}
-
- /* check for buggy pg_test call(s) */
- WARN_ON_ONCE(subreq->wb_bytes + subreq->wb_pgbase > PAGE_SIZE);
- WARN_ON_ONCE(subreq->wb_bytes > bytes_left);
- WARN_ON_ONCE(subreq->wb_bytes == 0);
-
- bytes_left -= subreq->wb_bytes;
- offset += subreq->wb_bytes;
- pgbase += subreq->wb_bytes;
-
- if (bytes_left) {
- subreq = nfs_create_subreq(req, subreq, pgbase,
- offset, bytes_left);
- if (IS_ERR(subreq))
- goto err_ptr;
- }
- } while (bytes_left > 0);
+ subreq = nfs_create_subreq(req, req->wb_pgbase,
+ req->wb_offset, size);
+ if (IS_ERR(subreq))
+ goto err_ptr;
+ subreq_size = size;
+ }
nfs_page_group_unlock(req);
return 1;
@@ -1172,10 +1177,6 @@ static int __nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
desc->pg_error = PTR_ERR(subreq);
nfs_page_group_unlock(req);
return 0;
-out_cleanup_subreq:
- if (req != subreq)
- nfs_pageio_cleanup_request(desc, subreq);
- return 0;
}
static int nfs_do_recoalesce(struct nfs_pageio_descriptor *desc)
@@ -1244,7 +1245,7 @@ int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
{
u32 midx;
unsigned int pgbase, offset, bytes;
- struct nfs_page *dupreq, *lastreq;
+ struct nfs_page *dupreq;
pgbase = req->wb_pgbase;
offset = req->wb_offset;
@@ -1258,13 +1259,7 @@ int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
for (midx = 1; midx < desc->pg_mirror_count; midx++) {
nfs_page_group_lock(req);
- /* find the last request */
- for (lastreq = req->wb_head;
- lastreq->wb_this_page != req->wb_head;
- lastreq = lastreq->wb_this_page)
- ;
-
- dupreq = nfs_create_subreq(req, lastreq,
+ dupreq = nfs_create_subreq(req,
pgbase, offset, bytes);
nfs_page_group_unlock(req);