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authorTrond Myklebust <Trond.Myklebust@netapp.com>2011-07-12 13:42:02 -0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2011-07-15 09:12:21 -0400
commitd9156f9f364897e93bdd98b4ad22138de18f7c24 (patch)
treef748c7b8d4a0eff52fcaa78fb4de216391efedf2 /fs/nfs/pagelist.c
parentd097971d8ab4042eaa4bff98698ae9cc55942327 (diff)
NFS: Allow the nfs_pageio_descriptor to signal that a re-coalesce is needed
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>
Diffstat (limited to 'fs/nfs/pagelist.c')
-rw-r--r--fs/nfs/pagelist.c57
1 files changed, 54 insertions, 3 deletions
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index d421e19557a..7139dbf8784 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -240,6 +240,7 @@ void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
desc->pg_bsize = bsize;
desc->pg_base = 0;
desc->pg_moreio = 0;
+ desc->pg_recoalesce = 0;
desc->pg_inode = inode;
desc->pg_ops = pg_ops;
desc->pg_ioflags = io_flags;
@@ -331,7 +332,7 @@ static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc)
* Returns true if the request 'req' was successfully coalesced into the
* existing list of pages 'desc'.
*/
-int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
+static int __nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
struct nfs_page *req)
{
while (!nfs_pageio_do_add_request(desc, req)) {
@@ -340,17 +341,67 @@ int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
if (desc->pg_error < 0)
return 0;
desc->pg_moreio = 0;
+ if (desc->pg_recoalesce)
+ return 0;
}
return 1;
}
+static int nfs_do_recoalesce(struct nfs_pageio_descriptor *desc)
+{
+ LIST_HEAD(head);
+
+ do {
+ list_splice_init(&desc->pg_list, &head);
+ desc->pg_bytes_written -= desc->pg_count;
+ desc->pg_count = 0;
+ desc->pg_base = 0;
+ desc->pg_recoalesce = 0;
+
+ while (!list_empty(&head)) {
+ struct nfs_page *req;
+
+ req = list_first_entry(&head, struct nfs_page, wb_list);
+ nfs_list_remove_request(req);
+ if (__nfs_pageio_add_request(desc, req))
+ continue;
+ if (desc->pg_error < 0)
+ return 0;
+ break;
+ }
+ } while (desc->pg_recoalesce);
+ return 1;
+}
+
+int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
+ struct nfs_page *req)
+{
+ int ret;
+
+ do {
+ ret = __nfs_pageio_add_request(desc, req);
+ if (ret)
+ break;
+ if (desc->pg_error < 0)
+ break;
+ ret = nfs_do_recoalesce(desc);
+ } while (ret);
+ return ret;
+}
+
/**
* nfs_pageio_complete - Complete I/O on an nfs_pageio_descriptor
* @desc: pointer to io descriptor
*/
void nfs_pageio_complete(struct nfs_pageio_descriptor *desc)
{
- nfs_pageio_doio(desc);
+ for (;;) {
+ nfs_pageio_doio(desc);
+ if (!desc->pg_recoalesce)
+ break;
+ if (!nfs_do_recoalesce(desc))
+ break;
+ }
}
/**
@@ -369,7 +420,7 @@ void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *desc, pgoff_t index)
if (!list_empty(&desc->pg_list)) {
struct nfs_page *prev = nfs_list_entry(desc->pg_list.prev);
if (index != prev->wb_index + 1)
- nfs_pageio_doio(desc);
+ nfs_pageio_complete(desc);
}
}