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>
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parent
d097971d8a
commit
d9156f9f36
2 changed files with 56 additions and 4 deletions
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@ -240,6 +240,7 @@ void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
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desc->pg_bsize = bsize;
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desc->pg_base = 0;
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desc->pg_moreio = 0;
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desc->pg_recoalesce = 0;
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desc->pg_inode = inode;
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desc->pg_ops = pg_ops;
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desc->pg_ioflags = io_flags;
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@ -331,7 +332,7 @@ static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc)
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* Returns true if the request 'req' was successfully coalesced into the
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* existing list of pages 'desc'.
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*/
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int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
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static int __nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
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struct nfs_page *req)
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{
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while (!nfs_pageio_do_add_request(desc, req)) {
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@ -340,17 +341,67 @@ int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
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if (desc->pg_error < 0)
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return 0;
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desc->pg_moreio = 0;
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if (desc->pg_recoalesce)
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return 0;
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}
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return 1;
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}
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static int nfs_do_recoalesce(struct nfs_pageio_descriptor *desc)
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{
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LIST_HEAD(head);
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do {
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list_splice_init(&desc->pg_list, &head);
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desc->pg_bytes_written -= desc->pg_count;
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desc->pg_count = 0;
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desc->pg_base = 0;
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desc->pg_recoalesce = 0;
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while (!list_empty(&head)) {
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struct nfs_page *req;
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req = list_first_entry(&head, struct nfs_page, wb_list);
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nfs_list_remove_request(req);
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if (__nfs_pageio_add_request(desc, req))
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continue;
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if (desc->pg_error < 0)
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return 0;
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break;
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}
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} while (desc->pg_recoalesce);
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return 1;
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}
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int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
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struct nfs_page *req)
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{
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int ret;
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do {
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ret = __nfs_pageio_add_request(desc, req);
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if (ret)
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break;
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if (desc->pg_error < 0)
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break;
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ret = nfs_do_recoalesce(desc);
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} while (ret);
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return ret;
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}
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/**
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* nfs_pageio_complete - Complete I/O on an nfs_pageio_descriptor
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* @desc: pointer to io descriptor
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*/
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void nfs_pageio_complete(struct nfs_pageio_descriptor *desc)
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{
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for (;;) {
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nfs_pageio_doio(desc);
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if (!desc->pg_recoalesce)
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break;
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if (!nfs_do_recoalesce(desc))
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break;
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}
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}
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/**
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@ -369,7 +420,7 @@ void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *desc, pgoff_t index)
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if (!list_empty(&desc->pg_list)) {
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struct nfs_page *prev = nfs_list_entry(desc->pg_list.prev);
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if (index != prev->wb_index + 1)
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nfs_pageio_doio(desc);
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nfs_pageio_complete(desc);
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}
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}
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@ -68,7 +68,8 @@ struct nfs_pageio_descriptor {
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size_t pg_count;
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size_t pg_bsize;
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unsigned int pg_base;
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char pg_moreio;
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unsigned char pg_moreio : 1,
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pg_recoalesce : 1;
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struct inode *pg_inode;
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const struct nfs_pageio_ops *pg_ops;
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