From a7d42ddb3099727f58366fa006f850a219cce6c8 Mon Sep 17 00:00:00 2001 From: Weston Andros Adamson Date: Fri, 19 Sep 2014 10:55:07 -0400 Subject: nfs: add mirroring support to pgio layer This patch adds mirrored write support to the pgio layer. The default is to use one mirror, but pgio callers may define callbacks to change this to any value up to the (arbitrarily selected) limit of 16. The basic idea is to break out members of nfs_pageio_descriptor that cannot be shared between mirrored DSes and put them in a new structure. Signed-off-by: Weston Andros Adamson --- fs/nfs/read.c | 30 +++++++++++++++++++++++++----- 1 file changed, 25 insertions(+), 5 deletions(-) (limited to 'fs/nfs/read.c') diff --git a/fs/nfs/read.c b/fs/nfs/read.c index 092ab499f2b6..568ecf0a880f 100644 --- a/fs/nfs/read.c +++ b/fs/nfs/read.c @@ -70,8 +70,15 @@ EXPORT_SYMBOL_GPL(nfs_pageio_init_read); void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor *pgio) { + struct nfs_pgio_mirror *mirror; + pgio->pg_ops = &nfs_pgio_rw_ops; - pgio->pg_bsize = NFS_SERVER(pgio->pg_inode)->rsize; + + /* read path should never have more than one mirror */ + WARN_ON_ONCE(pgio->pg_mirror_count != 1); + + mirror = &pgio->pg_mirrors[0]; + mirror->pg_bsize = NFS_SERVER(pgio->pg_inode)->rsize; } EXPORT_SYMBOL_GPL(nfs_pageio_reset_read_mds); @@ -81,6 +88,7 @@ int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode, struct nfs_page *new; unsigned int len; struct nfs_pageio_descriptor pgio; + struct nfs_pgio_mirror *pgm; len = nfs_page_length(page); if (len == 0) @@ -97,7 +105,13 @@ int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode, &nfs_async_read_completion_ops); nfs_pageio_add_request(&pgio, new); nfs_pageio_complete(&pgio); - NFS_I(inode)->read_io += pgio.pg_bytes_written; + + /* It doesn't make sense to do mirrored reads! */ + WARN_ON_ONCE(pgio.pg_mirror_count != 1); + + pgm = &pgio.pg_mirrors[0]; + NFS_I(inode)->read_io += pgm->pg_bytes_written; + return 0; } @@ -352,6 +366,7 @@ int nfs_readpages(struct file *filp, struct address_space *mapping, struct list_head *pages, unsigned nr_pages) { struct nfs_pageio_descriptor pgio; + struct nfs_pgio_mirror *pgm; struct nfs_readdesc desc = { .pgio = &pgio, }; @@ -387,10 +402,15 @@ int nfs_readpages(struct file *filp, struct address_space *mapping, &nfs_async_read_completion_ops); ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc); - nfs_pageio_complete(&pgio); - NFS_I(inode)->read_io += pgio.pg_bytes_written; - npages = (pgio.pg_bytes_written + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; + + /* It doesn't make sense to do mirrored reads! */ + WARN_ON_ONCE(pgio.pg_mirror_count != 1); + + pgm = &pgio.pg_mirrors[0]; + NFS_I(inode)->read_io += pgm->pg_bytes_written; + npages = (pgm->pg_bytes_written + PAGE_CACHE_SIZE - 1) >> + PAGE_CACHE_SHIFT; nfs_add_stats(inode, NFSIOS_READPAGES, npages); read_complete: put_nfs_open_context(desc.ctx); -- cgit v1.2.3-58-ga151