NFS: readdir with vmapped pages

We can use vmapped pages to read more information from the network at once.
This will reduce the number of calls needed to complete a readdir.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
[trondmy: Added #include for linux/vmalloc.h> in fs/nfs/dir.c]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 5f01f42..876ba85 100644 (file)
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -903,8 +903,8 @@ static void nfs_server_set_fsinfo(struct nfs_server *server, struct nfs_fsinfo *
        server->wtmult = nfs_block_bits(fsinfo->wtmult, NULL);
 
        server->dtsize = nfs_block_size(fsinfo->dtpref, NULL);
-       if (server->dtsize > PAGE_CACHE_SIZE)
-               server->dtsize = PAGE_CACHE_SIZE;
+       if (server->dtsize > PAGE_CACHE_SIZE * NFS_MAX_READDIR_PAGES)
+               server->dtsize = PAGE_CACHE_SIZE * NFS_MAX_READDIR_PAGES;
        if (server->dtsize > server->rsize)
                server->dtsize = server->rsize;
 

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 88cbcda..5d7da3a 100644 (file)
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -33,6 +33,7 @@
 #include <linux/namei.h>
 #include <linux/mount.h>
 #include <linux/sched.h>
+#include <linux/vmalloc.h>
 
 #include "delegation.h"
 #include "iostat.h"
@@ -327,7 +328,7 @@ out:
 
 /* Fill a page with xdr information before transferring to the cache page */
 static
-int nfs_readdir_xdr_filler(struct page *xdr_page, nfs_readdir_descriptor_t *desc,
+int nfs_readdir_xdr_filler(struct page **pages, nfs_readdir_descriptor_t *desc,
                        struct nfs_entry *entry, struct file *file, struct inode *inode)
 {
        struct rpc_cred *cred = nfs_file_cred(file);
@@ -337,7 +338,7 @@ int nfs_readdir_xdr_filler(struct page *xdr_page, nfs_readdir_descriptor_t *desc
  again:
        timestamp = jiffies;
        gencount = nfs_inc_attr_generation_counter();
-       error = NFS_PROTO(inode)->readdir(file->f_path.dentry, cred, entry->cookie, xdr_page,
+       error = NFS_PROTO(inode)->readdir(file->f_path.dentry, cred, entry->cookie, pages,
                                          NFS_SERVER(inode)->dtsize, desc->plus);
        if (error < 0) {
                /* We requested READDIRPLUS, but the server doesn't grok it */
@@ -436,11 +437,11 @@ out:
 /* Perform conversion from xdr to cache array */
 static
 void nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry,
-                               struct page *xdr_page, struct page *page, unsigned int buflen)
+                               void *xdr_page, struct page *page, unsigned int buflen)
 {
        struct xdr_stream stream;
        struct xdr_buf buf;
-       __be32 *ptr = kmap(xdr_page);
+       __be32 *ptr = xdr_page;
 
        buf.head->iov_base = xdr_page;
        buf.head->iov_len = buflen;
@@ -458,18 +459,59 @@ void nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *e
                if (desc->plus == 1)
                        nfs_prime_dcache(desc->file->f_path.dentry, entry);
        }
-       kunmap(xdr_page);
+}
+
+static
+void nfs_readdir_free_pagearray(struct page **pages, unsigned int npages)
+{
+       unsigned int i;
+       for (i = 0; i < npages; i++)
+               put_page(pages[i]);
+}
+
+static
+void nfs_readdir_free_large_page(void *ptr, struct page **pages,
+               unsigned int npages)
+{
+       vm_unmap_ram(ptr, npages);
+       nfs_readdir_free_pagearray(pages, npages);
+}
+
+/*
+ * nfs_readdir_large_page will allocate pages that must be freed with a call
+ * to nfs_readdir_free_large_page
+ */
+static
+void *nfs_readdir_large_page(struct page **pages, unsigned int npages)
+{
+       void *ptr;
+       unsigned int i;
+
+       for (i = 0; i < npages; i++) {
+               struct page *page = alloc_page(GFP_KERNEL);
+               if (page == NULL)
+                       goto out_freepages;
+               pages[i] = page;
+       }
+
+       ptr = vm_map_ram(pages, NFS_MAX_READDIR_PAGES, 0, PAGE_KERNEL);
+       if (!IS_ERR_OR_NULL(ptr))
+               return ptr;
+out_freepages:
+       nfs_readdir_free_pagearray(pages, i);
+       return NULL;
 }
 
 static
 int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page, struct inode *inode)
 {
-       struct page *xdr_page;
+       struct page *pages[NFS_MAX_READDIR_PAGES];
+       void *pages_ptr = NULL;
        struct nfs_entry entry;
        struct file     *file = desc->file;
        struct nfs_cache_array *array;
        int status = 0;
-       unsigned int array_size = 1;
+       unsigned int array_size = ARRAY_SIZE(pages);
 
        entry.prev_cookie = 0;
        entry.cookie = *desc->dir_cookie;
@@ -483,18 +525,18 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page,
        memset(array, 0, sizeof(struct nfs_cache_array));
        array->eof_index = -1;
 
-       xdr_page = alloc_page(GFP_KERNEL);
-       if (!xdr_page)
+       pages_ptr = nfs_readdir_large_page(pages, array_size);
+       if (!pages_ptr)
                goto out_release_array;
        do {
-               status = nfs_readdir_xdr_filler(xdr_page, desc, &entry, file, inode);
+               status = nfs_readdir_xdr_filler(pages, desc, &entry, file, inode);
 
                if (status < 0)
                        break;
-               nfs_readdir_page_filler(desc, &entry, xdr_page, page, array_size * PAGE_SIZE);
+               nfs_readdir_page_filler(desc, &entry, pages_ptr, page, array_size * PAGE_SIZE);
        } while (array->eof_index < 0 && array->size < MAX_READDIR_ARRAY);
 
-       put_page(xdr_page);
+       nfs_readdir_free_large_page(pages_ptr, pages, array_size);
 out_release_array:
        nfs_readdir_release_array(page);
 out:

diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 74b0155..7b0e894 100644 (file)
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -62,6 +62,12 @@ struct nfs_clone_mount {
  */
 #define NFS_UNSPEC_PORT                (-1)
 
+/*
+ * Maximum number of pages that readdir can use for creating
+ * a vmapped array of pages.
+ */
+#define NFS_MAX_READDIR_PAGES 8
+
 /*
  * In-kernel mount arguments
  */

diff --git a/fs/nfs/nfs3proc.c b/fs/nfs/nfs3proc.c
index f8446b3..ce939c0 100644 (file)
--- a/fs/nfs/nfs3proc.c
+++ b/fs/nfs/nfs3proc.c
@@ -630,7 +630,7 @@ out:
  */
 static int
 nfs3_proc_readdir(struct dentry *dentry, struct rpc_cred *cred,
-                 u64 cookie, struct page *page, unsigned int count, int plus)
+                 u64 cookie, struct page **pages, unsigned int count, int plus)
 {
        struct inode            *dir = dentry->d_inode;
        __be32                  *verf = NFS_COOKIEVERF(dir);
@@ -640,7 +640,7 @@ nfs3_proc_readdir(struct dentry *dentry, struct rpc_cred *cred,
                .verf           = {verf[0], verf[1]},
                .plus           = plus,
                .count          = count,
-               .pages          = &page
+               .pages          = pages
        };
        struct nfs3_readdirres  res = {
                .verf           = verf,

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index aa771c1..cb33c73 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2823,12 +2823,12 @@ static int nfs4_proc_mkdir(struct inode *dir, struct dentry *dentry,
 }
 
 static int _nfs4_proc_readdir(struct dentry *dentry, struct rpc_cred *cred,
-                  u64 cookie, struct page *page, unsigned int count, int plus)
+               u64 cookie, struct page **pages, unsigned int count, int plus)
 {
        struct inode            *dir = dentry->d_inode;
        struct nfs4_readdir_arg args = {
                .fh = NFS_FH(dir),
-               .pages = &page,
+               .pages = pages,
                .pgbase = 0,
                .count = count,
                .bitmask = NFS_SERVER(dentry->d_inode)->attr_bitmask,
@@ -2859,14 +2859,14 @@ static int _nfs4_proc_readdir(struct dentry *dentry, struct rpc_cred *cred,
 }
 
 static int nfs4_proc_readdir(struct dentry *dentry, struct rpc_cred *cred,
-                  u64 cookie, struct page *page, unsigned int count, int plus)
+               u64 cookie, struct page **pages, unsigned int count, int plus)
 {
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(NFS_SERVER(dentry->d_inode),
                                _nfs4_proc_readdir(dentry, cred, cookie,
-                                       page, count, plus),
+                                       pages, count, plus),
                                &exception);
        } while (exception.retry);
        return err;

diff --git a/fs/nfs/proc.c b/fs/nfs/proc.c
index e5e84aa..58e7f84 100644 (file)
--- a/fs/nfs/proc.c
+++ b/fs/nfs/proc.c
@@ -534,14 +534,14 @@ nfs_proc_rmdir(struct inode *dir, struct qstr *name)
  */
 static int
 nfs_proc_readdir(struct dentry *dentry, struct rpc_cred *cred,
-                u64 cookie, struct page *page, unsigned int count, int plus)
+                u64 cookie, struct page **pages, unsigned int count, int plus)
 {
        struct inode            *dir = dentry->d_inode;
        struct nfs_readdirargs  arg = {
                .fh             = NFS_FH(dir),
                .cookie         = cookie,
                .count          = count,
-               .pages          = &page,
+               .pages          = pages,
        };
        struct rpc_message      msg = {
                .rpc_proc       = &nfs_procedures[NFSPROC_READDIR],

diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index ca0e8fd..1b9a17a 100644 (file)
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -1026,7 +1026,7 @@ struct nfs_rpc_ops {
        int     (*mkdir)   (struct inode *, struct dentry *, struct iattr *);
        int     (*rmdir)   (struct inode *, struct qstr *);
        int     (*readdir) (struct dentry *, struct rpc_cred *,
-                           u64, struct page *, unsigned int, int);
+                           u64, struct page **, unsigned int, int);
        int     (*mknod)   (struct inode *, struct dentry *, struct iattr *,
                            dev_t);
        int     (*statfs)  (struct nfs_server *, struct nfs_fh *,