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@xxxxxxxxxx>
---
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 4e7df2a..dde5a89 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -901,8 +901,8 @@ 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 6971946..ece0526 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -278,7 +278,7 @@ exit:
/* Fill a page with xdr information before transferring to the cache page */
static inline
-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);
@@ -288,7 +288,7 @@ 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 */
@@ -388,22 +388,53 @@ out:
/* Perform conversion from xdr to cache array */
static inline
void nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry,
- struct page *xdr_page, struct page *page)
+ void *xdr_page, struct page *page)
{
- __be32 *ptr = kmap(xdr_page);
+ __be32 *ptr = xdr_page;
while (xdr_decode(desc, entry, &ptr) == 0) {
if (nfs_readdir_add_to_array(entry, page) == -1)
break;
if (desc->plus == 1)
nfs_prime_dcache(desc->file->f_path.dentry, entry);
}
- kunmap(xdr_page);
+}
+
+static inline
+void nfs_readdir_free_large_page(void *ptr, struct page **pages)
+{
+ unsigned int i;
+ if (ptr)
+ vm_unmap_ram(ptr, NFS_MAX_READDIR_PAGES);
+ for (i = 0; i < NFS_MAX_READDIR_PAGES; i++)
+ put_page(pages[i]);
+}
+
+/*
+ * nfs_readdir_large_page will allocate pages that must be freed with a call
+ * to nfs_readdir_free_large_page
+ */
+static inline
+void *nfs_readdir_large_page(struct page **pages)
+{
+ void *ptr = NULL;
+ struct page *page = NULL;
+ int i;
+ for (i = 0; i < NFS_MAX_READDIR_PAGES; i++) {
+ page = alloc_page(GFP_KERNEL);
+ pages[i] = page;
+ }
+
+ ptr = vm_map_ram(pages, NFS_MAX_READDIR_PAGES, 0, PAGE_KERNEL);
+ if (IS_ERR_OR_NULL(ptr))
+ nfs_readdir_free_large_page(ptr, pages);
+ return ptr;
}
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;
@@ -416,6 +447,7 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page,
entry.fattr = nfs_alloc_fattr();
if (entry.fh == NULL || entry.fattr == NULL)
goto out;
+ printk(KERN_DEBUG "%d %s %s", __LINE__, __FILE__, __func__);
array = nfs_readdir_get_array(page);
memset(array, 0, sizeof(struct nfs_cache_array));
@@ -426,18 +458,18 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page,
goto out;
}
- xdr_page = alloc_page(GFP_KERNEL);
- if (!xdr_page)
+ pages_ptr = nfs_readdir_large_page(pages);
+ if (!pages_ptr)
goto out_put_page;
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);
+ nfs_readdir_page_filler(desc, &entry, pages_ptr, page);
} while (array->eof_index < 0 && array->size < MAX_READDIR_ARRAY);
out_put_page:
- put_page(xdr_page);
+ nfs_readdir_free_large_page(pages_ptr, pages);
out:
nfs_free_fattr(entry.fattr);
nfs_free_fhandle(entry.fh);
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index c961bc9..f64382c 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -63,6 +63,12 @@ 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
*/
struct nfs_parsed_mount_data {
diff --git a/fs/nfs/nfs3proc.c b/fs/nfs/nfs3proc.c
index fabb4f2..033ed04 100644
--- a/fs/nfs/nfs3proc.c
+++ b/fs/nfs/nfs3proc.c
@@ -611,7 +611,7 @@ 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);
@@ -621,7 +621,7 @@ 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 089da5b..479f422 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2896,12 +2896,12 @@ 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,
@@ -2932,14 +2932,14 @@ 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/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 08ef912..f2e2f97 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -4225,7 +4225,7 @@ static int decode_readdir(struct xdr_stream *xdr, struct rpc_rqst *req, struct n
pglen = recvd;
xdr_read_pages(xdr, pglen);
- BUG_ON(pglen + readdir->pgbase > PAGE_CACHE_SIZE);
+ BUG_ON(pglen + readdir->pgbase > PAGE_CACHE_SIZE * NFS_MAX_READDIR_PAGES);
kaddr = p = kmap_atomic(page, KM_USER0);
end = p + ((pglen + readdir->pgbase) >> 2);
entry = p;
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index fc46192..7d8cafa 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -1044,7 +1044,7 @@ 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 *,
--
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