[PATCH v4 11/21] NFS: Support larger readdir buffers

trondmy
2020-11-07T14:13:53Z

Support readdir buffers of up to 1MB in size so that we can read
large directories using few RPC calls.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
fs/nfs/client.c | 4 ++--
fs/nfs/dir.c | 33 +++++++++++++++++++--------------
fs/nfs/internal.h | 6 ------
3 files changed, 21 insertions(+), 22 deletions(-)

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 4b8cc93913f7..f6454ba53d05 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -781,8 +781,8 @@ static void nfs_server_set_fsinfo(struct nfs_server *server,
server->wtmult = nfs_block_bits(fsinfo->wtmult, NULL);

server->dtsize = nfs_block_size(fsinfo->dtpref, NULL);
- if (server->dtsize > PAGE_SIZE * NFS_MAX_READDIR_PAGES)
- server->dtsize = PAGE_SIZE * NFS_MAX_READDIR_PAGES;
+ if (server->dtsize > NFS_MAX_FILE_IO_SIZE)
+ server->dtsize = NFS_MAX_FILE_IO_SIZE;
if (server->dtsize > server->rsize)
server->dtsize = server->rsize;

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index be0e2891fecc..438906dae083 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -727,44 +727,47 @@ static int nfs_readdir_page_filler(struct nfs_readdir_descriptor *desc,
return status;
}

-static
-void nfs_readdir_free_pages(struct page **pages, unsigned int npages)
+static void nfs_readdir_free_pages(struct page **pages, size_t npages)
{
- unsigned int i;
- for (i = 0; i < npages; i++)
- put_page(pages[i]);
+ while (npages--)
+ put_page(pages[npages]);
+ kfree(pages);
}

/*
* nfs_readdir_alloc_pages() will allocate pages that must be freed with a call
* to nfs_readdir_free_pages()
*/
-static
-int nfs_readdir_alloc_pages(struct page **pages, unsigned int npages)
+static struct page **nfs_readdir_alloc_pages(size_t npages)
{
- unsigned int i;
+ struct page **pages;
+ size_t i;

+ pages = kmalloc_array(npages, sizeof(*pages), GFP_KERNEL);
+ if (!pages)
+ return NULL;
for (i = 0; i < npages; i++) {
struct page *page = alloc_page(GFP_KERNEL);
if (page == NULL)
goto out_freepages;
pages[i] = page;
}
- return 0;
+ return pages;

out_freepages:
nfs_readdir_free_pages(pages, i);
- return -ENOMEM;
+ return NULL;
}

static
int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page, struct inode *inode)
{
- struct page *pages[NFS_MAX_READDIR_PAGES];
+ struct page **pages;
struct nfs_entry entry;
struct file *file = desc->file;
+ size_t array_size;
+ size_t dtsize = NFS_SERVER(inode)->dtsize;
int status = -ENOMEM;
- unsigned int array_size = ARRAY_SIZE(pages);

entry.prev_cookie = 0;
entry.cookie = nfs_readdir_page_last_cookie(page);
@@ -781,9 +784,11 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page,
goto out;
}

- status = nfs_readdir_alloc_pages(pages, array_size);
- if (status < 0)
+ array_size = (dtsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ pages = nfs_readdir_alloc_pages(array_size);
+ if (!pages)
goto out_release_label;
+
do {
unsigned int pglen;
status = nfs_readdir_xdr_filler(pages, desc, &entry, file, inode);
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 6673a77884d9..b840d0a91c9d 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -56,12 +56,6 @@ static inline bool nfs_lookup_is_soft_revalidate(const struct dentry *dentry)
#define NFS_UNSPEC_RETRANS (UINT_MAX)
#define NFS_UNSPEC_TIMEO (UINT_MAX)

-/*
- * Maximum number of pages that readdir can use for creating
- * a vmapped array of pages.
- */
-#define NFS_MAX_READDIR_PAGES 8
-
struct nfs_client_initdata {
unsigned long init_flags;
const char *hostname; /* Hostname of the server */
--
2.28.0