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Commit 9a9fc1c0 authored by David Howells's avatar David Howells
Browse files

NFS: Read pages from FS-Cache into an NFS inode 



Read pages from an FS-Cache data storage object representing an inode into an
NFS inode.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Acked-by: default avatarSteve Dickson <steved@redhat.com>
Acked-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Tested-by: default avatarDaire Byrne <Daire.Byrne@framestore.com>
parent f42b293d

fs/nfs/fscache.c

+112 −0
Original line number Diff line number Diff line
@@ -381,3 +381,115 @@ void __nfs_fscache_invalidate_page(struct page *page, struct inode *inode) 
	nfs_add_fscache_stats(page->mapping->host,

			      NFSIOS_FSCACHE_PAGES_UNCACHED, 1);

}



/*

 * Handle completion of a page being read from the cache.

 * - Called in process (keventd) context.

 */

static void nfs_readpage_from_fscache_complete(struct page *page,

					       void *context,

					       int error)

{

	dfprintk(FSCACHE,

		 "NFS: readpage_from_fscache_complete (0x%p/0x%p/%d)\n",

		 page, context, error);



	/* if the read completes with an error, we just unlock the page and let

	 * the VM reissue the readpage */

	if (!error) {

		SetPageUptodate(page);

		unlock_page(page);

	} else {

		error = nfs_readpage_async(context, page->mapping->host, page);

		if (error)

			unlock_page(page);

	}

}



/*

 * Retrieve a page from fscache

 */

int __nfs_readpage_from_fscache(struct nfs_open_context *ctx,

				struct inode *inode, struct page *page)

{

	int ret;



	dfprintk(FSCACHE,

		 "NFS: readpage_from_fscache(fsc:%p/p:%p(i:%lx f:%lx)/0x%p)\n",

		 NFS_I(inode)->fscache, page, page->index, page->flags, inode);



	ret = fscache_read_or_alloc_page(NFS_I(inode)->fscache,

					 page,

					 nfs_readpage_from_fscache_complete,

					 ctx,

					 GFP_KERNEL);



	switch (ret) {

	case 0: /* read BIO submitted (page in fscache) */

		dfprintk(FSCACHE,

			 "NFS:    readpage_from_fscache: BIO submitted\n");

		nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK, 1);

		return ret;



	case -ENOBUFS: /* inode not in cache */

	case -ENODATA: /* page not in cache */

		nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL, 1);

		dfprintk(FSCACHE,

			 "NFS:    readpage_from_fscache %d\n", ret);

		return 1;



	default:

		dfprintk(FSCACHE, "NFS:    readpage_from_fscache %d\n", ret);

		nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL, 1);

	}

	return ret;

}



/*

 * Retrieve a set of pages from fscache

 */

int __nfs_readpages_from_fscache(struct nfs_open_context *ctx,

				 struct inode *inode,

				 struct address_space *mapping,

				 struct list_head *pages,

				 unsigned *nr_pages)

{

	int ret, npages = *nr_pages;



	dfprintk(FSCACHE, "NFS: nfs_getpages_from_fscache (0x%p/%u/0x%p)\n",

		 NFS_I(inode)->fscache, npages, inode);



	ret = fscache_read_or_alloc_pages(NFS_I(inode)->fscache,

					  mapping, pages, nr_pages,

					  nfs_readpage_from_fscache_complete,

					  ctx,

					  mapping_gfp_mask(mapping));

	if (*nr_pages < npages)

		nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK,

				      npages);

	if (*nr_pages > 0)

		nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL,

				      *nr_pages);



	switch (ret) {

	case 0: /* read submitted to the cache for all pages */

		BUG_ON(!list_empty(pages));

		BUG_ON(*nr_pages != 0);

		dfprintk(FSCACHE,

			 "NFS: nfs_getpages_from_fscache: submitted\n");



		return ret;



	case -ENOBUFS: /* some pages aren't cached and can't be */

	case -ENODATA: /* some pages aren't cached */

		dfprintk(FSCACHE,

			 "NFS: nfs_getpages_from_fscache: no page: %d\n", ret);

		return 1;



	default:

		dfprintk(FSCACHE,

			 "NFS: nfs_getpages_from_fscache: ret  %d\n", ret);

	}



	return ret;

}

fs/nfs/fscache.h

+47 −0
Original line number Diff line number Diff line
@@ -86,6 +86,12 @@ extern void nfs_fscache_reset_inode_cookie(struct inode *); 
extern void __nfs_fscache_invalidate_page(struct page *, struct inode *);

extern int nfs_fscache_release_page(struct page *, gfp_t);



extern int __nfs_readpage_from_fscache(struct nfs_open_context *,

				       struct inode *, struct page *);

extern int __nfs_readpages_from_fscache(struct nfs_open_context *,

					struct inode *, struct address_space *,

					struct list_head *, unsigned *);



/*

 * wait for a page to complete writing to the cache

 */
@@ -107,6 +113,32 @@ static inline void nfs_fscache_invalidate_page(struct page *page, 
		__nfs_fscache_invalidate_page(page, inode);

}



/*

 * Retrieve a page from an inode data storage object.

 */

static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,

					    struct inode *inode,

					    struct page *page)

{

	if (NFS_I(inode)->fscache)

		return __nfs_readpage_from_fscache(ctx, inode, page);

	return -ENOBUFS;

}



/*

 * Retrieve a set of pages from an inode data storage object.

 */

static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,

					     struct inode *inode,

					     struct address_space *mapping,

					     struct list_head *pages,

					     unsigned *nr_pages)

{

	if (NFS_I(inode)->fscache)

		return __nfs_readpages_from_fscache(ctx, inode, mapping, pages,

						    nr_pages);

	return -ENOBUFS;

}



#else /* CONFIG_NFS_FSCACHE */

static inline int nfs_fscache_register(void) { return 0; }
@@ -138,5 +170,20 @@ static inline void nfs_fscache_invalidate_page(struct page *page, 
static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,

						  struct page *page) {}



static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,

					    struct inode *inode,

					    struct page *page)

{

	return -ENOBUFS;

}

static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,

					     struct inode *inode,

					     struct address_space *mapping,

					     struct list_head *pages,

					     unsigned *nr_pages)

{

	return -ENOBUFS;

}



#endif /* CONFIG_NFS_FSCACHE */

#endif /* _NFS_FSCACHE_H */

fs/nfs/read.c

+18 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 


#include "internal.h"

#include "iostat.h"

#include "fscache.h"



#define NFSDBG_FACILITY		NFSDBG_PAGECACHE
@@ -510,8 +511,15 @@ int nfs_readpage(struct file *file, struct page *page) 
	} else

		ctx = get_nfs_open_context(nfs_file_open_context(file));



	if (!IS_SYNC(inode)) {

		error = nfs_readpage_from_fscache(ctx, inode, page);

		if (error == 0)

			goto out;

	}



	error = nfs_readpage_async(ctx, inode, page);



out:

	put_nfs_open_context(ctx);

	return error;

out_unlock:
@@ -584,6 +592,15 @@ int nfs_readpages(struct file *filp, struct address_space *mapping, 
			return -EBADF;

	} else

		desc.ctx = get_nfs_open_context(nfs_file_open_context(filp));



	/* attempt to read as many of the pages as possible from the cache

	 * - this returns -ENOBUFS immediately if the cookie is negative

	 */

	ret = nfs_readpages_from_fscache(desc.ctx, inode, mapping,

					 pages, &nr_pages);

	if (ret == 0)

		goto read_complete; /* all pages were read */



	if (rsize < PAGE_CACHE_SIZE)

		nfs_pageio_init(&pgio, inode, nfs_pagein_multi, rsize, 0);

	else
@@ -594,6 +611,7 @@ int nfs_readpages(struct file *filp, struct address_space *mapping, 
	nfs_pageio_complete(&pgio);

	npages = (pgio.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);

out:

	return ret;