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Commit 545db45f authored by David Howells's avatar David Howells
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NFS: FS-Cache page management 



FS-Cache page management for NFS.  This includes hooking the releasing and
invalidation of pages marked with PG_fscache (aka PG_private_2) and waiting for
completion of the write-to-cache flag (PG_fscache_write aka PG_owner_priv_2).

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 6a51091d

fs/nfs/file.c

+14 −4
Original line number Diff line number Diff line
@@ -35,6 +35,7 @@ 
#include "delegation.h"

#include "internal.h"

#include "iostat.h"

#include "fscache.h"



#define NFSDBG_FACILITY		NFSDBG_FILE
@@ -413,7 +414,7 @@ static int nfs_write_end(struct file *file, struct address_space *mapping, 
 * Partially or wholly invalidate a page

 * - Release the private state associated with a page if undergoing complete

 *   page invalidation

 * - Called if either PG_private or PG_private_2 is set on the page

 * - Called if either PG_private or PG_fscache is set on the page

 * - Caller holds page lock

 */

static void nfs_invalidate_page(struct page *page, unsigned long offset)
@@ -424,11 +425,13 @@ static void nfs_invalidate_page(struct page *page, unsigned long offset) 
		return;

	/* Cancel any unstarted writes on this page */

	nfs_wb_page_cancel(page->mapping->host, page);



	nfs_fscache_invalidate_page(page, page->mapping->host);

}



/*

 * Attempt to release the private state associated with a page

 * - Called if either PG_private or PG_private_2 is set on the page

 * - Called if either PG_private or PG_fscache is set on the page

 * - Caller holds page lock

 * - Return true (may release page) or false (may not)

 */
@@ -437,24 +440,28 @@ static int nfs_release_page(struct page *page, gfp_t gfp) 
	dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page);



	/* If PagePrivate() is set, then the page is not freeable */

	if (PagePrivate(page))

		return 0;

	return nfs_fscache_release_page(page, gfp);

}



/*

 * Attempt to clear the private state associated with a page when an error

 * occurs that requires the cached contents of an inode to be written back or

 * destroyed

 * - Called if either PG_private or PG_private_2 is set on the page

 * - Called if either PG_private or fscache is set on the page

 * - Caller holds page lock

 * - Return 0 if successful, -error otherwise

 */

static int nfs_launder_page(struct page *page)

{

	struct inode *inode = page->mapping->host;

	struct nfs_inode *nfsi = NFS_I(inode);



	dfprintk(PAGECACHE, "NFS: launder_page(%ld, %llu)\n",

		inode->i_ino, (long long)page_offset(page));



	nfs_fscache_wait_on_page_write(nfsi, page);

	return nfs_wb_page(inode, page);

}
@@ -491,6 +498,9 @@ static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) 
		filp->f_mapping->host->i_ino,

		(long long)page_offset(page));



	/* make sure the cache has finished storing the page */

	nfs_fscache_wait_on_page_write(NFS_I(dentry->d_inode), page);



	lock_page(page);

	mapping = page->mapping;

	if (mapping != dentry->d_inode->i_mapping)

fs/nfs/fscache.c

+53 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <linux/seq_file.h>



#include "internal.h"

#include "iostat.h"

#include "fscache.h"



#define NFSDBG_FACILITY		NFSDBG_FSCACHE
@@ -328,3 +329,55 @@ void nfs_fscache_reset_inode_cookie(struct inode *inode) 
	}

	nfs_fscache_inode_unlock(inode);

}



/*

 * Release the caching state associated with a page, if the page isn't busy

 * interacting with the cache.

 * - Returns true (can release page) or false (page busy).

 */

int nfs_fscache_release_page(struct page *page, gfp_t gfp)

{

	struct nfs_inode *nfsi = NFS_I(page->mapping->host);

	struct fscache_cookie *cookie = nfsi->fscache;



	BUG_ON(!cookie);



	if (fscache_check_page_write(cookie, page)) {

		if (!(gfp & __GFP_WAIT))

			return 0;

		fscache_wait_on_page_write(cookie, page);

	}



	if (PageFsCache(page)) {

		dfprintk(FSCACHE, "NFS: fscache releasepage (0x%p/0x%p/0x%p)\n",

			 cookie, page, nfsi);



		fscache_uncache_page(cookie, page);

		nfs_add_fscache_stats(page->mapping->host,

				      NFSIOS_FSCACHE_PAGES_UNCACHED, 1);

	}



	return 1;

}



/*

 * Release the caching state associated with a page if undergoing complete page

 * invalidation.

 */

void __nfs_fscache_invalidate_page(struct page *page, struct inode *inode)

{

	struct nfs_inode *nfsi = NFS_I(inode);

	struct fscache_cookie *cookie = nfsi->fscache;



	BUG_ON(!cookie);



	dfprintk(FSCACHE, "NFS: fscache invalidatepage (0x%p/0x%p/0x%p)\n",

		 cookie, page, nfsi);



	fscache_wait_on_page_write(cookie, page);



	BUG_ON(!PageLocked(page));

	fscache_uncache_page(cookie, page);

	nfs_add_fscache_stats(page->mapping->host,

			      NFSIOS_FSCACHE_PAGES_UNCACHED, 1);

}

fs/nfs/fscache.h

+34 −0
Original line number Diff line number Diff line
@@ -83,6 +83,31 @@ extern void nfs_fscache_zap_inode_cookie(struct inode *); 
extern void nfs_fscache_set_inode_cookie(struct inode *, struct file *);

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);



/*

 * wait for a page to complete writing to the cache

 */

static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,

						  struct page *page)

{

	if (PageFsCache(page))

		fscache_wait_on_page_write(nfsi->fscache, page);

}



/*

 * release the caching state associated with a page if undergoing complete page

 * invalidation

 */

static inline void nfs_fscache_invalidate_page(struct page *page,

					       struct inode *inode)

{

	if (PageFsCache(page))

		__nfs_fscache_invalidate_page(page, inode);

}





#else /* CONFIG_NFS_FSCACHE */

static inline int nfs_fscache_register(void) { return 0; }

static inline void nfs_fscache_unregister(void) {}
@@ -104,5 +129,14 @@ static inline void nfs_fscache_set_inode_cookie(struct inode *inode, 
						struct file *filp) {}

static inline void nfs_fscache_reset_inode_cookie(struct inode *inode) {}



static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp)

{

	return 1; /* True: may release page */

}

static inline void nfs_fscache_invalidate_page(struct page *page,

					       struct inode *inode) {}

static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,

						  struct page *page) {}



#endif /* CONFIG_NFS_FSCACHE */

#endif /* _NFS_FSCACHE_H */