--- /dev/null
+From: Suresh Jayaraman <sjayaraman-l3A5Bk7waGM@public.gmane.org>
+Subject: [RFC][PATCH 09/10] cifs: read pages from FS-Cache
+Date: Tue, 22 Jun 2010 20:54:21 +0530
+Lines: 219
+Message-ID: <1277220261-3717-1-git-send-email-sjayaraman@suse.de>
+References: <yes>
+Cc: linux-cifs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
+ linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, David Howells <dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
+To: Steve French <smfrench-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
+X-From: linux-cifs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Tue Jun 22 17:44:46 2010
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+Archived-At: <http://permalink.gmane.org/gmane.linux.kernel/1001762>
+
+Read pages from a FS-Cache data storage object into a CIFS inode.
+
+Signed-off-by: Suresh Jayaraman <sjayaraman-l3A5Bk7waGM@public.gmane.org>
+---
+ fs/cifs/file.c | 19 ++++++++++++++
+ fs/cifs/fscache.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++++
+ fs/cifs/fscache.h | 40 ++++++++++++++++++++++++++++-
+ 3 files changed, 131 insertions(+), 1 deletions(-)
+
+diff --git a/fs/cifs/file.c b/fs/cifs/file.c
+index 39c1ce0..42d2f25 100644
+--- a/fs/cifs/file.c
++++ b/fs/cifs/file.c
+@@ -1978,6 +1978,16 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
+ cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
+ pTcon = cifs_sb->tcon;
+
++ /*
++ * Reads as many pages as possible from fscache. Returns -ENOBUFS
++ * immediately if the cookie is negative
++ */
++ rc = cifs_readpages_from_fscache(mapping->host, mapping, page_list,
++ &num_pages);
++ cFYI(1, "CIFS: readpages_from_fscache returned %d\n", rc);
++ if (rc == 0)
++ goto read_complete;
++
+ cFYI(DBG2, "rpages: num pages %d", num_pages);
+ for (i = 0; i < num_pages; ) {
+ unsigned contig_pages;
+@@ -2090,6 +2100,7 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
+ smb_read_data = NULL;
+ }
+
++read_complete:
+ FreeXid(xid);
+ return rc;
+ }
+@@ -2100,6 +2111,12 @@ static int cifs_readpage_worker(struct file *file, struct page *page,
+ char *read_data;
+ int rc;
+
++ /* Is the page cached? */
++ rc = cifs_readpage_from_fscache(file->f_path.dentry->d_inode, page);
++ cFYI(1, "CIFS: cifs_readpage_from_fscache returned %d\n", rc);
++ if (rc == 0)
++ goto read_complete;
++
+ page_cache_get(page);
+ read_data = kmap(page);
+ /* for reads over a certain size could initiate async read ahead */
+@@ -2128,6 +2145,8 @@ static int cifs_readpage_worker(struct file *file, struct page *page,
+ io_error:
+ kunmap(page);
+ page_cache_release(page);
++
++read_complete:
+ return rc;
+ }
+
+diff --git a/fs/cifs/fscache.c b/fs/cifs/fscache.c
+index 13e47d5..6813737 100644
+--- a/fs/cifs/fscache.c
++++ b/fs/cifs/fscache.c
+@@ -145,6 +145,79 @@ int cifs_fscache_release_page(struct page *page, gfp_t gfp)
+ return 1;
+ }
+
++static void cifs_readpage_from_fscache_complete(struct page *page, void *ctx,
++ int error)
++{
++ cFYI(1, "CFS: readpage_from_fscache_complete (0x%p/%d)\n",
++ page, error);
++ if (!error)
++ SetPageUptodate(page);
++ unlock_page(page);
++}
++
++/*
++ * Retrieve a page from FS-Cache
++ */
++int __cifs_readpage_from_fscache(struct inode *inode, struct page *page)
++{
++ int ret;
++
++ cFYI(1, "CIFS: readpage_from_fscache(fsc:%p, p:%p, i:0x%p\n",
++ CIFS_I(inode)->fscache, page, inode);
++ ret = fscache_read_or_alloc_page(CIFS_I(inode)->fscache, page,
++ cifs_readpage_from_fscache_complete,
++ NULL,
++ GFP_KERNEL);
++ switch (ret) {
++
++ case 0: /* page found in fscache, read submitted */
++ cFYI(1, "CIFS: readpage_from_fscache: submitted\n");
++ return ret;
++ case -ENOBUFS: /* page won't be cached */
++ case -ENODATA: /* page not in cache */
++ cFYI(1, "CIFS: readpage_from_fscache %d\n", ret);
++ return 1;
++
++ default:
++ cFYI(1, "unknown error ret = %d", ret);
++ }
++ return ret;
++}
++
++/*
++ * Retrieve a set of pages from FS-Cache
++ */
++int __cifs_readpages_from_fscache(struct inode *inode,
++ struct address_space *mapping,
++ struct list_head *pages,
++ unsigned *nr_pages)
++{
++ int ret;
++
++ cFYI(1, "CIFS: __cifs_readpages_from_fscache (0x%p/%u/0x%p)\n",
++ CIFS_I(inode)->fscache, *nr_pages, inode);
++ ret = fscache_read_or_alloc_pages(CIFS_I(inode)->fscache, mapping,
++ pages, nr_pages,
++ cifs_readpage_from_fscache_complete,
++ NULL,
++ mapping_gfp_mask(mapping));
++ switch (ret) {
++ case 0: /* read submitted to the cache for all pages */
++ cFYI(1, "CIFS: readpages_from_fscache\n");
++ return ret;
++
++ case -ENOBUFS: /* some pages are not cached and can't be */
++ case -ENODATA: /* some pages are not cached */
++ cFYI(1, "CIFS: readpages_from_fscache: no page\n");
++ return 1;
++
++ default:
++ cFYI(1, "unknown error ret = %d", ret);
++ }
++
++ return ret;
++}
++
+ void __cifs_readpage_to_fscache(struct inode *inode, struct page *page)
+ {
+ int ret;
+diff --git a/fs/cifs/fscache.h b/fs/cifs/fscache.h
+index e34d8ab..03bd3fe 100644
+--- a/fs/cifs/fscache.h
++++ b/fs/cifs/fscache.h
+@@ -31,7 +31,6 @@ extern const struct fscache_cookie_def cifs_fscache_server_index_def;
+ extern const struct fscache_cookie_def cifs_fscache_super_index_def;
+ extern const struct fscache_cookie_def cifs_fscache_inode_object_def;
+
+-
+ extern int cifs_fscache_register(void);
+ extern void cifs_fscache_unregister(void);
+
+@@ -49,6 +48,11 @@ extern void cifs_fscache_reset_inode_cookie(struct inode *);
+
+ extern void __cifs_fscache_invalidate_page(struct page *, struct inode *);
+ extern int cifs_fscache_release_page(struct page *page, gfp_t gfp);
++extern int __cifs_readpage_from_fscache(struct inode *, struct page *);
++extern int __cifs_readpages_from_fscache(struct inode *,
++ struct address_space *,
++ struct list_head *,
++ unsigned *);
+
+ extern void __cifs_readpage_to_fscache(struct inode *, struct page *);
+
+@@ -59,6 +63,26 @@ static inline void cifs_fscache_invalidate_page(struct page *page,
+ __cifs_fscache_invalidate_page(page, inode);
+ }
+
++static inline int cifs_readpage_from_fscache(struct inode *inode,
++ struct page *page)
++{
++ if (CIFS_I(inode)->fscache)
++ return __cifs_readpage_from_fscache(inode, page);
++
++ return -ENOBUFS;
++}
++
++static inline int cifs_readpages_from_fscache(struct inode *inode,
++ struct address_space *mapping,
++ struct list_head *pages,
++ unsigned *nr_pages)
++{
++ if (CIFS_I(inode)->fscache)
++ return __cifs_readpages_from_fscache(inode, mapping, pages,
++ nr_pages);
++ return -ENOBUFS;
++}
++
+ static inline void cifs_readpage_to_fscache(struct inode *inode,
+ struct page *page)
+ {
+@@ -89,6 +113,20 @@ static inline void cifs_fscache_release_page(struct page *page, gfp_t gfp)
+
+ static inline int cifs_fscache_invalidate_page(struct page *page,
+ struct inode *) {}
++static inline int
++cifs_readpage_from_fscache(struct inode *inode, struct page *page)
++{
++ return -ENOBUFS;
++}
++
++static inline int cifs_readpages_from_fscache(struct inode *inode,
++ struct address_space *mapping,
++ struct list_head *pages,
++ unsigned *nr_pages)
++{
++ return -ENOBUFS;
++}
++
+ static inline void cifs_readpage_to_fscache(struct inode *inode,
+ struct page *page) {}
+
+--
+1.6.4.2
+
+
+