[patch 38/44] jffs2 convert to new aops

[Nick Piggin <npiggin@suse.de>]

[-- Attachment #1: fs-jffs2-aops.patch --]
[-- Type: text/plain, Size: 7474 bytes --]

Cc: dwmw2@infradead.org
Cc: jffs-dev@axis.com
Cc: Linux Filesystems <linux-fsdevel@vger.kernel.org>
Signed-off-by: Nick Piggin <npiggin@suse.de>

 fs/jffs2/file.c |  105 +++++++++++++++++++++++++++++++++++---------------------
 1 file changed, 66 insertions(+), 39 deletions(-)

Index: linux-2.6/fs/jffs2/file.c
===================================================================
--- linux-2.6.orig/fs/jffs2/file.c
+++ linux-2.6/fs/jffs2/file.c
@@ -21,10 +21,12 @@
 #include <linux/jffs2.h>
 #include "nodelist.h"
 
-static int jffs2_commit_write (struct file *filp, struct page *pg,
-			       unsigned start, unsigned end);
-static int jffs2_prepare_write (struct file *filp, struct page *pg,
-				unsigned start, unsigned end);
+static int jffs2_write_end(struct file *filp, struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned copied,
+			struct page *pg, void *fsdata);
+static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned flags,
+			struct page **pagep, void **fsdata);
 static int jffs2_readpage (struct file *filp, struct page *pg);
 
 int jffs2_fsync(struct file *filp, struct dentry *dentry, int datasync)
@@ -67,8 +69,8 @@ const struct inode_operations jffs2_file
 const struct address_space_operations jffs2_file_address_operations =
 {
 	.readpage =	jffs2_readpage,
-	.prepare_write =jffs2_prepare_write,
-	.commit_write =	jffs2_commit_write
+	.write_begin =	jffs2_write_begin,
+	.write_end =	jffs2_write_end,
 };
 
 static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
@@ -121,15 +123,23 @@ static int jffs2_readpage (struct file *
 	return ret;
 }
 
-static int jffs2_prepare_write (struct file *filp, struct page *pg,
-				unsigned start, unsigned end)
+static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned flags,
+			struct page **pagep, void **fsdata)
 {
-	struct inode *inode = pg->mapping->host;
+	struct page *pg;
+	struct inode *inode = mapping->host;
 	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
-	uint32_t pageofs = pg->index << PAGE_CACHE_SHIFT;
+	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+	uint32_t pageofs = pos & (PAGE_CACHE_SIZE - 1);
 	int ret = 0;
 
-	D1(printk(KERN_DEBUG "jffs2_prepare_write()\n"));
+	pg = __grab_cache_page(mapping, index);
+	if (!pg)
+		return -ENOMEM;
+	*pagep = pg;
+
+	D1(printk(KERN_DEBUG "jffs2_write_begin()\n"));
 
 	if (pageofs > inode->i_size) {
 		/* Make new hole frag from old EOF to new page */
@@ -144,7 +154,7 @@ static int jffs2_prepare_write (struct f
 		ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
 					  ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
 		if (ret)
-			return ret;
+			goto out_page;
 
 		down(&f->sem);
 		memset(&ri, 0, sizeof(ri));
@@ -174,7 +184,7 @@ static int jffs2_prepare_write (struct f
 			ret = PTR_ERR(fn);
 			jffs2_complete_reservation(c);
 			up(&f->sem);
-			return ret;
+			goto out_page;
 		}
 		ret = jffs2_add_full_dnode_to_inode(c, f, fn);
 		if (f->metadata) {
@@ -183,65 +193,79 @@ static int jffs2_prepare_write (struct f
 			f->metadata = NULL;
 		}
 		if (ret) {
-			D1(printk(KERN_DEBUG "Eep. add_full_dnode_to_inode() failed in prepare_write, returned %d\n", ret));
+			D1(printk(KERN_DEBUG "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n", ret));
 			jffs2_mark_node_obsolete(c, fn->raw);
 			jffs2_free_full_dnode(fn);
 			jffs2_complete_reservation(c);
 			up(&f->sem);
-			return ret;
+			goto out_page;
 		}
 		jffs2_complete_reservation(c);
 		inode->i_size = pageofs;
 		up(&f->sem);
 	}
 
-	/* Read in the page if it wasn't already present, unless it's a whole page */
-	if (!PageUptodate(pg) && (start || end < PAGE_CACHE_SIZE)) {
+	/*
+	 * Read in the page if it wasn't already present. Cannot optimize away
+	 * the whole page write case until jffs2_write_end can handle the
+	 * case of a short-copy.
+	 */
+	if (!PageUptodate(pg)) {
 		down(&f->sem);
 		ret = jffs2_do_readpage_nolock(inode, pg);
 		up(&f->sem);
+		if (ret)
+			goto out_page;
 	}
-	D1(printk(KERN_DEBUG "end prepare_write(). pg->flags %lx\n", pg->flags));
+	D1(printk(KERN_DEBUG "end write_begin(). pg->flags %lx\n", pg->flags));
+	return ret;
+
+out_page:
+	unlock_page(pg);
+	page_cache_release(pg);
 	return ret;
 }
 
-static int jffs2_commit_write (struct file *filp, struct page *pg,
-			       unsigned start, unsigned end)
+static int jffs2_write_end(struct file *filp, struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned copied,
+			struct page *pg, void *fsdata)
 {
 	/* Actually commit the write from the page cache page we're looking at.
 	 * For now, we write the full page out each time. It sucks, but it's simple
 	 */
-	struct inode *inode = pg->mapping->host;
+	struct inode *inode = mapping->host;
 	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 	struct jffs2_raw_inode *ri;
+	unsigned start = pos & (PAGE_CACHE_SIZE - 1);
+	unsigned end = start + copied;
 	unsigned aligned_start = start & ~3;
 	int ret = 0;
 	uint32_t writtenlen = 0;
 
-	D1(printk(KERN_DEBUG "jffs2_commit_write(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
+	D1(printk(KERN_DEBUG "jffs2_write_end(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
 		  inode->i_ino, pg->index << PAGE_CACHE_SHIFT, start, end, pg->flags));
 
+	/* We need to avoid deadlock with page_cache_read() in
+	   jffs2_garbage_collect_pass(). So the page must be
+	   up to date to prevent page_cache_read() from trying
+	   to re-lock it. */
+	BUG_ON(!PageUptodate(pg));
+
 	if (end == PAGE_CACHE_SIZE) {
-		if (!start) {
-			/* We need to avoid deadlock with page_cache_read() in
-			   jffs2_garbage_collect_pass(). So we have to mark the
-			   page up to date, to prevent page_cache_read() from
-			   trying to re-lock it. */
-			SetPageUptodate(pg);
-		} else {
-			/* When writing out the end of a page, write out the 
-			   _whole_ page. This helps to reduce the number of
-			   nodes in files which have many short writes, like
-			   syslog files. */
-			start = aligned_start = 0;
-		}
+		/* When writing out the end of a page, write out the
+		   _whole_ page. This helps to reduce the number of
+		   nodes in files which have many short writes, like
+		   syslog files. */
+		start = aligned_start = 0;
 	}
 
 	ri = jffs2_alloc_raw_inode();
 
 	if (!ri) {
-		D1(printk(KERN_DEBUG "jffs2_commit_write(): Allocation of raw inode failed\n"));
+		D1(printk(KERN_DEBUG "jffs2_write_end(): Allocation of raw inode failed\n"));
+		unlock_page(pg);
+		page_cache_release(pg);
 		return -ENOMEM;
 	}
 
@@ -289,11 +313,14 @@ static int jffs2_commit_write (struct fi
 		/* generic_file_write has written more to the page cache than we've
 		   actually written to the medium. Mark the page !Uptodate so that
 		   it gets reread */
-		D1(printk(KERN_DEBUG "jffs2_commit_write(): Not all bytes written. Marking page !uptodate\n"));
+		D1(printk(KERN_DEBUG "jffs2_write_end(): Not all bytes written. Marking page !uptodate\n"));
 		SetPageError(pg);
 		ClearPageUptodate(pg);
 	}
 
-	D1(printk(KERN_DEBUG "jffs2_commit_write() returning %d\n",start+writtenlen==end?0:ret));
-	return start+writtenlen==end?0:ret;
+	D1(printk(KERN_DEBUG "jffs2_write_end() returning %d\n",
+					writtenlen > 0 ? writtenlen : ret));
+	unlock_page(pg);
+	page_cache_release(pg);
+	return writtenlen > 0 ? writtenlen : ret;
 }

--