On Thu, Mar 15, 2007 at 05:17:04PM +0100, Nick Piggin wrote:
> (excludes the OCFS2 patch that Mark sent, in anticipation of an update)

Attached is said patch. I needed to export __grab_cache_page (ext2/ext3 also
need this if they're to be built as modules), so a patch to do that is also
attached.

This passed some preliminary testing on a two node cluster I have here at
Oracle.
        --Mark

--
Mark Fasheh
Senior Software Developer, Oracle
[EMAIL PROTECTED]

From: Mark Fasheh <[EMAIL PROTECTED]>

ocfs2: Convert to new aops

Turn ocfs2_prepare_write() and ocfs2_commit_write() into ocfs2_write_begin()
and ocfs2_write_end(). This conveniently eliminates the need for
AOP_TRUNCATED_PAGE during write.

Signed-off-by: Mark Fasheh <[EMAIL PROTECTED]>


e28911070b02362a9a3a543646da84a8fbf9f63b
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 875c114..cbec0e1 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -293,29 +293,67 @@ int ocfs2_prepare_write_nolock(struct in
 }
 
 /*
- * ocfs2_prepare_write() can be an outer-most ocfs2 call when it is called
- * from loopback.  It must be able to perform its own locking around
- * ocfs2_get_block().
+ * ocfs2_write_begin() can be an outer-most ocfs2 call when it is
+ * called from elsewhere in the kernel. It must be able to perform its
+ * own locking around ocfs2_get_block().
  */
-static int ocfs2_prepare_write(struct file *file, struct page *page,
-                              unsigned from, unsigned to)
+static int ocfs2_write_begin(struct file *file, struct address_space *mapping,
+                            loff_t pos, unsigned len, unsigned flags,
+                            struct page **pagep, void **fsdata)
 {
-       struct inode *inode = page->mapping->host;
+       struct inode *inode = mapping->host;
+       struct buffer_head *di_bh = NULL;
+       struct page *page = NULL;
        int ret;
 
-       mlog_entry("(0x%p, 0x%p, %u, %u)\n", file, page, from, to);
-
-       ret = ocfs2_meta_lock_with_page(inode, NULL, 0, page);
+       ret = ocfs2_meta_lock(inode, &di_bh, 1);
        if (ret != 0) {
                mlog_errno(ret);
+               return ret;
+       }
+
+       ret = ocfs2_data_lock(inode, 1);
+       if (ret) {
+               ocfs2_meta_unlock(inode, 1);
+
+               mlog_errno(ret);
+               return ret;
+       }
+
+       /*
+        * Lock the page out here to preserve ordering with
+        * ip_alloc_sem.
+        */
+       page = __grab_cache_page(mapping, pos >> PAGE_CACHE_SHIFT);
+       if (!page) {
+               ret = -ENOMEM;
+               mlog_errno(ret);
                goto out;
        }
 
-       ret = ocfs2_prepare_write_nolock(inode, page, from, to);
+       *pagep = page;
 
-       ocfs2_meta_unlock(inode, 0);
+       down_read(&OCFS2_I(inode)->ip_alloc_sem);
+       ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
+                               ocfs2_get_block);
+       up_read(&OCFS2_I(inode)->ip_alloc_sem);
 out:
-       mlog_exit(ret);
+       if (ret == 0) {
+               *fsdata = di_bh;
+       } else {
+               /*
+                * Error return - the caller won't call
+                * ocfs2_write_end, so drop cluster locks here.
+                */
+               brelse(di_bh);
+               if (page) {
+                       unlock_page(page);
+                       page_cache_release(page);
+               }
+               ocfs2_data_unlock(inode, 1);
+               ocfs2_meta_unlock(inode, 1);
+       }
+
        return ret;
 }
 
@@ -388,16 +426,18 @@ out:
        return handle;
 }
 
-static int ocfs2_commit_write(struct file *file, struct page *page,
-                             unsigned from, unsigned to)
+static int ocfs2_write_end(struct file *file, struct address_space *mapping,
+                          loff_t pos, unsigned len, unsigned copied,
+                          struct page *page, void *fsdata)
 {
        int ret;
-       struct buffer_head *di_bh = NULL;
+       unsigned from, to;
+       struct buffer_head *di_bh = fsdata;
        struct inode *inode = page->mapping->host;
        handle_t *handle = NULL;
        struct ocfs2_dinode *di;
 
-       mlog_entry("(0x%p, 0x%p, %u, %u)\n", file, page, from, to);
+       mlog_entry("(0x%p, 0x%p)\n", file, page);
 
        /* NOTE: ocfs2_file_aio_write has ensured that it's safe for
         * us to continue here without rechecking the I/O against
@@ -412,22 +452,13 @@ static int ocfs2_commit_write(struct fil
         *    stale inode allocation image (i_size, i_clusters, etc).
         */
 
-       ret = ocfs2_meta_lock_with_page(inode, &di_bh, 1, page);
-       if (ret != 0) {
-               mlog_errno(ret);
-               goto out;
-       }
-
-       ret = ocfs2_data_lock_with_page(inode, 1, page);
-       if (ret != 0) {
-               mlog_errno(ret);
-               goto out_unlock_meta;
-       }
+       from = pos & (PAGE_CACHE_SIZE - 1);
+       to = from + len;
 
        handle = ocfs2_start_walk_page_trans(inode, page, from, to);
        if (IS_ERR(handle)) {
                ret = PTR_ERR(handle);
-               goto out_unlock_data;
+               goto out_unlock;
        }
 
        /* Mark our buffer early. We'd rather catch this error up here
@@ -441,8 +472,10 @@ static int ocfs2_commit_write(struct fil
        }
 
        /* might update i_size */
-       ret = generic_commit_write(file, page, from, to);
-       if (ret < 0) {
+       copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
+       if (copied < 0) {
+               ret = copied;
+               copied = 0;
                mlog_errno(ret);
                goto out_commit;
        }
@@ -458,23 +491,30 @@ static int ocfs2_commit_write(struct fil
        di->i_size = cpu_to_le64((u64)i_size_read(inode));
 
        ret = ocfs2_journal_dirty(handle, di_bh);
-       if (ret < 0) {
+       if (ret < 0)
                mlog_errno(ret);
-               goto out_commit;
-       }
 
+       ret = 0;
 out_commit:
        ocfs2_commit_trans(OCFS2_SB(inode->i_sb), handle);
-out_unlock_data:
+out_unlock:
        ocfs2_data_unlock(inode, 1);
-out_unlock_meta:
        ocfs2_meta_unlock(inode, 1);
-out:
+
+       if (ret) {
+               /*
+                * We caught an error before block_write_end() -
+                * unlock and free the page.
+                */
+               unlock_page(page);
+               page_cache_release(page);
+       }
+
        if (di_bh)
                brelse(di_bh);
 
        mlog_exit(ret);
-       return ret;
+       return copied ? copied : ret;
 }
 
 static sector_t ocfs2_bmap(struct address_space *mapping, sector_t block)
@@ -678,8 +718,8 @@ out:
 const struct address_space_operations ocfs2_aops = {
        .readpage       = ocfs2_readpage,
        .writepage      = ocfs2_writepage,
-       .prepare_write  = ocfs2_prepare_write,
-       .commit_write   = ocfs2_commit_write,
+       .write_begin    = ocfs2_write_begin,
+       .write_end      = ocfs2_write_end,
        .bmap           = ocfs2_bmap,
        .sync_page      = block_sync_page,
        .direct_IO      = ocfs2_direct_IO,
-- 
1.3.3

From: Mark Fasheh <[EMAIL PROTECTED]>

[PATCH] Export __grab_cache_page

Needed at least by ocfs2 and ext[23].

Signed-off-by: Mark Fasheh <[EMAIL PROTECTED]>


ec4c66f0e6012a182105405aa11813fbf836629f
diff --git a/mm/filemap.c b/mm/filemap.c
index 327c20f..c4a2d68 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2196,6 +2196,7 @@ repeat:
        }
        return page;
 }
+EXPORT_SYMBOL(__grab_cache_page);
 
 static ssize_t generic_perform_write_2copy(struct file *file,
                                struct iov_iter *i, loff_t pos)
-- 
1.3.3

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