fs: restore nobh

Implement nobh in new aops.  This is a bit tricky.  FWIW, nobh_truncate is
now implemented in a way that does not create blocks in sparse regions,
which is a silly thing for it to have been doing (isn't it?)

ext2 survives fsx and fsstress. jfs is converted as well... ext3
should be easy to do (but not done yet).

[akpm@linux-foundation.org: coding-style fixes]
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 18 insertions, 2 deletions

diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 63ab02aa4c52..1b102a1ccebb 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -659,6 +659,20 @@ ext2_write_begin(struct file *file, struct address_space *mapping,
         return __ext2_write_begin(file, mapping, pos, len, flags, pagep,fsdata);
 }
 
+static int
+ext2_nobh_write_begin(struct file *file, struct address_space *mapping,
+                loff_t pos, unsigned len, unsigned flags,
+                struct page **pagep, void **fsdata)
+{
+        /*
+         * Dir-in-pagecache still uses ext2_write_begin. Would have to rework
+         * directory handling code to pass around offsets rather than struct
+         * pages in order to make this work easily.
+         */
+        return nobh_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
+                                                        ext2_get_block);
+}
+
 static int ext2_nobh_writepage(struct page *page,
                         struct writeback_control *wbc)
 {
@@ -710,7 +724,8 @@ const struct address_space_operations ext2_nobh_aops = {
         .readpages              = ext2_readpages,
         .writepage              = ext2_nobh_writepage,
         .sync_page              = block_sync_page,
-        /* XXX: todo */
+        .write_begin            = ext2_nobh_write_begin,
+        .write_end              = nobh_write_end,
         .bmap                   = ext2_bmap,
         .direct_IO              = ext2_direct_IO,
         .writepages             = ext2_writepages,
@@ -927,7 +942,8 @@ void ext2_truncate (struct inode * inode)
         if (mapping_is_xip(inode->i_mapping))
                 xip_truncate_page(inode->i_mapping, inode->i_size);
         else if (test_opt(inode->i_sb, NOBH))
-                nobh_truncate_page(inode->i_mapping, inode->i_size);
+                nobh_truncate_page(inode->i_mapping,
+                                inode->i_size, ext2_get_block);
         else
                 block_truncate_page(inode->i_mapping,
                                 inode->i_size, ext2_get_block);