Give appropriate and separate backing_dev_info's to both the ramdisk blockdev
inode and to the files which live atop the ramdisk.
Everything works now.
---
25-akpm/drivers/block/rd.c | 26 ++++++++++++++++----------
1 files changed, 16 insertions(+), 10 deletions(-)
diff -puN drivers/block/rd.c~ramdisk-split-backing_dev_info drivers/block/rd.c
--- 25/drivers/block/rd.c~ramdisk-split-backing_dev_info 2004-05-19 02:33:07.411221776 -0700
+++ 25-akpm/drivers/block/rd.c 2004-05-19 02:33:07.415221168 -0700
@@ -310,20 +310,25 @@ static int rd_ioctl(struct inode *inode,
}
/*
- * The backing_dev_info is shared between files which are backed by the ramdisk
- * inode and by the ramdisk inode itself. This is a bit unfortunate because
- * they really want separate semantics. The files *do* want full writeback
- * and dirty-memory accounting treatment, whereas the ramdisk blockdev mapping
- * wants neither.
- *
- * So we make things look like a regular blockdev and the cheat in various ways
- * in the ramdisk inode's a_ops.
+ * This is the backing_dev_info for the blockdev inode itself. It doesn't need
+ * writeback and it does not contribute to dirty memory accounting.
*/
-
static struct backing_dev_info rd_backing_dev_info = {
.ra_pages = 0, /* No readahead */
.no_dirty_acct = 1, /* Does not contribute to dirty memory */
- .no_writeback = 0, /* DOES need writeback */
+ .no_writeback = 1, /* Does not need writeback */
+ .unplug_io_fn = default_unplug_io_fn,
+};
+
+/*
+ * This is the backing_dev_info for the files which live atop the ramdisk
+ * "device". These files do need writeback and they do contribute to dirty
+ * memory accounting.
+ */
+static struct backing_dev_info rd_file_backing_dev_info = {
+ .ra_pages = 0, /* No readahead */
+ .no_dirty_acct = 0, /* Does contribute to dirty memory */
+ .no_writeback = 0, /* Does need writeback */
.unplug_io_fn = default_unplug_io_fn,
};
@@ -344,6 +349,7 @@ static int rd_open(struct inode *inode,
mapping = inode->i_mapping;
mapping->a_ops = &ramdisk_aops;
mapping->backing_dev_info = &rd_backing_dev_info;
+ bdev->bd_inode_backing_dev_info = &rd_file_backing_dev_info;
/*
* Deep badness. rd_blkdev_pagecache_IO() needs to allocate
_