On Tue, 9 Aug 2005, Arjan van de Ven wrote:
> On Tue, 2005-08-09 at 18:35 +0530, [email protected] wrote:
> > Hi,
> >
> > This is back-port of O_DIRECT support for ext3 from 2.6 to 2.4.31
> > kernel.
> >
> > Any suggestions/comments ?
>
> why?
>
> personally I think this is way out of scope for a 2.4.x release in this
> phase of 2.4's life.
>
> (also you wrapped your patch)
All other journal file systems in 2.4 have been supporting directIO and
there are multiple threads where people have been asking for it in ext3.
I needed it for one of my applications and sent it since it might be
useful for others as well.
(Resending the patch after getting the wrapping corrected)
Thanks.
--- linux-2.4-latest/fs/ext3/inode.c 2005-08-08 11:46:52.000000000 +0530
+++ linux-2.4.31/fs/ext3/inode.c 2005-08-09 14:59:16.000000000 +0530
@@ -31,6 +31,7 @@
#include <linux/highuid.h>
#include <linux/quotaops.h>
#include <linux/module.h>
+#include <linux/iobuf.h>
/*
* SEARCH_FROM_ZERO forces each block allocation to search from the start
@@ -1388,6 +1389,68 @@
}
+#define DIO_CREDITS (EXT3_RESERVE_TRANS_BLOCKS + 32)
+
+static int ext3_direct_IO(int rw, struct inode * inode, struct kiobuf * iobuf, unsigned long blocknr, int blocksize)
+{
+ ssize_t ret;
+ loff_t offset, final_size;
+ handle_t *handle = NULL;
+ int orphan = 0;
+ struct ext3_inode_info *ei = EXT3_I(inode);
+
+ offset = ((loff_t)blocknr) * blocksize;
+ final_size = offset + iobuf->length;
+
+ if (rw == WRITE) {
+
+ handle = ext3_journal_start(inode, DIO_CREDITS);
+ if (IS_ERR(handle)) {
+ ret = PTR_ERR(handle);
+ goto out;
+ }
+ if (final_size > inode->i_size) {
+ ret = ext3_orphan_add(handle, inode);
+ if (ret)
+ goto out_stop;
+ orphan = 1;
+ ei->i_disksize = inode->i_size;
+ }
+ }
+
+ ret = generic_direct_IO(rw, inode, iobuf, blocknr, blocksize, ext3_get_block);
+
+ handle = journal_current_handle();
+
+out_stop:
+ if (handle) {
+ int err;
+
+ if (orphan && inode->i_nlink)
+ ext3_orphan_del(handle, inode);
+ if (orphan && ret > 0) {
+ loff_t end = offset + ret;
+ if (end > inode->i_size) {
+ ei->i_disksize = end;
+ inode->i_size = end;
+ /*
+ * We're going to return a positive `ret'
+ * here due to non-zero-length I/O, so there's
+ * no way of reporting error returns from
+ * ext3_mark_inode_dirty() to userspace. So
+ * ignore it.
+ */
+ ext3_mark_inode_dirty(handle, inode);
+ }
+ }
+ err = ext3_journal_stop(handle, inode);
+ if (ret == 0)
+ ret = err;
+ }
+out:
+ return ret;
+}
+
struct address_space_operations ext3_aops = {
readpage: ext3_readpage, /* BKL not held. Don't need */
writepage: ext3_writepage, /* BKL not held. We take it */
@@ -1397,6 +1460,7 @@
bmap: ext3_bmap, /* BKL held */
flushpage: ext3_flushpage, /* BKL not held. Don't need */
releasepage: ext3_releasepage, /* BKL not held. Don't need */
+ direct_IO: ext3_direct_IO,
};
/*
-
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