Attachment 306272 Details for Bug 439194 – patch.

[patch] patch.

ext3-fix-dio-memory-pressure-problem.patch (text/plain), 4.65 KB, created by Josef Bacik on 2008-05-21 16:03:27 UTC

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Creator: Josef Bacik

Created: 2008-05-21 16:03:27 UTC

Size: 4.65 KB

patch

obsolete

>Index: kernel/fs/ext3/inode.c
>===================================================================
>--- kernel.orig/fs/ext3/inode.c
>+++ kernel/fs/ext3/inode.c
>@@ -941,55 +941,45 @@ out:
> 	return err;
> }
> 
>-#define DIO_CREDITS (EXT3_RESERVE_TRANS_BLOCKS + 32)
>+/* Maximum number of blocks we map for direct IO at once. */
>+#define DIO_MAX_BLOCKS 4096
>+/*
>+ * Number of credits we need for writing DIO_MAX_BLOCKS:
>+ * We need sb + group descriptor + bitmap + inode -> 4
>+ * For B blocks with A block pointers per block we need:
>+ * 1 (triple ind.) + (B/A/A + 2) (doubly ind.) + (B/A + 2) (indirect).
>+ * If we plug in 4096 for B and 256 for A (for 1KB block size), we get 25.
>+ */
>+#define DIO_CREDITS 25
> 
> static int ext3_get_block(struct inode *inode, sector_t iblock,
> 			struct buffer_head *bh_result, int create)
> {
> 	handle_t *handle = journal_current_handle();
>-	int ret = 0;
>+	int ret = 0, started = 0;
> 	unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
> 
>-	if (!create)
>-		goto get_block;		/* A read */
>-
>-	if (max_blocks == 1)
>-		goto get_block;		/* A single block get */
>-
>-	if (handle->h_transaction->t_state == T_LOCKED) {
>-		/*
>-		 * Huge direct-io writes can hold off commits for long
>-		 * periods of time.  Let this commit run.
>-		 */
>-		ext3_journal_stop(handle);
>-		handle = ext3_journal_start(inode, DIO_CREDITS);
>-		if (IS_ERR(handle))
>+	if (create && !handle) {	/* Direct IO write... */
>+		if (max_blocks > DIO_MAX_BLOCKS)
>+			max_blocks = DIO_MAX_BLOCKS;
>+		handle = ext3_journal_start(inode, DIO_CREDITS +
>+				2 * EXT3_QUOTA_TRANS_BLOCKS(inode->i_sb));
>+		if (IS_ERR(handle)) {
> 			ret = PTR_ERR(handle);
>-		goto get_block;
>-	}
>-
>-	if (handle->h_buffer_credits <= EXT3_RESERVE_TRANS_BLOCKS) {
>-		/*
>-		 * Getting low on buffer credits...
>-		 */
>-		ret = ext3_journal_extend(handle, DIO_CREDITS);
>-		if (ret > 0) {
>-			/*
>-			 * Couldn't extend the transaction.  Start a new one.
>-			 */
>-			ret = ext3_journal_restart(handle, DIO_CREDITS);
>+			goto out;
> 		}
>+		started = 1;
> 	}
> 
>-get_block:
>-	if (ret == 0) {
>-		ret = ext3_get_blocks_handle(handle, inode, iblock,
>+	ret = ext3_get_blocks_handle(handle, inode, iblock,
> 					max_blocks, bh_result, create, 0);
>-		if (ret > 0) {
>-			bh_result->b_size = (ret << inode->i_blkbits);
>-			ret = 0;
>-		}
>+	if (ret > 0) {
>+		bh_result->b_size = (ret << inode->i_blkbits);
>+		ret = 0;
> 	}
>+	if (started)
>+		ext3_journal_stop(handle);
>+out:
> 	return ret;
> }
> 
>@@ -1613,7 +1603,8 @@ static int ext3_releasepage(struct page 
>  * if the machine crashes during the write.
>  *
>  * If the O_DIRECT write is intantiating holes inside i_size and the machine
>- * crashes then stale disk data _may_ be exposed inside the file.
>+ * crashes then stale disk data _may_ be exposed inside the file. But current
>+ * VFS code falls back into buffered path in that case so we are safe.
>  */
> static ssize_t ext3_direct_IO(int rw, struct kiocb *iocb,
> 			const struct iovec *iov, loff_t offset,
>@@ -1622,7 +1613,7 @@ static ssize_t ext3_direct_IO(int rw, st
> 	struct file *file = iocb->ki_filp;
> 	struct inode *inode = file->f_mapping->host;
> 	struct ext3_inode_info *ei = EXT3_I(inode);
>-	handle_t *handle = NULL;
>+	handle_t *handle;
> 	ssize_t ret;
> 	int orphan = 0;
> 	size_t count = iov_length(iov, nr_segs);
>@@ -1630,17 +1621,21 @@ static ssize_t ext3_direct_IO(int rw, st
> 	if (rw == WRITE) {
> 		loff_t final_size = offset + count;
> 
>-		handle = ext3_journal_start(inode, DIO_CREDITS);
>-		if (IS_ERR(handle)) {
>-			ret = PTR_ERR(handle);
>-			goto out;
>-		}
> 		if (final_size > inode->i_size) {
>+			/* Credits for sb + inode write */
>+			handle = ext3_journal_start(inode, 2);
>+			if (IS_ERR(handle)) {
>+				ret = PTR_ERR(handle);
>+				goto out;
>+			}
> 			ret = ext3_orphan_add(handle, inode);
>-			if (ret)
>-				goto out_stop;
>+			if (ret) {
>+				ext3_journal_stop(handle);
>+				goto out;
>+			}
> 			orphan = 1;
> 			ei->i_disksize = inode->i_size;
>+			ext3_journal_stop(handle);
> 		}
> 	}
> 
>@@ -1648,18 +1643,21 @@ static ssize_t ext3_direct_IO(int rw, st
> 				 offset, nr_segs,
> 				 ext3_get_block, NULL);
> 
>-	/*
>-	 * Reacquire the handle: ext3_get_block() can restart the transaction
>-	 */
>-	handle = journal_current_handle();
>-
>-out_stop:
>-	if (handle) {
>+	if (orphan) {
> 		int err;
> 
>-		if (orphan && inode->i_nlink)
>+		/* Credits for sb + inode write */
>+		handle = ext3_journal_start(inode, 2);
>+		if (IS_ERR(handle)) {
>+			/* This is really bad luck. We've written the data
>+			 * but cannot extend i_size. Bail out and pretend
>+			 * the write failed... */
>+			ret = PTR_ERR(handle);
>+			goto out;
>+		}
>+		if (inode->i_nlink)
> 			ext3_orphan_del(handle, inode);
>-		if (orphan && ret > 0) {
>+		if (ret > 0) {
> 			loff_t end = offset + ret;
> 			if (end > inode->i_size) {
> 				ei->i_disksize = end;

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Attachments on bug 439194: 306272