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FAILED: patch "[PATCH] block: Hold invalidate_lock in BLKZEROOUT ioctl" failed to apply to 5.4-stable tree

PATCH [email protected] 1 participant 1 message Nov 15, 2021

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The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 35e4c6c1a2fc2eb11b9306e95cda1fa06a511948 Mon Sep 17 00:00:00 2001
From: Shin'ichiro Kawasaki <[email protected]>
Date: Tue, 9 Nov 2021 19:47:23 +0900
Subject: [PATCH] block: Hold invalidate_lock in BLKZEROOUT ioctl

When BLKZEROOUT ioctl and data read race, the data read leaves stale page cache. To avoid the stale page cache, hold invalidate_lock of the block device file mapping. The stale page cache is observed when blktests test case block/009 is modified to call "blkdiscard -z" command and repeated hundreds of times.

This patch can be applied back to the stable kernel version v5.15.y. Rework is required for older stable kernels.

Fixes 22dd6d356628 ("block: invalidate the page cache when issuing BLKZEROOUT")
Signed-off-by Shin'ichiro Kawasaki <[email protected]>
Cc [email protected] # v5.15
Reviewed-by Jan Kara <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
Signed-off-by Jens Axboe <[email protected]>
block/ioctl.c +9 -3
index 9fa87f64f703..0a1d10ac2e1a 100644
@@ -154,6 +154,7 @@ static int blk_ioctl_zeroout(struct block_device *bdev, fmode_t mode,
 {
 	uint64_t range[2];
 	uint64_t start, end, len;
+	struct inode *inode = bdev->bd_inode;
 	int err;
 
 	if (!(mode & FMODE_WRITE))

@@ -176,12 +177,17 @@ static int blk_ioctl_zeroout(struct block_device *bdev, fmode_t mode,
 		return -EINVAL;
 
 	/* Invalidate the page cache, including dirty pages */
+	filemap_invalidate_lock(inode->i_mapping);
 	err = truncate_bdev_range(bdev, mode, start, end);
 	if (err)
-		return err;
+		goto fail;
+
+	err = blkdev_issue_zeroout(bdev, start >> 9, len >> 9, GFP_KERNEL,
+				   BLKDEV_ZERO_NOUNMAP);
 
-	return blkdev_issue_zeroout(bdev, start >> 9, len >> 9, GFP_KERNEL,
-			BLKDEV_ZERO_NOUNMAP);
+fail:
+	filemap_invalidate_unlock(inode->i_mapping);
+	return err;
 }
 
 static int put_ushort(unsigned short __user *argp, unsigned short val)