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FAILED: patch "[PATCH] block: Hold invalidate_lock in BLKDISCARD ioctl" failed to apply to 4.19-stable tree

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

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The patch below does not apply to the 4.19-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 7607c44c157d343223510c8ffdf7206fdd2a6213 Mon Sep 17 00:00:00 2001
From: Shin'ichiro Kawasaki <[email protected]>
Date: Tue, 9 Nov 2021 19:47:22 +0900
Subject: [PATCH] block: Hold invalidate_lock in BLKDISCARD ioctl

When BLKDISCARD 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 repeated hundreds of times.

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

Fixes 351499a172c0 ("block: Invalidate cache on discard v2")
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 d6af0ac97e57..9fa87f64f703 100644
@@ -113,6 +113,7 @@ static int blk_ioctl_discard(struct block_device *bdev, fmode_t mode,
 	uint64_t range[2];
 	uint64_t start, len;
 	struct request_queue *q = bdev_get_queue(bdev);
+	struct inode *inode = bdev->bd_inode;
 	int err;
 
 	if (!(mode & FMODE_WRITE))

@@ -135,12 +136,17 @@ static int blk_ioctl_discard(struct block_device *bdev, fmode_t mode,
 	if (start + len > bdev_nr_bytes(bdev))
 		return -EINVAL;
 
+	filemap_invalidate_lock(inode->i_mapping);
 	err = truncate_bdev_range(bdev, mode, start, start + len - 1);
 	if (err)
-		return err;
+		goto fail;
+
+	err = blkdev_issue_discard(bdev, start >> 9, len >> 9,
+				   GFP_KERNEL, flags);
 
-	return blkdev_issue_discard(bdev, start >> 9, len >> 9,
-				    GFP_KERNEL, flags);
+fail:
+	filemap_invalidate_unlock(inode->i_mapping);
+	return err;
 }
 
 static int blk_ioctl_zeroout(struct block_device *bdev, fmode_t mode,