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From: Domenico Andreoli <domenico.andreoli@linux.com>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>,
	Linux PM <linux-pm@vger.kernel.org>,
	Linux Memory Management List <linux-mm@kvack.org>,
	linux-fsdevel@vger.kernel.org, mkleinsoft@gmail.com,
	Christoph Hellwig <hch@lst.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>
Subject: [PATCH] hibernate: Allow uswsusp to write to swap
Date: Wed, 4 Mar 2020 09:23:27 +0100	[thread overview]
Message-ID: <20200304082327.GA14236@dumbo> (raw)
In-Reply-To: <20200304011840.GD1752567@magnolia>

From: Domenico Andreoli <domenico.andreoli@linux.com>

It turns out that there is one use case for programs being able to
write to swap devices, and that is the userspace hibernation code.

Quick fix: disable the S_SWAPFILE check if hibernation is configured.

Fixes: 1638045c3677 ("mm: set S_SWAPFILE on blockdev swap devices")
Reported-by: Domenico Andreoli <domenico.andreoli@linux.com>
Reported-by: Marian Klein <mkleinsoft@gmail.com>
Signed-off-by: Domenico Andreoli <domenico.andreoli@linux.com>

---
 fs/block_dev.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Index: b/fs/block_dev.c
===================================================================
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -2001,7 +2001,8 @@ ssize_t blkdev_write_iter(struct kiocb *
 	if (bdev_read_only(I_BDEV(bd_inode)))
 		return -EPERM;
 
-	if (IS_SWAPFILE(bd_inode))
+	/* uswsusp needs to write to the swap */
+	if (IS_SWAPFILE(bd_inode) && !IS_ENABLED(CONFIG_HIBERNATION))
 		return -ETXTBSY;
 
 	if (!iov_iter_count(from))


  reply	other threads:[~2020-03-04  8:26 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-29 17:08 [PATCH] hibernate: unlock swap bdev for writing when uswsusp is active Darrick J. Wong
2020-02-29 18:07 ` Domenico Andreoli
2020-02-29 18:38   ` Darrick J. Wong
2020-02-29 20:02     ` Domenico Andreoli
2020-03-01 21:35       ` Rafael J. Wysocki
2020-03-02  4:51         ` Marian Klein
2020-03-03 19:02         ` Darrick J. Wong
2020-03-03 22:51           ` Domenico Andreoli
2020-03-04  1:18             ` Darrick J. Wong
2020-03-04  8:23               ` Domenico Andreoli [this message]
2020-03-04 15:45                 ` [PATCH] hibernate: Allow uswsusp to write to swap Darrick J. Wong
2020-03-04 16:31                   ` Domenico Andreoli
2020-03-04  8:34               ` [PATCH] hibernate: unlock swap bdev for writing when uswsusp is active Domenico Andreoli
2020-04-20 18:52         ` Domenico Andreoli
2020-04-21 15:43           ` Darrick J. Wong
2020-04-21 18:39             ` Domenico Andreoli

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