linux-kernel - [PATCH 3.16 125/346] fuse: fuse_flush must check mapping->flags for errors

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Message-ID: <lsq.1479082460.184085985@decadent.org.uk>
Date:   Mon, 14 Nov 2016 00:14:20 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org,
        "Maxim Patlasov" <mpatlasov@...tuozzo.com>,
        "Miklos Szeredi" <mszeredi@...hat.com>
Subject: [PATCH 3.16 125/346] fuse: fuse_flush must check mapping->flags
 for errors

3.16.39-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Maxim Patlasov <mpatlasov@...tuozzo.com>

commit 9ebce595f63a407c5cec98f98f9da8459b73740a upstream.

fuse_flush() calls write_inode_now() that triggers writeback, but actual
writeback will happen later, on fuse_sync_writes(). If an error happens,
fuse_writepage_end() will set error bit in mapping->flags. So, we have to
check mapping->flags after fuse_sync_writes().

Signed-off-by: Maxim Patlasov <mpatlasov@...tuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@...hat.com>
Fixes: 4d99ff8f12eb ("fuse: Turn writeback cache on")
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 fs/fuse/file.c | 9 +++++++++
 1 file changed, 9 insertions(+)

--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -454,6 +454,15 @@ static int fuse_flush(struct file *file,
 	fuse_sync_writes(inode);
 	mutex_unlock(&inode->i_mutex);
 
+	if (test_bit(AS_ENOSPC, &file->f_mapping->flags) &&
+	    test_and_clear_bit(AS_ENOSPC, &file->f_mapping->flags))
+		err = -ENOSPC;
+	if (test_bit(AS_EIO, &file->f_mapping->flags) &&
+	    test_and_clear_bit(AS_EIO, &file->f_mapping->flags))
+		err = -EIO;
+	if (err)
+		return err;
+
 	req = fuse_get_req_nofail_nopages(fc, file);
 	memset(&inarg, 0, sizeof(inarg));
 	inarg.fh = ff->fh;