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From:   ira.weiny@intel.com
To:     Dan Williams <dan.j.williams@intel.com>, Jan Kara <jack@suse.cz>,
        "Theodore Ts'o" <tytso@mit.edu>, Jeff Layton <jlayton@kernel.org>,
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        Andrew Morton <akpm@linux-foundation.org>,
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Subject: [PATCH RFC 07/10] fs/ext4: Fail truncate if pages are GUP pinned
Date:   Wed,  5 Jun 2019 18:45:40 -0700
Message-Id: <20190606014544.8339-8-ira.weiny@intel.com>
In-Reply-To: <20190606014544.8339-1-ira.weiny@intel.com>
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From: Ira Weiny <ira.weiny@intel.com>

If pages are actively gup pinned fail the truncate operation.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
---
 fs/ext4/inode.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 75f543f384e4..1ded83ec08c0 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4250,6 +4250,9 @@ int ext4_break_layouts(struct inode *inode, loff_t offset, loff_t len)
 		if (!page)
 			return 0;
 
+		if (page_gup_pinned(page))
+			return -ETXTBSY;
+
 		error = ___wait_var_event(&page->_refcount,
 				atomic_read(&page->_refcount) == 1,
 				TASK_INTERRUPTIBLE, 0, 0,
-- 
2.20.1