linux-kernel - [PATCH AUTOSEL for 4.9 22/55] xfs: always free inline data before resetting inode fork during ifree

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Date:   Wed, 24 Jan 2018 04:15:40 +0000
From:   Sasha Levin <Alexander.Levin@...rosoft.com>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
CC:     "Darrick J. Wong" <darrick.wong@...cle.com>,
        Sasha Levin <Alexander.Levin@...rosoft.com>
Subject: [PATCH AUTOSEL for 4.9 22/55] xfs: always free inline data before
 resetting inode fork during ifree

From: "Darrick J. Wong" <darrick.wong@...cle.com>

[ Upstream commit 98c4f78dcdd8cec112d1cbc5e9a792ee6e5ab7a6 ]

In xfs_ifree, we reset the data/attr forks to extents format without
bothering to free any inline data buffer that might still be around
after all the blocks have been truncated off the file.  Prior to commit
43518812d2 ("xfs: remove support for inlining data/extents into the
inode fork") nobody noticed because the leftover inline data after
truncation was small enough to fit inside the inline buffer inside the
fork itself.

However, now that we've removed the inline buffer, we /always/ have to
free the inline data buffer or else we leak them like crazy.  This test
was found by turning on kmemleak for generic/001 or generic/388.

Signed-off-by: Darrick J. Wong <darrick.wong@...cle.com>
Reviewed-by: Christoph Hellwig <hch@....de>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
---
 fs/xfs/xfs_inode.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 98ca9f1b6a07..c5f2f1e3cc4b 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -2430,6 +2430,24 @@ retry:
 }
 
 /*
+ * Free any local-format buffers sitting around before we reset to
+ * extents format.
+ */
+static inline void
+xfs_ifree_local_data(
+	struct xfs_inode	*ip,
+	int			whichfork)
+{
+	struct xfs_ifork	*ifp;
+
+	if (XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_LOCAL)
+		return;
+
+	ifp = XFS_IFORK_PTR(ip, whichfork);
+	xfs_idata_realloc(ip, -ifp->if_bytes, whichfork);
+}
+
+/*
  * This is called to return an inode to the inode free list.
  * The inode should already be truncated to 0 length and have
  * no pages associated with it.  This routine also assumes that
@@ -2466,6 +2484,9 @@ xfs_ifree(
 	if (error)
 		return error;
 
+	xfs_ifree_local_data(ip, XFS_DATA_FORK);
+	xfs_ifree_local_data(ip, XFS_ATTR_FORK);
+
 	VFS_I(ip)->i_mode = 0;		/* mark incore inode as free */
 	ip->i_d.di_flags = 0;
 	ip->i_d.di_dmevmask = 0;
-- 
2.11.0