[PATCH 4.9 38/86] xfs: always free inline data before resetting inode fork during ifree

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

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

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


[ 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@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 fs/xfs/xfs_inode.c |   21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

--- 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;