linux-kernel - [PATCH 5.10 430/452] xfs: set inode size after creating symlink

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Date:   Tue,  7 Jun 2022 19:04:47 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Jeffrey Mitchell <jeffrey.mitchell@...rlab.io>,
        "Darrick J. Wong" <djwong@...nel.org>,
        Christoph Hellwig <hch@....de>,
        Brian Foster <bfoster@...hat.com>,
        Amir Goldstein <amir73il@...il.com>
Subject: [PATCH 5.10 430/452] xfs: set inode size after creating symlink

From: Jeffrey Mitchell <jeffrey.mitchell@...rlab.io>

commit 8aa921a95335d0a8c8e2be35a44467e7c91ec3e4 upstream.

When XFS creates a new symlink, it writes its size to disk but not to the
VFS inode. This causes i_size_read() to return 0 for that symlink until
it is re-read from disk, for example when the system is rebooted.

I found this inconsistency while protecting directories with eCryptFS.
The command "stat path/to/symlink/in/ecryptfs" will report "Size: 0" if
the symlink was created after the last reboot on an XFS root.

Call i_size_write() in xfs_symlink()

Signed-off-by: Jeffrey Mitchell <jeffrey.mitchell@...rlab.io>
Reviewed-by: Darrick J. Wong <djwong@...nel.org>
Signed-off-by: Darrick J. Wong <djwong@...nel.org>
Reviewed-by: Christoph Hellwig <hch@....de>
Reviewed-by: Brian Foster <bfoster@...hat.com>
Signed-off-by: Amir Goldstein <amir73il@...il.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/xfs/xfs_symlink.c |    1 +
 1 file changed, 1 insertion(+)

--- a/fs/xfs/xfs_symlink.c
+++ b/fs/xfs/xfs_symlink.c
@@ -300,6 +300,7 @@ xfs_symlink(
 		}
 		ASSERT(pathlen == 0);
 	}
+	i_size_write(VFS_I(ip), ip->i_d.di_size);
 
 	/*
 	 * Create the directory entry for the symlink.