[RFC][PATCH 14/15] tmpfs whiteout support

[Bharata B Rao <bharata@linux.vnet.ibm.com>]

From: Jan Blunck <j.blunck@tu-harburg.de>
Subject: tmpfs whiteout support

Introduce whiteout support to tmpfs.

Signed-off-by: Jan Blunck <j.blunck@tu-harburg.de>
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
---
 mm/shmem.c |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletion(-)

--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -74,7 +74,7 @@
 #define LATENCY_LIMIT	 64
 
 /* Pretend that each entry is of this size in directory's i_size */
-#define BOGO_DIRENT_SIZE 20
+#define BOGO_DIRENT_SIZE 1
 
 /* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */
 enum sgp_type {
@@ -1772,6 +1772,11 @@ static int shmem_create(struct inode *di
 	return shmem_mknod(dir, dentry, mode | S_IFREG, 0);
 }
 
+static int shmem_whiteout(struct inode *dir, struct dentry *dentry)
+{
+	return shmem_mknod(dir, dentry, S_IRUGO | S_IWUGO | S_IFWHT, 0);
+}
+
 /*
  * Link a file..
  */
@@ -2400,6 +2405,7 @@ static const struct inode_operations shm
 	.rmdir		= shmem_rmdir,
 	.mknod		= shmem_mknod,
 	.rename		= shmem_rename,
+	.whiteout       = shmem_whiteout,
 #endif
 #ifdef CONFIG_TMPFS_POSIX_ACL
 	.setattr	= shmem_notify_change,
@@ -2454,6 +2460,7 @@ static struct file_system_type tmpfs_fs_
 	.name		= "tmpfs",
 	.get_sb		= shmem_get_sb,
 	.kill_sb	= kill_litter_super,
+	.fs_flags	= FS_WHT,
 };
 static struct vfsmount *shm_mnt;