[PATCH 04/10] ovl: initialise is_real before use.

From: NeilBrown
Date: Sun Sep 05 2010 - 20:51:42 EST


The previous patch can use od->is_real before it is properly
initialised is llseek is called before readdir.
So factor out the initialisation of is_real and call it from both
readdir and llseek when f_pos is 0.

Signed-off-by: NeilBrown <neilb@xxxxxxx>
---
fs/overlayfs/overlayfs.c | 24 +++++++++++++++++-------
1 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/fs/overlayfs/overlayfs.c b/fs/overlayfs/overlayfs.c
index 306de45..de854e1 100644
--- a/fs/overlayfs/overlayfs.c
+++ b/fs/overlayfs/overlayfs.c
@@ -240,6 +240,17 @@ static int ovl_fill_cache(struct path *realpath, struct ovl_cache_callback *cb,
return 0;
}

+static void ovl_dir_reset(struct file *file)
+{
+ struct ovl_dir_file *od = file->private_data;
+ struct ovl_entry *ue = file->f_path.dentry->d_fsdata;
+
+ ovl_cache_free(od->cache);
+ od->cache = NULL;
+
+ od->is_real = (!ue->lowerpath.dentry || !ue->upperpath.dentry);
+}
+
static int ovl_readdir(struct file *file, void *buf, filldir_t filler)
{
struct ovl_dir_file *od = file->private_data;
@@ -248,14 +259,10 @@ static int ovl_readdir(struct file *file, void *buf, filldir_t filler)
loff_t off;
int res = 0;

- if (!file->f_pos) {
- ovl_cache_free(od->cache);
- od->cache = NULL;
- od->is_real = false;
- }
+ if (!file->f_pos)
+ ovl_dir_reset(file);

- if (od->is_real || !ue->lowerpath.dentry || !ue->upperpath.dentry) {
- od->is_real = true;
+ if (od->is_real) {
res = vfs_readdir(od->realfile, filler, buf);
file->f_pos = od->realfile->f_pos;

@@ -307,6 +314,9 @@ static loff_t ovl_dir_llseek(struct file *file, loff_t offset, int origin)
loff_t res;
struct ovl_dir_file *od = file->private_data;

+ if (!file->f_pos)
+ ovl_dir_reset(file);
+
if (od->is_real) {
res = vfs_llseek(od->realfile, offset, origin);
file->f_pos = od->realfile->f_pos;


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