From: Miklos Szeredi <mszeredi@xxxxxxxxxx>
commit 130fdbc3d1f9966dd4230709c30f3768bccd3065 upstream.
The three instances of ovl_path_open() in overlayfs/readdir.c do three
different things:
- pass f_flags from overlay file
- pass O_RDONLY | O_DIRECTORY
- pass just O_RDONLY
The value of f_flags can be (other than O_RDONLY):
O_WRONLY - not possible for a directory
O_RDWR - not possible for a directory
O_CREAT - masked out by dentry_open()
O_EXCL - masked out by dentry_open()
O_NOCTTY - masked out by dentry_open()
O_TRUNC - masked out by dentry_open()
O_APPEND - no effect on directory ops
O_NDELAY - no effect on directory ops
O_NONBLOCK - no effect on directory ops
__O_SYNC - no effect on directory ops
O_DSYNC - no effect on directory ops
FASYNC - no effect on directory ops
O_DIRECT - no effect on directory ops
O_LARGEFILE - ?
O_DIRECTORY - only affects lookup
O_NOFOLLOW - only affects lookup
O_NOATIME - overlay sets this unconditionally in ovl_path_open()
O_CLOEXEC - only affects fd allocation
O_PATH - no effect on directory ops
__O_TMPFILE - not possible for a directory
Fon non-merge directories we use the underlying filesystem's iterate; in
this case honor O_LARGEFILE from the original file to make sure that open
doesn't get rejected.
For merge directories it's safe to pass O_LARGEFILE unconditionally since
userspace will only see the artificial offsets created by overlayfs.
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Signed-off-by: Hugo SIMELIERE <hsimeliere.opensource@xxxxxxxxxxx>
---
fs/overlayfs/readdir.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index db9132a020de..2e12b756cc82 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -300,7 +300,7 @@ static inline int ovl_dir_read(struct path *realpath,
struct file *realfile;
int err;
- realfile = ovl_path_open(realpath, O_RDONLY | O_DIRECTORY);
+ realfile = ovl_path_open(realpath, O_RDONLY | O_LARGEFILE);
if (IS_ERR(realfile))
return PTR_ERR(realfile);
@@ -831,6 +831,12 @@ static loff_t ovl_dir_llseek(struct file *file, loff_t offset, int origin)
return res;
}
+static struct file *ovl_dir_open_realfile(struct file *file,
+ struct path *realpath)
+{
+ return ovl_path_open(realpath, O_RDONLY | (file->f_flags & O_LARGEFILE));
+}
+
static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,
int datasync)
{
@@ -853,7 +859,7 @@ static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,
struct path upperpath;
ovl_path_upper(dentry, &upperpath);
- realfile = ovl_path_open(&upperpath, O_RDONLY);
+ realfile = ovl_dir_open_realfile(file, &upperpath);
inode_lock(inode);
if (!od->upperfile) {
@@ -904,7 +910,7 @@ static int ovl_dir_open(struct inode *inode, struct file *file)
return -ENOMEM;
type = ovl_path_real(file->f_path.dentry, &realpath);
- realfile = ovl_path_open(&realpath, file->f_flags);
+ realfile = ovl_dir_open_realfile(file, &realpath);
if (IS_ERR(realfile)) {
kfree(od);
return PTR_ERR(realfile);
--
2.43.0
