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authorMiklos Szeredi <mszeredi@redhat.com>2020-06-02 22:20:25 +0200
committerMiklos Szeredi <mszeredi@redhat.com>2020-06-02 22:20:25 +0200
commit130fdbc3d1f9966dd4230709c30f3768bccd3065 (patch)
tree14a6b29ee13fd5133070580d3326e2cac41c60b1 /fs/overlayfs
parent21d8d66abffb0c7834c1b09b8b043ea6a66d6089 (diff)
downloadlwn-130fdbc3d1f9966dd4230709c30f3768bccd3065.tar.gz
lwn-130fdbc3d1f9966dd4230709c30f3768bccd3065.zip
ovl: pass correct flags for opening real directory
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@redhat.com>
Diffstat (limited to 'fs/overlayfs')
-rw-r--r--fs/overlayfs/readdir.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index a10b21b562ad..3bc97065cc70 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -297,7 +297,7 @@ 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 @@ out_unlock:
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);