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author | Miklos Szeredi <mszeredi@redhat.com> | 2020-06-02 23:20:25 +0300 |
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committer | Miklos Szeredi <mszeredi@redhat.com> | 2020-06-02 23:20:25 +0300 |
commit | 130fdbc3d1f9966dd4230709c30f3768bccd3065 (patch) | |
tree | 14a6b29ee13fd5133070580d3326e2cac41c60b1 /fs/overlayfs | |
parent | 21d8d66abffb0c7834c1b09b8b043ea6a66d6089 (diff) | |
download | linux-130fdbc3d1f9966dd4230709c30f3768bccd3065.tar.xz |
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.c | 12 |
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); |