From: Miklos Szeredi mszeredi@redhat.com
commit 82a763e61e2b601309d696d4fa514c77d64ee1be upstream.
generic_file_splice_read() and iter_file_splice_write() will call back into f_op->iter_read() and f_op->iter_write() respectively. These already do the real file lookup and cred override. So the code in ovl_splice_read() and ovl_splice_write() is redundant.
In addition the ovl_file_accessed() call in ovl_splice_write() is incorrect, though probably harmless.
Fix by calling generic_file_splice_read() and iter_file_splice_write() directly.
Signed-off-by: Miklos Szeredi mszeredi@redhat.com Cc: Stan Hu stanhu@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/overlayfs/file.c | 46 ++-------------------------------------------- 1 file changed, 2 insertions(+), 44 deletions(-)
--- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -422,48 +422,6 @@ out_unlock: return ret; }
-static ssize_t ovl_splice_read(struct file *in, loff_t *ppos, - struct pipe_inode_info *pipe, size_t len, - unsigned int flags) -{ - ssize_t ret; - struct fd real; - const struct cred *old_cred; - - ret = ovl_real_fdget(in, &real); - if (ret) - return ret; - - old_cred = ovl_override_creds(file_inode(in)->i_sb); - ret = generic_file_splice_read(real.file, ppos, pipe, len, flags); - revert_creds(old_cred); - - ovl_file_accessed(in); - fdput(real); - return ret; -} - -static ssize_t -ovl_splice_write(struct pipe_inode_info *pipe, struct file *out, - loff_t *ppos, size_t len, unsigned int flags) -{ - struct fd real; - const struct cred *old_cred; - ssize_t ret; - - ret = ovl_real_fdget(out, &real); - if (ret) - return ret; - - old_cred = ovl_override_creds(file_inode(out)->i_sb); - ret = iter_file_splice_write(pipe, real.file, ppos, len, flags); - revert_creds(old_cred); - - ovl_file_accessed(out); - fdput(real); - return ret; -} - static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync) { struct fd real; @@ -772,8 +730,8 @@ const struct file_operations ovl_file_op #ifdef CONFIG_COMPAT .compat_ioctl = ovl_compat_ioctl, #endif - .splice_read = ovl_splice_read, - .splice_write = ovl_splice_write, + .splice_read = generic_file_splice_read, + .splice_write = iter_file_splice_write,
.copy_file_range = ovl_copy_file_range, .remap_file_range = ovl_remap_file_range,