| From 82a763e61e2b601309d696d4fa514c77d64ee1be Mon Sep 17 00:00:00 2001 |
| From: Miklos Szeredi <mszeredi@redhat.com> |
| Date: Mon, 14 Dec 2020 15:26:14 +0100 |
| Subject: ovl: simplify file splice |
| |
| 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, |
