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ovl: simplify file splice

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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>
This commit is contained in:
Miklos Szeredi 2020-12-14 15:26:14 +01:00 committed by Greg Kroah-Hartman
parent 7774dd934a
commit dca4f9a581
1 changed files with 2 additions and 44 deletions
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46
fs/overlayfs/file.c
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@ -422,48 +422,6 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
return ret; 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) static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync)
{ {
struct fd real; struct fd real;
@ -772,8 +730,8 @@ const struct file_operations ovl_file_operations = {
#ifdef CONFIG_COMPAT #ifdef CONFIG_COMPAT
.compat_ioctl = ovl_compat_ioctl, .compat_ioctl = ovl_compat_ioctl,
#endif #endif
.splice_read = ovl_splice_read, .splice_read = generic_file_splice_read,
.splice_write = ovl_splice_write, .splice_write = iter_file_splice_write,
.copy_file_range = ovl_copy_file_range, .copy_file_range = ovl_copy_file_range,
.remap_file_range = ovl_remap_file_range, .remap_file_range = ovl_remap_file_range,