| Message ID | 20190526061100.21761-2-amir73il@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Fixes for major copy_file_range() issues | expand |
On Sun, May 26, 2019 at 09:10:52AM +0300, Amir Goldstein wrote: > From: Dave Chinner <dchinner@redhat.com> > > Right now if vfs_copy_file_range() does not use any offload > mechanism, it falls back to calling do_splice_direct(). This fails > to do basic sanity checks on the files being copied. Before we > start adding this necessarily functionality to the fallback path, > separate it out into generic_copy_file_range(). > > generic_copy_file_range() has the same prototype as > ->copy_file_range() so that filesystems can use it in their custom > ->copy_file_range() method if they so choose. > > Signed-off-by: Dave Chinner <dchinner@redhat.com> > Signed-off-by: Amir Goldstein <amir73il@gmail.com> > --- Looks ok, Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> --D > fs/read_write.c | 35 ++++++++++++++++++++++++++++++++--- > include/linux/fs.h | 3 +++ > 2 files changed, 35 insertions(+), 3 deletions(-) > > diff --git a/fs/read_write.c b/fs/read_write.c > index c543d965e288..676b02fae589 100644 > --- a/fs/read_write.c > +++ b/fs/read_write.c > @@ -1565,6 +1565,36 @@ COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, > } > #endif > > +/** > + * generic_copy_file_range - copy data between two files > + * @file_in: file structure to read from > + * @pos_in: file offset to read from > + * @file_out: file structure to write data to > + * @pos_out: file offset to write data to > + * @len: amount of data to copy > + * @flags: copy flags > + * > + * This is a generic filesystem helper to copy data from one file to another. > + * It has no constraints on the source or destination file owners - the files > + * can belong to different superblocks and different filesystem types. Short > + * copies are allowed. > + * > + * This should be called from the @file_out filesystem, as per the > + * ->copy_file_range() method. > + * > + * Returns the number of bytes copied or a negative error indicating the > + * failure. > + */ > + > +ssize_t generic_copy_file_range(struct file *file_in, loff_t pos_in, > + struct file *file_out, loff_t pos_out, > + size_t len, unsigned int flags) > +{ > + return do_splice_direct(file_in, &pos_in, file_out, &pos_out, > + len > MAX_RW_COUNT ? MAX_RW_COUNT : len, 0); > +} > +EXPORT_SYMBOL(generic_copy_file_range); > + > /* > * copy_file_range() differs from regular file read and write in that it > * specifically allows return partial success. When it does so is up to > @@ -1632,9 +1662,8 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, > goto done; > } > > - ret = do_splice_direct(file_in, &pos_in, file_out, &pos_out, > - len > MAX_RW_COUNT ? MAX_RW_COUNT : len, 0); > - > + ret = generic_copy_file_range(file_in, pos_in, file_out, pos_out, len, > + flags); > done: > if (ret > 0) { > fsnotify_access(file_in); > diff --git a/include/linux/fs.h b/include/linux/fs.h > index f7fdfe93e25d..ea17858310ff 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -1889,6 +1889,9 @@ extern ssize_t vfs_readv(struct file *, const struct iovec __user *, > unsigned long, loff_t *, rwf_t); > extern ssize_t vfs_copy_file_range(struct file *, loff_t , struct file *, > loff_t, size_t, unsigned int); > +extern ssize_t generic_copy_file_range(struct file *file_in, loff_t pos_in, > + struct file *file_out, loff_t pos_out, > + size_t len, unsigned int flags); > extern int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, > struct file *file_out, loff_t pos_out, > loff_t *count, > -- > 2.17.1 >
diff --git a/fs/read_write.c b/fs/read_write.c index c543d965e288..676b02fae589 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -1565,6 +1565,36 @@ COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, } #endif +/** + * generic_copy_file_range - copy data between two files + * @file_in: file structure to read from + * @pos_in: file offset to read from + * @file_out: file structure to write data to + * @pos_out: file offset to write data to + * @len: amount of data to copy + * @flags: copy flags + * + * This is a generic filesystem helper to copy data from one file to another. + * It has no constraints on the source or destination file owners - the files + * can belong to different superblocks and different filesystem types. Short + * copies are allowed. + * + * This should be called from the @file_out filesystem, as per the + * ->copy_file_range() method. + * + * Returns the number of bytes copied or a negative error indicating the + * failure. + */ + +ssize_t generic_copy_file_range(struct file *file_in, loff_t pos_in, + struct file *file_out, loff_t pos_out, + size_t len, unsigned int flags) +{ + return do_splice_direct(file_in, &pos_in, file_out, &pos_out, + len > MAX_RW_COUNT ? MAX_RW_COUNT : len, 0); +} +EXPORT_SYMBOL(generic_copy_file_range); + /* * copy_file_range() differs from regular file read and write in that it * specifically allows return partial success. When it does so is up to @@ -1632,9 +1662,8 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, goto done; } - ret = do_splice_direct(file_in, &pos_in, file_out, &pos_out, - len > MAX_RW_COUNT ? MAX_RW_COUNT : len, 0); - + ret = generic_copy_file_range(file_in, pos_in, file_out, pos_out, len, + flags); done: if (ret > 0) { fsnotify_access(file_in); diff --git a/include/linux/fs.h b/include/linux/fs.h index f7fdfe93e25d..ea17858310ff 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1889,6 +1889,9 @@ extern ssize_t vfs_readv(struct file *, const struct iovec __user *, unsigned long, loff_t *, rwf_t); extern ssize_t vfs_copy_file_range(struct file *, loff_t , struct file *, loff_t, size_t, unsigned int); +extern ssize_t generic_copy_file_range(struct file *file_in, loff_t pos_in, + struct file *file_out, loff_t pos_out, + size_t len, unsigned int flags); extern int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, struct file *file_out, loff_t pos_out, loff_t *count,