diff options
| author | Amir Goldstein <amir73il@gmail.com> | 2019-06-05 08:04:50 -0700 |
|---|---|---|
| committer | Darrick J. Wong <darrick.wong@oracle.com> | 2019-06-09 10:06:20 -0700 |
| commit | 5dae222a5ff0c269730393018a5539cc970a4726 (patch) | |
| tree | e1e4e1634de00d8fb7668f575d7e25acace6518f /fs/read_write.c | |
| parent | 8c3f406c097b83846c7d18438a905b49d17ae528 (diff) | |
vfs: allow copy_file_range to copy across devices
We want to enable cross-filesystem copy_file_range functionality
where possible, so push the "same superblock only" checks down to
the individual filesystem callouts so they can make their own
decisions about cross-superblock copy offload and fallack to
generic_copy_file_range() for cross-superblock copy.
[Amir] We do not call ->remap_file_range() in case the files are not
on the same sb and do not call ->copy_file_range() in case the files
do not belong to the same filesystem driver.
This changes behavior of the copy_file_range(2) syscall, which will
now allow cross filesystem in-kernel copy. CIFS already supports
cross-superblock copy, between two shares to the same server. This
functionality will now be available via the copy_file_range(2) syscall.
Cc: Steve French <stfrench@microsoft.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Diffstat (limited to 'fs/read_write.c')
| -rw-r--r-- | fs/read_write.c | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/fs/read_write.c b/fs/read_write.c index cec7e7b1f693..1f5088dec566 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -1599,7 +1599,16 @@ static ssize_t do_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) { - if (file_out->f_op->copy_file_range) + /* + * Although we now allow filesystems to handle cross sb copy, passing + * a file of the wrong filesystem type to filesystem driver can result + * in an attempt to dereference the wrong type of ->private_data, so + * avoid doing that until we really have a good reason. NFS defines + * several different file_system_type structures, but they all end up + * using the same ->copy_file_range() function pointer. + */ + if (file_out->f_op->copy_file_range && + file_out->f_op->copy_file_range == file_in->f_op->copy_file_range) return file_out->f_op->copy_file_range(file_in, pos_in, file_out, pos_out, len, flags); @@ -1622,10 +1631,6 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, if (flags != 0) return -EINVAL; - /* this could be relaxed once a method supports cross-fs copies */ - if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb) - return -EXDEV; - ret = generic_copy_file_checks(file_in, pos_in, file_out, pos_out, &len, flags); if (unlikely(ret)) @@ -1648,7 +1653,8 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, * Try cloning first, this is supported by more file systems, and * more efficient if both clone and copy are supported (e.g. NFS). */ - if (file_in->f_op->remap_file_range) { + if (file_in->f_op->remap_file_range && + file_inode(file_in)->i_sb == file_inode(file_out)->i_sb) { loff_t cloned; cloned = file_in->f_op->remap_file_range(file_in, pos_in, |