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>

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 31d450536175214506eb5be81bf708fabd0f722c..c5517ffeb11c7cdf2f3c7c0599b8cf4c675976a9 100644 (file)
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -1909,6 +1909,8 @@ static ssize_t __ceph_copy_file_range(struct file *src_file, loff_t src_off,
 
        if (src_inode == dst_inode)
                return -EINVAL;
+       if (src_inode->i_sb != dst_inode->i_sb)
+               return -EXDEV;
        if (ceph_snap(dst_inode) != CEPH_NOSNAP)
                return -EROFS;
 
@@ -2109,7 +2111,7 @@ static ssize_t ceph_copy_file_range(struct file *src_file, loff_t src_off,
        ret = __ceph_copy_file_range(src_file, src_off, dst_file, dst_off,
                                     len, flags);
 
-       if (ret == -EOPNOTSUPP)
+       if (ret == -EOPNOTSUPP || ret == -EXDEV)
                ret = generic_copy_file_range(src_file, src_off, dst_file,
                                              dst_off, len, flags);
        return ret;

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index c658232703133bbecc2559a3893c639773ebe1bf..f11eea6125c123f8f7ef96114778dbe8e8927e64 100644 (file)
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -1149,7 +1149,7 @@ static ssize_t cifs_copy_file_range(struct file *src_file, loff_t off,
                                        len, flags);
        free_xid(xid);
 
-       if (rc == -EOPNOTSUPP)
+       if (rc == -EOPNOTSUPP || rc == -EXDEV)
                rc = generic_copy_file_range(src_file, off, dst_file,
                                             destoff, len, flags);
        return rc;

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 4c20bf61d9c38d59c1a275f3085d5d1669dd18d8..dc342edb399ba3a139e6d7146a0b071a999efee1 100644 (file)
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -3142,6 +3142,9 @@ static ssize_t __fuse_copy_file_range(struct file *file_in, loff_t pos_in,
        if (fc->no_copy_file_range)
                return -EOPNOTSUPP;
 
+       if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb)
+               return -EXDEV;
+
        if (fc->writeback_cache) {
                inode_lock(inode_in);
                err = fuse_writeback_range(inode_in, pos_in, pos_in + len);
@@ -3203,7 +3206,7 @@ static ssize_t fuse_copy_file_range(struct file *src_file, loff_t src_off,
        ret = __fuse_copy_file_range(src_file, src_off, dst_file, dst_off,
                                     len, flags);
 
-       if (ret == -EOPNOTSUPP)
+       if (ret == -EOPNOTSUPP || ret == -EXDEV)
                ret = generic_copy_file_range(src_file, src_off, dst_file,
                                              dst_off, len, flags);
        return ret;

diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
index 4842f3ab31615d5c38797c2ad72b66eaa012d4c4..f4157eb1f69dd0c2910ebff3904fdedf76c13ad9 100644 (file)
--- a/fs/nfs/nfs4file.c
+++ b/fs/nfs/nfs4file.c
@@ -133,6 +133,9 @@ static ssize_t __nfs4_copy_file_range(struct file *file_in, loff_t pos_in,
                                      struct file *file_out, loff_t pos_out,
                                      size_t count, unsigned int flags)
 {
+       /* Only offload copy if superblock is the same */
+       if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb)
+               return -EXDEV;
        if (!nfs_server_capable(file_inode(file_out), NFS_CAP_COPY))
                return -EOPNOTSUPP;
        if (file_inode(file_in) == file_inode(file_out))
@@ -148,7 +151,7 @@ static ssize_t nfs4_copy_file_range(struct file *file_in, loff_t pos_in,
 
        ret = __nfs4_copy_file_range(file_in, pos_in, file_out, pos_out, count,
                                     flags);
-       if (ret == -EOPNOTSUPP)
+       if (ret == -EOPNOTSUPP || ret == -EXDEV)
                ret = generic_copy_file_range(file_in, pos_in, file_out,
                                              pos_out, count, flags);
        return ret;

diff --git a/fs/read_write.c b/fs/read_write.c
index cec7e7b1f6934523b71397869bf1c5413b143f78..1f5088dec566b71a37f697edd7419b7813edbb4c 100644 (file)
--- 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,