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Diffstat (limited to 'fs/read_write.c')
-rw-r--r--fs/read_write.c77
1 files changed, 44 insertions, 33 deletions
diff --git a/fs/read_write.c b/fs/read_write.c
index b1b1cdfee9d3..e0777eefd846 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1397,28 +1397,6 @@ ssize_t generic_copy_file_range(struct file *file_in, loff_t pos_in,
}
EXPORT_SYMBOL(generic_copy_file_range);
-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)
-{
- /*
- * 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);
-
- return generic_copy_file_range(file_in, pos_in, file_out, pos_out, len,
- flags);
-}
-
/*
* Performs necessary checks before doing a file copy
*
@@ -1440,6 +1418,24 @@ static int generic_copy_file_checks(struct file *file_in, loff_t pos_in,
if (ret)
return ret;
+ /*
+ * We allow some filesystems to handle cross sb copy, but 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 and cifs define several different file_system_type structures
+ * and several different sets of file_operations, but they all end up
+ * using the same ->copy_file_range() function pointer.
+ */
+ if (file_out->f_op->copy_file_range) {
+ if (file_in->f_op->copy_file_range !=
+ file_out->f_op->copy_file_range)
+ return -EXDEV;
+ } else if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb) {
+ return -EXDEV;
+ }
+
/* Don't touch certain kinds of inodes */
if (IS_IMMUTABLE(inode_out))
return -EPERM;
@@ -1505,26 +1501,41 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
file_start_write(file_out);
/*
- * Try cloning first, this is supported by more file systems, and
- * more efficient if both clone and copy are supported (e.g. NFS).
+ * Cloning is supported by more file systems, so we implement copy on
+ * same sb using clone, but for filesystems where both clone and copy
+ * are supported (e.g. nfs,cifs), we only call the copy method.
*/
+ if (file_out->f_op->copy_file_range) {
+ ret = file_out->f_op->copy_file_range(file_in, pos_in,
+ file_out, pos_out,
+ len, flags);
+ goto done;
+ }
+
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,
+ ret = file_in->f_op->remap_file_range(file_in, pos_in,
file_out, pos_out,
min_t(loff_t, MAX_RW_COUNT, len),
REMAP_FILE_CAN_SHORTEN);
- if (cloned > 0) {
- ret = cloned;
+ if (ret > 0)
goto done;
- }
}
- ret = do_copy_file_range(file_in, pos_in, file_out, pos_out, len,
- flags);
- WARN_ON_ONCE(ret == -EOPNOTSUPP);
+ /*
+ * We can get here for same sb copy of filesystems that do not implement
+ * ->copy_file_range() in case filesystem does not support clone or in
+ * case filesystem supports clone but rejected the clone request (e.g.
+ * because it was not block aligned).
+ *
+ * In both cases, fall back to kernel copy so we are able to maintain a
+ * consistent story about which filesystems support copy_file_range()
+ * and which filesystems do not, that will allow userspace tools to
+ * make consistent desicions w.r.t using copy_file_range().
+ */
+ ret = generic_copy_file_range(file_in, pos_in, file_out, pos_out, len,
+ flags);
+
done:
if (ret > 0) {
fsnotify_access(file_in);