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Diffstat (limited to 'fs/read_write.c')
-rw-r--r--fs/read_write.c72
1 files changed, 72 insertions, 0 deletions
diff --git a/fs/read_write.c b/fs/read_write.c
index 6cfad4761fd8..c75d02cb13ec 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1451,3 +1451,75 @@ out1:
out2:
return ret;
}
+
+static int clone_verify_area(struct file *file, loff_t pos, u64 len, bool write)
+{
+ struct inode *inode = file_inode(file);
+
+ if (unlikely(pos < 0))
+ return -EINVAL;
+
+ if (unlikely((loff_t) (pos + len) < 0))
+ return -EINVAL;
+
+ if (unlikely(inode->i_flctx && mandatory_lock(inode))) {
+ loff_t end = len ? pos + len - 1 : OFFSET_MAX;
+ int retval;
+
+ retval = locks_mandatory_area(inode, file, pos, end,
+ write ? F_WRLCK : F_RDLCK);
+ if (retval < 0)
+ return retval;
+ }
+
+ return security_file_permission(file, write ? MAY_WRITE : MAY_READ);
+}
+
+int vfs_clone_file_range(struct file *file_in, loff_t pos_in,
+ struct file *file_out, loff_t pos_out, u64 len)
+{
+ struct inode *inode_in = file_inode(file_in);
+ struct inode *inode_out = file_inode(file_out);
+ int ret;
+
+ if (inode_in->i_sb != inode_out->i_sb ||
+ file_in->f_path.mnt != file_out->f_path.mnt)
+ return -EXDEV;
+
+ if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode))
+ return -EISDIR;
+ if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode))
+ return -EOPNOTSUPP;
+
+ if (!(file_in->f_mode & FMODE_READ) ||
+ !(file_out->f_mode & FMODE_WRITE) ||
+ (file_out->f_flags & O_APPEND) ||
+ !file_in->f_op->clone_file_range)
+ return -EBADF;
+
+ ret = clone_verify_area(file_in, pos_in, len, false);
+ if (ret)
+ return ret;
+
+ ret = clone_verify_area(file_out, pos_out, len, true);
+ if (ret)
+ return ret;
+
+ if (pos_in + len > i_size_read(inode_in))
+ return -EINVAL;
+
+ ret = mnt_want_write_file(file_out);
+ if (ret)
+ return ret;
+
+ ret = file_in->f_op->clone_file_range(file_in, pos_in,
+ file_out, pos_out, len);
+ if (!ret) {
+ fsnotify_access(file_in);
+ fsnotify_modify(file_out);
+ }
+
+ mnt_drop_write_file(file_out);
+ return ret;
+}
+EXPORT_SYMBOL(vfs_clone_file_range);