diff options
| -rw-r--r-- | fs/read_write.c | 120 | ||||
| -rw-r--r-- | include/linux/fs.h | 3 | ||||
| -rw-r--r-- | include/linux/syscalls.h | 3 | ||||
| -rw-r--r-- | include/uapi/asm-generic/unistd.h | 4 | ||||
| -rw-r--r-- | kernel/sys_ni.c | 1 |
5 files changed, 130 insertions, 1 deletions
diff --git a/fs/read_write.c b/fs/read_write.c index 819ef3f..1731400 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -16,6 +16,7 @@ #include <linux/pagemap.h> #include <linux/splice.h> #include <linux/compat.h> +#include <linux/mount.h> #include "internal.h" #include <asm/uaccess.h> @@ -1327,3 +1328,122 @@ COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, return do_sendfile(out_fd, in_fd, NULL, count, 0); } #endif + +/* + * 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 + * the copy_file_range method. + */ +ssize_t vfs_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) +{ + struct inode *inode_in = file_inode(file_in); + struct inode *inode_out = file_inode(file_out); + ssize_t ret; + + if (flags != 0) + return -EINVAL; + + /* copy_file_range allows full ssize_t len, ignoring MAX_RW_COUNT */ + ret = rw_verify_area(READ, file_in, &pos_in, len); + if (ret >= 0) + ret = rw_verify_area(WRITE, file_out, &pos_out, len); + if (ret < 0) + return ret; + + if (!(file_in->f_mode & FMODE_READ) || + !(file_out->f_mode & FMODE_WRITE) || + (file_out->f_flags & O_APPEND) || + !file_out->f_op->copy_file_range) + return -EBADF; + + /* this could be relaxed once a method supports cross-fs copies */ + if (inode_in->i_sb != inode_out->i_sb) + return -EXDEV; + + if (len == 0) + return 0; + + ret = mnt_want_write_file(file_out); + if (ret) + return ret; + + ret = file_out->f_op->copy_file_range(file_in, pos_in, file_out, pos_out, + len, flags); + if (ret > 0) { + fsnotify_access(file_in); + add_rchar(current, ret); + fsnotify_modify(file_out); + add_wchar(current, ret); + } + inc_syscr(current); + inc_syscw(current); + + mnt_drop_write_file(file_out); + + return ret; +} +EXPORT_SYMBOL(vfs_copy_file_range); + +SYSCALL_DEFINE6(copy_file_range, int, fd_in, loff_t __user *, off_in, + int, fd_out, loff_t __user *, off_out, + size_t, len, unsigned int, flags) +{ + loff_t pos_in; + loff_t pos_out; + struct fd f_in; + struct fd f_out; + ssize_t ret = -EBADF; + + f_in = fdget(fd_in); + if (!f_in.file) + goto out2; + + f_out = fdget(fd_out); + if (!f_out.file) + goto out1; + + ret = -EFAULT; + if (off_in) { + if (copy_from_user(&pos_in, off_in, sizeof(loff_t))) + goto out; + } else { + pos_in = f_in.file->f_pos; + } + + if (off_out) { + if (copy_from_user(&pos_out, off_out, sizeof(loff_t))) + goto out; + } else { + pos_out = f_out.file->f_pos; + } + + ret = vfs_copy_file_range(f_in.file, pos_in, f_out.file, pos_out, len, + flags); + if (ret > 0) { + pos_in += ret; + pos_out += ret; + + if (off_in) { + if (copy_to_user(off_in, &pos_in, sizeof(loff_t))) + ret = -EFAULT; + } else { + f_in.file->f_pos = pos_in; + } + + if (off_out) { + if (copy_to_user(off_out, &pos_out, sizeof(loff_t))) + ret = -EFAULT; + } else { + f_out.file->f_pos = pos_out; + } + } + +out: + fdput(f_out); +out1: + fdput(f_in); +out2: + return ret; +} diff --git a/include/linux/fs.h b/include/linux/fs.h index 3aa5142..e8a7362 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1629,6 +1629,7 @@ struct file_operations { #ifndef CONFIG_MMU unsigned (*mmap_capabilities)(struct file *); #endif + ssize_t (*copy_file_range)(struct file *, loff_t, struct file *, loff_t, size_t, unsigned int); }; struct inode_operations { @@ -1680,6 +1681,8 @@ extern ssize_t vfs_readv(struct file *, const struct iovec __user *, unsigned long, loff_t *); extern ssize_t vfs_writev(struct file *, const struct iovec __user *, unsigned long, loff_t *); +extern ssize_t vfs_copy_file_range(struct file *, loff_t , struct file *, + loff_t, size_t, unsigned int); struct super_operations { struct inode *(*alloc_inode)(struct super_block *sb); diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index c2b66a2..185815c 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -886,6 +886,9 @@ asmlinkage long sys_execveat(int dfd, const char __user *filename, const char __user *const __user *envp, int flags); asmlinkage long sys_membarrier(int cmd, int flags); +asmlinkage long sys_copy_file_range(int fd_in, loff_t __user *off_in, + int fd_out, loff_t __user *off_out, + size_t len, unsigned int flags); asmlinkage long sys_mlock2(unsigned long start, size_t len, int flags); diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h index 1324b02..2622b33 100644 --- a/include/uapi/asm-generic/unistd.h +++ b/include/uapi/asm-generic/unistd.h @@ -715,9 +715,11 @@ __SYSCALL(__NR_userfaultfd, sys_userfaultfd) __SYSCALL(__NR_membarrier, sys_membarrier) #define __NR_mlock2 284 __SYSCALL(__NR_mlock2, sys_mlock2) +#define __NR_copy_file_range 285 +__SYSCALL(__NR_copy_file_range, sys_copy_file_range) #undef __NR_syscalls -#define __NR_syscalls 285 +#define __NR_syscalls 286 /* * All syscalls below here should go away really, diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index 0623787..2c5e3a8 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -174,6 +174,7 @@ cond_syscall(sys_setfsuid); cond_syscall(sys_setfsgid); cond_syscall(sys_capget); cond_syscall(sys_capset); +cond_syscall(sys_copy_file_range); /* arch-specific weak syscall entries */ cond_syscall(sys_pciconfig_read); |
