fs/ext4/ioctl.c

Source file repositories/reference/linux-study-clean/fs/ext4/ioctl.c

File Facts

System
Linux kernel
Corpus path
fs/ext4/ioctl.c
Extension
.c
Size
55069 bytes
Lines
2029
Domain
Core OS
Bucket
VFS And Filesystem Core
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

struct getfsmap_info {
	struct super_block	*gi_sb;
	struct fsmap_head __user *gi_data;
	unsigned int		gi_idx;
	__u32			gi_last_flags;
};

static int ext4_getfsmap_format(struct ext4_fsmap *xfm, void *priv)
{
	struct getfsmap_info *info = priv;
	struct fsmap fm;

	trace_ext4_getfsmap_mapping(info->gi_sb, xfm);

	info->gi_last_flags = xfm->fmr_flags;
	ext4_fsmap_from_internal(info->gi_sb, &fm, xfm);
	if (copy_to_user(&info->gi_data->fmh_recs[info->gi_idx++], &fm,
			sizeof(struct fsmap)))
		return -EFAULT;

	return 0;
}

static int ext4_ioc_getfsmap(struct super_block *sb,
			     struct fsmap_head __user *arg)
{
	struct getfsmap_info info = { NULL };
	struct ext4_fsmap_head xhead = {0};
	struct fsmap_head head;
	bool aborted = false;
	int error;

	if (copy_from_user(&head, arg, sizeof(struct fsmap_head)))
		return -EFAULT;
	if (memchr_inv(head.fmh_reserved, 0, sizeof(head.fmh_reserved)) ||
	    memchr_inv(head.fmh_keys[0].fmr_reserved, 0,
		       sizeof(head.fmh_keys[0].fmr_reserved)) ||
	    memchr_inv(head.fmh_keys[1].fmr_reserved, 0,
		       sizeof(head.fmh_keys[1].fmr_reserved)))
		return -EINVAL;
	/*
	 * ext4 doesn't report file extents at all, so the only valid
	 * file offsets are the magic ones (all zeroes or all ones).
	 */
	if (head.fmh_keys[0].fmr_offset ||
	    (head.fmh_keys[1].fmr_offset != 0 &&
	     head.fmh_keys[1].fmr_offset != -1ULL))
		return -EINVAL;

	xhead.fmh_iflags = head.fmh_iflags;
	xhead.fmh_count = head.fmh_count;
	ext4_fsmap_to_internal(sb, &xhead.fmh_keys[0], &head.fmh_keys[0]);
	ext4_fsmap_to_internal(sb, &xhead.fmh_keys[1], &head.fmh_keys[1]);

	trace_ext4_getfsmap_low_key(sb, &xhead.fmh_keys[0]);
	trace_ext4_getfsmap_high_key(sb, &xhead.fmh_keys[1]);

	info.gi_sb = sb;
	info.gi_data = arg;
	error = ext4_getfsmap(sb, &xhead, ext4_getfsmap_format, &info);
	if (error == EXT4_QUERY_RANGE_ABORT)
		aborted = true;
	else if (error)
		return error;

	/* If we didn't abort, set the "last" flag in the last fmx */
	if (!aborted && info.gi_idx) {
		info.gi_last_flags |= FMR_OF_LAST;
		if (copy_to_user(&info.gi_data->fmh_recs[info.gi_idx - 1].fmr_flags,
				 &info.gi_last_flags,
				 sizeof(info.gi_last_flags)))
			return -EFAULT;
	}

	/* copy back header */
	head.fmh_entries = xhead.fmh_entries;
	head.fmh_oflags = xhead.fmh_oflags;
	if (copy_to_user(arg, &head, sizeof(struct fsmap_head)))
		return -EFAULT;

	return 0;
}

static long ext4_ioctl_group_add(struct file *file,
				 struct ext4_new_group_data *input)
{
	struct super_block *sb = file_inode(file)->i_sb;
	int err, err2=0;

	err = ext4_resize_begin(sb);

Annotation

Implementation Notes