On Mar 17, 2008 15:28 +0900, Akira Fujita wrote:
> Hi Andreas,
>>> How about renaming this structure from ext4_extent_data to
>>> ext4_extent_info which used the extent in-core structure
>>> and put it into ext4_fs_extents.h? Because in-core super_block is
>>> ext4_sb_info.
>>>
>>> /*
>>> * This is the extent in-core structure.
>>> */
>>> struct ext4_extent_info {
>>> ext4_lblk_t ee_block; /* first logical block extent covers */
>>> int ee_len; /* number of blocks covered by extent */
>>> ext4_fsblk_t ee_start; /* first physical block extent covers */
>>> };
>>
>> Would it be possible to use the FIEMAP interface to get the file mapping
>> data to userspace? That would avoid the need to have a second ioctl
>> with nearly the same data.
>
> Reducing ioctl makes sense.
> But EXT4_EXTENTS_INFO needs to get the file mapping data
> with inode number not file name.
> So we should keep ext4_extents_info structure
> or put ino entry in fiemap structure.
We introduced a special ioctl for this which would allow root to perform
ioctl() on any inode by inode number. We call this EXT4_IOC_WRAPPER, and
it is called on the root inode and specifies the inode number and real
ioctl number before the rest of the ioctl data.
struct ext4_ioctl_wrapper {
__u32 ioctl_cmd;
__u32 padding;
__u64 ioctl_ino;
char ioctl_data[0];
};
More patch is available, but it isn't in a self-contained patch.
Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.
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