a9d0ffbd0d
The next commit will make mode_t 32-bits, ino_t 64-bits, nlink_t 32-bits, and off_t 64-bits. However, in the protocol there is no room for that. When analyzing the usage of these data types we can see that of mode_t we currently use 15 bits and that future flags (if copied from NetBSD) are only of importance to VFS and not to the actual file system on disk. Therefore we can get away with keeping the protocol version of mode_t (pmode_t) 16 bits. At this point it is unlikely that MINIX will support file systems that can hold more than 2^32 files. Keeping the protocol version of ino_t (pino_t) 32-bits and exposing it as 64-bits to the rest of the system is fine. uid_t and gid_t are already 32-bits, but in behind the scenes they're 16-bits. This is sufficient since we don't support uid/gids larger than 2^16-1. off_t will become 64-bits, but the protocol had room reserved for that since it was revised years ago. So to make the difference clear between what the protocol supports and what is exposed to the system, we define protocol version of these data types. Change-Id: Ifb883aafb222142e69d6dcc3049a47170b78b3ee
50 lines
1.5 KiB
C
50 lines
1.5 KiB
C
#include "fs.h"
|
|
#include "buf.h"
|
|
#include "inode.h"
|
|
#include <minix/vfsif.h>
|
|
|
|
/*===========================================================================*
|
|
* fs_ftrunc *
|
|
*===========================================================================*/
|
|
int fs_ftrunc(message *fs_m_in, message *fs_m_out)
|
|
{
|
|
struct inode *rip;
|
|
off_t start;
|
|
pino_t inumb;
|
|
|
|
inumb = (pino_t) fs_m_in->REQ_INODE_NR;
|
|
|
|
if( (rip = find_inode(inumb)) == NULL) return(EINVAL);
|
|
|
|
start = fs_m_in->REQ_TRC_START_LO;
|
|
|
|
return truncate_inode(rip, start);
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* truncate_inode *
|
|
*===========================================================================*/
|
|
int truncate_inode(rip, newsize)
|
|
register struct inode *rip; /* pointer to inode to be truncated */
|
|
off_t newsize; /* inode must become this size */
|
|
{
|
|
/* Set inode to a certain size, freeing any zones no longer referenced
|
|
* and updating the size in the inode. If the inode is extended, the
|
|
* extra space is a hole that reads as zeroes.
|
|
*
|
|
* Nothing special has to happen to file pointers if inode is opened in
|
|
* O_APPEND mode, as this is different per fd and is checked when
|
|
* writing is done.
|
|
*/
|
|
|
|
/* Pipes can shrink, so adjust size to make sure all zones are removed. */
|
|
if(newsize != 0) return(EINVAL); /* Only truncate pipes to 0. */
|
|
rip->i_size = newsize;
|
|
|
|
/* Next correct the inode size. */
|
|
wipe_inode(rip); /* Pipes can only be truncated to 0. */
|
|
|
|
return(OK);
|
|
}
|