minix/servers/pfs/link.c
Lionel Sambuc 135346dfc3 Message types for VFS ftrunc
Change-Id: I593a4d91b1d974f632f6cb4eb23aabee5b65df7b
2014-07-28 17:05:26 +02:00

49 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;
ino_t inumb;
inumb = fs_m_in->m_vfs_fs_ftrunc.inode;
if( (rip = find_inode(inumb)) == NULL) return(EINVAL);
start = fs_m_in->m_vfs_fs_ftrunc.trc_start;
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);
}