minix/servers/pfs/link.c

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2009-12-20 21:41:50 +01:00
#include "fs.h"
#include <string.h>
#include "buf.h"
#include "inode.h"
#include <minix/vfsif.h>
/*===========================================================================*
* fs_ftrunc *
*===========================================================================*/
PUBLIC int fs_ftrunc(void)
{
struct inode *rip;
off_t start, end;
ino_t inumb;
inumb = fs_m_in.REQ_INODE_NR;
if( (rip = find_inode(inumb)) == NULL) return(EINVAL);
2009-12-20 21:41:50 +01:00
start = fs_m_in.REQ_TRC_START_LO;
end = fs_m_in.REQ_TRC_END_LO;
return truncate_inode(rip, start);
}
/*===========================================================================*
* truncate_inode *
*===========================================================================*/
PUBLIC 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);
}