51 lines
1.5 KiB
C
51 lines
1.5 KiB
C
#include "fs.h"
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#include "buf.h"
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#include "inode.h"
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#include <minix/vfsif.h>
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/*===========================================================================*
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* fs_ftrunc *
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*===========================================================================*/
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PUBLIC int fs_ftrunc(message *fs_m_in, message *fs_m_out)
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{
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struct inode *rip;
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off_t start, end;
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ino_t inumb;
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inumb = (ino_t) fs_m_in->REQ_INODE_NR;
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if( (rip = find_inode(inumb)) == NULL) return(EINVAL);
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start = fs_m_in->REQ_TRC_START_LO;
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end = fs_m_in->REQ_TRC_END_LO;
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return truncate_inode(rip, start);
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}
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/*===========================================================================*
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* truncate_inode *
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*===========================================================================*/
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PUBLIC int truncate_inode(rip, newsize)
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register struct inode *rip; /* pointer to inode to be truncated */
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off_t newsize; /* inode must become this size */
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{
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/* Set inode to a certain size, freeing any zones no longer referenced
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* and updating the size in the inode. If the inode is extended, the
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* extra space is a hole that reads as zeroes.
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*
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* Nothing special has to happen to file pointers if inode is opened in
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* O_APPEND mode, as this is different per fd and is checked when
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* writing is done.
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*/
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/* Pipes can shrink, so adjust size to make sure all zones are removed. */
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if(newsize != 0) return(EINVAL); /* Only truncate pipes to 0. */
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rip->i_size = newsize;
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/* Next correct the inode size. */
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wipe_inode(rip); /* Pipes can only be truncated to 0. */
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return(OK);
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}
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