minix/servers/vfs/vnode.c
Ben Gras dc1238b7b9 make unpause() decrease susp_count, as it shouldn't be decreased
if the process was REVIVING. (susp_count doesn't count those
 processes.) this together with dev_io SELECT suspend side effect
 for asynch. character devices solves the hanging pipe bug. or
 at last vastly improves it.

 added sanity checks, turned off by default.

 made the {NOT_,}{SUSPENDING,REVIVING} constants weirder to
 help sanity checking.
2009-05-08 13:56:41 +00:00

249 lines
6.2 KiB
C

/* This file contains the routines related to vnodes.
* The entry points are:
*
* get_vnode - increase counter and get details of an inode
* get_free_vnode - get a pointer to a free vnode obj
* find_vnode - find a vnode according to the FS endpoint and the inode num.
* dup_vnode - duplicate vnode (i.e. increase counter)
* put_vnode - drop vnode (i.e. decrease counter)
*
* Jul 2006 (Balazs Gerofi)
*/
#include "fs.h"
#include "vnode.h"
#include "vmnt.h"
#include "fproc.h"
#include "file.h"
#include <minix/vfsif.h>
/* Is vnode pointer reasonable? */
#define SANEVP(v) ((((v) >= &vnode[0] && (v) < &vnode[NR_VNODES])))
#define BADVP(v, f, l) printf("%s:%d: bad vp 0x%x\n", f, l, v)
/* vp check that returns 0 for use in check_vrefs() */
#define CHECKVN(v) if(!SANEVP(v)) { \
BADVP(v, __FILE__, __LINE__); \
return 0; \
}
/* vp check that panics */
#define ASSERTVP(v) if(!SANEVP(v)) { \
BADVP(v, __FILE__, __LINE__); panic("vfs", "bad vp", NO_NUM); }
/*===========================================================================*
* get_free_vnode *
*===========================================================================*/
PUBLIC struct vnode *get_free_vnode(file, line)
char *file;
int line;
{
/* Find a free vnode slot in the vnode table */
struct vnode *vp;
for (vp = &vnode[0]; vp < &vnode[NR_VNODES]; ++vp)
if (vp->v_ref_count == 0)
{
vp->v_pipe= NO_PIPE;
vp->v_uid= -1;
vp->v_gid= -1;
vp->v_sdev= -1;
vp->v_file= file;
vp->v_line= line;
return vp;
}
err_code = ENFILE;
return NIL_VNODE;
}
/*===========================================================================*
* find_vnode *
*===========================================================================*/
PUBLIC struct vnode *find_vnode(int fs_e, int numb)
{
/* Find a specified (FS endpoint and inode number) vnode in the
* vnode table */
struct vnode *vp;
for (vp = &vnode[0]; vp < &vnode[NR_VNODES]; ++vp)
if (vp->v_ref_count > 0 && vp->v_inode_nr == numb
&& vp->v_fs_e == fs_e) return vp;
return NIL_VNODE;
}
/*===========================================================================*
* dup_vnode *
*===========================================================================*/
PUBLIC void dup_vnode(struct vnode *vp)
{
/* dup_vnode() is called to increment the vnode and therefore the
* referred inode's counter.
*/
ASSERTVP(vp);
vp->v_ref_count++;
}
/*===========================================================================*
* put_vnode *
*===========================================================================*/
PUBLIC void put_vnode(struct vnode *vp)
{
/* Decrease vnode's usage counter and decrease inode's usage counter in the
* corresponding FS process.
*/
ASSERTVP(vp);
if (vp->v_ref_count > 1)
{
/* Decrease counter */
vp->v_ref_count--;
if (vp->v_fs_count > 256)
vnode_clean_refs(vp);
return;
}
if (vp->v_ref_count <= 0)
{
printf("put_vnode: bad v_ref_count %d\n", vp->v_ref_count);
panic(__FILE__, "put_vnode failed", NO_NUM);
}
if (vp->v_fs_count <= 0)
{
printf("put_vnode: bad v_fs_count %d\n", vp->v_fs_count);
panic(__FILE__, "put_vnode failed", NO_NUM);
}
/* Send request */
if (req_putnode(vp->v_fs_e, vp->v_inode_nr, vp->v_fs_count) != OK)
printf("VFSput_vnode Warning: inode doesn't exist\n");
vp->v_fs_count= 0;
vp->v_ref_count= 0;
vp->v_pipe = NO_PIPE;
vp->v_sdev = NO_DEV;
vp->v_index = 0;
}
/*===========================================================================*
* vnode_clean_refs *
*===========================================================================*/
PUBLIC void vnode_clean_refs(struct vnode *vp)
{
/* Tell the underlying FS to drop all reference but one. */
if (vp == NIL_VNODE) {
return;
}
if (vp->v_fs_count <= 1)
return; /* Nothing to do */
if (req_putnode(vp->v_fs_e, vp->v_inode_nr, vp->v_fs_count-1) != OK)
printf("vnode_clean_refs: req_putnode failed\n");
vp->v_fs_count= 1;
}
#if 0
/*===========================================================================*
* mark_vn *
*===========================================================================*/
PUBLIC void mark_vn(vp, file, line)
struct vnode *vp;
char *file;
int line;
{
if (!vp)
return;
vp->v_file= file;
vp->v_line= line;
}
#endif
#define REFVP(v) { vp = (v); CHECKVN(v); vp->v_ref_check++; }
#if DO_SANITYCHECKS
/*===========================================================================*
* check_vrefs *
*===========================================================================*/
PUBLIC int check_vrefs()
{
int i, bad;
int ispipe_flag, ispipe_mode;
struct vnode *vp;
struct vmnt *vmp;
struct fproc *rfp;
struct filp *f;
/* Clear v_ref_check */
for (vp = &vnode[0]; vp < &vnode[NR_VNODES]; ++vp)
vp->v_ref_check= 0;
/* Count reference for processes */
for (rfp=&fproc[0]; rfp < &fproc[NR_PROCS]; rfp++) {
if (rfp->fp_pid == PID_FREE)
continue;
if(rfp->fp_rd) REFVP(rfp->fp_rd);
if(rfp->fp_wd) REFVP(rfp->fp_wd);
}
/* Count references from filedescriptors */
for (f = &filp[0]; f < &filp[NR_FILPS]; f++)
{
if (f->filp_count == 0)
continue;
REFVP(f->filp_vno);
}
/* Count references to mount points */
for (vmp = &vmnt[0]; vmp < &vmnt[NR_MNTS]; ++vmp)
{
if (vmp->m_dev == NO_DEV)
continue;
REFVP(vmp->m_root_node);
if(vmp->m_mounted_on)
REFVP(vmp->m_mounted_on);
}
/* Check references */
bad= 0;
for (vp = &vnode[0]; vp < &vnode[NR_VNODES]; ++vp)
{
if (vp->v_ref_count != vp->v_ref_check)
{
printf(
"Bad reference count for inode %d on device 0x%x: found %d, listed %d\n",
vp->v_inode_nr, vp->v_dev, vp->v_ref_check,
vp->v_ref_count);
printf("last marked at %s, %d\n",
vp->v_file, vp->v_line);
bad= 1;
}
/* Also check v_pipe */
if (vp->v_ref_count != 0)
{
ispipe_flag= (vp->v_pipe == I_PIPE);
ispipe_mode= ((vp->v_mode & I_TYPE) == I_NAMED_PIPE);
if (ispipe_flag != ispipe_mode)
{
printf(
"Bad v_pipe for inode %d on device 0x%x: found %d, mode 0%o\n",
vp->v_inode_nr, vp->v_dev, vp->v_pipe,
vp->v_mode);
printf("last marked at %s, %d\n",
vp->v_file, vp->v_line);
bad= 1;
}
}
}
return !bad;
}
#endif