minix/servers/vfs/vnode.c

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/* 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"
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#include "fproc.h"
#include "file.h"
#include <minix/vfsif.h>
/*===========================================================================*
* get_vnode *
*===========================================================================*/
PUBLIC struct vnode *get_vnode(int fs_e, int inode_nr)
{
/* get_vnode() is called to get the details of the specified inode.
* Note that inode's usage counter in the FS is supposed to be incremented.
*/
struct vnode *vp, *vp2;
struct vmnt *vmp;
/* Request & response structures */
struct node_req req;
struct node_details res;
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/* XXX remove this when debugging is complete */
if (find_vnode(fs_e, inode_nr) != NULL)
panic(__FILE__, "get_vnode: vnode already present", NO_NUM);
/* Check whether a free vnode is avaliable */
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if ((vp = get_free_vnode(__FILE__, __LINE__)) == NIL_VNODE) {
printf("VFSget_vnode: no vnode available\n");
return NIL_VNODE;
}
/* Fill req struct */
req.inode_nr = inode_nr;
req.fs_e = fs_e;
/* Send request to FS */
if (req_getnode(&req, &res) != OK) {
printf("VFSget_vnode: couldn't find vnode\n");
return NIL_VNODE;
}
/* Fill in the free vnode's fields and return it */
vp->v_fs_e = res.fs_e;
vp->v_inode_nr = res.inode_nr;
vp->v_mode = res.fmode;
vp->v_size = res.fsize;
vp->v_sdev = res.dev;
/* Find corresponding virtual mount object */
if ( (vmp = find_vmnt(vp->v_fs_e)) == NIL_VMNT)
printf("VFS: vmnt not found by get_vnode()\n");
vp->v_vmnt = vmp;
vp->v_dev = vmp->m_dev;
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vp->v_fs_count = 1;
vp->v_ref_count = 1;
return vp;
}
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/*===========================================================================*
* get_vnode *
*===========================================================================*/
PUBLIC struct vnode *get_vnode_x(int fs_e, int inode_nr)
{
/* get_vnode() is called to get the details of the specified inode.
* Note that inode's usage counter in the FS is supposed to be incremented.
*/
struct vnode *vp, *vp2;
struct vmnt *vmp;
/* Request & response structures */
struct node_req req;
struct node_details res;
vp= find_vnode(fs_e, inode_nr);
if (vp)
{
vp->v_ref_count++;
return vp;
}
return get_vnode(fs_e, inode_nr);
}
/*===========================================================================*
* get_free_vnode *
*===========================================================================*/
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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)
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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)
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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.
*/
if (vp == NIL_VNODE) {
printf("VFSdup_vnode NIL_VNODE\n");
return;
}
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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.
*/
if (vp == NIL_VNODE) {
/*printf("VFSput_vnode NIL_VNODE\n");*/
return;
}
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if (vp < &vnode[0] || vp >= &vnode[NR_VNODES])
{
printf("put_vnode: &vnode[0] = %p, &vnode[NR_VNODES] = %p, vp = %p\n",
&vnode[0], &vnode[NR_VNODES], vp);
panic(__FILE__, "put_vnode: bad vnode pointer", NO_NUM);
}
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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);
}
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/* 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");
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vp->v_fs_count= 0;
vp->v_ref_count= 0;
vp->v_pipe = NO_PIPE;
vp->v_sdev = NO_DEV;
vp->v_index = 0;
}
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/*===========================================================================*
* 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 */
printf("vnode_clean_refs: dropping some references at FS\n");
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;
}
/*===========================================================================*
* 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;
vp= rfp->fp_rd;
if (vp < &vnode[0] || vp >= &vnode[NR_VNODES])
panic(__FILE__, "check_vrefs: bad vnode", NO_NUM);
vp->v_ref_check++;
vp= rfp->fp_wd;
if (vp < &vnode[0] || vp >= &vnode[NR_VNODES])
panic(__FILE__, "check_vrefs: bad vnode", NO_NUM);
vp->v_ref_check++;
}
/* Count references from filedescriptors */
for (f = &filp[0]; f < &filp[NR_FILPS]; f++)
{
if (f->filp_count == 0)
continue;
vp= f->filp_vno;
if (vp < &vnode[0] || vp >= &vnode[NR_VNODES])
panic(__FILE__, "check_vrefs: bad vnode", NO_NUM);
vp->v_ref_check++;
}
/* Count references to mount points */
for (vmp = &vmnt[0]; vmp < &vmnt[NR_MNTS]; ++vmp)
{
if (vmp->m_dev == NO_DEV)
continue;
vp= vmp->m_mounted_on;
if (vp < &vnode[0] || vp >= &vnode[NR_VNODES])
panic(__FILE__, "check_vrefs: bad vnode", NO_NUM);
vp->v_ref_check++;
vp= vmp->m_root_node;
if (vp < &vnode[0] || vp >= &vnode[NR_VNODES])
panic(__FILE__, "check_vrefs: bad vnode", NO_NUM);
vp->v_ref_check++;
}
/* 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