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minix/servers/vfs/vnode.c
Ben Gras 35a108b911 panic() cleanup. 
this change
   - makes panic() variadic, doing full printf() formatting -
     no more NO_NUM, and no more separate printf() statements
     needed to print extra info (or something in hex) before panicing
   - unifies panic() - same panic() name and usage for everyone -
     vm, kernel and rest have different names/syntax currently
     in order to implement their own luxuries, but no longer
   - throws out the 1st argument, to make source less noisy.
     the panic() in syslib retrieves the server name from the kernel
     so it should be clear enough who is panicing; e.g.
         panic("sigaction failed: %d", errno);
     looks like:
         at_wini(73130): panic: sigaction failed: 0
         syslib:panic.c: stacktrace: 0x74dc 0x2025 0x100a
   - throws out report() - printf() is more convenient and powerful
   - harmonizes/fixes the use of panic() - there were a few places
     that used printf-style formatting (didn't work) and newlines
     (messes up the formatting) in panic()
   - throws out a few per-server panic() functions
   - cleans up a tie-in of tty with panic()

merging printf() and panic() statements to be done incrementally.
2010-03-05 15:05:11 +00:00

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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)
*/
#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("bad vp"); }
/*===========================================================================*
* get_free_vnode *
*===========================================================================*/
PUBLIC struct vnode *get_free_vnode()
{
/* Find a free vnode slot in the vnode table (it's not actually allocated) */
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 = NO_DEV;
vp->v_mapfs_e = 0;
vp->v_mapinode_nr = 0;
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. Decreasing the fs_count each time we decrease the
* ref count would lead to poor performance. Instead, only decrease fs_count
* when the ref count hits zero. However, this could lead to fs_count to wrap.
* To prevent this, we drop the counter to 1 when the counter hits 256.
* We maintain fs_count as a sanity check to make sure VFS and the FS are in
* sync.
*/
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;
}
/* A vnode that's not in use can't be put. */
if (vp->v_ref_count <= 0) {
printf("put_vnode: bad v_ref_count %d\n", vp->v_ref_count);
panic("put_vnode failed");
}
/* fs_count should indicate that the file is in use. */
if (vp->v_fs_count <= 0) {
printf("put_vnode: bad v_fs_count %d\n", vp->v_fs_count);
panic("put_vnode failed");
}
/* Tell FS we don't need this inode to be open anymore. */
req_putnode(vp->v_fs_e, vp->v_inode_nr, vp->v_fs_count);
/* This inode could've been mapped. If so, tell PFS to close it as well. */
if(vp->v_mapfs_e != 0 && vp->v_mapinode_nr != vp->v_inode_nr &&
vp->v_mapfs_e != vp->v_fs_e) {
req_putnode(vp->v_mapfs_e, vp->v_mapinode_nr, vp->v_mapfs_count);
}
vp->v_fs_count = 0;
vp->v_ref_count = 0;
vp->v_pipe = NO_PIPE;
vp->v_sdev = NO_DEV;
vp->v_mapfs_e = 0;
vp->v_mapinode_nr = 0;
vp->v_mapfs_count = 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 */
/* Drop all references except one */
req_putnode(vp->v_fs_e, vp->v_inode_nr, vp->v_fs_count - 1);
vp->v_fs_count = 1;
}
#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
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