168 lines
4.7 KiB
C
168 lines
4.7 KiB
C
/* Virtual mount table related routines.
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*
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*/
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#include "fs.h"
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#include "threads.h"
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#include "vmnt.h"
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#include <assert.h>
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#include "fproc.h"
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FORWARD _PROTOTYPE( int is_vmnt_locked, (struct vmnt *vmp) );
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/* Is vmp pointer reasonable? */
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#define SANEVMP(v) ((((v) >= &vmnt[0] && (v) < &vmnt[NR_MNTS])))
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#define BADVMP(v, f, l) printf("%s:%d: bad vmp %p\n", f, l, v)
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/* vp check that panics */
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#define ASSERTVMP(v) if(!SANEVMP(v)) { \
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BADVMP(v, __FILE__, __LINE__); panic("bad vmp"); }
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#if LOCK_DEBUG
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/*===========================================================================*
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* check_vmnt_locks_by_me *
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*===========================================================================*/
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PUBLIC void check_vmnt_locks_by_me(struct fproc *rfp)
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{
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/* Check whether this thread still has locks held on vmnts */
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struct vmnt *vmp;
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for (vmp = &vmnt[0]; vmp < &vmnt[NR_MNTS]; vmp++) {
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if (tll_locked_by_me(&vmp->m_lock))
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panic("Thread %d still holds vmnt lock on vmp %p call_nr=%d\n",
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mthread_self(), vmp, call_nr);
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}
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if (rfp->fp_vmnt_rdlocks != 0)
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panic("Thread %d still holds read locks on a vmnt (%d) call_nr=%d\n",
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mthread_self(), rfp->fp_vmnt_rdlocks, call_nr);
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}
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#endif
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/*===========================================================================*
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* check_vmnt_locks *
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*===========================================================================*/
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PUBLIC void check_vmnt_locks()
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{
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struct vmnt *vmp;
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int count = 0;
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for (vmp = &vmnt[0]; vmp < &vmnt[NR_MNTS]; vmp++)
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if (is_vmnt_locked(vmp)) {
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count++;
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printf("vmnt %p is %s, fs_e=%d dev=%d\n", vmp, (tll_islocked(&vmp->m_lock) ? "locked":"pending locked"), vmp->m_fs_e, vmp->m_dev);
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}
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if (count) panic("%d locked vmnts\n", count);
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#if 0
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printf("check_vmnt_locks OK\n");
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#endif
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}
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/*===========================================================================*
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* get_free_vmnt *
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*===========================================================================*/
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PUBLIC struct vmnt *get_free_vmnt(void)
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{
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struct vmnt *vp;
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for (vp = &vmnt[0]; vp < &vmnt[NR_MNTS]; ++vp)
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if (vp->m_dev == NO_DEV) return(vp);
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return(NULL);
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}
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/*===========================================================================*
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* find_vmnt *
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*===========================================================================*/
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PUBLIC struct vmnt *find_vmnt(endpoint_t fs_e)
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{
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/* Find the vmnt belonging to an FS with endpoint 'fs_e' iff it's in use */
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struct vmnt *vp;
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for (vp = &vmnt[0]; vp < &vmnt[NR_MNTS]; ++vp)
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if (vp->m_fs_e == fs_e && vp->m_dev != NO_DEV)
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return(vp);
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return(NULL);
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}
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/*===========================================================================*
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* init_vmnts *
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*===========================================================================*/
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PUBLIC void init_vmnts(void)
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{
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/* Initialize vmnt table */
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struct vmnt *vp;
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for (vp = &vmnt[0]; vp < &vmnt[NR_MNTS]; vp++) {
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vp->m_fs_e = NONE;
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vp->m_dev = NO_DEV;
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vp->m_flags = 0;
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vp->m_mounted_on = NULL;
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vp->m_root_node = NULL;
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vp->m_label[0] = '\0';
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vp->m_comm.c_max_reqs = 1;
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vp->m_comm.c_cur_reqs = 0;
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vp->m_comm.c_req_queue = NULL;
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tll_init(&vp->m_lock);
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}
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}
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/*===========================================================================*
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* is_vmnt_locked *
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*===========================================================================*/
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PRIVATE int is_vmnt_locked(struct vmnt *vmp)
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{
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ASSERTVMP(vmp);
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return(tll_islocked(&vmp->m_lock) || tll_haspendinglock(&vmp->m_lock));
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}
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/*===========================================================================*
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* lock_vmnt *
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*===========================================================================*/
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PUBLIC int lock_vmnt(struct vmnt *vmp, tll_access_t locktype)
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{
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int r;
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tll_access_t initial_locktype;
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ASSERTVMP(vmp);
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initial_locktype = (locktype == VMNT_EXCL) ? VMNT_WRITE : locktype;
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r = tll_lock(&vmp->m_lock, initial_locktype);
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if (r == EBUSY) return(r);
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if (initial_locktype != locktype) {
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tll_upgrade(&vmp->m_lock);
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}
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#if LOCK_DEBUG
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if (locktype == VMNT_READ)
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fp->fp_vmnt_rdlocks++;
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#endif
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return(OK);
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}
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/*===========================================================================*
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* unlock_vmnt *
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*===========================================================================*/
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PUBLIC void unlock_vmnt(struct vmnt *vmp)
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{
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ASSERTVMP(vmp);
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#if LOCK_DEBUG
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/* Decrease read-only lock counter when not locked as VMNT_WRITE or
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* VMNT_EXCL */
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if (!tll_locked_by_me(&vmp->m_lock))
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fp->fp_vmnt_rdlocks--;
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#endif
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tll_unlock(&vmp->m_lock);
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#if LOCK_DEBUG
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assert(!tll_locked_by_me(&vmp->m_lock));
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#endif
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}
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