291 lines
8.3 KiB
C
291 lines
8.3 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 "vmnt.h"
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#include <assert.h>
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#include <string.h>
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static int is_vmnt_locked(struct vmnt *vmp);
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static void clear_vmnt(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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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, job_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, job_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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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=%llx\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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* mark_vmnt_free *
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*===========================================================================*/
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void mark_vmnt_free(struct vmnt *vmp)
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{
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ASSERTVMP(vmp);
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vmp->m_fs_e = NONE;
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vmp->m_dev = NO_DEV;
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}
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/*===========================================================================*
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* clear_vmnt *
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*===========================================================================*/
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static void clear_vmnt(struct vmnt *vmp)
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{
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/* Reset vmp to initial parameters */
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ASSERTVMP(vmp);
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vmp->m_fs_e = NONE;
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vmp->m_dev = NO_DEV;
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vmp->m_flags = 0;
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vmp->m_mounted_on = NULL;
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vmp->m_root_node = NULL;
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vmp->m_label[0] = '\0';
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vmp->m_comm.c_max_reqs = 1;
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vmp->m_comm.c_cur_reqs = 0;
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vmp->m_comm.c_req_queue = NULL;
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}
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/*===========================================================================*
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* get_free_vmnt *
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*===========================================================================*/
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struct vmnt *get_free_vmnt(void)
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{
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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 (vmp->m_dev == NO_DEV) {
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clear_vmnt(vmp);
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return(vmp);
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}
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}
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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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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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void init_vmnts(void)
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{
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/* Initialize vmnt table */
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struct vmnt *vmp;
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for (vmp = &vmnt[0]; vmp < &vmnt[NR_MNTS]; vmp++) {
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clear_vmnt(vmp);
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tll_init(&vmp->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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static 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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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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if (vmp->m_fs_e == who_e) return(EDEADLK);
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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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upgrade_vmnt_lock(vmp);
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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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* vmnt_unmap_by_endpoint *
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*===========================================================================*/
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void vmnt_unmap_by_endpt(endpoint_t proc_e)
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{
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struct vmnt *vmp;
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if ((vmp = find_vmnt(proc_e)) != NULL) {
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mark_vmnt_free(vmp);
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fs_cancel(vmp);
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invalidate_filp_by_endpt(proc_e);
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if (vmp->m_mounted_on) {
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/* Only put mount point when it was actually used as mount
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* point. That is, the mount was succesful. */
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put_vnode(vmp->m_mounted_on);
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}
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}
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}
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/*===========================================================================*
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* unlock_vmnt *
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*===========================================================================*/
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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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/*===========================================================================*
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* downgrade_vmnt_lock *
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*===========================================================================*/
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void downgrade_vmnt_lock(struct vmnt *vmp)
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{
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ASSERTVMP(vmp);
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tll_downgrade(&vmp->m_lock);
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#if LOCK_DEBUG
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/* If we're no longer the owner of a lock, we downgraded to VMNT_READ */
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if (!tll_locked_by_me(&vmp->m_lock)) {
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fp->fp_vmnt_rdlocks++;
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}
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#endif
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}
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/*===========================================================================*
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* upgrade_vmnt_lock *
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*===========================================================================*/
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void upgrade_vmnt_lock(struct vmnt *vmp)
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{
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ASSERTVMP(vmp);
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tll_upgrade(&vmp->m_lock);
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}
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/*===========================================================================*
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* fetch_vmnt_paths *
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*===========================================================================*/
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void fetch_vmnt_paths(void)
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{
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struct vmnt *vmp;
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struct vnode *cur_wd;
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char orig_path[PATH_MAX];
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cur_wd = fp->fp_wd;
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for (vmp = &vmnt[0]; vmp < &vmnt[NR_MNTS]; vmp++) {
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if (vmp->m_dev == NO_DEV)
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continue;
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if (vmp->m_fs_e == PFS_PROC_NR)
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continue;
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strlcpy(orig_path, vmp->m_mount_path, PATH_MAX);
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/* Find canonical path */
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if (canonical_path(vmp->m_mount_path, fp) != OK) {
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/* We failed to find it (moved somewhere else?). Let's try
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* again by starting at the node on which we are mounted:
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* pretend that node is our working directory and look for the
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* canonical path of the relative path to the mount point
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* (which should be in our 'working directory').
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*/
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char *mp;
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int len;
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fp->fp_wd = vmp->m_mounted_on; /* Change our working dir */
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/* Isolate the mount point name of the full path */
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len = strlen(vmp->m_mount_path);
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if (vmp->m_mount_path[len - 1] == '/') {
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vmp->m_mount_path[len - 1] = '\0';
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}
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mp = strrchr(vmp->m_mount_path, '/');
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strlcpy(vmp->m_mount_path, mp+1, NAME_MAX+1);
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if (canonical_path(vmp->m_mount_path, fp) != OK) {
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/* Our second try failed too. Maybe an FS has crashed
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* and we're missing part of the tree. Revert path.
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*/
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strlcpy(vmp->m_mount_path, orig_path, PATH_MAX);
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}
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fp->fp_wd = cur_wd; /* Revert working dir */
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}
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}
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}
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