If re-open fails, mark fd as unusable but not-reusable either (until

close()d).

servers/fs/device.c

@@ -596,10 +596,23 @@ PUBLIC void dev_up(int maj)
 		
 		minor = ((in->i_zone[0] >> MINOR) & BYTE);
 
-		if((r = dev_open(in->i_dev, FS_PROC_NR,
+		printf("FS: reopening special %d/%d..\n", maj, minor);
+
+		if((r = dev_open(in->i_zone[0], FS_PROC_NR,
 		   in->i_mode & (R_BIT|W_BIT))) != OK) {
-			printf("FS: file on dev %d/%d re-open failed: %d.\n",
-				maj, minor, r);
+			int n;
+			/* This function will set the fp_filp[]s of processes
+			 * holding that fp to NULL, but _not_ clear
+			 * fp_filp_inuse, so that fd can't be recycled until
+			 * it's close()d.
+			 */
+			n = inval_filp(fp);
+			if(n != fp->filp_count)
+				printf("FS: warning: invalidate/count "
+				 "discrepancy (%d, %d)\n", n, fp->filp_count);
+			fp->filp_count = 0;
+			printf("FS: file on dev %d/%d re-open failed: %d; "
+				"invalidated %d fd's.\n", maj, minor, r, n);
 		}
 	}
 

servers/fs/filedes.c

@@ -1,11 +1,15 @@
 /* This file contains the procedures that manipulate file descriptors.
  *
  * The entry points into this file are
- *   get_fd:	look for free file descriptor and free filp slots
- *   get_filp:	look up the filp entry for a given file descriptor
- *   find_filp:	find a filp slot that points to a given inode
+ *   get_fd:	 look for free file descriptor and free filp slots
+ *   get_filp:	 look up the filp entry for a given file descriptor
+ *   find_filp:	 find a filp slot that points to a given inode
+ *   inval_filp: invalidate a filp and associated fd's, only let close()
+ *               happen on it
  */
 
+#include <sys/select.h>
+
 #include "fs.h"
 #include "file.h"
 #include "fproc.h"
@@ -28,7 +32,7 @@ PUBLIC int get_fd(int start, mode_t bits, int *k, struct filp **fpt)
 
   /* Search the fproc fp_filp table for a free file descriptor. */
   for (i = start; i < OPEN_MAX; i++) {
-	if (fp->fp_filp[i] == NIL_FILP) {
+	if (fp->fp_filp[i] == NIL_FILP && !FD_ISSET(i, &fp->fp_filp_inuse)) {
 		/* A file descriptor has been located. */
 		*k = i;
 		break;
@@ -92,3 +96,21 @@ PUBLIC struct filp *find_filp(register struct inode *rip, mode_t bits)
   /* If control passes here, the filp wasn't there.  Report that back. */
   return(NIL_FILP);
 }
+
+/*===========================================================================*
+ *				inval_filp				     *
+ *===========================================================================*/
+PUBLIC int inval_filp(struct filp *fp)
+{
+	int f, fd, n = 0;
+	for(f = 0; f < NR_PROCS; f++) {
+		if(fproc[f].fp_pid == PID_FREE) continue;
+		for(fd = 0; fd < OPEN_MAX; fd++) {
+			if(fproc[f].fp_filp[fd] && fproc[f].fp_filp[fd] == fp) {
+				fproc[f].fp_filp[fd] = NIL_FILP;
+			}
+		}
+	}
+
+	return n;
+}

servers/fs/fproc.h

@@ -1,3 +1,5 @@
+#include <sys/select.h>
+
 /* This is the per-process information.  A slot is reserved for each potential
  * process. Thus NR_PROCS must be the same as in the kernel. It is not 
  * possible or even necessary to tell when a slot is free here.
@@ -7,6 +9,7 @@ EXTERN struct fproc {
   struct inode *fp_workdir;	/* pointer to working directory's inode */
   struct inode *fp_rootdir;	/* pointer to current root dir (see chroot) */
   struct filp *fp_filp[OPEN_MAX];/* the file descriptor table */
+  fd_set fp_filp_inuse;		/* which fd's are in use? */
   uid_t fp_realuid;		/* real user id */
   uid_t fp_effuid;		/* effective user id */
   gid_t fp_realgid;		/* real group id */

servers/fs/main.c

@@ -18,6 +18,7 @@ struct super_block;		/* proto.h needs to know this */
 #include <stdlib.h>
 #include <sys/ioc_memory.h>
 #include <sys/svrctl.h>
+#include <sys/select.h>
 #include <minix/callnr.h>
 #include <minix/com.h>
 #include <minix/keymap.h>
@@ -251,6 +252,7 @@ PRIVATE void fs_init()
 
   /* The root device can now be accessed; set process directories. */
   for (rfp=&fproc[0]; rfp < &fproc[NR_PROCS]; rfp++) {
+	FD_ZERO(&(rfp->fp_filp_inuse));
   	if (rfp->fp_pid != PID_FREE) {
 		rip = get_inode(root_dev, ROOT_INODE);
 		dup_inode(rip);

servers/fs/misc.c

@@ -101,6 +101,7 @@ PUBLIC int do_dup()
   /* Success. Set up new file descriptors. */
   f->filp_count++;
   fp->fp_filp[m_in.fd2] = f;
+  FD_SET(m_in.fd2, &fp->fp_filp_inuse);
   return(m_in.fd2);
 }
 

servers/fs/open.c

@@ -108,6 +108,7 @@ PRIVATE int common_open(register int oflags, mode_t omode)
 
   /* Claim the file descriptor and filp slot and fill them in. */
   fp->fp_filp[m_in.fd] = fil_ptr;
+  FD_SET(m_in.fd, &fp->fp_filp_inuse);
   fil_ptr->filp_count = 1;
   fil_ptr->filp_ino = rip;
   fil_ptr->filp_flags = oflags;
@@ -187,6 +188,7 @@ PRIVATE int common_open(register int oflags, mode_t omode)
   if (r != OK) {
 	if (r == SUSPEND) return(r);		/* Oops, just suspended */
 	fp->fp_filp[m_in.fd] = NIL_FILP;
+  	FD_CLR(m_in.fd, &fp->fp_filp_inuse);
 	fil_ptr->filp_count= 0;
 	put_inode(rip);
 	return(r);
@@ -434,6 +436,7 @@ PUBLIC int do_close()
 
   fp->fp_cloexec &= ~(1L << m_in.fd);	/* turn off close-on-exec bit */
   fp->fp_filp[m_in.fd] = NIL_FILP;
+  FD_CLR(m_in.fd, &fp->fp_filp_inuse);
 
   /* Check to see if the file is locked.  If so, release all locks. */
   if (nr_locks == 0) return(OK);

servers/fs/pipe.c

@@ -47,20 +47,25 @@ PUBLIC int do_pipe()
   rfp = fp;
   if ( (r = get_fd(0, R_BIT, &fil_des[0], &fil_ptr0)) != OK) return(r);
   rfp->fp_filp[fil_des[0]] = fil_ptr0;
+  FD_SET(fil_des[0], &rfp->fp_filp_inuse);
   fil_ptr0->filp_count = 1;
   if ( (r = get_fd(0, W_BIT, &fil_des[1], &fil_ptr1)) != OK) {
 	rfp->fp_filp[fil_des[0]] = NIL_FILP;
+  	FD_CLR(fil_des[0], &rfp->fp_filp_inuse);
 	fil_ptr0->filp_count = 0;
 	return(r);
   }
   rfp->fp_filp[fil_des[1]] = fil_ptr1;
+  FD_SET(fil_des[1], &rfp->fp_filp_inuse);
   fil_ptr1->filp_count = 1;
 
   /* Make the inode on the pipe device. */
   if ( (rip = alloc_inode(root_dev, I_REGULAR) ) == NIL_INODE) {
 	rfp->fp_filp[fil_des[0]] = NIL_FILP;
+  	FD_CLR(fil_des[0], &rfp->fp_filp_inuse);
 	fil_ptr0->filp_count = 0;
 	rfp->fp_filp[fil_des[1]] = NIL_FILP;
+  	FD_CLR(fil_des[1], &rfp->fp_filp_inuse);
 	fil_ptr1->filp_count = 0;
 	return(err_code);
   }

servers/fs/proto.h

@@ -59,6 +59,7 @@ _PROTOTYPE( void dmap_endpt_up, (int proc_nr)				);
 _PROTOTYPE( struct filp *find_filp, (struct inode *rip, mode_t bits)	);
 _PROTOTYPE( int get_fd, (int start, mode_t bits, int *k, struct filp **fpt) );
 _PROTOTYPE( struct filp *get_filp, (int fild)				);
+_PROTOTYPE( int inval_filp, (struct filp *)				);
 
 /* inode.c */
 _PROTOTYPE( struct inode *alloc_inode, (dev_t dev, mode_t bits)		);