From: Thomas Veerman <thomas@minix3.org>
Date: Tue, 22 Jan 2013 16:40:53 +0000 (+0000)
Subject: VFS/PFS: remove remnants of file position in pipes
X-Git-Tag: v3.2.1~81
X-Git-Url: http://zhaoyanbai.com/repos/%22http:/www.isc.org/icons/mdoc.3.txt?a=commitdiff_plain;h=b180f32ab31e242bdf4fb80fc6606e32fb3e38dd;p=minix.git

VFS/PFS: remove remnants of file position in pipes
---

diff --git a/servers/pfs/read.c b/servers/pfs/read.c
index d80647b58..86a4f0b1e 100644
--- a/servers/pfs/read.c
+++ b/servers/pfs/read.c
@@ -1,7 +1,8 @@
 #include "fs.h"
 #include "buf.h"
-#include <minix/com.h>
 #include "inode.h"
+#include <minix/com.h>
+#include <string.h>
 
 
 /*===========================================================================*
@@ -53,10 +54,10 @@ int fs_readwrite(message *fs_m_in, message *fs_m_out)
 		return(EFBIG);
 	}
   } else {
-	position = bp->b_bytes;
-	if (nrbytes > rip->i_size - position) {
+	position = 0;
+	if (nrbytes > rip->i_size) {
 		/* There aren't that many bytes to read */
-		nrbytes = rip->i_size - position;
+		nrbytes = rip->i_size;
 	}
   }
 
@@ -75,25 +76,18 @@ int fs_readwrite(message *fs_m_in, message *fs_m_out)
 	cum_io += nrbytes;
   }
 
-  fs_m_out->RES_SEEK_POS_LO = position; /* It might change later and the VFS
-					   has to know this value */
-
   /* On write, update file size and access time. */
   if (rw_flag == WRITING) {
-	  if (position > f_size) rip->i_size = position;
+	rip->i_size = position;
   } else {
-	if(position >= rip->i_size) {
-		/* All data in the pipe is read, so reset pipe pointers */
-		rip->i_size = 0;	/* no data left */
-		position = 0;		/* reset reader(s) */
-	}
+	memmove(bp->b_data, bp->b_data+nrbytes, rip->i_size - nrbytes);
+	rip->i_size -= nrbytes;
   }
 
-  if (rw_flag == READING)
-	bp->b_bytes = position;
   if (rw_flag == READING) rip->i_update |= ATIME;
   if (rw_flag == WRITING) rip->i_update |= CTIME | MTIME;
   fs_m_out->RES_NBYTES = (size_t) cum_io;
+  fs_m_out->RES_SEEK_POS_LO = rip->i_size;
 
   put_inode(rip);
   put_block(rip->i_dev, rip->i_num);
diff --git a/servers/vfs/read.c b/servers/vfs/read.c
index 65722ab41..05f173aa2 100644
--- a/servers/vfs/read.c
+++ b/servers/vfs/read.c
@@ -297,46 +297,33 @@ size_t req_size;
   r = req_readwrite(vp->v_mapfs_e, vp->v_mapinode_nr, position, rw_flag, usr_e,
 		    buf, size, &new_pos, &cum_io_incr);
 
-  if (r >= 0) {
-	if (ex64hi(new_pos))
-		panic("rw_pipe: bad new pos");
-
-	cum_io += cum_io_incr;
-	buf += cum_io_incr;
-	req_size -= cum_io_incr;
+  if (r != OK) {
+	return(r);
   }
 
-  /* On write, update file size and access time. */
-  if (rw_flag == WRITING) {
-	if (cmp64ul(new_pos, vp->v_size) > 0) {
-		if (ex64hi(new_pos) != 0) {
-			panic("read_write: file size too big for v_size");
-		}
-		vp->v_size = ex64lo(new_pos);
-	}
-  } else {
-	if (cmp64ul(new_pos, vp->v_size) >= 0) {
-		/* Pipe emtpy; reset size */
-		vp->v_size = 0;
+  if (ex64hi(new_pos))
+	panic("rw_pipe: bad new pos");
+
+  cum_io += cum_io_incr;
+  buf += cum_io_incr;
+  req_size -= cum_io_incr;
+
+  vp->v_size = ex64lo(new_pos);
+
+  if (partial_pipe) {
+	/* partial write on pipe with */
+	/* O_NONBLOCK, return write count */
+	if (!(oflags & O_NONBLOCK)) {
+		/* partial write on pipe with req_size > PIPE_SIZE,
+		 * non-atomic
+		 */
+		fp->fp_cum_io_partial = cum_io;
+		pipe_suspend(f, buf, req_size);
+		return(SUSPEND);
 	}
   }
 
-  if (r == OK) {
-	if (partial_pipe) {
-		/* partial write on pipe with */
-		/* O_NONBLOCK, return write count */
-		if (!(oflags & O_NONBLOCK)) {
-			/* partial write on pipe with req_size > PIPE_SIZE,
-			 * non-atomic
-			 */
-			fp->fp_cum_io_partial = cum_io;
-			pipe_suspend(f, buf, req_size);
-			return(SUSPEND);
-		}
-	}
-	fp->fp_cum_io_partial = 0;
-	return(cum_io);
-  }
+  fp->fp_cum_io_partial = 0;
 
-  return(r);
+  return(cum_io);
 }