From: wessels <>
Date: Fri, 16 May 1997 05:35:59 +0000 (+0000)
Subject: Dont' flush write buffers on write error, UNLESS there is no callback handler.
X-Git-Tag: SQUID_3_0_PRE1~5007
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=de866d201ec88988ab7d9e92bac8a1828a3b2d2d;p=thirdparty%2Fsquid.git

Dont' flush write buffers on write error, UNLESS there is no callback handler.
The callback should check the status return code and take necessary measures,
the disk module will keep the data queued.

I'm pretty sure we don't need to seek on disk files since they are only
open for reading or writing, never both.
    Remove all seek calls
    Remove FD_AT_EOF wierdness
    Remove wierd dread_ctrl->cur_len member
---

diff --git a/src/disk.cc b/src/disk.cc
index d9e4b2f610..0b460ef415 100644
--- a/src/disk.cc
+++ b/src/disk.cc
@@ -1,5 +1,5 @@
 /*
- * $Id: disk.cc,v 1.68 1997/05/05 03:43:39 wessels Exp $
+ * $Id: disk.cc,v 1.69 1997/05/15 23:35:59 wessels Exp $
  *
  * DEBUG: section 6     Disk I/O Routines
  * AUTHOR: Harvest Derived
@@ -123,17 +123,17 @@ typedef struct open_ctrl_t {
 typedef struct _dwalk_ctrl {
     int fd;
     off_t offset;
+    int cur_len;
     char *buf;			/* line buffer */
-    int cur_len;		/* line len */
     FILE_WALK_HD *handler;
     void *client_data;
     FILE_WALK_LHD *line_handler;
     void *line_data;
 } dwalk_ctrl;
 
-static int diskHandleWriteComplete _PARAMS((void *, int, int));
-static int diskHandleReadComplete _PARAMS((void *, int, int));
-static int diskHandleWalkComplete _PARAMS((void *, int, int));
+static AIOCB diskHandleWriteComplete;
+static AIOCB diskHandleReadComplete;
+static AIOCB diskHandleWalkComplete;
 static PF diskHandleWalk;
 static PF diskHandleRead;
 static PF diskHandleWrite;
@@ -267,13 +267,13 @@ diskHandleWrite(int fd, void *unused)
     dwrite_q *q = NULL;
     dwrite_q *wq = NULL;
     FD_ENTRY *fde = &fd_table[fd];
-    if (!fde->disk.write_q)
+    struct _fde_disk *fdd = &fde->disk;
+    if (!fdd->write_q)
 	return;
-    if (!BIT_TEST(fde->flags, FD_AT_EOF))
-	lseek(fd, 0, SEEK_END);
     /* We need to combine subsequent write requests after the first */
-    if (fde->disk.write_q->next != NULL && fde->disk.write_q->next->next != NULL) {
-	for (len = 0, q = fde->disk.write_q->next; q != NULL; q = q->next)
+    if (fdd->write_q->next != NULL && fdd->write_q->next->next != NULL) {
+	len = 0;
+	for (q = fdd->write_q->next; q != NULL; q = q->next)
 	    len += q->len - q->cur_offset;
 	wq = xcalloc(1, sizeof(dwrite_q));
 	wq->buf = xmalloc(len);
@@ -282,99 +282,90 @@ diskHandleWrite(int fd, void *unused)
 	wq->next = NULL;
 	wq->free = xfree;
 	do {
-	    q = fde->disk.write_q->next;
+	    q = fdd->write_q->next;
 	    len = q->len - q->cur_offset;
-	    memcpy(wq->buf + wq->len, q->buf + q->cur_offset, len);
+	    xmemcpy(wq->buf + wq->len, q->buf + q->cur_offset, len);
 	    wq->len += len;
-	    fde->disk.write_q->next = q->next;
+	    fdd->write_q->next = q->next;
 	    if (q->free)
 		(q->free) (q->buf);
 	    safe_free(q);
-	} while (fde->disk.write_q->next != NULL);
-	fde->disk.write_q_tail = wq;
-	fde->disk.write_q->next = wq;
+	} while (fdd->write_q->next != NULL);
+	fdd->write_q_tail = wq;
+	fdd->write_q->next = wq;
     }
     ctrlp = xcalloc(1, sizeof(disk_ctrl_t));
     ctrlp->fd = fd;
 #if USE_ASYNC_IO
     aioWrite(fd,
-	fde->disk.write_q->buf + fde->disk.write_q->cur_offset,
-	fde->disk.write_q->len - fde->disk.write_q->cur_offset,
+	fdd->write_q->buf + fdd->write_q->cur_offset,
+	fdd->write_q->len - fdd->write_q->cur_offset,
 	diskHandleWriteComplete,
 	ctrlp);
 #else
     len = write(fd,
-	fde->disk.write_q->buf + fde->disk.write_q->cur_offset,
-	fde->disk.write_q->len - fde->disk.write_q->cur_offset);
+	fdd->write_q->buf + fdd->write_q->cur_offset,
+	fdd->write_q->len - fdd->write_q->cur_offset);
     diskHandleWriteComplete(ctrlp, len, errno);
 #endif
 }
 
-static int
+static void
 diskHandleWriteComplete(void *data, int len, int errcode)
 {
     disk_ctrl_t *ctrlp = data;
     int fd = ctrlp->fd;
     FD_ENTRY *fde = &fd_table[fd];
-    dwrite_q *q = fde->disk.write_q;
+    struct _fde_disk *fdd = &fde->disk;
+    dwrite_q *q = fdd->write_q;
+    int status = DISK_OK;
     errno = errcode;
     safe_free(data);
     fd_bytes(fd, len, FD_WRITE);
-    if (q == NULL)		/* Someone aborted and then the write */
-	return DISK_ERROR;	/* completed anyway. :( */
-    BIT_SET(fde->flags, FD_AT_EOF);
+    if (q == NULL)		/* Someone aborted then write completed */
+	return;
     if (len < 0) {
 	if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR) {
-	    len = 0;
+	    (void) 0;
 	} else {
-	    /* disk i/o failure--flushing all outstanding writes  */
+	    status = errno == ENOSPC ? DISK_NO_SPACE_LEFT : DISK_ERROR;
 	    debug(50, 1, "diskHandleWrite: FD %d: disk write error: %s\n",
 		fd, xstrerror());
-	    BIT_RESET(fde->flags, FD_WRITE_DAEMON);
-	    BIT_RESET(fde->flags, FD_WRITE_PENDING);
-	    /* call finish handler */
-	    do {
-		fde->disk.write_q = q->next;
-		if (q->free)
-		    (q->free) (q->buf);
-		safe_free(q);
-	    } while ((q = fde->disk.write_q));
-	    if (fde->disk.wrt_handle) {
-		fde->disk.wrt_handle(fd,
-		    errno == ENOSPC ? DISK_NO_SPACE_LEFT : DISK_ERROR,
-		    fde->disk.wrt_handle_data);
+	    if (fdd->wrt_handle == NULL) {
+		/* FLUSH PENDING BUFFERS */
+		do {
+		    fdd->write_q = q->next;
+		    if (q->free)
+			(q->free) (q->buf);
+		    safe_free(q);
+		} while ((q = fdd->write_q));
 	    }
-	    return DISK_ERROR;
 	}
+	len = 0;
     }
     q->cur_offset += len;
-    if (q->cur_offset > q->len)
-	fatal_dump("diskHandleWriteComplete: offset > len");
+    assert(q->cur_offset <= q->len);
     if (q->cur_offset == q->len) {
 	/* complete write */
-	fde->disk.write_q = q->next;
+	fdd->write_q = q->next;
 	if (q->free)
 	    (q->free) (q->buf);
 	safe_free(q);
     }
-    if (fde->disk.write_q != NULL) {
+    if (fdd->write_q == NULL) {
+	/* no more data */
+	fdd->write_q_tail = NULL;
+	BIT_RESET(fde->flags, FD_WRITE_PENDING);
+	BIT_RESET(fde->flags, FD_WRITE_DAEMON);
+    } else {
 	/* another block is queued */
-	commSetSelect(fd,
-	    COMM_SELECT_WRITE,
-	    diskHandleWrite,
-	    NULL,
-	    0);
-	return DISK_OK;
+	commSetSelect(fd, COMM_SELECT_WRITE, diskHandleWrite, NULL, 0);
+	BIT_SET(fde->flags, FD_WRITE_DAEMON);
     }
-    /* no more data */
-    fde->disk.write_q = fde->disk.write_q_tail = NULL;
-    BIT_RESET(fde->flags, FD_WRITE_PENDING);
-    BIT_RESET(fde->flags, FD_WRITE_DAEMON);
-    if (fde->disk.wrt_handle)
-	fde->disk.wrt_handle(fd, DISK_OK, fde->disk.wrt_handle_data);
+    if (fdd->wrt_handle)
+	fdd->wrt_handle(fd, status, fdd->wrt_handle_data);
     if (BIT_TEST(fde->flags, FD_CLOSE_REQUEST))
 	file_close(fd);
-    return DISK_OK;
 }
 
 
@@ -435,31 +426,27 @@ file_write(int fd,
 static void
 diskHandleRead(int fd, void *data)
 {
-    FD_ENTRY *fde = &fd_table[fd];
     dread_ctrl *ctrl_dat = data;
     int len;
     disk_ctrl_t *ctrlp;
     ctrlp = xcalloc(1, sizeof(disk_ctrl_t));
     ctrlp->fd = fd;
     ctrlp->data = ctrl_dat;
-    /* go to requested position. */
-    lseek(fd, ctrl_dat->offset, SEEK_SET);
-    BIT_RESET(fde->flags, FD_AT_EOF);
 #if USE_ASYNC_IO
     aioRead(fd,
-	ctrl_dat->buf + ctrl_dat->cur_len,
-	ctrl_dat->req_len - ctrl_dat->cur_len,
+	ctrl_dat->buf + ctrl_dat->offset,
+	ctrl_dat->req_len - ctrl_dat->offset,
 	diskHandleReadComplete,
 	ctrlp);
 #else
     len = read(fd,
-	ctrl_dat->buf + ctrl_dat->cur_len,
-	ctrl_dat->req_len - ctrl_dat->cur_len);
+	ctrl_dat->buf + ctrl_dat->offset,
+	ctrl_dat->req_len - ctrl_dat->offset);
     diskHandleReadComplete(ctrlp, len, errno);
 #endif
 }
 
-static int
+static void
 diskHandleReadComplete(void *data, int len, int errcode)
 {
     disk_ctrl_t *ctrlp = data;
@@ -475,49 +462,48 @@ diskHandleReadComplete(void *data, int len, int errcode)
 		diskHandleRead,
 		ctrl_dat,
 		0);
-	    return DISK_OK;
+	    return;
 	}
 	debug(50, 1, "diskHandleRead: FD %d: error reading: %s\n",
 	    fd, xstrerror());
 	ctrl_dat->handler(fd, ctrl_dat->buf,
-	    ctrl_dat->cur_len,
+	    ctrl_dat->offset,
 	    DISK_ERROR,
 	    ctrl_dat->client_data);
 	safe_free(ctrl_dat);
-	return DISK_ERROR;
+	return;
     } else if (len == 0) {
 	/* EOF */
 	ctrl_dat->end_of_file = 1;
 	/* call handler */
 	ctrl_dat->handler(fd,
 	    ctrl_dat->buf,
-	    ctrl_dat->cur_len,
+	    ctrl_dat->offset,
 	    DISK_EOF,
 	    ctrl_dat->client_data);
 	safe_free(ctrl_dat);
-	return DISK_OK;
+	return;
     } else {
-	ctrl_dat->cur_len += len;
-	ctrl_dat->offset = lseek(fd, 0L, SEEK_CUR);
+	ctrl_dat->offset += len;
     }
     /* reschedule if need more data. */
-    if (ctrl_dat->cur_len < ctrl_dat->req_len) {
+    if (ctrl_dat->offset < ctrl_dat->req_len) {
 	commSetSelect(fd,
 	    COMM_SELECT_READ,
 	    diskHandleRead,
 	    ctrl_dat,
 	    0);
-	return DISK_OK;
+	return;
     } else {
 	/* all data we need is here. */
 	/* call handler */
 	ctrl_dat->handler(fd,
 	    ctrl_dat->buf,
-	    ctrl_dat->cur_len,
+	    ctrl_dat->offset,
 	    DISK_OK,
 	    ctrl_dat->client_data);
 	safe_free(ctrl_dat);
-	return DISK_OK;
+	return;
     }
 }
 
@@ -537,7 +523,7 @@ file_read(int fd, char *buf, int req_len, int offset, FILE_READ_HD * handler, vo
     ctrl_dat->offset = offset;
     ctrl_dat->req_len = req_len;
     ctrl_dat->buf = buf;
-    ctrl_dat->cur_len = 0;
+    ctrl_dat->offset = 0;
     ctrl_dat->end_of_file = 0;
     ctrl_dat->handler = handler;
     ctrl_dat->client_data = client_data;
@@ -558,15 +544,12 @@ file_read(int fd, char *buf, int req_len, int offset, FILE_READ_HD * handler, vo
 static void
 diskHandleWalk(int fd, void *data)
 {
-    FD_ENTRY *fde = &fd_table[fd];
     dwalk_ctrl *walk_dat = data;
     int len;
     disk_ctrl_t *ctrlp;
     ctrlp = xcalloc(1, sizeof(disk_ctrl_t));
     ctrlp->fd = fd;
     ctrlp->data = walk_dat;
-    lseek(fd, walk_dat->offset, SEEK_SET);
-    BIT_RESET(fde->flags, FD_AT_EOF);
 #if USE_ASYNC_IO
     aioRead(fd, walk_dat->buf,
 	DISK_LINE_LEN - 1,
@@ -579,7 +562,7 @@ diskHandleWalk(int fd, void *data)
 }
 
 
-static int
+static void
 diskHandleWalkComplete(void *data, int retcode, int errcode)
 {
     disk_ctrl_t *ctrlp = (disk_ctrl_t *) data;
@@ -600,20 +583,20 @@ diskHandleWalkComplete(void *data, int retcode, int errcode)
     if (len < 0) {
 	if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR) {
 	    commSetSelect(fd, COMM_SELECT_READ, diskHandleWalk, walk_dat, 0);
-	    return DISK_OK;
+	    return;
 	}
 	debug(50, 1, "diskHandleWalk: FD %d: error readingd: %s\n",
 	    fd, xstrerror());
 	walk_dat->handler(fd, DISK_ERROR, walk_dat->client_data);
 	safe_free(walk_dat->buf);
 	safe_free(walk_dat);
-	return DISK_ERROR;
+	return;
     } else if (len == 0) {
 	/* EOF */
 	walk_dat->handler(fd, DISK_EOF, walk_dat->client_data);
 	safe_free(walk_dat->buf);
 	safe_free(walk_dat);
-	return DISK_OK;
+	return;
     }
     /* emulate fgets here. Cut the into separate line. newline is excluded */
     /* it throws last partial line, if exist, away. */
@@ -639,7 +622,6 @@ diskHandleWalkComplete(void *data, int retcode, int errcode)
 
     /* reschedule it for next line. */
     commSetSelect(fd, COMM_SELECT_READ, diskHandleWalk, walk_dat, 0);
-    return DISK_OK;
 }