2004-12-03 Jeremy Katz <katzj@redhat.com>

	* loader2/mediacheck.c: Disable read-ahead for the last meg or so
	of the CD to try to avoid mediacheck problems (#131051 and others)
	* loader2/mediacheck.h (mediaCheckFile): Add new arg.
	* loader2/cdinstall.c (mediaCheckCdrom): Likewise.
	* loader2/method.c (queryISOMediaCheck): Likewise.

5 files changed, 61 insertions, 9 deletions

diff --git a/ChangeLog b/ChangeLog
index 30729f037..44ceaee92 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,12 @@
 2004-12-03  Jeremy Katz  <katzj@redhat.com>
 
 	* anaconda.spec: Bump version.
+	
+	* loader2/mediacheck.c: Disable read-ahead for the last meg or so
+	of the CD to try to avoid mediacheck problems (#131051 and others)
+	* loader2/mediacheck.h (mediaCheckFile): Add new arg.
+	* loader2/cdinstall.c (mediaCheckCdrom): Likewise.
+	* loader2/method.c (queryISOMediaCheck): Likewise.
 
 	* constants.py (BETANAG): turn off beta nag.
 
diff --git a/loader2/cdinstall.c b/loader2/cdinstall.c
index eac9f6c96..af842229c 100644
--- a/loader2/cdinstall.c
+++ b/loader2/cdinstall.c
@@ -98,7 +98,7 @@ static char * mediaCheckCdrom(char *cddriver) {
 	if (!ejectcd) {
 	    /* XXX MSFFIXME: should check return code for error */
 	    readStampFileFromIso("/tmp/cdrom", &tstamp, &descr);
-	    mediaCheckFile("/tmp/cdrom", descr);
+	    mediaCheckFile("/tmp/cdrom", descr, 1);
 
 	    if (descr)
 		free(descr);
diff --git a/loader2/mediacheck.c b/loader2/mediacheck.c
index e507050e1..6f387e7f3 100644
--- a/loader2/mediacheck.c
+++ b/loader2/mediacheck.c
@@ -9,8 +9,13 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <string.h>
+#include <errno.h>
 #include <newt.h>
 
+/* FIXME: for turning off read-ahead */
+#include <sys/ioctl.h>
+#include <linux/fs.h>
+
 #include "md5.h"
 
 #include "log.h"
@@ -145,7 +150,7 @@ int parsepvd(int isofd, char *mediasum, int *skipsectors, long long *isosize, in
 /* mediasum is the sum encoded in media, computedsum is one we compute   */
 /* both strings must be pre-allocated at least 33 chars in length        */
 int checkmd5sum(int isofd, char *mediasum, char *computedsum, 
-		checkCallback cb, void *cbdata) {
+		checkCallback cb, void *cbdata, int isCD) {
     int nread;
     int i;
     int appdata_start_offset, appdata_end_offset;
@@ -157,8 +162,22 @@ int checkmd5sum(int isofd, char *mediasum, char *computedsum,
     unsigned int len;
     unsigned char *buf;
     long long isosize, offset, pvd_offset, apoff;
+    int cfd, readahead_hack = 1, readahead_disabled = 0;
     MD5_CTX md5ctx;
 
+    /* FIXME: the kernel doesn't properly handle EOF on ide-cds.  
+     * turning off read-ahead for the last meg or so should help, per alan.  
+     * let people opt out of this with "nocdhack" on the boot command line */
+    if ((cfd = open("/proc/cmdline", O_RDONLY)) >= 0) {
+        char buf[1024];
+        int len;
+
+        len = read(cfd, buf, sizeof(buf) - 1);
+        close(cfd);
+        if (strstr(buf, "nocdhack") == NULL)
+            readahead_hack = 0;
+    }
+
     isostatus = 0;
     if ((pvd_offset = parsepvd(isofd, mediasum, &skipsectors, &isosize, &isostatus)) < 0)
 	return -1;
@@ -173,6 +192,21 @@ int checkmd5sum(int isofd, char *mediasum, char *computedsum,
 
     buf = malloc(bufsize * sizeof(unsigned char));
     while (offset < isosize - skipsectors*2048) {
+        /* turn off read-ahead for the last meg of the CD.  see above
+         * for the gory details */
+        if ((isCD == 1) && (offset > (isosize - 1024 * 1024 * 1024))) {
+            if ((readahead_disabled == 0) && (readahead_hack == 1)) {
+                if (ioctl(isofd, BLKRASET, (unsigned long) 0) == -1) {
+                    logMessage("failed to disable readahead: %s",
+                               strerror(errno));
+                    readahead_disabled = -1;
+                } else {
+                    logMessage("disabled readahead");
+                    readahead_disabled = 1;
+                }
+            }
+        }
+
 	nattempt = MIN(isosize - skipsectors*2048 - offset, bufsize);
 
 	nread = read(isofd, buf, nattempt);
@@ -220,6 +254,18 @@ int checkmd5sum(int isofd, char *mediasum, char *computedsum,
 	strcat(computedsum, tmpstr);
     }
 
+    /* if we disabled readahead, then we should probably turn it back on.
+     * otherwise, people are going to hate life as their installs take a 
+     * week */
+    if (readahead_disabled == 1) {
+        if (ioctl(isofd, BLKRASET, (unsigned long) 256) == -1) {
+        logMessage("failed to re-enable readahead: %s",
+                   strerror(errno));
+        } else {
+            logMessage("re-enabled readahead");
+        }
+    }
+
     if (strcmp(mediasum, computedsum))
 	return 0;
     else
@@ -242,7 +288,7 @@ static void readCB(void *co, long long pos) {
     newtRefresh();
 }
 
-int doMediaCheck(int isofd, char *descr, char *mediasum, char *computedsum, long long *isosize, int *isostatus) {
+int doMediaCheck(int isofd, char *descr, char *mediasum, char *computedsum, long long *isosize, int *isostatus, int isCD) {
     struct progressCBdata data;
     newtComponent t, f, scale, label;
     int rc;
@@ -287,7 +333,7 @@ int doMediaCheck(int isofd, char *descr, char *mediasum, char *computedsum, long
     data.scale = scale;
     data.label = label;
 
-    rc = checkmd5sum(isofd, mediasum, computedsum, readCB, &data);
+    rc = checkmd5sum(isofd, mediasum, computedsum, readCB, &data, isCD);
 
     newtFormDestroy(f);
     newtPopWindow();
@@ -295,7 +341,7 @@ int doMediaCheck(int isofd, char *descr, char *mediasum, char *computedsum, long
     return rc;
 }
 
-int mediaCheckFile(char *file, char *descr) {
+int mediaCheckFile(char *file, char *descr, int isCD) {
     int isofd;
     int rc;
     int isostatus;
@@ -315,7 +361,7 @@ int mediaCheckFile(char *file, char *descr) {
     }
 
     isostatus = 0;
-    rc = doMediaCheck(isofd, descr, mediasum, computedsum, &isosize, &isostatus);
+    rc = doMediaCheck(isofd, descr, mediasum, computedsum, &isosize, &isostatus, isCD);
     close(isofd);
 
     if (rc == 0) {
@@ -371,7 +417,7 @@ int main(int argc, char **argv) {
 
     newtInit();
     newtCls();
-    rc = mediaCheckFile(argv[1], "TESTING");
+    rc = mediaCheckFile(argv[1], "TESTING", 0);
     newtFinished();
     exit (0);
 }
diff --git a/loader2/mediacheck.h b/loader2/mediacheck.h
index 26f7bfbf9..5cfb963ea 100644
--- a/loader2/mediacheck.h
+++ b/loader2/mediacheck.h
@@ -5,7 +5,7 @@
 /* Copyright 2001 Red Hat, Inc.                                    */
 /* Michael Fulbright msf@redhat.com                                */
 
-int mediaCheckFile(char *file, char *descr);
+int mediaCheckFile(char *file, char *descr, int isCD);
 int parsepvd(int isofd, char *mediasum, int *skipsectors, long long *isosize, int *isostatus);
 
 #endif
diff --git a/loader2/method.c b/loader2/method.c
index ca31da481..04d9beb2e 100644
--- a/loader2/method.c
+++ b/loader2/method.c
@@ -417,7 +417,7 @@ void queryIsoMediaCheck(char *isoFile, int flags) {
 		free(tdescr);
 	    continue;
 	} else {
-	    mediaCheckFile(isoImage, tdescr);
+	    mediaCheckFile(isoImage, tdescr, 0);
 	    if (tdescr)
 		free(tdescr);