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authorPete Zaitcev <zaitcev@redhat.com>2005-07-05 21:18:08 -0400
committerJames Bottomley <jejb@titanic.(none)>2005-08-28 12:14:12 -0400
commit51490c89f95b8581782e9baa855da166441852be (patch)
tree3be27d5e30c114d5d69fe21a4a079a64f2016354 /drivers/scsi
parent8224bfa84d510630b40ea460b2bb380c91acb8ae (diff)
[SCSI] sr.c: Fix getting wrong size
Here's the problem. Try to do this on 2.6.12: - Kill udev and HAL - Insert a CD-ROM into a SCSI or USB CD-ROM drive - Run dd if=/dev/scd0 - cat /sys/block/sr0/size - Eject the CD, insert a different one - Run dd if=/dev/scd0 This is likely to do "access beyond the end of device", if you let it - cat /sys/block/sr0/size This shows the size of a previous CD, even though dd was supposed to revalidate the device. - Run dd if=/dev/scd0 The second run of dd works correctly! The bug was introduced in 2.5.31, when Al fixes the recursive opens in partitioning. Before, the code worked like this: - Block layer called cdrom_open directly - cdrom_open called sr_open - sr_open called check_disk_change - check_disk_change called sr_media_change - sr_media_change did cd->needs_disk_change=1 - before returning sr_open tested cd->needs_disk_change and called get_sector_size. In 2.6.12, the check_disk_change is called from cdrom_open only. Thus: - Block layer calls sr_bd_open - sr_bd_open calls cdrom_open - cdrom_open calls sr_open - sr_open tests cd->needs_disk_change, which wasn't set yet; returns - cdrom_open calls check_disk_change - check_disk_change calls sr_media_change - sr_media_change does cd->needs_disk_change=1, but nobody cares Acked by: Alexander Viro <aviro@redhat.com> Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Diffstat (limited to 'drivers/scsi')
-rw-r--r--drivers/scsi/sr.c24
-rw-r--r--drivers/scsi/sr.h1
2 files changed, 2 insertions, 23 deletions
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index 2f259f249522..f63d8c6c2a33 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -199,15 +199,7 @@ int sr_media_change(struct cdrom_device_info *cdi, int slot)
199 /* check multisession offset etc */ 199 /* check multisession offset etc */
200 sr_cd_check(cdi); 200 sr_cd_check(cdi);
201 201
202 /* 202 get_sectorsize(cd);
203 * If the disk changed, the capacity will now be different,
204 * so we force a re-read of this information
205 * Force 2048 for the sector size so that filesystems won't
206 * be trying to use something that is too small if the disc
207 * has changed.
208 */
209 cd->needs_sector_size = 1;
210 cd->device->sector_size = 2048;
211 } 203 }
212 return retval; 204 return retval;
213} 205}
@@ -538,13 +530,6 @@ static int sr_open(struct cdrom_device_info *cdi, int purpose)
538 if (!scsi_block_when_processing_errors(sdev)) 530 if (!scsi_block_when_processing_errors(sdev))
539 goto error_out; 531 goto error_out;
540 532
541 /*
542 * If this device did not have media in the drive at boot time, then
543 * we would have been unable to get the sector size. Check to see if
544 * this is the case, and try again.
545 */
546 if (cd->needs_sector_size)
547 get_sectorsize(cd);
548 return 0; 533 return 0;
549 534
550error_out: 535error_out:
@@ -604,7 +589,6 @@ static int sr_probe(struct device *dev)
604 cd->driver = &sr_template; 589 cd->driver = &sr_template;
605 cd->disk = disk; 590 cd->disk = disk;
606 cd->capacity = 0x1fffff; 591 cd->capacity = 0x1fffff;
607 cd->needs_sector_size = 1;
608 cd->device->changed = 1; /* force recheck CD type */ 592 cd->device->changed = 1; /* force recheck CD type */
609 cd->use = 1; 593 cd->use = 1;
610 cd->readcd_known = 0; 594 cd->readcd_known = 0;
@@ -694,7 +678,6 @@ static void get_sectorsize(struct scsi_cd *cd)
694 if (the_result) { 678 if (the_result) {
695 cd->capacity = 0x1fffff; 679 cd->capacity = 0x1fffff;
696 sector_size = 2048; /* A guess, just in case */ 680 sector_size = 2048; /* A guess, just in case */
697 cd->needs_sector_size = 1;
698 } else { 681 } else {
699#if 0 682#if 0
700 if (cdrom_get_last_written(&cd->cdi, 683 if (cdrom_get_last_written(&cd->cdi,
@@ -727,7 +710,6 @@ static void get_sectorsize(struct scsi_cd *cd)
727 printk("%s: unsupported sector size %d.\n", 710 printk("%s: unsupported sector size %d.\n",
728 cd->cdi.name, sector_size); 711 cd->cdi.name, sector_size);
729 cd->capacity = 0; 712 cd->capacity = 0;
730 cd->needs_sector_size = 1;
731 } 713 }
732 714
733 cd->device->sector_size = sector_size; 715 cd->device->sector_size = sector_size;
@@ -736,7 +718,6 @@ static void get_sectorsize(struct scsi_cd *cd)
736 * Add this so that we have the ability to correctly gauge 718 * Add this so that we have the ability to correctly gauge
737 * what the device is capable of. 719 * what the device is capable of.
738 */ 720 */
739 cd->needs_sector_size = 0;
740 set_capacity(cd->disk, cd->capacity); 721 set_capacity(cd->disk, cd->capacity);
741 } 722 }
742 723
@@ -748,8 +729,7 @@ out:
748 729
749Enomem: 730Enomem:
750 cd->capacity = 0x1fffff; 731 cd->capacity = 0x1fffff;
751 sector_size = 2048; /* A guess, just in case */ 732 cd->device->sector_size = 2048; /* A guess, just in case */
752 cd->needs_sector_size = 1;
753 if (SRpnt) 733 if (SRpnt)
754 scsi_release_request(SRpnt); 734 scsi_release_request(SRpnt);
755 goto out; 735 goto out;
diff --git a/drivers/scsi/sr.h b/drivers/scsi/sr.h
index 0b3178007203..d2bcd99c272f 100644
--- a/drivers/scsi/sr.h
+++ b/drivers/scsi/sr.h
@@ -33,7 +33,6 @@ typedef struct scsi_cd {
33 struct scsi_device *device; 33 struct scsi_device *device;
34 unsigned int vendor; /* vendor code, see sr_vendor.c */ 34 unsigned int vendor; /* vendor code, see sr_vendor.c */
35 unsigned long ms_offset; /* for reading multisession-CD's */ 35 unsigned long ms_offset; /* for reading multisession-CD's */
36 unsigned needs_sector_size:1; /* needs to get sector size */
37 unsigned use:1; /* is this device still supportable */ 36 unsigned use:1; /* is this device still supportable */
38 unsigned xa_flag:1; /* CD has XA sectors ? */ 37 unsigned xa_flag:1; /* CD has XA sectors ? */
39 unsigned readcd_known:1; /* drive supports READ_CD (0xbe) */ 38 unsigned readcd_known:1; /* drive supports READ_CD (0xbe) */