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authorPete Zaitcev <zaitcev@redhat.com>2005-07-05 18:18:08 -0700
committerJames Bottomley <jejb@titanic.(none)>2005-08-28 11:14:12 -0500
commit51490c89f95b8581782e9baa855da166441852be (patch)
tree3be27d5e30c114d5d69fe21a4a079a64f2016354
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>
-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 2f259f24952..f63d8c6c2a3 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)
/* check multisession offset etc */
sr_cd_check(cdi);
- /*
- * If the disk changed, the capacity will now be different,
- * so we force a re-read of this information
- * Force 2048 for the sector size so that filesystems won't
- * be trying to use something that is too small if the disc
- * has changed.
- */
- cd->needs_sector_size = 1;
- cd->device->sector_size = 2048;
+ get_sectorsize(cd);
}
return retval;
}
@@ -538,13 +530,6 @@ static int sr_open(struct cdrom_device_info *cdi, int purpose)
if (!scsi_block_when_processing_errors(sdev))
goto error_out;
- /*
- * If this device did not have media in the drive at boot time, then
- * we would have been unable to get the sector size. Check to see if
- * this is the case, and try again.
- */
- if (cd->needs_sector_size)
- get_sectorsize(cd);
return 0;
error_out:
@@ -604,7 +589,6 @@ static int sr_probe(struct device *dev)
cd->driver = &sr_template;
cd->disk = disk;
cd->capacity = 0x1fffff;
- cd->needs_sector_size = 1;
cd->device->changed = 1; /* force recheck CD type */
cd->use = 1;
cd->readcd_known = 0;
@@ -694,7 +678,6 @@ static void get_sectorsize(struct scsi_cd *cd)
if (the_result) {
cd->capacity = 0x1fffff;
sector_size = 2048; /* A guess, just in case */
- cd->needs_sector_size = 1;
} else {
#if 0
if (cdrom_get_last_written(&cd->cdi,
@@ -727,7 +710,6 @@ static void get_sectorsize(struct scsi_cd *cd)
printk("%s: unsupported sector size %d.\n",
cd->cdi.name, sector_size);
cd->capacity = 0;
- cd->needs_sector_size = 1;
}
cd->device->sector_size = sector_size;
@@ -736,7 +718,6 @@ static void get_sectorsize(struct scsi_cd *cd)
* Add this so that we have the ability to correctly gauge
* what the device is capable of.
*/
- cd->needs_sector_size = 0;
set_capacity(cd->disk, cd->capacity);
}
@@ -748,8 +729,7 @@ out:
Enomem:
cd->capacity = 0x1fffff;
- sector_size = 2048; /* A guess, just in case */
- cd->needs_sector_size = 1;
+ cd->device->sector_size = 2048; /* A guess, just in case */
if (SRpnt)
scsi_release_request(SRpnt);
goto out;
diff --git a/drivers/scsi/sr.h b/drivers/scsi/sr.h
index 0b317800720..d2bcd99c272 100644
--- a/drivers/scsi/sr.h
+++ b/drivers/scsi/sr.h
@@ -33,7 +33,6 @@ typedef struct scsi_cd {
struct scsi_device *device;
unsigned int vendor; /* vendor code, see sr_vendor.c */
unsigned long ms_offset; /* for reading multisession-CD's */
- unsigned needs_sector_size:1; /* needs to get sector size */
unsigned use:1; /* is this device still supportable */
unsigned xa_flag:1; /* CD has XA sectors ? */
unsigned readcd_known:1; /* drive supports READ_CD (0xbe) */