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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/sr.h
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/sr.h')
-rw-r--r--drivers/scsi/sr.h1
1 files changed, 0 insertions, 1 deletions
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) */