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7b3d9545f9
This reverts commitac40532ef0, which gets us back the original cleanup of6f5391c283. It turns out that the bug that was triggered by that commit was apparently not actually triggered by that commit at all, and just the testing conditions had changed enough to make it appear to be due to it. The real problem seems to have been found by Peter Osterlund: "pktcdvd sets it [block device size] when opening the /dev/pktcdvd device, but when the drive is later opened as /dev/scd0, there is nothing that sets it back. (Btw, 40944 is possible if the disk is a CDRW that was formatted with "cdrwtool -m 10236".) The problem is that pktcdvd opens the cd device in non-blocking mode when pktsetup is run, and doesn't close it again until pktsetup -d is run. The effect is that if you meanwhile open the cd device, blkdev.c:do_open() doesn't call bd_set_size() because bdev->bd_openers is non-zero." In particular, to repeat the bug (regardless of whether commit6f5391c283is applied or not): " 1. Start with an empty drive. 2. pktsetup 0 /dev/scd0 3. Insert a CD containing an isofs filesystem. 4. mount /dev/pktcdvd/0 /mnt/tmp 5. umount /mnt/tmp 6. Press the eject button. 7. Insert a DVD containing a non-writable filesystem. 8. mount /dev/scd0 /mnt/tmp 9. find /mnt/tmp -type f -print0 | xargs -0 sha1sum >/dev/null 10. If the DVD contains data beyond the physical size of a CD, you get I/O errors in the terminal, and dmesg reports lots of "attempt to access beyond end of device" errors." which in turn is because the nested open after the media change won't cause the size to be set properly (because the original open still holds the block device, and we only do the bd_set_size() when we don't have other people holding the device open). The proper fix for that is probably to just do something like bdev->bd_inode->i_size = (loff_t)get_capacity(disk)<<9; in fs/block_dev.c:do_open() even for the cases where we're not the original opener (but *not* call bd_set_size(), since that will also change the block size of the device). Cc: Peter Osterlund <petero2@telia.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Ingo Molnar <mingo@elte.hu> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
37 lines
995 B
C
37 lines
995 B
C
#ifndef _SCSI_SCSI_DRIVER_H
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#define _SCSI_SCSI_DRIVER_H
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#include <linux/device.h>
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struct module;
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struct scsi_cmnd;
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struct scsi_device;
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struct request;
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struct request_queue;
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struct scsi_driver {
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struct module *owner;
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struct device_driver gendrv;
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void (*rescan)(struct device *);
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int (*done)(struct scsi_cmnd *);
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};
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#define to_scsi_driver(drv) \
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container_of((drv), struct scsi_driver, gendrv)
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extern int scsi_register_driver(struct device_driver *);
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#define scsi_unregister_driver(drv) \
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driver_unregister(drv);
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extern int scsi_register_interface(struct class_interface *);
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#define scsi_unregister_interface(intf) \
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class_interface_unregister(intf)
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int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req);
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int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req);
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int scsi_prep_state_check(struct scsi_device *sdev, struct request *req);
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int scsi_prep_return(struct request_queue *q, struct request *req, int ret);
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#endif /* _SCSI_SCSI_DRIVER_H */
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