[patch 5/5] make st seekable again

[patch 5/5] make st seekable again

[akpm]

From: Kai Makisara <kai.makisara@kolumbus.fi>

Apparently `tar' errors out if it cannot perform lseek() against a tape.  Work
around that in-kernel.

Signed-off-by: Kai Makisara <kai.makisara@kolumbus.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 25-akpm/drivers/ide/ide-tape.c |    8 +++++++-
 25-akpm/drivers/scsi/osst.c    |    8 +++++++-
 25-akpm/drivers/scsi/st.c      |    8 +++++++-
 3 files changed, 21 insertions(+), 3 deletions(-)

diff -puN drivers/ide/ide-tape.c~make-st-seekable-again drivers/ide/ide-tape.c
--- 25/drivers/ide/ide-tape.c~make-st-seekable-again	2005-03-04 13:16:32.000000000 -0800
+++ 25-akpm/drivers/ide/ide-tape.c	2005-03-04 13:16:32.000000000 -0800
@@ -4100,7 +4100,13 @@ static int idetape_chrdev_open (struct i
 	idetape_pc_t pc;
 	int retval;
 
-	nonseekable_open(inode, filp);
+	/*
+	 * We really want to do nonseekable_open(inode, filp); here, but some
+	 * versions of tar incorrectly call lseek on tapes and bail out if that
+	 * fails.  So we disallow pread() and pwrite(), but permit lseeks.
+	 */
+	filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
+
 #if IDETAPE_DEBUG_LOG
 	printk(KERN_INFO "ide-tape: Reached idetape_chrdev_open\n");
 #endif /* IDETAPE_DEBUG_LOG */
diff -puN drivers/scsi/st.c~make-st-seekable-again drivers/scsi/st.c
--- 25/drivers/scsi/st.c~make-st-seekable-again	2005-03-04 13:16:32.000000000 -0800
+++ 25-akpm/drivers/scsi/st.c	2005-03-04 13:16:32.000000000 -0800
@@ -1004,7 +1004,13 @@ static int st_open(struct inode *inode, 
 	int dev = TAPE_NR(inode);
 	char *name;
 
-	nonseekable_open(inode, filp);
+	/*
+	 * We really want to do nonseekable_open(inode, filp); here, but some
+	 * versions of tar incorrectly call lseek on tapes and bail out if that
+	 * fails.  So we disallow pread() and pwrite(), but permit lseeks.
+	 */
+	filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
+
 	write_lock(&st_dev_arr_lock);
 	if (dev >= st_dev_max || scsi_tapes == NULL ||
 	    ((STp = scsi_tapes[dev]) == NULL)) {
diff -puN drivers/scsi/osst.c~make-st-seekable-again drivers/scsi/osst.c
--- 25/drivers/scsi/osst.c~make-st-seekable-again	2005-03-04 13:16:32.000000000 -0800
+++ 25-akpm/drivers/scsi/osst.c	2005-03-04 13:16:32.000000000 -0800
@@ -4318,7 +4318,13 @@ static int os_scsi_tape_open(struct inod
 	int		      dev  = TAPE_NR(inode);
 	int		      mode = TAPE_MODE(inode);
 
-	nonseekable_open(inode, filp);
+	/*
+	 * We really want to do nonseekable_open(inode, filp); here, but some
+	 * versions of tar incorrectly call lseek on tapes and bail out if that
+	 * fails.  So we disallow pread() and pwrite(), but permit lseeks.
+	 */
+	filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
+
 	write_lock(&os_scsi_tapes_lock);
 	if (dev >= osst_max_dev || os_scsi_tapes == NULL ||
 	    (STp = os_scsi_tapes[dev]) == NULL || !STp->device) {
_

Re: [patch 5/5] make st seekable again

[Greg KH]

On Fri, Mar 04, 2005 at 01:16:58PM -0800, akpm@osdl.org wrote:
> 
> From: Kai Makisara <kai.makisara@kolumbus.fi>
> 
> Apparently `tar' errors out if it cannot perform lseek() against a tape.  Work
> around that in-kernel.
> 
> Signed-off-by: Kai Makisara <kai.makisara@kolumbus.fi>
> Signed-off-by: Andrew Morton <akpm@osdl.org>

Added to the -stable queue, thanks.

greg k-h