This patch implements tape statistics in the st module via
sysfs. Current no statistics are available for tape I/O and there
is no easy way to reuse the block layer statistics for tape
as tape is a character device and does not have perform I/O in
sector sized chunks (the size of the data written to tape
can change). For tapes we also need extra stats related to
things like tape movement (via other I/O).
There have been multiple end users requesting statistics
including AT&T (and some HP customers who have not given
permission to be named). It is impossible for them
to investigate any issues related to tape performance
in a non-invasive way.
[jejb: eliminate PRId64]
Signed-off-by: Shane Seymour <shane.seymour@hp.com>
Tested-by: Shane Seymour <shane.seymour@hp.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
This patch adds a debug_flag parameter that can be set on module load, and allows the DEBUG facility without a module recompile.
Note that now DEBUG 1 is the default with this patch.
Usage: modprobe st debug_flag=1
Signed-off-by: Laurence Oberman <loberman@redhat.com>
Acked-by: Kai M??kisara <kai.makisara@kolumbus.fi>
Signed-off-by: Christoph Hellwig <hch@lst.de>
The device limit of 128 tape drives was established in 2003 as a
significant increase from the 8 tape drives allowed previously.
We're seeing customer sites that between a large number of drives
and multipath are discovering more than 128 devices and running
into problems.
Now that we're not stuck having to store a pointer in array
and aren't limited by kmalloc failing on higher order allocs we can
lift the limit to fill the entire minor range based on the number
of modes.
Based on the current code, that's 2^17 devices.
Reviewed-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Acked-by: Kai Mäkisara <kai.makisara@kolumbus.fi>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
The st tape driver recently added the MTWEOFI ioctl, which writes
a tape filemark (EOF), like the MTWEOF ioctl, except that MTWEOFI
returns immediately. This makes certain applications, like backup
software, run much more quickly on buffered tape drives.
Since legacy applications do not know about this new MTWEOFI ioctl,
this patch adds a new ioctl option that tells the st driver to return
immediately when writing an EOF (i.e. a filemark). This new flag
is much like the existing flag that tells the st driver to perform
writes (and certain other IOs) immediately, but this new flag only
applies to writing EOFs.
This new feature is controlled via the MTSETDRVBUFFER ioctl, using
the newly-defined MT_ST_NOWAIT_EOF flag.
Use of this new feature is displayed via the sysfs tape "options"
attribute.
The st documentation was updated to mention this new flag, as well
as the problems that can occur from using it.
Signed-off-by: Lee Duncan <lduncan@suse.com>
Acked-by: Kai Makisara <kai.makisara@kolumbus.fi>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This patch adds a new MTIOCTOP operation MTWEOFI that writes filemarks with
immediate bit set. This means that the drive does not flush its buffer and the
next file can be started immediately. This speeds up writing in applications
that have to write multiple small files.
Signed-off-by: Kai Makisara <kai.makisara@kolumbus.fi>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Show the current binary tape driver and mode options is sysfs. A file
(options) is created in each directory in /sys/class/scsi_tape. The files
contain masks showing the options. The mask bit definitions are the same as
used when setting the options using the MTSETDRVBUFFER function in the
MTIOCTOP ioctl (defined in include/linux/mtio.h). For example:
> cat /sys/class/scsi_tape/nst0/options
0x00000d07
[jejb: updated doc with correction from Randy Dunlap]
Signed-off-by: Kai Makisara <kai.makisara@kolumbus.fi>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Add new option MT_ST_SILI to enable setting the SILI bit in reads in variable
block mode. If SILI is set, reading a block shorter than the byte count does
not result in CHECK CONDITION. The length of the block is determined using the
residual count from the HBA. Avoiding the REQUEST SENSE command for every
block speeds up some real applications considerably.
Signed-off-by: Kai Makisara <kai.makisara@kolumbus.fi>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Convert files within the Documentation directory to UTF-8.
Adrian Bunk:
small additional fixes
Signed-off-by: John Anthony Kazos Jr. <jakj@j-a-k-j.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
This patch fixes typos in various Documentation txts. The patch addresses some
+words starting with the letter 'T'.
Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Remove many duplicated words under Documentation/ and do other small
cleanups.
Examples:
"and and" --> "and"
"in in" --> "in"
"the the" --> "the"
"the the" --> "to the"
...
Signed-off-by: Paolo Ornati <ornati@fastwebnet.it>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
This patch fixes typos in various Documentation txts. The patch addresses
some words starting with the letter 'S'.
Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Acked-by: Alan Cox <alan@redhat.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
