I have a fairly large set of changes to the sa(4) driver and mt(1) driver that I'm planning to commit in the near future.
A description of the changes is here and below in this message. If you have tape hardware and the inclination, I'd appreciate testing and feedback. ============ Rough draft commit message: http://people.freebsd.org/~ken/sa_changes_commitmsg.20150213.3.txt The patches against FreeBSD/head as of SVN revision 278706: http://people.freebsd.org/~ken/sa_changes.20150213.3.txt And (untested) patches against FreeBSD stable/10 as of SVN revision 278721. http://people.freebsd.org/~ken/sa_changes.stable_10.20150213.3.txt ============ The intent is to get the tape infrastructure more up to date, so we can support LTFS and more modern tape drives: http://www.ibm.com/systems/storage/tape/ltfs/ I have ported IBM's LTFS Single Drive Edition to FreeBSD. The port depends on the patches linked above. It isn't fully cleaned up and ready for redistribution. If you're interested, though, let me know and I'll tell you when it is ready to go out. You need an IBM LTO-5, LTO-6, TS1140 or TS1150 tape drive. HP drives aren't supported by IBM's LTFS, and older drives don't have the necessary features to support LTFS. The commit message below outlines most of the changes. A few comments: 1. I'm planning to commit the XPT_DEV_ADVINFO changes separately. 2. The XML output is similar to what GEOM and CTL do. It would be nice to figure out how to put a standard schema on it so that standard tools could read it. I don't know how feasible that is, since I haven't time to dig into it. If anyone has suggestions on whether that is feasible or advisable, I'd appreciate feedback. 3. I have tested with a reasonable amount of tape hardware (see below for a list), but more testing and feedback would be good. 4. Standard 'mt status' output looks like this: # mt -f /dev/nsa3 status -v Drive: sa3: <IBM ULTRIUM-HH6 E4J1> Serial Number: 101500520A --------------------------------- Mode Density Blocksize bpi Compression Current: 0x5a:LTO-6 variable 384607 enabled (0xff) --------------------------------- Current Driver State: at rest. --------------------------------- Partition: 0 Calc File Number: 0 Calc Record Number: 0 Residual: 0 Reported File Number: 0 Reported Record Number: 0 Flags: BOP 5. 'mt status -v' looks like this: # mt -f /dev/nsa3 status -v Drive: sa3: <IBM ULTRIUM-HH6 E4J1> Serial Number: 101500520A --------------------------------- Mode Density Blocksize bpi Compression Current: 0x5a:LTO-6 variable 384607 enabled (0xff) --------------------------------- Current Driver State: at rest. --------------------------------- Partition: 0 Calc File Number: 0 Calc Record Number: 0 Residual: 0 Reported File Number: 0 Reported Record Number: 0 Flags: BOP --------------------------------- Tape I/O parameters: Maximum I/O size allowed by driver and controller (maxio): 1081344 bytes Maximum I/O size reported by controller (cpi_maxio): 5197824 bytes Maximum block size supported by tape drive and media (max_blk): 8388608 bytes Minimum block size supported by tape drive and media (min_blk): 1 bytes Block granularity supported by tape drive and media (blk_gran): 0 bytes Maximum possible I/O size (max_effective_iosize): 1081344 bytes 6. Existing applications should work without changes. If not, please let me know. Hopefully they will move over time to the new interfaces. 7. There are lots of additional features that could be added later. Append-only support, encryption, more log pages, etc. 8. I have SCSI READ ATTRIBUTE changes for camcontrol(8) that will go in separately. These changes allow displaying the contents of the MAM (Medium Auxiliary Memory) chips on LTO, TS and other modern tape drives. These are good, and a future possible direction is adding attributes to the status XML from the sa(4) driver. ============ Significant upgrades to sa(4) and mt(1). The primary focus of these changes is to modernize FreeBSD's tape infrastructure so that we can take advantage of some of the features of modern tape drives and allow support for LTFS. Significant changes and new features include: o sa(4) driver status and parameter information is now exported via an XML structure. This will allow for changes and improvements later on that will not break userland applications. The old MTIOCGET status ioctl remains, so applications using the existing interface will not break. o 'mt status' now reports drive-reported tape position information as well as the previously available calculated tape position information. These numbers will be different at times, because the drive-reported block numbers are relative to BOP (Beginning of Partition), but the block numbers calculated previously via sa(4) (and still provided) are relative to the last filemark. Both numbers are now provided. 'mt status' now also shows the drive INQUIRY information, serial number and any position flags (BOP, EOT, etc.) provided with the tape position information. 'mt status -v' adds information on the maximum possible I/O size, and the underlying values used to calculate it. o The extra sa(4) /dev entries (/dev/saN.[0-3]) have been removed. The extra devices were originally added as place holders for density-specific device nodes. Some OSes (NetBSD, NetApp's OnTap and Solaris) have had device nodes that, when you write to them, will automatically select a given density for particular tape drives. This is a convenient way of switching densities, but it was never implemented in FreeBSD. Only the device nodes were there, and that sometimes confused users. For modern tape devices, the density is generally not selectable (e.g. with LTO) or defaults to the highest availble density when the tape is rewritten from BOT (e.g. TS11X0). So, for most users, density selection won't be necessary. If they do need to select the density, it is easy enough to use 'mt density' to change it. o Protection information is now supported. This is either a Reed-Solomon CRC or CRC32 that is included at the end of each block read and written. On write, the tape drive verifies the CRC, and on read, the tape drive provides a CRC for the userland application to verify. o New, extensible tape driver parameter get/set interface. o Density reporting information. For drives that support it, 'mt getdensity' will show detailed information on what formats the tape drive supports, and what formats the tape drive supports. o Some mt(1) functionality moved into a new mt(3) library so that external applications can reuse the code. o The new mt(3) library includes helper routines to aid in parsing the XML output of the sa(4) driver, and build a tree of driver metadata. o Support for the MTLOAD (load a tape in the drive) and MTWEOFI (write filemark immediate) ioctls needed by IBM's LTFS implementation. o Improve device departure behavior for the sa(4) driver. The previous implementation led to hangs when the device was open. o This has been tested on the following types of drives: IBM TS1150 IBM TS1140 IBM LTO-6 IBM LTO-5 HP LTO-2 Seagate DDS-4 Quantum DLT-4000 Exabyte 8505 Sony DDS-2 contrib/groff/tmac/doc-syms, share/mk/bsd.libnames.mk, lib/Makefile, Add libmt. lib/libmt/Makefile, lib/libmt/mt.3, lib/libmt/mtlib.c, lib/libmt/mtlib.h, New mt(3) library that contains functions moved from mt(1) and new functions needed to interact with the updated sa(4) driver. This includes XML parser helper functions that application writers can use when writing code to query tape parameters. rescue/rescue/Makefile: Add -lmt to CRUNCH_LIBS. sys/cam/cam_ccb.h Add a new flag value for the XPT_DEV_ADVINFO CCB, CDAI_FLAG_NONE. sbin/camcontrol/camcontrol.c, sys/cam/scsi/scsi_da.c, sys/cam/scsi/scsi_enc_ses.c, sys/dev/mps/mps_sas.c: Make sure the flags for the XPT_DEV_ADVINFO CCB are set correctly. This prevents unintended attempts to set advanced information values when XPT_DEV_ADVINFO CCBs are not pre-zeroed. src/share/man/man4/mtio.4 Clarify this man page a bit, and since it contains what is essentially the mtio.h header file, add new ioctls and structure definitions from mtio.h. src/share/man/man4/sa.4 Update BUGS and maintainer section. sys/cam/scsi/scsi_all.c, sys/cam/scsi/scsi_all.h: Add SCSI SECURITY PROTOCOL IN/OUT CDB definitions and CDB building functions. sys/cam/scsi/scsi_sa.c sys/cam/scsi/scsi_sa.h Many tape driver changes, largely outlined above. Increase the sa(4) driver read/write timeout from 4 to 32 minutes. This is based on the recommended values for IBM LTO 5/6 drives. This may also avoid timeouts for other tape hardware that can take a long time to do retries and error recovery. Longer term, a better way to handle this is to ask the drive for recommended timeout values using the REPORT SUPPORTED OPCODES command. Modern IBM and Oracle tape drives at least support that command, and it would allow for more accurate timeout values. Add XML status generation. This is done with a series of macros to eliminate as much duplicate code as possible. The new XML-based status values are reported through the new MTIOCEXTGET ioctl. Add XML driver parameter reporting, using the new MTIOCPARAMGET ioctl. Add a new driver parameter setting interface, using the new MTIOCPARAMSET and MTIOCSETLIST ioctls. Add a new MTIOCRBLIM ioctl to get block limits information. Add CCB/CDB building routines scsi_locate_16, scsi_locate_10, and scsi_read_position_10(). scsi_locate_10 implements the LOCATE command, as does the existing scsi_set_position() command. It just supports additional arguments and features. If/when we figure out a good way to provide backward compatibility for older applications using the old function API, we can just revamp scsi_set_position(). The same goes for scsi_read_position_10() and the existing scsi_read_position() function. Revamp sasetpos() to take the new mtlocate structure as an argument. It now will use either scsi_locate_10() or scsi_locate_16(), depending upon the arguments the user supplies. As before, once we change position we don't have a clear idea of what the current logical position of the tape drive is. For tape drives that support long form position data, we read the current position and store that for later reporting after changing the position. This should help applications like Bacula speed tape access under FreeBSD once they are modified to support the new ioctls. Add a new quirk, SA_QUIRK_NO_LONG_POS, that is set for all drives that report SCSI-2 or older, as well as drives that report an Illegal Request type error for READ POSITION with the long format. So we should automatically detect drives that don't support the long form and stop asking for it after an initial try. Add a partition number to the sa(4) softc. Improve device departure handling. The previous implementation led to hangs when the device was open. If an application had the sa(4) driver open, and attempted to close it after it went away, the cam_periph_release() call in saclose() would cause the periph to get destroyed because that was the last reference to it. Because destroy_dev() was called from the sa(4) driver's cleanup routine (sacleanup()), and would block waiting for the close to happen, a deadlock would result. So instead of calling destroy_dev() from the cleanup routine, call destroy_dev_sched_cb() from saoninvalidate() and wait for the callback. Acquire a reference for devfs in saregister(), and release it in the new sadevgonecb() routine when all devfs devices for the particular sa(4) driver instance are gone. Add a new function, sasetupdev(), to centralize setting per-instance devfs device parameters instead of repeating the code in saregister(). Add an open count to the softc, so we know how many peripheral driver references are a result of open sessions. Add the D_TRACKCLOSE flag to the cdevsw flags so that we get a 1:1 mapping of open to close calls instead of a N:1 mapping. This should be a no-op for everything except the control device, since we don't allow more than one open on non-control devices. However, since we do allow multiple opens on the control device, the combination of the open count and the D_TRACKCLOSE flag should result in an accurate peripheral driver reference count, and an accurate open count. The accurate open count allows us to release all peripheral driver references that are the result of open contexts once we get the callback from devfs. sys/sys/mtio.h: Add a number of new mt(4) ioctls and the requisite data structures. None of the existing interfaces been removed or changed. This includes definitions for the following new ioctls: MTIOCRBLIM /* get block limits */ MTIOCEXTLOCATE /* seek to position */ MTIOCEXTGET /* get tape status */ MTIOCPARAMGET /* get tape params */ MTIOCPARAMSET /* set tape params */ MTIOCSETLIST /* set N params */ usr.bin/mt/Makefile: mt(1) now depends on libmt, libsbuf and libbsdxml. usr.bin/mt/mt.1: Document new mt(1) features and subcommands. usr.bin/mt/mt.c: Implement support for mt(1) subcommands that need to use getopt(3) for their arguments. Implement a new 'mt status' command to replace the old 'mt status' command. The old status command has been renamed 'ostatus'. The new status function uses the MTIOCEXTGET ioctl, and therefore parses the XML data to determine drive status. The -x argument to 'mt status' allows the user to dump out the raw XML reported by the kernel. The new status display is mostly the same as the old status display, except that it doesn't print the redundant density mode information, and it does print the current partition number and position flags. Add a new command, 'mt locate', that will supersede the old 'mt setspos' and 'mt sethpos' commands. 'mt locate' implements all of the functionality of the MTIOCEXTLOCATE ioctl, and allows the user to change the logical position of the tape drive in a number of ways. (Partition, block number, file number, set mark number, end of data.) The immediate bit and the explicit address bits are implemented, but not documented in the man page. Add a new 'mt weofi' command to use the new MTWEOFI ioctl. This allows the user to ask the drive to write a filemark without waiting around for the operation to complete. Add a new 'mt getdensity' command that gets the XML-based tape drive density report from the sa(4) driver and displays it. This uses the SCSI REPORT DENSITY SUPPORT command to get comprehensive information from the tape drive about what formats it is able to read and write. Add a new 'mt protect' command that allows getting and setting tape drive protection information. The protection information is a CRC tacked on to the end of every read/write from and to the tape drive. Sponsored by: Spectra Logic MFC after: 1 month Thanks, Ken -- Kenneth Merry k...@freebsd.org _______________________________________________ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
