Commit Graph

11 Commits

Author SHA1 Message Date
Boaz Harrosh 04dc1e88ad exofs: Multi-device mirror support
This patch changes on-disk format, it is accompanied with a parallel
patch to mkfs.exofs that enables multi-device capabilities.

After this patch, old exofs will refuse to mount a new formatted FS and
new exofs will refuse an old format. This is done by moving the magic
field offset inside the FSCB. A new FSCB *version* field was added. In
the future, exofs will refuse to mount unmatched FSCB version. To
up-grade or down-grade an exofs one must use mkfs.exofs --upgrade option
before mounting.

Introduced, a new object that contains a *device-table*. This object
contains the default *data-map* and a linear array of devices
information, which identifies the devices used in the filesystem. This
object is only written to offline by mkfs.exofs. This is why it is kept
separate from the FSCB, since the later is written to while mounted.

Same partition number, same object number is used on all devices only
the device varies.

* define the new format, then load the device table on mount time make
  sure every thing is supported.

* Change I/O engine to now support Mirror IO, .i.e write same data
  to multiple devices, read from a random device to spread the
  read-load from multiple clients (TODO: stripe read)

Implementation notes:
 A few points introduced in previous patch should be mentioned here:

* Special care was made so absolutlly all operation that have any chance
  of failing are done before any osd-request is executed. This is to
  minimize the need for a data consistency recovery, to only real IO
  errors.

* Each IO state has a kref. It starts at 1, any osd-request executed
  will increment the kref, finally when all are executed the first ref
  is dropped. At IO-done, each request completion decrements the kref,
  the last one to return executes the internal _last_io() routine.
  _last_io() will call the registered io_state_done. On sync mode a
  caller does not supply a done method, indicating a synchronous
  request, the caller is put to sleep and a special io_state_done is
  registered that will awaken the caller. Though also in sync mode all
  operations are executed in parallel.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2009-12-10 09:59:23 +02:00
Boaz Harrosh 06886a5a3d exofs: Move all operations to an io_engine
In anticipation for multi-device operations, we separate osd operations
into an abstract I/O API. Currently only one device is used but later
when adding more devices, we will drive all devices in parallel according
to a "data_map" that describes how data is arranged on multiple devices.
The file system level operates, like before, as if there is one object
(inode-number) and an i_size. The io engine will split this to the same
object-number but on multiple device.

At first we introduce Mirror (raid 1) layout. But at the final outcome
we intend to fully implement the pNFS-Objects data-map, including
raid 0,4,5,6 over mirrored devices, over multiple device-groups. And
more. See: http://tools.ietf.org/html/draft-ietf-nfsv4-pnfs-obj-12

* Define an io_state based API for accessing osd storage devices
  in an abstract way.
  Usage:
	First a caller allocates an io state with:
		exofs_get_io_state(struct exofs_sb_info *sbi,
				   struct exofs_io_state** ios);

	Then calles one of:
		exofs_sbi_create(struct exofs_io_state *ios);
		exofs_sbi_remove(struct exofs_io_state *ios);
		exofs_sbi_write(struct exofs_io_state *ios);
		exofs_sbi_read(struct exofs_io_state *ios);
		exofs_oi_truncate(struct exofs_i_info *oi, u64 new_len);

	And when done
		exofs_put_io_state(struct exofs_io_state *ios);

* Convert all source files to use this new API
* Convert from bio_alloc to bio_kmalloc
* In io engine we make use of the now fixed osd_req_decode_sense

There are no functional changes or on disk additions after this patch.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2009-12-10 09:59:22 +02:00
Boaz Harrosh baaf94cdc7 exofs: Avoid using file_fsync()
The use of file_fsync() in exofs_file_sync() is not necessary since it
does some extra stuff not used by exofs. Open code just the parts that
are currently needed.

TODO: Farther optimization can be done to sync the sb only on inode
update of new files, Usually the sb update is not needed in exofs.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2009-06-21 17:53:47 +03:00
Boaz Harrosh 27d2e14919 exofs: Remove IBM copyrights
Boaz,
Congrats on getting all the OSD stuff into 2.6.30!
I just pulled the git, and saw that the IBM copyrights are still there.
Please remove them from all files:
 * Copyright (C) 2005, 2006
 * International Business Machines

IBM has revoked all rights on the code - they gave it to me.

Thanks!
Avishay

Signed-off-by: Avishay Traeger <avishay@gmail.com>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2009-06-21 17:53:47 +03:00
Boaz Harrosh 8cf74b3936 exofs: export_operations
implement export_operations and set in superblock.
It is now posible to export exofs via nfs

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2009-03-31 19:44:36 +03:00
Boaz Harrosh ba9e5e98ca exofs: super_operations and file_system_type
This patch ties all operation vectors into a file system superblock
and registers the exofs file_system_type at module's load time.

* The file system control block (AKA on-disk superblock) resides in
  an object with a special ID (defined in common.h).
  Information included in the file system control block is used to
  fill the in-memory superblock structure at mount time. This object
  is created before the file system is used by mkexofs.c It contains
  information such as:
	- The file system's magic number
	- The next inode number to be allocated

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2009-03-31 19:44:34 +03:00
Boaz Harrosh e6af00f1d1 exofs: dir_inode and directory operations
implementation of directory and inode operations.

* A directory is treated as a file, and essentially contains a list
  of <file name, inode #> pairs for files that are found in that
  directory. The object IDs correspond to the files' inode numbers
  and are allocated using a 64bit incrementing global counter.
* Each file's control block (AKA on-disk inode) is stored in its
  object's attributes. This applies to both regular files and other
  types (directories, device files, symlinks, etc.).

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2009-03-31 19:44:31 +03:00
Boaz Harrosh beaec07ba6 exofs: address_space_operations
OK Now we start to read and write from osd-objects. We try to
collect at most contiguous pages as possible in a single write/read.
The first page index is the object's offset.

TODO:
   In 64-bit a single bio can carry at most 128 pages.
   Add support of chaining multiple bios

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2009-03-31 19:44:29 +03:00
Boaz Harrosh 982980d753 exofs: symlink_inode and fast_symlink_inode operations
Generic implementation of symlink ops.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2009-03-31 19:44:27 +03:00
Boaz Harrosh e806271916 exofs: file and file_inode operations
implementation of the file_operations and inode_operations for
regular data files.

Most file_operations are generic vfs implementations except:
- exofs_truncate will truncate the OSD object as well
- Generic file_fsync is not good for none_bd devices so open code it
- The default for .flush in Linux is todo nothing so call exofs_fsync
  on the file.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2009-03-31 19:44:24 +03:00
Boaz Harrosh b14f8ab284 exofs: Kbuild, Headers and osd utils
This patch includes osd infrastructure that will be used later by
the file system.

Also the declarations of constants, on disk structures,
and prototypes.

And the Kbuild+Kconfig files needed to build the exofs module.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2009-03-31 19:44:20 +03:00