1. 05 Mar, 2010 1 commit
  2. 28 Feb, 2010 6 commits
    • Boaz Harrosh's avatar
      exofs: groups support · 50a76fd3
      Boaz Harrosh authored
      * _calc_stripe_info() changes to accommodate for grouping
        calculations. Returns additional information
      
      * old _prepare_pages() becomes _prepare_one_group()
        which stores pages belonging to one device group.
      
      * New _prepare_for_striping iterates on all groups calling
        _prepare_one_group().
      
      * Enable mounting of groups data_maps (group_width != 0)
      
      [QUESTION]
      what is faster A or B;
      A.	x += stride;
      	x = x % width + first_x;
      
      B	x += stride
      	if (x < last_x)
      		x = first_x;
      Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
      50a76fd3
    • Boaz Harrosh's avatar
      exofs: convert io_state to use pages array instead of bio at input · 86093aaf
      Boaz Harrosh authored
      * inode.c operations are full-pages based, and not actually
        true scatter-gather
      * Lets us use more pages at once upto 512 (from 249) in 64 bit
      * Brings us much much closer to be able to use exofs's io_state engine
        from objlayout driver. (Once I decide where to put the common code)
      
      After RAID0 patch the outer (input) bio was never used as a bio, but
      was simply a page carrier into the raid engine. Even in the simple
      mirror/single-dev arrangement pages info was copied into a second bio.
      It is now easer to just pass a pages array into the io_state and prepare
      bio(s) once.
      Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
      86093aaf
    • Boaz Harrosh's avatar
      exofs: RAID0 support · 5d952b83
      Boaz Harrosh authored
      We now support striping over mirror devices. Including variable sized
      stripe_unit.
      
      Some limits:
      * stripe_unit must be a multiple of PAGE_SIZE
      * stripe_unit * stripe_count is maximum upto 32-bit (4Gb)
      
      Tested RAID0 over mirrors, RAID0 only, mirrors only. All check.
      
      Design notes:
      * I'm not using a vectored raid-engine mechanism yet. Following the
        pnfs-objects-layout data-map structure, "Mirror" is just a private
        case of "group_width" == 1, and RAID0 is a private case of
        "Mirrors" == 1. The performance lose of the general case over the
        particular special case optimization is totally negligible, also
        considering the extra code size.
      
      * In general I added a prepare_stripes() stage that divides the
        to-be-io pages to the participating devices, the previous
        exofs_ios_write/read, now becomes _write/read_mirrors and a new
        write/read upper layer loops on all devices calling
        _write/read_mirrors. Effectively the prepare_stripes stage is the all
        secret.
        Also truncate need fixing to accommodate for striping.
      
      * In a RAID0 arrangement, in a regular usage scenario, if all inode
        layouts will start at the same device, the small files fill up the
        first device and the later devices stay empty, the farther the device
        the emptier it is.
      
        To fix that, each inode will start at a different stripe_unit,
        according to it's obj_id modulus number-of-stripe-units. And
        will then span all stripe-units in the same incrementing order
        wrapping back to the beginning of the device table. We call it
        a stripe-units moving window.
      
        Special consideration was taken to keep all devices in a mirror
        arrangement identical. So a broken osd-device could just be cloned
        from one of the mirrors and no FS scrubbing is needed. (We do that
        by rotating stripe-unit at a time and not a single device at a time.)
      
      TODO:
       We no longer verify object_length == inode->i_size in exofs_iget.
       (since i_size is stripped on multiple objects now).
       I should introduce a multiple-device attribute reading, and use
       it in exofs_iget.
      Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
      5d952b83
    • Boaz Harrosh's avatar
      exofs: Define on-disk per-inode optional layout attribute · d9c740d2
      Boaz Harrosh authored
      * Layouts describe the way a file is spread on multiple devices.
        The layout information is stored in the objects attribute introduced
        in this patch.
      
      * There can be multiple generating function for the layout.
        Currently defined:
          - No attribute present - use below moving-window on global
            device table, all devices.
            (This is the only one currently used in exofs)
          - an obj_id generated moving window - the obj_id is a randomizing
            factor in the otherwise global map layout.
          - An explicit layout stored, including a data_map and a device
            index list.
          - More might be defined in future ...
      
      * There are two attributes defined of the same structure:
        A-data-files-layout - This layout is used by data-files. If present
                              at a directory, all files of that directory will
                              be created with this layout.
        A-meta-data-layout - This layout is used by a directory and other
                             meta-data information. Also inherited at creation
                             of subdirectories.
      
      * At creation time inodes are created with the layout specified above.
        A usermode utility may change the creation layout on a give directory
        or file. Which in the case of directories, will also apply to newly
        created files/subdirectories, children of that directory.
        In the simple unaltered case of a newly created exofs, no layout
        attributes are present, and all layouts adhere to the layout specified
        at the device-table.
      
      * In case of a future file system loaded in an old exofs-driver.
        At iget(), the generating_function is inspected and if not supported
        will return an IO error to the application and the inode will not
        be loaded. So not to damage any data.
        Note: After this patch we do not yet support any type of layout
              only the RAID0 patch that enables striping at the super-block
              level will add support for RAID0 layouts above. This way we
              are past and future compatible and fully bisectable.
      
      * Access to the device table is done by an accessor since
        it will change according to above information.
      Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
      d9c740d2
    • Boaz Harrosh's avatar
      exofs: Move layout related members to a layout structure · 45d3abcb
      Boaz Harrosh authored
      * Abstract away those members in exofs_sb_info that are related/needed
        by a layout into a new exofs_layout structure. Embed it in exofs_sb_info.
      
      * At exofs_io_state receive/keep a pointer to an exofs_layout. No need for
        an exofs_sb_info pointer, all we need is at exofs_layout.
      
      * Change any usage of above exofs_sb_info members to their new name.
      Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
      45d3abcb
    • Boaz Harrosh's avatar
      exofs: Micro-optimize exofs_i_info · 518f167a
      Boaz Harrosh authored
      optimize the exofs_i_info struct usage by moving the embedded
      vfs_inode to be first. A compiler might optimize away an "add"
      operation with constant zero. (Which it cannot with other constants)
      Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
      518f167a
  3. 10 Dec, 2009 2 commits
    • Boaz Harrosh's avatar
      exofs: Multi-device mirror support · 04dc1e88
      Boaz Harrosh authored
      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: default avatarBoaz Harrosh <bharrosh@panasas.com>
      04dc1e88
    • Boaz Harrosh's avatar
      exofs: Move all operations to an io_engine · 06886a5a
      Boaz Harrosh authored
      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: default avatarBoaz Harrosh <bharrosh@panasas.com>
      06886a5a
  4. 21 Jun, 2009 2 commits
    • Boaz Harrosh's avatar
      exofs: Avoid using file_fsync() · baaf94cd
      Boaz Harrosh authored
      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: default avatarBoaz Harrosh <bharrosh@panasas.com>
      baaf94cd
    • Boaz Harrosh's avatar
      exofs: Remove IBM copyrights · 27d2e149
      Boaz Harrosh authored
      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: default avatarAvishay Traeger <avishay@gmail.com>
      Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
      27d2e149
  5. 31 Mar, 2009 7 commits
    • Boaz Harrosh's avatar
      exofs: export_operations · 8cf74b39
      Boaz Harrosh authored
      implement export_operations and set in superblock.
      It is now posible to export exofs via nfs
      Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
      8cf74b39
    • Boaz Harrosh's avatar
      exofs: super_operations and file_system_type · ba9e5e98
      Boaz Harrosh authored
      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: default avatarBoaz Harrosh <bharrosh@panasas.com>
      ba9e5e98
    • Boaz Harrosh's avatar
      exofs: dir_inode and directory operations · e6af00f1
      Boaz Harrosh authored
      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: default avatarBoaz Harrosh <bharrosh@panasas.com>
      e6af00f1
    • Boaz Harrosh's avatar
      exofs: address_space_operations · beaec07b
      Boaz Harrosh authored
      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: default avatarBoaz Harrosh <bharrosh@panasas.com>
      beaec07b
    • Boaz Harrosh's avatar
      exofs: symlink_inode and fast_symlink_inode operations · 982980d7
      Boaz Harrosh authored
      Generic implementation of symlink ops.
      Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
      982980d7
    • Boaz Harrosh's avatar
      exofs: file and file_inode operations · e8062719
      Boaz Harrosh authored
      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: default avatarBoaz Harrosh <bharrosh@panasas.com>
      e8062719
    • Boaz Harrosh's avatar
      exofs: Kbuild, Headers and osd utils · b14f8ab2
      Boaz Harrosh authored
      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: default avatarBoaz Harrosh <bharrosh@panasas.com>
      b14f8ab2