06 Nov, 2011

1 commit

  • fs_info has now ~9kb, more than fits into one page. This will cause
    mount failure when memory is too fragmented. Top space consumers are
    super block structures super_copy and super_for_commit, ~2.8kb each.
    Allocate them dynamically. fs_info will be ~3.5kb. (measured on x86_64)

    Add a wrapper for freeing fs_info and all of it's dynamically allocated
    members.

    Signed-off-by: David Sterba

    David Sterba
     

02 Aug, 2011

1 commit


23 May, 2011

1 commit


02 May, 2011

1 commit


25 Apr, 2011

1 commit

  • There's a potential problem in 32bit system when we exhaust 32bit inode
    numbers and start to allocate big inode numbers, because btrfs uses
    inode->i_ino in many places.

    So here we always use BTRFS_I(inode)->location.objectid, which is an
    u64 variable.

    There are 2 exceptions that BTRFS_I(inode)->location.objectid !=
    inode->i_ino: the btree inode (0 vs 1) and empty subvol dirs (256 vs 2),
    and inode->i_ino will be used in those cases.

    Another reason to make this change is I'm going to use a special inode
    to save free ino cache, and the inode number must be > (u64)-256.

    Signed-off-by: Li Zefan

    Li Zefan
     

28 Mar, 2011

2 commits


06 Feb, 2011

1 commit


29 Jan, 2011

1 commit


22 Dec, 2010

3 commits

  • Add a common function to copy decompressed data from working buffer
    to bio pages.

    Signed-off-by: Li Zefan

    Li Zefan
     
  • Lzo is a much faster compression algorithm than gzib, so would allow
    more users to enable transparent compression, and some users can
    choose from compression ratio and speed for different applications

    Usage:

    # mount -t btrfs -o compress[=] dev /mnt
    or
    # mount -t btrfs -o compress-force[=] dev /mnt

    "-o compress" without argument is still allowed for compatability.

    Compatibility:

    If we mount a filesystem with lzo compression, it will not be able be
    mounted in old kernels. One reason is, otherwise btrfs will directly
    dump compressed data, which sits in inline extent, to user.

    Performance:

    The test copied a linux source tarball (~400M) from an ext4 partition
    to the btrfs partition, and then extracted it.

    (time in second)
    lzo zlib nocompress
    copy: 10.6 21.7 14.9
    extract: 70.1 94.4 66.6

    (data size in MB)
    lzo zlib nocompress
    copy: 185.87 108.69 394.49
    extract: 193.80 132.36 381.21

    Changelog:

    v1 -> v2:
    - Select LZO_COMPRESS and LZO_DECOMPRESS in btrfs Kconfig.
    - Add incompability flag.
    - Fix error handling in compress code.

    Signed-off-by: Li Zefan

    Li Zefan
     
  • Make the code aware of compression type, instead of always assuming
    zlib compression.

    Also make the zlib workspace function as common code for all
    compression types.

    Signed-off-by: Li Zefan

    Li Zefan
     

22 Nov, 2010

1 commit


30 Oct, 2010

1 commit

  • These are all the cases where a variable is set, but not read which are
    not bugs as far as I can see, but simply leftovers.

    Still needs more review.

    Found by gcc 4.6's new warnings

    Signed-off-by: Andi Kleen
    Cc: Chris Mason
    Signed-off-by: Andrew Morton
    Signed-off-by: Chris Mason

    Andi Kleen
     

06 Apr, 2010

2 commits

  • * git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
    Btrfs: add check for changed leaves in setup_leaf_for_split
    Btrfs: create snapshot references in same commit as snapshot
    Btrfs: fix small race with delalloc flushing waitqueue's
    Btrfs: use add_to_page_cache_lru, use __page_cache_alloc
    Btrfs: fix chunk allocate size calculation
    Btrfs: kill max_extent mount option
    Btrfs: fail to mount if we have problems reading the block groups
    Btrfs: check btrfs_get_extent return for IS_ERR()
    Btrfs: handle kmalloc() failure in inode lookup ioctl
    Btrfs: dereferencing freed memory
    Btrfs: Simplify num_stripes's calculation logical for __btrfs_alloc_chunk()
    Btrfs: Add error handle for btrfs_search_slot() in btrfs_read_chunk_tree()
    Btrfs: Remove unnecessary finish_wait() in wait_current_trans()
    Btrfs: add NULL check for do_walk_down()
    Btrfs: remove duplicate include in ioctl.c

    Fix trivial conflict in fs/btrfs/compression.c due to slab.h include
    cleanups.

    Linus Torvalds
     
  • Pagecache pages should be allocated with __page_cache_alloc, so they
    obey pagecache memory policies.

    add_to_page_cache_lru is exported, so it should be used. Benefits over
    using a private pagevec: neater code, 128 bytes fewer stack used, percpu
    lru ordering is preserved, and finally don't need to flush pagevec
    before returning so batching may be shared with other LRU insertions.

    Signed-off-by: Nick Piggin :
    Signed-off-by: Chris Mason

    Nick Piggin
     

30 Mar, 2010

1 commit

  • …it slab.h inclusion from percpu.h

    percpu.h is included by sched.h and module.h and thus ends up being
    included when building most .c files. percpu.h includes slab.h which
    in turn includes gfp.h making everything defined by the two files
    universally available and complicating inclusion dependencies.

    percpu.h -> slab.h dependency is about to be removed. Prepare for
    this change by updating users of gfp and slab facilities include those
    headers directly instead of assuming availability. As this conversion
    needs to touch large number of source files, the following script is
    used as the basis of conversion.

    http://userweb.kernel.org/~tj/misc/slabh-sweep.py

    The script does the followings.

    * Scan files for gfp and slab usages and update includes such that
    only the necessary includes are there. ie. if only gfp is used,
    gfp.h, if slab is used, slab.h.

    * When the script inserts a new include, it looks at the include
    blocks and try to put the new include such that its order conforms
    to its surrounding. It's put in the include block which contains
    core kernel includes, in the same order that the rest are ordered -
    alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
    doesn't seem to be any matching order.

    * If the script can't find a place to put a new include (mostly
    because the file doesn't have fitting include block), it prints out
    an error message indicating which .h file needs to be added to the
    file.

    The conversion was done in the following steps.

    1. The initial automatic conversion of all .c files updated slightly
    over 4000 files, deleting around 700 includes and adding ~480 gfp.h
    and ~3000 slab.h inclusions. The script emitted errors for ~400
    files.

    2. Each error was manually checked. Some didn't need the inclusion,
    some needed manual addition while adding it to implementation .h or
    embedding .c file was more appropriate for others. This step added
    inclusions to around 150 files.

    3. The script was run again and the output was compared to the edits
    from #2 to make sure no file was left behind.

    4. Several build tests were done and a couple of problems were fixed.
    e.g. lib/decompress_*.c used malloc/free() wrappers around slab
    APIs requiring slab.h to be added manually.

    5. The script was run on all .h files but without automatically
    editing them as sprinkling gfp.h and slab.h inclusions around .h
    files could easily lead to inclusion dependency hell. Most gfp.h
    inclusion directives were ignored as stuff from gfp.h was usually
    wildly available and often used in preprocessor macros. Each
    slab.h inclusion directive was examined and added manually as
    necessary.

    6. percpu.h was updated not to include slab.h.

    7. Build test were done on the following configurations and failures
    were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
    distributed build env didn't work with gcov compiles) and a few
    more options had to be turned off depending on archs to make things
    build (like ipr on powerpc/64 which failed due to missing writeq).

    * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
    * powerpc and powerpc64 SMP allmodconfig
    * sparc and sparc64 SMP allmodconfig
    * ia64 SMP allmodconfig
    * s390 SMP allmodconfig
    * alpha SMP allmodconfig
    * um on x86_64 SMP allmodconfig

    8. percpu.h modifications were reverted so that it could be applied as
    a separate patch and serve as bisection point.

    Given the fact that I had only a couple of failures from tests on step
    6, I'm fairly confident about the coverage of this conversion patch.
    If there is a breakage, it's likely to be something in one of the arch
    headers which should be easily discoverable easily on most builds of
    the specific arch.

    Signed-off-by: Tejun Heo <tj@kernel.org>
    Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

    Tejun Heo
     

15 Mar, 2010

1 commit


12 Sep, 2009

2 commits


13 Jul, 2009

1 commit

  • * Remove smp_lock.h from files which don't need it (including some headers!)
    * Add smp_lock.h to files which do need it
    * Make smp_lock.h include conditional in hardirq.h
    It's needed only for one kernel_locked() usage which is under CONFIG_PREEMPT

    This will make hardirq.h inclusion cheaper for every PREEMPT=n config
    (which includes allmodconfig/allyesconfig, BTW)

    Signed-off-by: Alexey Dobriyan
    Signed-off-by: Linus Torvalds

    Alexey Dobriyan
     

10 Jun, 2009

1 commit

  • Add support for the standard attributes set via chattr and read via
    lsattr. Currently we store the attributes in the flags value in
    the btrfs inode, but I wonder whether we should split it into two so
    that we don't have to keep converting between the two formats.

    Remove the btrfs_clear_flag/btrfs_set_flag/btrfs_test_flag macros
    as they were confusing the existing code and got in the way of the
    new additions.

    Also add the FS_IOC_GETVERSION ioctl for getting i_generation as it's
    trivial.

    Signed-off-by: Christoph Hellwig
    Signed-off-by: Chris Mason

    Christoph Hellwig
     

21 Jan, 2009

1 commit


06 Jan, 2009

1 commit


12 Dec, 2008

1 commit

  • Checksums on data can be disabled by mount option, so it's
    possible some data extents don't have checksums or have
    invalid checksums. This causes trouble for data relocation.
    This patch contains following things to make data relocation
    work.

    1) make nodatasum/nodatacow mount option only affects new
    files. Checksums and COW on data are only controlled by the
    inode flags.

    2) check the existence of checksum in the nodatacow checker.
    If checksums exist, force COW the data extent. This ensure that
    checksum for a given block is either valid or does not exist.

    3) update data relocation code to properly handle the case
    of checksum missing.

    Signed-off-by: Yan Zheng

    Yan Zheng
     

09 Dec, 2008

1 commit

  • Btrfs stores checksums for each data block. Until now, they have
    been stored in the subvolume trees, indexed by the inode that is
    referencing the data block. This means that when we read the inode,
    we've probably read in at least some checksums as well.

    But, this has a few problems:

    * The checksums are indexed by logical offset in the file. When
    compression is on, this means we have to do the expensive checksumming
    on the uncompressed data. It would be faster if we could checksum
    the compressed data instead.

    * If we implement encryption, we'll be checksumming the plain text and
    storing that on disk. This is significantly less secure.

    * For either compression or encryption, we have to get the plain text
    back before we can verify the checksum as correct. This makes the raid
    layer balancing and extent moving much more expensive.

    * It makes the front end caching code more complex, as we have touch
    the subvolume and inodes as we cache extents.

    * There is potentitally one copy of the checksum in each subvolume
    referencing an extent.

    The solution used here is to store the extent checksums in a dedicated
    tree. This allows us to index the checksums by phyiscal extent
    start and length. It means:

    * The checksum is against the data stored on disk, after any compression
    or encryption is done.

    * The checksum is stored in a central location, and can be verified without
    following back references, or reading inodes.

    This makes compression significantly faster by reducing the amount of
    data that needs to be checksummed. It will also allow much faster
    raid management code in general.

    The checksums are indexed by a key with a fixed objectid (a magic value
    in ctree.h) and offset set to the starting byte of the extent. This
    allows us to copy the checksum items into the fsync log tree directly (or
    any other tree), without having to invent a second format for them.

    Signed-off-by: Chris Mason

    Chris Mason
     

20 Nov, 2008

2 commits


11 Nov, 2008

2 commits


10 Nov, 2008

1 commit

  • The decompress code doesn't take the logical offset in extent
    pointer into account. If the logical offset isn't zero, data
    will be decompressed into wrong pages.

    The solution used here is to record the starting offset of the extent
    in the file separately from the logical start of the extent_map struct.
    This allows us to avoid problems inserting overlapping extents.

    Signed-off-by: Yan Zheng

    Yan Zheng
     

08 Nov, 2008

1 commit

  • When writing a compressed extent, a number of bios are created that
    point to a single struct compressed_bio. At end_io time an atomic counter in
    the compressed_bio struct makes sure that all of the bios have finished
    before final end_io processing is done.

    But when multiple bios are needed to write a compressed extent, the
    counter was being incremented after the first bio was sent to submit_bio.
    It is possible the bio will complete before the counter is incremented,
    making the end_io handler free the compressed_bio struct before
    processing is finished.

    The fix is to increment the atomic counter before bio submission,
    both for compressed reads and writes.

    Signed-off-by: Chris Mason

    Chris Mason
     

07 Nov, 2008

1 commit

  • When reading compressed extents, try to put pages into the page cache
    for any pages covered by the compressed extent that readpages didn't already
    preload.

    Add an async work queue to handle transformations at delayed allocation processing
    time. Right now this is just compression. The workflow is:

    1) Find offsets in the file marked for delayed allocation
    2) Lock the pages
    3) Lock the state bits
    4) Call the async delalloc code

    The async delalloc code clears the state lock bits and delalloc bits. It is
    important this happens before the range goes into the work queue because
    otherwise it might deadlock with other work queue items that try to lock
    those extent bits.

    The file pages are compressed, and if the compression doesn't work the
    pages are written back directly.

    An ordered work queue is used to make sure the inodes are written in the same
    order that pdflush or writepages sent them down.

    This changes extent_write_cache_pages to let the writepage function
    update the wbc nr_written count.

    Signed-off-by: Chris Mason

    Chris Mason
     

01 Nov, 2008

1 commit

  • Make sure we keep page->mapping NULL on the pages we're getting
    via alloc_page. It gets set so a few of the callbacks can do the right
    thing, but in general these pages don't have a mapping.

    Don't try to truncate compressed inline items in btrfs_drop_extents.
    The whole compressed item must be preserved.

    Don't try to create multipage inline compressed items. When we try to
    overwrite just the first page of the file, we would have to read in and recow
    all the pages after it in the same compressed inline items. For now, only
    create single page inline items.

    Make sure we lock pages in the correct order during delalloc. The
    search into the state tree for delalloc bytes can return bytes before
    the page we already have locked.

    Signed-off-by: Chris Mason

    Chris Mason
     

31 Oct, 2008

1 commit


30 Oct, 2008

1 commit

  • This is a large change for adding compression on reading and writing,
    both for inline and regular extents. It does some fairly large
    surgery to the writeback paths.

    Compression is off by default and enabled by mount -o compress. Even
    when the -o compress mount option is not used, it is possible to read
    compressed extents off the disk.

    If compression for a given set of pages fails to make them smaller, the
    file is flagged to avoid future compression attempts later.

    * While finding delalloc extents, the pages are locked before being sent down
    to the delalloc handler. This allows the delalloc handler to do complex things
    such as cleaning the pages, marking them writeback and starting IO on their
    behalf.

    * Inline extents are inserted at delalloc time now. This allows us to compress
    the data before inserting the inline extent, and it allows us to insert
    an inline extent that spans multiple pages.

    * All of the in-memory extent representations (extent_map.c, ordered-data.c etc)
    are changed to record both an in-memory size and an on disk size, as well
    as a flag for compression.

    From a disk format point of view, the extent pointers in the file are changed
    to record the on disk size of a given extent and some encoding flags.
    Space in the disk format is allocated for compression encoding, as well
    as encryption and a generic 'other' field. Neither the encryption or the
    'other' field are currently used.

    In order to limit the amount of data read for a single random read in the
    file, the size of a compressed extent is limited to 128k. This is a
    software only limit, the disk format supports u64 sized compressed extents.

    In order to limit the ram consumed while processing extents, the uncompressed
    size of a compressed extent is limited to 256k. This is a software only limit
    and will be subject to tuning later.

    Checksumming is still done on compressed extents, and it is done on the
    uncompressed version of the data. This way additional encodings can be
    layered on without having to figure out which encoding to checksum.

    Compression happens at delalloc time, which is basically singled threaded because
    it is usually done by a single pdflush thread. This makes it tricky to
    spread the compression load across all the cpus on the box. We'll have to
    look at parallel pdflush walks of dirty inodes at a later time.

    Decompression is hooked into readpages and it does spread across CPUs nicely.

    Signed-off-by: Chris Mason

    Chris Mason