1. 17 Mar, 2011 1 commit
  2. 10 Mar, 2011 1 commit
  3. 12 Jan, 2011 1 commit
  4. 06 Jan, 2011 7 commits
    • Nick Piggin's avatar
      fs: dcache per-inode inode alias locking · 873feea0
      Nick Piggin authored
      dcache_inode_lock can be replaced with per-inode locking. Use existing
      inode->i_lock for this. This is slightly non-trivial because we sometimes
      need to find the inode from the dentry, which requires d_inode to be
      stabilised (either with refcount or d_lock).
      Signed-off-by: default avatarNick Piggin <npiggin@kernel.dk>
      873feea0
    • Nick Piggin's avatar
      fs: dcache reduce branches in lookup path · fb045adb
      Nick Piggin authored
      Reduce some branches and memory accesses in dcache lookup by adding dentry
      flags to indicate common d_ops are set, rather than having to check them.
      This saves a pointer memory access (dentry->d_op) in common path lookup
      situations, and saves another pointer load and branch in cases where we
      have d_op but not the particular operation.
      
      Patched with:
      
      git grep -E '[.>]([[:space:]])*d_op([[:space:]])*=' | xargs sed -e 's/\([^\t ]*\)->d_op = \(.*\);/d_set_d_op(\1, \2);/' -e 's/\([^\t ]*\)\.d_op = \(.*\);/d_set_d_op(\&\1, \2);/' -i
      Signed-off-by: default avatarNick Piggin <npiggin@kernel.dk>
      fb045adb
    • Nick Piggin's avatar
      fs: icache RCU free inodes · fa0d7e3d
      Nick Piggin authored
      RCU free the struct inode. This will allow:
      
      - Subsequent store-free path walking patch. The inode must be consulted for
        permissions when walking, so an RCU inode reference is a must.
      - sb_inode_list_lock to be moved inside i_lock because sb list walkers who want
        to take i_lock no longer need to take sb_inode_list_lock to walk the list in
        the first place. This will simplify and optimize locking.
      - Could remove some nested trylock loops in dcache code
      - Could potentially simplify things a bit in VM land. Do not need to take the
        page lock to follow page->mapping.
      
      The downsides of this is the performance cost of using RCU. In a simple
      creat/unlink microbenchmark, performance drops by about 10% due to inability to
      reuse cache-hot slab objects. As iterations increase and RCU freeing starts
      kicking over, this increases to about 20%.
      
      In cases where inode lifetimes are longer (ie. many inodes may be allocated
      during the average life span of a single inode), a lot of this cache reuse is
      not applicable, so the regression caused by this patch is smaller.
      
      The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU,
      however this adds some complexity to list walking and store-free path walking,
      so I prefer to implement this at a later date, if it is shown to be a win in
      real situations. I haven't found a regression in any non-micro benchmark so I
      doubt it will be a problem.
      Signed-off-by: default avatarNick Piggin <npiggin@kernel.dk>
      fa0d7e3d
    • Nick Piggin's avatar
      fs: dcache remove dcache_lock · b5c84bf6
      Nick Piggin authored
      dcache_lock no longer protects anything. remove it.
      Signed-off-by: default avatarNick Piggin <npiggin@kernel.dk>
      b5c84bf6
    • Nick Piggin's avatar
      fs: scale inode alias list · b23fb0a6
      Nick Piggin authored
      Add a new lock, dcache_inode_lock, to protect the inode's i_dentry list
      from concurrent modification. d_alias is also protected by d_lock.
      Signed-off-by: default avatarNick Piggin <npiggin@kernel.dk>
      b23fb0a6
    • Nick Piggin's avatar
      fs: change d_hash for rcu-walk · b1e6a015
      Nick Piggin authored
      Change d_hash so it may be called from lock-free RCU lookups. See similar
      patch for d_compare for details.
      
      For in-tree filesystems, this is just a mechanical change.
      Signed-off-by: default avatarNick Piggin <npiggin@kernel.dk>
      b1e6a015
    • Nick Piggin's avatar
      fs: change d_compare for rcu-walk · 621e155a
      Nick Piggin authored
      Change d_compare so it may be called from lock-free RCU lookups. This
      does put significant restrictions on what may be done from the callback,
      however there don't seem to have been any problems with in-tree fses.
      If some strange use case pops up that _really_ cannot cope with the
      rcu-walk rules, we can just add new rcu-unaware callbacks, which would
      cause name lookup to drop out of rcu-walk mode.
      
      For in-tree filesystems, this is just a mechanical change.
      Signed-off-by: default avatarNick Piggin <npiggin@kernel.dk>
      621e155a
  5. 29 Oct, 2010 1 commit
  6. 25 Oct, 2010 2 commits
  7. 12 Oct, 2010 1 commit
  8. 04 Oct, 2010 2 commits
    • Jan Blunck's avatar
      BKL: Remove BKL from Amiga FFS · 74c41429
      Jan Blunck authored
      The BKL is only used in put_super, fill_super and remount_fs that are all
      three protected by the superblocks s_umount rw_semaphore. Therefore it is
      safe to remove the BKL entirely.
      Signed-off-by: default avatarJan Blunck <jblunck@infradead.org>
      Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      74c41429
    • Jan Blunck's avatar
      BKL: Explicitly add BKL around get_sb/fill_super · db719222
      Jan Blunck authored
      This patch is a preparation necessary to remove the BKL from do_new_mount().
      It explicitly adds calls to lock_kernel()/unlock_kernel() around
      get_sb/fill_super operations for filesystems that still uses the BKL.
      
      I've read through all the code formerly covered by the BKL inside
      do_kern_mount() and have satisfied myself that it doesn't need the BKL
      any more.
      
      do_kern_mount() is already called without the BKL when mounting the rootfs
      and in nfsctl. do_kern_mount() calls vfs_kern_mount(), which is called
      from various places without BKL: simple_pin_fs(), nfs_do_clone_mount()
      through nfs_follow_mountpoint(), afs_mntpt_do_automount() through
      afs_mntpt_follow_link(). Both later functions are actually the filesystems
      follow_link inode operation. vfs_kern_mount() is calling the specified
      get_sb function and lets the filesystem do its job by calling the given
      fill_super function.
      
      Therefore I think it is safe to push down the BKL from the VFS to the
      low-level filesystems get_sb/fill_super operation.
      
      [arnd: do not add the BKL to those file systems that already
             don't use it elsewhere]
      Signed-off-by: default avatarJan Blunck <jblunck@infradead.org>
      Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      Cc: Matthew Wilcox <matthew@wil.cx>
      Cc: Christoph Hellwig <hch@infradead.org>
      db719222
  9. 09 Aug, 2010 5 commits
  10. 27 May, 2010 2 commits
  11. 30 Mar, 2010 1 commit
    • Tejun Heo's avatar
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking... · 5a0e3ad6
      Tejun Heo authored
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit 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: default avatarTejun Heo <tj@kernel.org>
      Guess-its-ok-by: default avatarChristoph Lameter <cl@linux-foundation.org>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
      5a0e3ad6
  12. 05 Mar, 2010 1 commit
  13. 09 Feb, 2010 1 commit
  14. 26 Jan, 2010 3 commits
  15. 11 Jun, 2009 5 commits
    • Christoph Hellwig's avatar
      affs: add ->sync_fs · e2896436
      Christoph Hellwig authored
      Add a ->sync_fs method for data integrity syncs.  Factor out common code
      between affs_put_super, affs_write_super and the new affs_sync_fs into
      a helper.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      e2896436
    • Al Viro's avatar
      sanitize ->fsync() for affs · c4758795
      Al Viro authored
      unfortunately, for affs (especially for affs directories) we have
      no real way to keep track of metadata ownership.  So we have to
      do more or less what file_fsync() does, but we do *not* need to
      call write_super() there.
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      c4758795
    • Alessio Igor Bogani's avatar
      Push BKL down into ->remount_fs() · 337eb00a
      Alessio Igor Bogani authored
      [xfs, btrfs, capifs, shmem don't need BKL, exempt]
      Signed-off-by: default avatarAlessio Igor Bogani <abogani@texware.it>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      337eb00a
    • Christoph Hellwig's avatar
      ->write_super lock_super pushdown · ebc1ac16
      Christoph Hellwig authored
      Push down lock_super into ->write_super instances and remove it from the
      caller.
      
      Following filesystem don't need ->s_lock in ->write_super and are skipped:
      
       * bfs, nilfs2 - no other uses of s_lock and have internal locks in
      	->write_super
       * ext2 - uses BKL in ext2_write_super and has internal calls without s_lock
       * reiserfs - no other uses of s_lock as has reiserfs_write_lock (BKL) in
       	->write_super
       * xfs - no other uses of s_lock and uses internal lock (buffer lock on
      	superblock buffer) to serialize ->write_super.  Also xfs_fs_write_super
      	is superflous and will go away in the next merge window
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      ebc1ac16
    • Christoph Hellwig's avatar
      push BKL down into ->put_super · 6cfd0148
      Christoph Hellwig authored
      Move BKL into ->put_super from the only caller.  A couple of
      filesystems had trivial enough ->put_super (only kfree and NULLing of
      s_fs_info + stuff in there) to not get any locking: coda, cramfs, efs,
      hugetlbfs, omfs, qnx4, shmem, all others got the full treatment.  Most
      of them probably don't need it, but I'd rather sort that out individually.
      Preferably after all the other BKL pushdowns in that area.
      
      [AV: original used to move lock_super() down as well; these changes are
      removed since we don't do lock_super() at all in generic_shutdown_super()
      now]
      [AV: fuse, btrfs and xfs are known to need no damn BKL, exempt]
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      6cfd0148
  16. 09 May, 2009 1 commit
    • Al Viro's avatar
      Fix races around the access to ->s_options · 2a32cebd
      Al Viro authored
      Put generic_show_options read access to s_options under rcu_read_lock,
      split save_mount_options() into "we are setting it the first time"
      (uses in foo_fill_super()) and "we are relacing and freeing the old one",
      synchronize_rcu() before kfree() in the latter.
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      2a32cebd
  17. 02 Apr, 2009 1 commit
  18. 27 Mar, 2009 2 commits
  19. 22 Jan, 2009 1 commit
  20. 05 Jan, 2009 1 commit