1. 28 Jul, 2010 12 commits
  2. 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
  3. 18 Oct, 2009 1 commit
    • Eric Paris's avatar
      fsnotify: do not set group for a mark before it is on the i_list · 9f0d793b
      Eric Paris authored
      
      
      fsnotify_add_mark is supposed to add a mark to the g_list and i_list and to
      set the group and inode for the mark.  fsnotify_destroy_mark_by_entry uses
      the fact that ->group != NULL to know if this group should be destroyed or
      if it's already been done.
      
      But fsnotify_add_mark sets the group and inode before it actually adds the
      mark to the i_list and g_list.  This can result in a race in inotify, it
      requires 3 threads.
      
      sys_inotify_add_watch("file")	sys_inotify_add_watch("file")	sys_inotify_rm_watch([a])
      inotify_update_watch()
      inotify_new_watch()
      inotify_add_to_idr()
         ^--- returns wd = [a]
      				inotfiy_update_watch()
      				inotify_new_watch()
      				inotify_add_to_idr()
      				fsnotify_add_mark()
      				   ^--- returns wd = [b]
      				returns to userspace;
      								inotify_idr_find([a])
      								   ^--- gives us the pointer from task 1
      fsnotify_add_mark()
         ^--- this is going to set the mark->group and mark->inode fields, but will
      return -EEXIST because of the race with [b].
      								fsnotify_destroy_mark()
      								   ^--- since ->group != NULL we call back
      									into inotify_freeing_mark() which calls
      								inotify_remove_from_idr([a])
      
      since fsnotify_add_mark() failed we call:
      inotify_remove_from_idr([a])     <------WHOOPS it's not in the idr, this could
      					have been any entry added later!
      
      The fix is to make sure we don't set mark->group until we are sure the mark is
      on the inode and fsnotify_add_mark will return success.
      Signed-off-by: default avatarEric Paris <eparis@redhat.com>
      9f0d793b
  4. 11 Jun, 2009 5 commits
    • Eric Paris's avatar
      fsnotify: allow groups to set freeing_mark to null · a092ee20
      Eric Paris authored
      
      
      Most fsnotify listeners (all but inotify) do not care about marks being
      freed.  Allow groups to set freeing_mark to null and do not call any
      function if it is set that way.
      Signed-off-by: default avatarEric Paris <eparis@redhat.com>
      a092ee20
    • Eric Paris's avatar
      fsnotify: handle filesystem unmounts with fsnotify marks · 164bc619
      Eric Paris authored
      
      
      When an fs is unmounted with an fsnotify mark entry attached to one of its
      inodes we need to destroy that mark entry and we also (like inotify) send
      an unmount event.
      Signed-off-by: default avatarEric Paris <eparis@redhat.com>
      Acked-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      Cc: Christoph Hellwig <hch@lst.de>
      164bc619
    • Eric Paris's avatar
      fsnotify: fsnotify marks on inodes pin them in core · 1ef5f13c
      Eric Paris authored
      
      
      This patch pins any inodes with an fsnotify mark in core.  The idea is that
      as soon as the mark is removed from the inode->fsnotify_mark_entries list
      the inode will be iput.  In reality is doesn't quite work exactly this way.
      The igrab will happen when the mark is added to an inode, but the iput will
      happen when the inode pointer is NULL'd inside the mark.
      
      It's possible that 2 racing things will try to remove the mark from
      different directions.  One may try to remove the mark because of an
      explicit request and one might try to remove it because the inode was
      deleted.  It's possible that the removal because of inode deletion will
      remove the mark from the inode's list, but the removal by explicit request
      will actually set entry->inode == NULL; and call the iput.  This is safe.
      Signed-off-by: default avatarEric Paris <eparis@redhat.com>
      Acked-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      Cc: Christoph Hellwig <hch@lst.de>
      1ef5f13c
    • Eric Paris's avatar
      fsnotify: parent event notification · c28f7e56
      Eric Paris authored
      
      
      inotify and dnotify both use a similar parent notification mechanism.  We
      add a generic parent notification mechanism to fsnotify for both of these
      to use.  This new machanism also adds the dentry flag optimization which
      exists for inotify to dnotify.
      Signed-off-by: default avatarEric Paris <eparis@redhat.com>
      Acked-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      Cc: Christoph Hellwig <hch@lst.de>
      c28f7e56
    • Eric Paris's avatar
      fsnotify: add marks to inodes so groups can interpret how to handle those inodes · 3be25f49
      Eric Paris authored
      
      
      This patch creates a way for fsnotify groups to attach marks to inodes.
      These marks have little meaning to the generic fsnotify infrastructure
      and thus their meaning should be interpreted by the group that attached
      them to the inode's list.
      
      dnotify and inotify  will make use of these markings to indicate which
      inodes are of interest to their respective groups.  But this implementation
      has the useful property that in the future other listeners could actually
      use the marks for the exact opposite reason, aka to indicate which inodes
      it had NO interest in.
      Signed-off-by: default avatarEric Paris <eparis@redhat.com>
      Acked-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      Cc: Christoph Hellwig <hch@lst.de>
      3be25f49