1. 13 Mar, 2014 1 commit
    • Theodore Ts'o's avatar
      fs: push sync_filesystem() down to the file system's remount_fs() · 02b9984d
      Theodore Ts'o authored
      Previously, the no-op "mount -o mount /dev/xxx" operation when the
      file system is already mounted read-write causes an implied,
      unconditional syncfs().  This seems pretty stupid, and it's certainly
      documented or guaraunteed to do this, nor is it particularly useful,
      except in the case where the file system was mounted rw and is getting
      remounted read-only.
      
      However, it's possible that there might be some file systems that are
      actually depending on this behavior.  In most file systems, it's
      probably fine to only call sync_filesystem() when transitioning from
      read-write to read-only, and there are some file systems where this is
      not needed at all (for example, for a pseudo-filesystem or something
      like romfs).
      Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
      Cc: linux-fsdevel@vger.kernel.org
      Cc: Christoph Hellwig <hch@infradead.org>
      Cc: Artem Bityutskiy <dedekind1@gmail.com>
      Cc: Adrian Hunter <adrian.hunter@intel.com>
      Cc: Evgeniy Dushistov <dushistov@mail.ru>
      Cc: Jan Kara <jack@suse.cz>
      Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
      Cc: Anders Larsen <al@alarsen.net>
      Cc: Phillip Lougher <phillip@squashfs.org.uk>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
      Cc: Petr Vandrovec <petr@vandrovec.name>
      Cc: xfs@oss.sgi.com
      Cc: linux-btrfs@vger.kernel.org
      Cc: linux-cifs@vger.kernel.org
      Cc: samba-technical@lists.samba.org
      Cc: codalist@coda.cs.cmu.edu
      Cc: linux-ext4@vger.kernel.org
      Cc: linux-f2fs-devel@lists.sourceforge.net
      Cc: fuse-devel@lists.sourceforge.net
      Cc: cluster-devel@redhat.com
      Cc: linux-mtd@lists.infradead.org
      Cc: jfs-discussion@lists.sourceforge.net
      Cc: linux-nfs@vger.kernel.org
      Cc: linux-nilfs@vger.kernel.org
      Cc: linux-ntfs-dev@lists.sourceforge.net
      Cc: ocfs2-devel@oss.oracle.com
      Cc: reiserfs-devel@vger.kernel.org
      02b9984d
  2. 13 Nov, 2013 1 commit
  3. 31 Jul, 2013 1 commit
    • Oleg Nesterov's avatar
      debugfs: debugfs_remove_recursive() must not rely on list_empty(d_subdirs) · 776164c1
      Oleg Nesterov authored
      debugfs_remove_recursive() is wrong,
      
      1. it wrongly assumes that !list_empty(d_subdirs) means that this
         dir should be removed.
      
         This is not that bad by itself, but:
      
      2. if d_subdirs does not becomes empty after __debugfs_remove()
         it gives up and silently fails, it doesn't even try to remove
         other entries.
      
         However ->d_subdirs can be non-empty because it still has the
         already deleted !debugfs_positive() entries.
      
      3. simple_release_fs() is called even if __debugfs_remove() fails.
      
      Suppose we have
      
      	dir1/
      		dir2/
      			file2
      		file1
      
      and someone opens dir1/dir2/file2.
      
      Now, debugfs_remove_recursive(dir1/dir2) succeeds, and dir1/dir2 goes
      away.
      
      But debugfs_remove_recursive(dir1) silently fails and doesn't remove
      this directory. Because it tries to delete (the already deleted)
      dir1/dir2/file2 again and then fails due to "Avoid infinite loop"
      logic.
      
      Test-case:
      
      	#!/bin/sh
      
      	cd /sys/kernel/debug/tracing
      	echo 'p:probe/sigprocmask sigprocmask' >> kprobe_events
      	sleep 1000 < events/probe/sigprocmask/id &
      	echo -n >| kprobe_events
      
      	[ -d events/probe ] && echo "ERR!! failed to rm probe"
      
      And after that it is not possible to create another probe entry.
      
      With this patch debugfs_remove_recursive() skips !debugfs_positive()
      files although this is not strictly needed. The most important change
      is that it does not try to make ->d_subdirs empty, it simply scans
      the whole list(s) recursively and removes as much as possible.
      
      Link: http://lkml.kernel.org/r/20130726151256.GC19472@redhat.comAcked-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      776164c1
  4. 04 Mar, 2013 1 commit
    • Eric W. Biederman's avatar
      fs: Limit sys_mount to only request filesystem modules. · 7f78e035
      Eric W. Biederman authored
      Modify the request_module to prefix the file system type with "fs-"
      and add aliases to all of the filesystems that can be built as modules
      to match.
      
      A common practice is to build all of the kernel code and leave code
      that is not commonly needed as modules, with the result that many
      users are exposed to any bug anywhere in the kernel.
      
      Looking for filesystems with a fs- prefix limits the pool of possible
      modules that can be loaded by mount to just filesystems trivially
      making things safer with no real cost.
      
      Using aliases means user space can control the policy of which
      filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf
      with blacklist and alias directives.  Allowing simple, safe,
      well understood work-arounds to known problematic software.
      
      This also addresses a rare but unfortunate problem where the filesystem
      name is not the same as it's module name and module auto-loading
      would not work.  While writing this patch I saw a handful of such
      cases.  The most significant being autofs that lives in the module
      autofs4.
      
      This is relevant to user namespaces because we can reach the request
      module in get_fs_type() without having any special permissions, and
      people get uncomfortable when a user specified string (in this case
      the filesystem type) goes all of the way to request_module.
      
      After having looked at this issue I don't think there is any
      particular reason to perform any filtering or permission checks beyond
      making it clear in the module request that we want a filesystem
      module.  The common pattern in the kernel is to call request_module()
      without regards to the users permissions.  In general all a filesystem
      module does once loaded is call register_filesystem() and go to sleep.
      Which means there is not much attack surface exposed by loading a
      filesytem module unless the filesystem is mounted.  In a user
      namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT,
      which most filesystems do not set today.
      Acked-by: default avatarSerge Hallyn <serge.hallyn@canonical.com>
      Acked-by: default avatarKees Cook <keescook@chromium.org>
      Reported-by: default avatarKees Cook <keescook@google.com>
      Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
      7f78e035
  5. 17 Jan, 2013 1 commit
  6. 11 Jan, 2013 1 commit
  7. 16 Nov, 2012 1 commit
  8. 07 Sep, 2012 1 commit
  9. 27 Aug, 2012 1 commit
  10. 16 Aug, 2012 1 commit
  11. 14 Jul, 2012 3 commits
  12. 13 Jun, 2012 1 commit
  13. 26 Jan, 2012 1 commit
    • Ludwig Nussel's avatar
      debugfs: add mode, uid and gid options · d6e48686
      Ludwig Nussel authored
      Cautious admins may want to restrict access to debugfs. Currently a
      manual chown/chmod e.g. in an init script is needed to achieve that.
      Distributions that want to make the mount options configurable need
      to add extra config files. By allowing to set the root inode's uid,
      gid and mode via mount options no such hacks are needed anymore.
      Instead configuration becomes straight forward via fstab.
      Signed-off-by: default avatarLudwig Nussel <ludwig.nussel@suse.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      d6e48686
  14. 04 Jan, 2012 2 commits
  15. 23 Aug, 2011 1 commit
  16. 18 Feb, 2011 1 commit
  17. 03 Feb, 2011 1 commit
  18. 29 Oct, 2010 1 commit
  19. 26 Oct, 2010 1 commit
    • Christoph Hellwig's avatar
      fs: do not assign default i_ino in new_inode · 85fe4025
      Christoph Hellwig authored
      Instead of always assigning an increasing inode number in new_inode
      move the call to assign it into those callers that actually need it.
      For now callers that need it is estimated conservatively, that is
      the call is added to all filesystems that do not assign an i_ino
      by themselves.  For a few more filesystems we can avoid assigning
      any inode number given that they aren't user visible, and for others
      it could be done lazily when an inode number is actually needed,
      but that's left for later patches.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      85fe4025
  20. 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
  21. 08 Feb, 2010 1 commit
  22. 27 Jan, 2010 1 commit
  23. 11 Dec, 2009 1 commit
  24. 04 Dec, 2009 1 commit
  25. 16 Jun, 2009 1 commit
    • Steven Rostedt's avatar
      debugfs: dont stop on first failed recursive delete · 56a83cc9
      Steven Rostedt authored
      debugfs: dont stop on first failed recursive delete
      
      While running a while loop of removing a module that removes a debugfs
      directory with debugfs_remove_recursive, and at the same time doing a
      while loop of cat of a file in that directory, I would hit a point where
      somehow the cat of the file caused the remove to fail.
      
      The result is that other files did not get removed when the module
      was removed. I simple read of one of those file can oops the kernel
      because the operations to the file no longer exist (removed by module).
      
      The funny thing is that the file being cat'ed was removed. It was
      the siblings that were not. I see in the code to debugfs_remove_recursive
      there's a test that checks if the child fails to bail out of the loop
      to prevent an infinite loop.
      
      What this patch does is to still try any siblings in that directory.
      If all the siblings fail, or there are no more siblings, then we exit
      the loop.
      
      This fixes the above symptom, but...
      
      This is no full proof. It makes the debugfs_remove_recursive a bit more
      robust, but it does not explain why the one file failed. There may
      be some kind of delay deletion that makes the debugfs think it did
      not succeed. So this patch is more of a fix for the symptom but not
      the disease.
      
      This patch still makes the debugfs_remove_recursive more robust and
      until I can find out why the bug exists, this patch will keep
      the kernel from oopsing in most cases.  Even after the cause is found
      I think this change can stand on its own and should be kept.
      
      [ Impact: prevent kernel oops on module unload and reading debugfs files ]
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      56a83cc9
  26. 23 Mar, 2009 1 commit
  27. 05 Jan, 2009 1 commit
  28. 12 Oct, 2008 1 commit
  29. 22 Jul, 2008 1 commit
    • Haavard Skinnemoen's avatar
      debugfs: Implement debugfs_remove_recursive() · 9505e637
      Haavard Skinnemoen authored
      debugfs_remove_recursive() will remove a dentry and all its children.
      Drivers can use this to zap their whole debugfs tree so that they don't
      need to keep track of every single debugfs dentry they created.
      
      It may fail to remove the whole tree in certain cases:
      
      sh-3.2# rmmod atmel-mci < /sys/kernel/debug/mmc0/ios/clock
      mmc0: card b368 removed
      atmel_mci atmel_mci.0: Lost dma0chan1, falling back to PIO
      sh-3.2# ls /sys/kernel/debug/mmc0/
      ios
      
      But I'm not sure if that case can be handled in any sane manner.
      Signed-off-by: default avatarHaavard Skinnemoen <haavard.skinnemoen@atmel.com>
      Cc: Pierre Ossman <drzeus-list@drzeus.cx>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      9505e637
  30. 04 Mar, 2008 1 commit
  31. 25 Jan, 2008 5 commits
  32. 21 Oct, 2007 1 commit
  33. 18 Jul, 2007 1 commit
    • Jens Axboe's avatar
      debugfs: remove rmdir() non-empty complaint · a6bb340d
      Jens Axboe authored
      Hi,
      
      This patch kills the pointless debugfs rmdir() printk() when called on a
      non-empty directory. blktrace will sometimes have to call it a few times
      when forcefully ending a trace, which polutes the log with pointless
      warnings.
      
      Rationale:
      
      - It's more code to work-around this "problem" in the debugfs users, and
        you would have to add code to check for empty directories to do so (or
        assume that debugfs is using simple_ helpers, but that would be a
        layering violation).
      
      - Other rmdir() implementations don't complain about something this
        silly.
      Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      a6bb340d