1. 17 Feb, 2015 3 commits
  2. 13 Oct, 2014 2 commits
  3. 06 Jun, 2014 2 commits
  4. 06 May, 2014 1 commit
  5. 07 Apr, 2014 2 commits
  6. 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
  7. 25 Jan, 2014 1 commit
  8. 03 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
  9. 02 Oct, 2012 1 commit
  10. 21 Sep, 2012 1 commit
  11. 20 Aug, 2012 1 commit
    • Tejun Heo's avatar
      workqueue: deprecate flush[_delayed]_work_sync() · 43829731
      Tejun Heo authored
      
      
      flush[_delayed]_work_sync() are now spurious.  Mark them deprecated
      and convert all users to flush[_delayed]_work().
      
      If you're cc'd and wondering what's going on: Now all workqueues are
      non-reentrant and the regular flushes guarantee that the work item is
      not pending or running on any CPU on return, so there's no reason to
      use the sync flushes at all and they're going away.
      
      This patch doesn't make any functional difference.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Russell King <linux@arm.linux.org.uk>
      Cc: Paul Mundt <lethal@linux-sh.org>
      Cc: Ian Campbell <ian.campbell@citrix.com>
      Cc: Jens Axboe <axboe@kernel.dk>
      Cc: Mattia Dongili <malattia@linux.it>
      Cc: Kent Yoder <key@linux.vnet.ibm.com>
      Cc: David Airlie <airlied@linux.ie>
      Cc: Jiri Kosina <jkosina@suse.cz>
      Cc: Karsten Keil <isdn@linux-pingi.de>
      Cc: Bryan Wu <bryan.wu@canonical.com>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Alasdair Kergon <agk@redhat.com>
      Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
      Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
      Cc: David Woodhouse <dwmw2@infradead.org>
      Cc: "David S. Miller" <davem@davemloft.net>
      Cc: linux-wireless@vger.kernel.org
      Cc: Anton Vorontsov <cbou@mail.ru>
      Cc: Sangbeom Kim <sbkim73@samsung.com>
      Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Cc: Eric Van Hensbergen <ericvh@gmail.com>
      Cc: Takashi Iwai <tiwai@suse.de>
      Cc: Steven Whitehouse <swhiteho@redhat.com>
      Cc: Petr Vandrovec <petr@vandrovec.name>
      Cc: Mark Fasheh <mfasheh@suse.com>
      Cc: Christoph Hellwig <hch@infradead.org>
      Cc: Avi Kivity <avi@redhat.com> 
      43829731
  12. 14 Jul, 2012 7 commits
    • Artem Bityutskiy's avatar
      affs: get rid of affs_sync_super · 3dd84782
      Artem Bityutskiy authored
      
      
      This patch makes affs stop using the VFS '->write_super()' method along with
      the 's_dirt' superblock flag, because they are on their way out.
      
      The whole "superblock write-out" VFS infrastructure is served by the
      'sync_supers()' kernel thread, which wakes up every 5 (by default) seconds and
      writes out all dirty superblocks using the '->write_super()' call-back.  But the
      problem with this thread is that it wastes power by waking up the system every
      5 seconds, even if there are no diry superblocks, or there are no client
      file-systems which would need this (e.g., btrfs does not use
      '->write_super()'). So we want to kill it completely and thus, we need to make
      file-systems to stop using the '->write_super()' VFS service, and then remove
      it together with the kernel thread.
      Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      3dd84782
    • Artem Bityutskiy's avatar
      affs: introduce VFS superblock object back-reference · a215fef7
      Artem Bityutskiy authored
      
      
      Add an 'sb' VFS superblock back-reference to the 'struct affs_sb_info' data
      structure - we will need to find the VFS superblock from a 'struct
      affs_sb_info' object in the next patch, so this change is jut a preparation.
      Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      a215fef7
    • Artem Bityutskiy's avatar
      affs: stop using lock_super · a8371074
      Artem Bityutskiy authored
      
      
      The VFS's 'lock_super()' and 'unlock_super()' calls are deprecated and unwanted
      and just wait for a brave knight who'd kill them. This patch makes AFFS stop
      using them and use the buffer-head's own lock instead.
      Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      a8371074
    • Artem Bityutskiy's avatar
      affs: re-structure superblock locking a bit · e0471c8d
      Artem Bityutskiy authored
      
      
      AFFS wants to serialize the superblock (the root block in AFFS terms) updates
      and uses 'lock_super()/unlock_super()' for these purposes. This patch pushes the
      locking down to the 'affs_commit_super()' from the callers.
      Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      e0471c8d
    • Artem Bityutskiy's avatar
      affs: remove useless superblock writeout on remount · 0164b1a3
      Artem Bityutskiy authored
      
      
      We do not need to write out the superblock from '->remount_fs()' because
      VFS has already called '->sync_fs()' by this time and the superblock has
      already been written out. Thus, remove the 'affs_write_super()'
      infocation from 'affs_remount()'.
      Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      0164b1a3
    • Artem Bityutskiy's avatar
      affs: remove useless superblock writeout on unmount · c9753b1d
      Artem Bityutskiy authored
      
      
      We do not need to write out the superblock from '->put_super()' because VFS has
      already called '->sync_fs()' by this time and the superblock has already been
      written out. Thus, remove the 'affs_commit_super()' infocation from
      'affs_put_super()'.
      Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      c9753b1d
    • Artem Bityutskiy's avatar
      affs: stop setting bm_flags · bc86256d
      Artem Bityutskiy authored
      
      
      AFFS stores values '1' and '2' in 'bm_flags', and I fail to see any logic when
      it prefers one or another. AFFS writes '1' only from '->put_super()', while
      '->sync_fs()' and '->write_super()' store value '2'.  So on the first glance,
      it looks like we want to have '1' if we unmount.  However, this does not really
      happen in these cases:
        1. superblock is written via 'write_super()' then we unmount;
        2. we re-mount R/O, then unmount.
      which are quite typical.
      
      I could not find good documentation describing this field, except of one random
      piece of documentation in the internet which says that -1 means that the root
      block is valid, which is not consistent with what we have in the Linux AFFS
      driver.
      
      Jan Kara commented on this: "I have some vague recollection that on Amiga
      boolean was usually encoded as: 0 == false, ~0 == -1 == true. But it has been
      ages..."
      
      Thus, my conclusion is that value of '1' is as good as value of '2' and we can
      just always use '2'. An Jan Kara suggested to go further: "generally bm_flags
      handling looks strange. If they are 0, we mount fs read only and thus cannot
      change them.  If they are != 0, we write 2 there. So IMHO if you just removed
      bm_flags setting, nothing will really happen."
      
      So this patch removes the bm_flags setting completely. This makes the "clean"
      argument of the 'affs_commit_super()' function unneeded, so it is also removed.
      Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      bc86256d
  13. 20 Mar, 2012 1 commit
  14. 03 Jan, 2012 1 commit
    • Al Viro's avatar
      vfs: fix the stupidity with i_dentry in inode destructors · 6b520e05
      Al Viro authored
      
      
      Seeing that just about every destructor got that INIT_LIST_HEAD() copied into
      it, there is no point whatsoever keeping this INIT_LIST_HEAD in inode_init_once();
      the cost of taking it into inode_init_always() will be negligible for pipes
      and sockets and negative for everything else.  Not to mention the removal of
      boilerplate code from ->destroy_inode() instances...
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      6b520e05
  15. 12 Jan, 2011 1 commit
  16. 06 Jan, 2011 2 commits
    • 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
  17. 29 Oct, 2010 1 commit
  18. 12 Oct, 2010 1 commit
  19. 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
  20. 09 Aug, 2010 3 commits
  21. 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
  22. 26 Jan, 2010 3 commits
  23. 11 Jun, 2009 1 commit