1. 12 Jun, 2016 2 commits
  2. 01 Jun, 2016 6 commits
  3. 09 May, 2016 1 commit
  4. 04 Apr, 2016 1 commit
    • Kirill A. Shutemov's avatar
      mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros · 09cbfeaf
      Kirill A. Shutemov authored
      PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
      ago with promise that one day it will be possible to implement page
      cache with bigger chunks than PAGE_SIZE.
      
      This promise never materialized.  And unlikely will.
      
      We have many places where PAGE_CACHE_SIZE assumed to be equal to
      PAGE_SIZE.  And it's constant source of confusion on whether
      PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
      especially on the border between fs and mm.
      
      Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
      breakage to be doable.
      
      Let's stop pretending that pages in page cache are special.  They are
      not.
      
      The changes are pretty straight-forward:
      
       - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
      
       - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
      
       - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};
      
       - page_cache_get() -> get_page();
      
       - page_cache_release() -> put_page();
      
      This patch contains automated changes generated with coccinelle using
      script below.  For some reason, coccinelle doesn't patch header files.
      I've called spatch for them manually.
      
      The only adjustment after coccinelle is revert of changes to
      PAGE_CAHCE_ALIGN definition: we are going to drop it later.
      
      There are few places in the code where coccinelle didn't reach.  I'll
      fix them manually in a separate patch.  Comments and documentation also
      will be addressed with the separate patch.
      
      virtual patch
      
      @@
      expression E;
      @@
      - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
      + E
      
      @@
      expression E;
      @@
      - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
      + E
      
      @@
      @@
      - PAGE_CACHE_SHIFT
      + PAGE_SHIFT
      
      @@
      @@
      - PAGE_CACHE_SIZE
      + PAGE_SIZE
      
      @@
      @@
      - PAGE_CACHE_MASK
      + PAGE_MASK
      
      @@
      expression E;
      @@
      - PAGE_CACHE_ALIGN(E)
      + PAGE_ALIGN(E)
      
      @@
      expression E;
      @@
      - page_cache_get(E)
      + get_page(E)
      
      @@
      expression E;
      @@
      - page_cache_release(E)
      + put_page(E)
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Acked-by: default avatarMichal Hocko <mhocko@suse.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      09cbfeaf
  5. 09 Dec, 2015 1 commit
    • Al Viro's avatar
      don't put symlink bodies in pagecache into highmem · 21fc61c7
      Al Viro authored
      kmap() in page_follow_link_light() needed to go - allowing to hold
      an arbitrary number of kmaps for long is a great way to deadlocking
      the system.
      
      new helper (inode_nohighmem(inode)) needs to be used for pagecache
      symlinks inodes; done for all in-tree cases.  page_follow_link_light()
      instrumented to yell about anything missed.
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      21fc61c7
  6. 07 Aug, 2015 1 commit
  7. 23 Jun, 2015 1 commit
  8. 11 May, 2015 1 commit
  9. 15 Apr, 2015 1 commit
  10. 03 Apr, 2014 2 commits
  11. 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
  12. 29 Jun, 2013 1 commit
  13. 13 Mar, 2013 1 commit
    • Eric W. Biederman's avatar
      fs: Readd the fs module aliases. · fa7614dd
      Eric W. Biederman authored
      I had assumed that the only use of module aliases for filesystems
      prior to "fs: Limit sys_mount to only request filesystem modules."
      was in request_module.  It turns out I was wrong.  At least mkinitcpio
      in Arch linux uses these aliases.
      
      So readd the preexising aliases, to keep from breaking userspace.
      
      Userspace eventually will have to follow and use the same aliases the
      kernel does.  So at some point we may be delete these aliases without
      problems.  However that day is not today.
      Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
      fa7614dd
  14. 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
  15. 23 Feb, 2013 1 commit
  16. 03 Oct, 2012 1 commit
  17. 21 Sep, 2012 1 commit
  18. 14 Jul, 2012 1 commit
    • Al Viro's avatar
      stop passing nameidata to ->lookup() · 00cd8dd3
      Al Viro authored
      Just the flags; only NFS cares even about that, but there are
      legitimate uses for such argument.  And getting rid of that
      completely would require splitting ->lookup() into a couple
      of methods (at least), so let's leave that alone for now...
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      00cd8dd3
  19. 06 May, 2012 1 commit
  20. 21 Mar, 2012 1 commit
  21. 04 Jan, 2012 2 commits
  22. 02 Nov, 2011 1 commit
  23. 10 May, 2011 1 commit
  24. 31 Mar, 2011 1 commit
  25. 10 Mar, 2011 1 commit
  26. 07 Jan, 2011 1 commit
    • 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
  27. 29 Oct, 2010 1 commit
  28. 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
  29. 21 Oct, 2010 1 commit
    • Arnd Bergmann's avatar
      BKL: remove BKL from freevxfs · 6d7bccc2
      Arnd Bergmann authored
      All uses of the BKL in freevxfs were the result of a pushdown into
      code that doesn't really need it. As Christoph points out, this
      is a read-only file system, which eliminates most of the races in
      readdir/lookup.
      Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      Cc: Christoph Hellwig <hch@infradead.org>
      6d7bccc2
  30. 04 Oct, 2010 1 commit
    • 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
  31. 09 Aug, 2010 1 commit
  32. 16 Jun, 2010 1 commit