1. 15 Mar, 2011 2 commits
    • Al Viro's avatar
      readlinkat(), fchownat() and fstatat() with empty relative pathnames · 65cfc672
      Al Viro authored
      For readlinkat() we simply allow empty pathname; it will fail unless
      we have dfd equal to O_PATH-opened symlink, so we are outside of
      POSIX scope here.  For fchownat() and fstatat() we allow AT_EMPTY_PATH;
      let the caller explicitly ask for such behaviour.
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      65cfc672
    • Al Viro's avatar
      New kind of open files - "location only". · 1abf0c71
      Al Viro authored
      New flag for open(2) - O_PATH.  Semantics:
      	* pathname is resolved, but the file itself is _NOT_ opened
      as far as filesystem is concerned.
      	* almost all operations on the resulting descriptors shall
      fail with -EBADF.  Exceptions are:
      	1) operations on descriptors themselves (i.e.
      		close(), dup(), dup2(), dup3(), fcntl(fd, F_DUPFD),
      		fcntl(fd, F_DUPFD_CLOEXEC, ...), fcntl(fd, F_GETFD),
      		fcntl(fd, F_SETFD, ...))
      	2) fcntl(fd, F_GETFL), for a common non-destructive way to
      		check if descriptor is open
      	3) "dfd" arguments of ...at(2) syscalls, i.e. the starting
      		points of pathname resolution
      	* closing such descriptor does *NOT* affect dnotify or
      posix locks.
      	* permissions are checked as usual along the way to file;
      no permission checks are applied to the file itself.  Of course,
      giving such thing to syscall will result in permission checks (at
      the moment it means checking that starting point of ....at() is
      a directory and caller has exec permissions on it).
      
      fget() and fget_light() return NULL on such descriptors; use of
      fget_raw() and fget_raw_light() is needed to get them.  That protects
      existing code from dealing with those things.
      
      There are two things still missing (they come in the next commits):
      one is handling of symlinks (right now we refuse to open them that
      way; see the next commit for semantics related to those) and another
      is descriptor passing via SCM_RIGHTS datagrams.
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      1abf0c71
  2. 14 Mar, 2011 2 commits
    • Al Viro's avatar
      open-style analog of vfs_path_lookup() · 73d049a4
      Al Viro authored
      new function: file_open_root(dentry, mnt, name, flags) opens the file
      vfs_path_lookup would arrive to.
      
      Note that name can be empty; in that case the usual requirement that
      dentry should be a directory is lifted.
      
      open-coded equivalents switched to it, may_open() got down exactly
      one caller and became static.
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      73d049a4
    • Al Viro's avatar
      switch do_filp_open() to struct open_flags · 47c805dc
      Al Viro authored
      take calculation of open_flags by open(2) arguments into new helper
      in fs/open.c, move filp_open() over there, have it and do_sys_open()
      use that helper, switch exec.c callers of do_filp_open() to explicit
      (and constant) struct open_flags.
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      47c805dc
  3. 10 Mar, 2011 1 commit
  4. 11 Feb, 2011 1 commit
    • Linus Torvalds's avatar
      Fix possible filp_cachep memory corruption · 2dab5974
      Linus Torvalds authored
      In commit 31e6b01f ("fs: rcu-walk for path lookup") we started doing
      path lookup using RCU, which then falls back to a careful non-RCU lookup
      in case of problems (LOOKUP_REVAL).  So do_filp_open() has this "re-do
      the lookup carefully" looping case.
      
      However, that means that we must not release the open-intent file data
      if we are going to loop around and use it once more!
      
      Fix this by moving the release of the open-intent data to the function
      that allocates it (do_filp_open() itself) rather than the helper
      functions that can get called multiple times (finish_open() and
      do_last()).  This makes the logic for the lifetime of that field much
      more obvious, and avoids the possible double free.
      Reported-by: default avatarJ. R. Okajima <hooanon05@yahoo.co.jp>
      Acked-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      Cc: Nick Piggin <npiggin@kernel.dk>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2dab5974
  5. 10 Feb, 2011 1 commit
  6. 17 Jan, 2011 1 commit
    • Christoph Hellwig's avatar
      fallocate should be a file operation · 2fe17c10
      Christoph Hellwig authored
      Currently all filesystems except XFS implement fallocate asynchronously,
      while XFS forced a commit.  Both of these are suboptimal - in case of O_SYNC
      I/O we really want our allocation on disk, especially for the !KEEP_SIZE
      case where we actually grow the file with user-visible zeroes.  On the
      other hand always commiting the transaction is a bad idea for fast-path
      uses of fallocate like for example in recent Samba versions.   Given
      that block allocation is a data plane operation anyway change it from
      an inode operation to a file operation so that we have the file structure
      available that lets us check for O_SYNC.
      
      This also includes moving the code around for a few of the filesystems,
      and remove the already unnedded S_ISDIR checks given that we only wire
      up fallocate for regular files.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      2fe17c10
  7. 13 Jan, 2011 1 commit
    • Josef Bacik's avatar
      fs: add hole punching to fallocate · 79124f18
      Josef Bacik authored
      Hole punching has already been implemented by XFS and OCFS2, and has the
      potential to be implemented on both BTRFS and EXT4 so we need a generic way to
      get to this feature.  The simplest way in my mind is to add FALLOC_FL_PUNCH_HOLE
      to fallocate() since it already looks like the normal fallocate() operation.
      I've tested this patch with XFS and BTRFS to make sure XFS did what it's
      supposed to do and that BTRFS failed like it was supposed to.  Thank you,
      Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      79124f18
  8. 29 Oct, 2010 1 commit
    • Al Viro's avatar
      fix open/umount race · d893f1bc
      Al Viro authored
      nameidata_to_filp() drops nd->path or transfers it to opened
      file.  In the former case it's a Bad Idea(tm) to do mnt_drop_write()
      on nd->path.mnt, since we might race with umount and vfsmount in
      question might be gone already.
      
      Fix: don't drop it, then...  IOW, have nameidata_to_filp() grab nd->path
      in case it transfers it to file and do path_drop() in callers.  After
      they are through with accessing nd->path...
      Reported-by: default avatarMiklos Szeredi <miklos@szeredi.hu>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      d893f1bc
  9. 18 Aug, 2010 1 commit
  10. 11 Aug, 2010 1 commit
  11. 02 Aug, 2010 2 commits
  12. 28 Jul, 2010 2 commits
  13. 21 May, 2010 1 commit
  14. 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
  15. 04 Mar, 2010 1 commit
    • Christoph Hellwig's avatar
      dquot: move dquot initialization responsibility into the filesystem · 907f4554
      Christoph Hellwig authored
      Currently various places in the VFS call vfs_dq_init directly.  This means
      we tie the quota code into the VFS.  Get rid of that and make the
      filesystem responsible for the initialization.   For most metadata operations
      this is a straight forward move into the methods, but for truncate and
      open it's a bit more complicated.
      
      For truncate we currently only call vfs_dq_init for the sys_truncate case
      because open already takes care of it for ftruncate and open(O_TRUNC) - the
      new code causes an additional vfs_dq_init for those which is harmless.
      
      For open the initialization is moved from do_filp_open into the open method,
      which means it happens slightly earlier now, and only for regular files.
      The latter is fine because we don't need to initialize it for operations
      on special files, and we already do it as part of the namespace operations
      for directories.
      
      Add a dquot_file_open helper that filesystems that support generic quotas
      can use to fill in ->open.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarJan Kara <jack@suse.cz>
      907f4554
  16. 03 Mar, 2010 1 commit
  17. 22 Dec, 2009 2 commits
  18. 16 Dec, 2009 2 commits
  19. 23 Nov, 2009 1 commit
  20. 11 Oct, 2009 2 commits
  21. 23 Sep, 2009 1 commit
    • Heiko Carstens's avatar
      fs: change sys_truncate length parameter type · 4fd8da8d
      Heiko Carstens authored
      For this system call user space passes a signed long length parameter,
      while the kernel side takes an unsigned long parameter and converts it
      later to signed long again.
      
      This has led to bugs in compat wrappers see e.g.  dd90bbd5 "powerpc: Add
      compat_sys_truncate".  The s390 compat wrapper for this functions is
      broken as well since it also performs zero extension instead of sign
      extension for the length parameter.
      
      In addition if hpa comes up with an automated way of generating
      compat wrappers it would generate a wrong one here.
      
      So change the length parameter from unsigned long to long.
      
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: Christoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4fd8da8d
  22. 02 Sep, 2009 1 commit
    • David Howells's avatar
      CRED: Add some configurable debugging [try #6] · e0e81739
      David Howells authored
      Add a config option (CONFIG_DEBUG_CREDENTIALS) to turn on some debug checking
      for credential management.  The additional code keeps track of the number of
      pointers from task_structs to any given cred struct, and checks to see that
      this number never exceeds the usage count of the cred struct (which includes
      all references, not just those from task_structs).
      
      Furthermore, if SELinux is enabled, the code also checks that the security
      pointer in the cred struct is never seen to be invalid.
      
      This attempts to catch the bug whereby inode_has_perm() faults in an nfsd
      kernel thread on seeing cred->security be a NULL pointer (it appears that the
      credential struct has been previously released):
      
      	http://www.kerneloops.org/oops.php?number=252883Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      Signed-off-by: default avatarJames Morris <jmorris@namei.org>
      e0e81739
  23. 21 Aug, 2009 1 commit
    • Amerigo Wang's avatar
      vfs: allow file truncations when both suid and write permissions set · 939a9421
      Amerigo Wang authored
      When suid is set and the non-owner user has write permission, any writing
      into this file should be allowed and suid should be removed after that.
      
      However, current kernel only allows writing without truncations, when we
      do truncations on that file, we get EPERM.  This is a bug.
      
      Steps to reproduce this bug:
      
      % ls -l rootdir/file1
      -rwsrwsrwx 1 root root 3 Jun 25 15:42 rootdir/file1
      % echo h > rootdir/file1
      zsh: operation not permitted: rootdir/file1
      % ls -l rootdir/file1
      -rwsrwsrwx 1 root root 3 Jun 25 15:42 rootdir/file1
      % echo h >> rootdir/file1
      % ls -l rootdir/file1
      -rwxrwxrwx 1 root root 5 Jun 25 16:34 rootdir/file1
      Signed-off-by: default avatarWANG Cong <amwang@redhat.com>
      Cc: Eric Sandeen <esandeen@redhat.com>
      Acked-by: default avatarEric Paris <eparis@redhat.com>
      Cc: Eugene Teo <eteo@redhat.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
      Cc: Christoph Hellwig <hch@lst.de>
      Cc: Stephen Smalley <sds@tycho.nsa.gov>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarJames Morris <jmorris@namei.org>
      939a9421
  24. 24 Jun, 2009 1 commit
  25. 12 Jun, 2009 1 commit
    • npiggin@suse.de's avatar
      fs: introduce mnt_clone_write · 96029c4e
      npiggin@suse.de authored
      This patch speeds up lmbench lat_mmap test by about another 2% after the
      first patch.
      
      Before:
       avg = 462.286
       std = 5.46106
      
      After:
       avg = 453.12
       std = 9.58257
      
      (50 runs of each, stddev gives a reasonable confidence)
      
      It does this by introducing mnt_clone_write, which avoids some heavyweight
      operations of mnt_want_write if called on a vfsmount which we know already
      has a write count; and mnt_want_write_file, which can call mnt_clone_write
      if the file is open for write.
      
      After these two patches, mnt_want_write and mnt_drop_write go from 7% on
      the profile down to 1.3% (including mnt_clone_write).
      
      [AV: mnt_want_write_file() should take file alone and derive mnt from it;
      not only all callers have that form, but that's the only mnt about which
      we know that it's already held for write if file is opened for write]
      
      Cc: Dave Hansen <haveblue@us.ibm.com>
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      96029c4e
  26. 09 May, 2009 1 commit
  27. 01 Apr, 2009 1 commit
  28. 26 Mar, 2009 1 commit
  29. 14 Jan, 2009 5 commits