1. 24 Aug, 2018 1 commit
  2. 19 Jul, 2018 1 commit
  3. 18 Jul, 2018 1 commit
  4. 12 Jul, 2018 17 commits
  5. 15 Jun, 2018 1 commit
    • David Howells's avatar
      afs: Display manually added cells in dynamic root mount · 0da0b7fd
      David Howells authored
      Alter the dynroot mount so that cells created by manipulation of
      /proc/fs/afs/cells and /proc/fs/afs/rootcell and by specification of a root
      cell as a module parameter will cause directories for those cells to be
      created in the dynamic root superblock for the network namespace[*].
      
      To this end:
      
       (1) Only one dynamic root superblock is now created per network namespace
           and this is shared between all attempts to mount it.  This makes it
           easier to find the superblock to modify.
      
       (2) When a dynamic root superblock is created, the list of cells is walked
           and directories created for each cell already defined.
      
       (3) When a new cell is added, if a dynamic root superblock exists, a
           directory is created for it.
      
       (4) When a cell is destroyed, the directory is removed.
      
       (5) These directories are created by calling lookup_one_len() on the root
           dir which automatically creates them if they don't exist.
      
      [*] Inasmuch as network namespaces are currently supported here.
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      0da0b7fd
  6. 12 Jun, 2018 1 commit
    • Kees Cook's avatar
      treewide: kmalloc() -> kmalloc_array() · 6da2ec56
      Kees Cook authored
      The kmalloc() function has a 2-factor argument form, kmalloc_array(). This
      patch replaces cases of:
      
              kmalloc(a * b, gfp)
      
      with:
              kmalloc_array(a * b, gfp)
      
      as well as handling cases of:
      
              kmalloc(a * b * c, gfp)
      
      with:
      
              kmalloc(array3_size(a, b, c), gfp)
      
      as it's slightly less ugly than:
      
              kmalloc_array(array_size(a, b), c, gfp)
      
      This does, however, attempt to ignore constant size factors like:
      
              kmalloc(4 * 1024, gfp)
      
      though any constants defined via macros get caught up in the conversion.
      
      Any factors with a sizeof() of "unsigned char", "char", and "u8" were
      dropped, since they're redundant.
      
      The tools/ directory was manually excluded, since it has its own
      implementation of kmalloc().
      
      The Coccinelle script used for this was:
      
      // Fix redundant parens around sizeof().
      @@
      type TYPE;
      expression THING, E;
      @@
      
      (
        kmalloc(
      -	(sizeof(TYPE)) * E
      +	sizeof(TYPE) * E
        , ...)
      |
        kmalloc(
      -	(sizeof(THING)) * E
      +	sizeof(THING) * E
        , ...)
      )
      
      // Drop single-byte sizes and redundant parens.
      @@
      expression COUNT;
      typedef u8;
      typedef __u8;
      @@
      
      (
        kmalloc(
      -	sizeof(u8) * (COUNT)
      +	COUNT
        , ...)
      |
        kmalloc(
      -	sizeof(__u8) * (COUNT)
      +	COUNT
        , ...)
      |
        kmalloc(
      -	sizeof(char) * (COUNT)
      +	COUNT
        , ...)
      |
        kmalloc(
      -	sizeof(unsigned char) * (COUNT)
      +	COUNT
        , ...)
      |
        kmalloc(
      -	sizeof(u8) * COUNT
      +	COUNT
        , ...)
      |
        kmalloc(
      -	sizeof(__u8) * COUNT
      +	COUNT
        , ...)
      |
        kmalloc(
      -	sizeof(char) * COUNT
      +	COUNT
        , ...)
      |
        kmalloc(
      -	sizeof(unsigned char) * COUNT
      +	COUNT
        , ...)
      )
      
      // 2-factor product with sizeof(type/expression) and identifier or constant.
      @@
      type TYPE;
      expression THING;
      identifier COUNT_ID;
      constant COUNT_CONST;
      @@
      
      (
      - kmalloc
      + kmalloc_array
        (
      -	sizeof(TYPE) * (COUNT_ID)
      +	COUNT_ID, sizeof(TYPE)
        , ...)
      |
      - kmalloc
      + kmalloc_array
        (
      -	sizeof(TYPE) * COUNT_ID
      +	COUNT_ID, sizeof(TYPE)
        , ...)
      |
      - kmalloc
      + kmalloc_array
        (
      -	sizeof(TYPE) * (COUNT_CONST)
      +	COUNT_CONST, sizeof(TYPE)
        , ...)
      |
      - kmalloc
      + kmalloc_array
        (
      -	sizeof(TYPE) * COUNT_CONST
      +	COUNT_CONST, sizeof(TYPE)
        , ...)
      |
      - kmalloc
      + kmalloc_array
        (
      -	sizeof(THING) * (COUNT_ID)
      +	COUNT_ID, sizeof(THING)
        , ...)
      |
      - kmalloc
      + kmalloc_array
        (
      -	sizeof(THING) * COUNT_ID
      +	COUNT_ID, sizeof(THING)
        , ...)
      |
      - kmalloc
      + kmalloc_array
        (
      -	sizeof(THING) * (COUNT_CONST)
      +	COUNT_CONST, sizeof(THING)
        , ...)
      |
      - kmalloc
      + kmalloc_array
        (
      -	sizeof(THING) * COUNT_CONST
      +	COUNT_CONST, sizeof(THING)
        , ...)
      )
      
      // 2-factor product, only identifiers.
      @@
      identifier SIZE, COUNT;
      @@
      
      - kmalloc
      + kmalloc_array
        (
      -	SIZE * COUNT
      +	COUNT, SIZE
        , ...)
      
      // 3-factor product with 1 sizeof(type) or sizeof(expression), with
      // redundant parens removed.
      @@
      expression THING;
      identifier STRIDE, COUNT;
      type TYPE;
      @@
      
      (
        kmalloc(
      -	sizeof(TYPE) * (COUNT) * (STRIDE)
      +	array3_size(COUNT, STRIDE, sizeof(TYPE))
        , ...)
      |
        kmalloc(
      -	sizeof(TYPE) * (COUNT) * STRIDE
      +	array3_size(COUNT, STRIDE, sizeof(TYPE))
        , ...)
      |
        kmalloc(
      -	sizeof(TYPE) * COUNT * (STRIDE)
      +	array3_size(COUNT, STRIDE, sizeof(TYPE))
        , ...)
      |
        kmalloc(
      -	sizeof(TYPE) * COUNT * STRIDE
      +	array3_size(COUNT, STRIDE, sizeof(TYPE))
        , ...)
      |
        kmalloc(
      -	sizeof(THING) * (COUNT) * (STRIDE)
      +	array3_size(COUNT, STRIDE, sizeof(THING))
        , ...)
      |
        kmalloc(
      -	sizeof(THING) * (COUNT) * STRIDE
      +	array3_size(COUNT, STRIDE, sizeof(THING))
        , ...)
      |
        kmalloc(
      -	sizeof(THING) * COUNT * (STRIDE)
      +	array3_size(COUNT, STRIDE, sizeof(THING))
        , ...)
      |
        kmalloc(
      -	sizeof(THING) * COUNT * STRIDE
      +	array3_size(COUNT, STRIDE, sizeof(THING))
        , ...)
      )
      
      // 3-factor product with 2 sizeof(variable), with redundant parens removed.
      @@
      expression THING1, THING2;
      identifier COUNT;
      type TYPE1, TYPE2;
      @@
      
      (
        kmalloc(
      -	sizeof(TYPE1) * sizeof(TYPE2) * COUNT
      +	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
        , ...)
      |
        kmalloc(
      -	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
      +	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
        , ...)
      |
        kmalloc(
      -	sizeof(THING1) * sizeof(THING2) * COUNT
      +	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
        , ...)
      |
        kmalloc(
      -	sizeof(THING1) * sizeof(THING2) * (COUNT)
      +	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
        , ...)
      |
        kmalloc(
      -	sizeof(TYPE1) * sizeof(THING2) * COUNT
      +	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
        , ...)
      |
        kmalloc(
      -	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
      +	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
        , ...)
      )
      
      // 3-factor product, only identifiers, with redundant parens removed.
      @@
      identifier STRIDE, SIZE, COUNT;
      @@
      
      (
        kmalloc(
      -	(COUNT) * STRIDE * SIZE
      +	array3_size(COUNT, STRIDE, SIZE)
        , ...)
      |
        kmalloc(
      -	COUNT * (STRIDE) * SIZE
      +	array3_size(COUNT, STRIDE, SIZE)
        , ...)
      |
        kmalloc(
      -	COUNT * STRIDE * (SIZE)
      +	array3_size(COUNT, STRIDE, SIZE)
        , ...)
      |
        kmalloc(
      -	(COUNT) * (STRIDE) * SIZE
      +	array3_size(COUNT, STRIDE, SIZE)
        , ...)
      |
        kmalloc(
      -	COUNT * (STRIDE) * (SIZE)
      +	array3_size(COUNT, STRIDE, SIZE)
        , ...)
      |
        kmalloc(
      -	(COUNT) * STRIDE * (SIZE)
      +	array3_size(COUNT, STRIDE, SIZE)
        , ...)
      |
        kmalloc(
      -	(COUNT) * (STRIDE) * (SIZE)
      +	array3_size(COUNT, STRIDE, SIZE)
        , ...)
      |
        kmalloc(
      -	COUNT * STRIDE * SIZE
      +	array3_size(COUNT, STRIDE, SIZE)
        , ...)
      )
      
      // Any remaining multi-factor products, first at least 3-factor products,
      // when they're not all constants...
      @@
      expression E1, E2, E3;
      constant C1, C2, C3;
      @@
      
      (
        kmalloc(C1 * C2 * C3, ...)
      |
        kmalloc(
      -	(E1) * E2 * E3
      +	array3_size(E1, E2, E3)
        , ...)
      |
        kmalloc(
      -	(E1) * (E2) * E3
      +	array3_size(E1, E2, E3)
        , ...)
      |
        kmalloc(
      -	(E1) * (E2) * (E3)
      +	array3_size(E1, E2, E3)
        , ...)
      |
        kmalloc(
      -	E1 * E2 * E3
      +	array3_size(E1, E2, E3)
        , ...)
      )
      
      // And then all remaining 2 factors products when they're not all constants,
      // keeping sizeof() as the second factor argument.
      @@
      expression THING, E1, E2;
      type TYPE;
      constant C1, C2, C3;
      @@
      
      (
        kmalloc(sizeof(THING) * C2, ...)
      |
        kmalloc(sizeof(TYPE) * C2, ...)
      |
        kmalloc(C1 * C2 * C3, ...)
      |
        kmalloc(C1 * C2, ...)
      |
      - kmalloc
      + kmalloc_array
        (
      -	sizeof(TYPE) * (E2)
      +	E2, sizeof(TYPE)
        , ...)
      |
      - kmalloc
      + kmalloc_array
        (
      -	sizeof(TYPE) * E2
      +	E2, sizeof(TYPE)
        , ...)
      |
      - kmalloc
      + kmalloc_array
        (
      -	sizeof(THING) * (E2)
      +	E2, sizeof(THING)
        , ...)
      |
      - kmalloc
      + kmalloc_array
        (
      -	sizeof(THING) * E2
      +	E2, sizeof(THING)
        , ...)
      |
      - kmalloc
      + kmalloc_array
        (
      -	(E1) * E2
      +	E1, E2
        , ...)
      |
      - kmalloc
      + kmalloc_array
        (
      -	(E1) * (E2)
      +	E1, E2
        , ...)
      |
      - kmalloc
      + kmalloc_array
        (
      -	E1 * E2
      +	E1, E2
        , ...)
      )
      Signed-off-by: default avatarKees Cook <keescook@chromium.org>
      6da2ec56
  7. 03 Jun, 2018 1 commit
    • Al Viro's avatar
      Revert "fs: fold open_check_o_direct into do_dentry_open" · af04fadc
      Al Viro authored
      This reverts commit cab64df1.
      
      Having vfs_open() in some cases drop the reference to
      struct file combined with
      
      	error = vfs_open(path, f, cred);
      	if (error) {
      		put_filp(f);
      		return ERR_PTR(error);
      	}
      	return f;
      
      is flat-out wrong.  It used to be
      
      		error = vfs_open(path, f, cred);
      		if (!error) {
      			/* from now on we need fput() to dispose of f */
      			error = open_check_o_direct(f);
      			if (error) {
      				fput(f);
      				f = ERR_PTR(error);
      			}
      		} else {
      			put_filp(f);
      			f = ERR_PTR(error);
      		}
      
      and sure, having that open_check_o_direct() boilerplate gotten rid of is
      nice, but not that way...
      
      Worse, another call chain (via finish_open()) is FUBAR now wrt
      FILE_OPENED handling - in that case we get error returned, with file
      already hit by fput() *AND* FILE_OPENED not set.  Guess what happens in
      path_openat(), when it hits
      
      	if (!(opened & FILE_OPENED)) {
      		BUG_ON(!error);
      		put_filp(file);
      	}
      
      The root cause of all that crap is that the callers of do_dentry_open()
      have no way to tell which way did it fail; while that could be fixed up
      (by passing something like int *opened to do_dentry_open() and have it
      marked if we'd called ->open()), it's probably much too late in the
      cycle to do so right now.
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      af04fadc
  8. 27 May, 2018 1 commit
    • Al Viro's avatar
      rmdir(),rename(): do shrink_dcache_parent() only on success · 8767712f
      Al Viro authored
      Once upon a time ->rmdir() instances used to check if victim inode
      had more than one (in-core) reference and failed with -EBUSY if it
      had.  The reason was race avoidance - emptiness check is worthless
      if somebody could just go and create new objects in the victim
      directory afterwards.
      
      With introduction of dcache the checks had been replaced with
      checking the refcount of dentry.  However, since a cached negative
      lookup leaves a negative child dentry, such check had lead to false
      positives - with empty foo/ doing stat foo/bar before rmdir foo
      ended up with -EBUSY unless the negative dentry of foo/bar happened
      to be evicted by the time of rmdir(2).  That had been fixed by
      doing shrink_dcache_parent() just before the refcount check.
      
      At the same time, ext2_rmdir() has grown a private solution that
      eliminated those -EBUSY - it did something (setting ->i_size to 0)
      which made any subsequent ext2_add_entry() fail.
      
      Unfortunately, even with shrink_dcache_parent() the check had been
      racy - after all, the victim itself could be found by dcache lookup
      just after we'd checked its refcount.  That got fixed by a new
      helper (dentry_unhash()) that did shrink_dcache_parent() and unhashed
      the sucker if its refcount ended up equal to 1.  That got called before
      ->rmdir(), turning the checks in ->rmdir() instances into "if not
      unhashed fail with -EBUSY".  Which reduced the boilerplate nicely, but
      had an unpleasant side effect - now shrink_dcache_parent() had been
      done before the emptiness checks, leading to easily triggerable calls
      of shrink_dcache_parent() on arbitrary large subtrees, quite possibly
      nested into each other.
      
      Several years later the ext2-private trick had been generalized -
      (in-core) inodes of dead directories are flagged and calls of
      lookup, readdir and all directory-modifying methods were prevented
      in so marked directories.  Remaining boilerplate in ->rmdir() instances
      became redundant and some instances got rid of it.
      
      In 2011 the call of dentry_unhash() got shifted into ->rmdir() instances
      and then killed off in all of them.  That has lead to another problem,
      though - in case of successful rmdir we *want* any (negative) child
      dentries dropped and the victim itself made negative.  There's no point
      keeping cached negative lookups in foo when we can get the negative
      lookup of foo itself cached.  So shrink_dcache_parent() call had been
      restored; unfortunately, it went into the place where dentry_unhash()
      used to be, i.e. before the ->rmdir() call.  Note that we don't unhash
      anymore, so any "is it busy" checks would be racy; fortunately, all of
      them are gone.
      
      We should've done that call right *after* successful ->rmdir().  That
      reduces contention caused by tree-walking in shrink_dcache_parent()
      and, especially, contention caused by evictions in two nested subtrees
      going on in parallel.  The same goes for directory-overwriting rename() -
      the story there had been parallel to that of rmdir().
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      8767712f
  9. 24 May, 2018 2 commits
  10. 18 May, 2018 1 commit
  11. 08 Apr, 2018 1 commit
  12. 06 Apr, 2018 3 commits
  13. 02 Apr, 2018 6 commits
  14. 29 Mar, 2018 1 commit
  15. 28 Mar, 2018 1 commit
  16. 21 Mar, 2018 1 commit