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  1. 27 Jul, 2008 8 commits
    • Al Viro's avatar
      [PATCH] sanitize proc_sysctl · 9043476f
      Al Viro authored 
      * keep references to ctl_table_head and ctl_table in /proc/sys inodes
* grab the former during operations, use the latter for access to
  entry if that succeeds
* have ->d_compare() check if table should be seen for one who does lookup;
  that allows us to avoid flipping inodes - if we have the same name resolve
  to different things, we'll just keep several dentries and ->d_compare()
  will reject the wrong ones.
* have ->lookup() and ->readdir() scan the table of our inode first, then
  walk all ctl_table_header and scan ->attached_by for those that are
  attached to our directory.
* implement ->getattr().
* get rid of insane amounts of tree-walking
* get rid of the need to know dentry in ->permission() and of the contortions
  induced by that.
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      9043476f
    • Al Viro's avatar
      [PATCH] sysctl: keep track of tree relationships · ae7edecc
      Al Viro authored 
      In a sense, that's the heart of the series.  It's based on the following
property of the trees we are actually asked to add: they can be split into
stem that is already covered by registered trees and crown that is entirely
new.  IOW, if a/b and a/c/d are introduced by our tree, then a/c is also
introduced by it.

That allows to associate tree and table entry with each node in the union;
while directory nodes might be covered by many trees, only one will cover
the node by its crown.  And that will allow much saner logics for /proc/sys
in the next patches.  This patch introduces the data structures needed to
keep track of that.

When adding a sysctl table, we find a "parent" one.  Which is to say,
find the deepest node on its stem that already is present in one of the
tables from our table set or its ancestor sets.  That table will be our
parent and that node in it - attachment point.  Add our table to list
anchored in parent, have it refer the parent and contents of attachment
point.  Also remember where its crown lives.
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      ae7edecc
    • Al Viro's avatar
      [PATCH] sysctl: make sure that /proc/sys/net/ipv4 appears before per-ns ones · bd7b1533
      Al Viro authored 
      Massage ipv4 initialization - make sure that net.ipv4 appears as
non-per-net-namespace before it shows up in per-net-namespace sysctls.
That's the only change outside of sysctl.c needed to get sane ordering
rules and data structures for sysctls (esp. for procfs side of that
mess).
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      bd7b1533
    • Al Viro's avatar
      [PATCH] allow delayed freeing of ctl_table_header · f7e6ced4
      Al Viro authored 
      Refcount the sucker; instead of freeing it by the end of unregistration
just drop the refcount and free only when it hits zero.  Make sure that
we _always_ make ->unregistering non-NULL in start_unregistering().

That allows anybody to get a reference to such puppy, preventing its
freeing and reuse.  It does *not* block unregistration.  Anybody who
holds such a reference can
	* try to grab a "use" reference (ctl_head_grab()); that will
succeeds if and only if it hadn't entered unregistration yet.  If it
succeeds, we can use it in all normal ways until we release the "use"
reference (with ctl_head_finish()).  Note that this relies on having
->unregistering become non-NULL in all cases when one starts to unregister
the sucker.
	* keep pointers to ctl_table entries; they *can* be freed if
the entire thing is unregistered.  However, if ctl_head_grab() succeeds,
we know that unregistration had not happened (and will not happen until
ctl_head_finish()) and such pointers can be used safely.

IOW, now we can have inodes under /proc/sys keep references to ctl_table
entries, protecting them with references to ctl_table_header and
grabbing the latter for the duration of operations that require access
to ctl_table.  That won't cause deadlocks, since unregistration will not
be stopped by mere keeping a reference to ctl_table_header.
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      f7e6ced4
    • Al Viro's avatar
      [PATCH] beginning of sysctl cleanup - ctl_table_set · 73455092
      Al Viro authored 
      New object: set of sysctls [currently - root and per-net-ns].
Contains: pointer to parent set, list of tables and "should I see this set?"
method (->is_seen(set)).
Current lists of tables are subsumed by that; net-ns contains such a beast.
->lookup() for ctl_table_root returns pointer to ctl_table_set instead of
that to ->list of that ctl_table_set.

[folded compile fixes by rdd for configs without sysctl]
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      73455092
    • Miklos Szeredi's avatar
      [patch] hppfs: remove hppfs_permission · 7ac6cd65
      Miklos Szeredi authored 
      hppfs_permission() is equivalent to the '.permission == NULL' case.
Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      7ac6cd65
    • Denys Vlasenko's avatar
      [PATCH] reuse xxx_fifo_fops for xxx_pipe_fops · d2d9648e
      Denys Vlasenko authored 
      Merge fifo and pipe file_operations.
Signed-off-by: default avatarDenys Vlasenko <vda.linux@googlemail.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      d2d9648e
    • Miklos Szeredi's avatar
      [patch] vfs: fix lookup on deleted directory · d70b67c8
      Miklos Szeredi authored 
      Lookup can install a child dentry for a deleted directory.  This keeps
the directory dentry alive, and the inode pinned in the cache and on
disk, even after all external references have gone away.

This isn't a big problem normally, since memory pressure or umount
will clear out the directory dentry and its children, releasing the
inode.  But for UBIFS this causes problems because its orphan area can
overflow.

Fix this by returning ENOENT for all lookups on a S_DEAD directory
before creating a child dentry.

Thanks to Zoltan Sogor for noticing this while testing UBIFS, and
Artem for the excellent analysis of the problem and testing.
Reported-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Tested-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      d70b67c8
  3. 26 Jul, 2008 32 commits
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