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  1. 17 6月, 2009 1 次提交
    • T
      ext4: avoid unnecessary spinlock in critical POSIX ACL path · 210ad6ae
      由 Theodore Ts'o 提交于 
      If a filesystem supports POSIX ACL's, the VFS layer expects the filesystem
to do POSIX ACL checks on any files not owned by the caller, and it does
this for every single pathname component that it looks up.

That obviously can be pretty expensive if the filesystem isn't careful
about it, especially with locking. That's doubly sad, since the common
case tends to be that there are no ACL's associated with the files in
question.

ext4 already caches the ACL data so that it doesn't have to look it up
over and over again, but it does so by taking the inode->i_lock spinlock
on every lookup. Which is a noticeable overhead even if it's a private
lock, especially on CPU's where the serialization is expensive (eg Intel
Netburst aka 'P4').

For the special case of not actually having any ACL's, all that locking is
unnecessary. Even if somebody else were to be changing the ACL's on
another CPU, we simply don't care - if we've seen a NULL ACL, we might as
well use it.

So just load the ACL speculatively without any locking, and if it was
NULL, just use it. If it's non-NULL (either because we had a cached
entry, or because the cache hasn't been filled in at all), it means that
we'll need to get the lock and re-load it properly.

(This commit was ported from a patch originally authored by Linus for
ext3.)
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      210ad6ae
  3. 01 4月, 2009 1 次提交
  5. 27 7月, 2008 2 次提交
  7. 30 4月, 2008 2 次提交
  9. 18 7月, 2007 1 次提交
    • S
      Introduce is_owner_or_cap() to wrap CAP_FOWNER use with fsuid check · 3bd858ab
      由 Satyam Sharma 提交于 
      Introduce is_owner_or_cap() macro in fs.h, and convert over relevant
users to it. This is done because we want to avoid bugs in the future
where we check for only effective fsuid of the current task against a
file's owning uid, without simultaneously checking for CAP_FOWNER as
well, thus violating its semantics.
[ XFS uses special macros and structures, and in general looked ...
untouchable, so we leave it alone -- but it has been looked over. ]

The (current->fsuid != inode->i_uid) check in generic_permission() and
exec_permission_lite() is left alone, because those operations are
covered by CAP_DAC_OVERRIDE and CAP_DAC_READ_SEARCH. Similarly operations
falling under the purview of CAP_CHOWN and CAP_LEASE are also left alone.
Signed-off-by: NSatyam Sharma <ssatyam@cse.iitk.ac.in>
Cc: Al Viro <viro@ftp.linux.org.uk>
Acked-by: NSerge E. Hallyn <serge@hallyn.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      3bd858ab
  11. 12 10月, 2006 4 次提交
  13. 27 9月, 2006 2 次提交
  15. 04 2月, 2006 1 次提交
  17. 12 1月, 2006 1 次提交
  19. 10 1月, 2006 1 次提交
  21. 24 6月, 2005 2 次提交
  23. 17 4月, 2005 2 次提交
    • A
      [PATCH] Fix acl Oops · e493073d
      由 akpm@osdl.org 提交于 
      )


From: Andreas Gruenbacher <agruen@suse.de>

ext[23]_get_acl will return an error when reading the attribute fails or
out-of-memory occurs.  Catch this case.
Signed-off-by: NAndreas Gruenbacher <agruen@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      e493073d
    • L
      Linux-2.6.12-rc2 · 1da177e4
      由 Linus Torvalds 提交于 
      Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
      1da177e4