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  1. 06 5月, 2011 1 次提交
  3. 04 5月, 2011 1 次提交
  5. 02 5月, 2011 12 次提交
  7. 29 4月, 2011 1 次提交
  9. 28 4月, 2011 3 次提交
  11. 27 4月, 2011 1 次提交
  13. 26 4月, 2011 14 次提交
  15. 25 4月, 2011 2 次提交
  17. 24 4月, 2011 2 次提交
    • L
      vfs: get rid of insane dentry hashing rules · dea3667b
      由 Linus Torvalds 提交于 
      The dentry hashing rules have been really quite complicated for a long
while, in odd ways.  That made functions like __d_drop() very fragile
and non-obvious.

In particular, whether a dentry was hashed or not was indicated with an
explicit DCACHE_UNHASHED bit.  That's despite the fact that the hash
abstraction that the dentries use actually have a 'is this entry hashed
or not' model (which is a simple test of the 'pprev' pointer).

The reason that was done is because we used the normal 'is this entry
unhashed' model to mark whether the dentry had _ever_ been hashed in the
dentry hash tables, and that logic goes back many years (commit
b3423415: "dcache: avoid RCU for never-hashed dentries").

That, in turn, meant that __d_drop had totally different unhashing logic
for the dentry hash table case and for the anonymous dcache case,
because in order to use the "is this dentry hashed" logic as a flag for
whether it had ever been on the RCU hash table, we had to unhash such a
dentry differently so that we'd never think that it wasn't 'unhashed'
and wouldn't be free'd correctly.

That's just insane.  It made the logic really hard to follow, when there
were two different kinds of "unhashed" states, and one of them (the one
that used "list_bl_unhashed()") really had nothing at all to do with
being unhashed per se, but with a very subtle lifetime rule instead.

So turn all of it around, and make it logical.

Instead of having a DENTRY_UNHASHED bit in d_flags to indicate whether
the dentry is on the hash chains or not, use the hash chain unhashed
logic for that.  Suddenly "d_unhashed()" just uses "list_bl_unhashed()",
and everything makes sense.

And for the lifetime rule, just use an explicit DENTRY_RCUACCEES bit.
If we ever insert the dentry into the dentry hash table so that it is
visible to RCU lookup, we mark it DENTRY_RCUACCESS to show that it now
needs the RCU lifetime rules.  Now suddently that test at dentry free
time makes sense too.

And because unhashing now is sane and doesn't depend on where the dentry
got unhashed from (because the dentry hash chain details doesn't have
some subtle side effects), we can re-unify the __d_drop() logic and use
common code for the unhashing.

Also fix one more open-coded hash chain bit_spin_lock() that I missed in
the previous chain locking cleanup commit.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      dea3667b
    • L
      vfs: get rid of 'struct dcache_hash_bucket' abstraction · b07ad996
      由 Linus Torvalds 提交于 
      It's a useless abstraction for 'hlist_bl_head', and it doesn't actually
help anything - quite the reverse.  All the users end up having to know
about the hlist_bl_head details anyway, using 'struct hlist_bl_node *'
etc. So it just makes the code look confusing.

And the cost of it is extra '&b->head' syntactic noise, but more
importantly it spuriously makes the hash table dentry list look
different from the per-superblock DCACHE_DISCONNECTED dentry list.

As a result, the code ended up using ad-hoc locking for one case and
special helper functions for what is really another totally identical
case in the very same function.

Make it all look and work the same.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      b07ad996
  19. 22 4月, 2011 1 次提交
  21. 21 4月, 2011 2 次提交
    • J
      vfs: Pass setxattr(2) flags properly · df7e1303
      由 Jan Kara 提交于 
      For some reason generic_setxattr() did not pass flags (XATTR_CREATE,
XATTR_REPLACE) to the filesystem specific helper. This caused that
setxattr(2) syscall just ignored these flags.

Fix the bug by passing flags correctly.
Signed-off-by: NJan Kara <jack@suse.cz>
Acked-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      df7e1303
    • A
      UBIFS: fix master node recovery · 6e0d9fd3
      由 Artem Bityutskiy 提交于 
      This patch fixes the following symptoms:
1. Unmount UBIFS cleanly.
2. Start mounting UBIFS R/W and have a power cut immediately
3. Start mounting UBIFS R/O, this succeeds
4. Try to re-mount UBIFS R/W - this fails immediately or later on,
   because UBIFS will write the master node to the flash area
   which has been written before.

The analysis of the problem:

1. UBIFS is unmounted cleanly, both copies of the master node are clean.
2. UBIFS is being mounter R/W, starts changing master node copy 1, and
   a power cut happens. The copy N1 becomes corrupted.
3. UBIFS is being mounted R/O. It notices the copy N1 is corrupted and
   reads copy N2. Copy N2 is clean.
4. Because of R/O mode, UBIFS cannot recover copy 1.
5. The mount code (ubifs_mount()) sees that the master node is clean,
   so it decides that no recovery is needed.
6. We are re-mounting R/W. UBIFS believes no recovery is needed and
   starts updating the master node, but copy N1 is still corrupted
   and was not recovered!

Fix this problem by marking the master node as dirty every time we
recover it and we are in R/O mode. This forces further recovery and
the UBIFS cleans-up the corruptions and recovers the copy N1 when
re-mounting R/W later.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Cc: stable@kernel.org
      6e0d9fd3