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  1. 17 Nov, 2011 2 commits
    • Wengang Wang's avatar
      ocfs2: make direntry invalid when deleting it · 82985248
      Wengang Wang authored 
      When we deleting a direntry from a directory, if it's the first in a block we
invalid it by setting inode to 0; otherwise, we merge the deleted one to the
prior and contiguous direntry. And we don't truncate directories.

There is a problem for the later case since inode is not set to 0.
This problem happens when the caller passes a file position as parameter to
ocfs2_dir_foreach_blk(). If the position happens to point to a stale(not
the first, deleted in betweens of ocfs2_dir_foreach_blk()s) direntry, we are
not able to recognize its staleness. So that we treat it as a live one wrongly.

The fix is to set inode to 0 in both cases indicating the direntry is stale.
This won't introduce additional IOs.
Signed-off-by: default avatarWengang Wang <wen.gang.wang@oracle.com>
Signed-off-by: default avatarJoel Becker <jlbec@evilplan.org>
      82985248
    • Julia Lawall's avatar
      fs/ocfs2/dlm/dlmlock.c: free kmem_cache_zalloc'd data using kmem_cache_free · fc9f8994
      Julia Lawall authored 
      Memory allocated using kmem_cache_zalloc should be freed using
kmem_cache_free, not kfree.

The semantic patch that fixes this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression x,e,e1,e2;
@@

x = kmem_cache_zalloc(e1,e2)
... when != x = e
?-kfree(x)
+kmem_cache_free(e1,x)
// </smpl>
Signed-off-by: default avatarJulia Lawall <julia@diku.dk>
Signed-off-by: default avatarJoel Becker <jlbec@evilplan.org>
      fc9f8994
  3. 22 Aug, 2011 1 commit
  5. 28 Jul, 2011 2 commits
    • Jan Kara's avatar
      ocfs2: Avoid livelock in ocfs2_readpage() · c7e25e6e
      Jan Kara authored 
      When someone writes to an inode, readers accessing the same inode via
ocfs2_readpage() just busyloop trying to get ip_alloc_sem because
do_generic_file_read() looks up the page again and retries ->readpage()
when previous attempt failed with AOP_TRUNCATED_PAGE. When there are enough
readers, they can occupy all CPUs and in non-preempt kernel the system is
deadlocked because writer holding ip_alloc_sem is never run to release the
semaphore. Fix the problem by making reader block on ip_alloc_sem to break
the busy loop.
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarJoel Becker <jlbec@evilplan.org>
      c7e25e6e
    • Mark Fasheh's avatar
      ocfs2: serialize unaligned aio · a11f7e63
      Mark Fasheh authored 
      Fix a corruption that can happen when we have (two or more) outstanding
aio's to an overlapping unaligned region.  Ext4
(e9e3bcec) and xfs recently had to fix
similar issues.

In our case what happens is that we can have an outstanding aio on a region
and if a write comes in with some bytes overlapping the original aio we may
decide to read that region into a page before continuing (typically because
of buffered-io fallback).  Since we have no ordering guarantees with the
aio, we can read stale or bad data into the page and then write it back out.

If the i/o is page and block aligned, then we avoid this issue as there
won't be any need to read data from disk.

I took the same approach as Eric in the ext4 patch and introduced some
serialization of unaligned async direct i/o.  I don't expect this to have an
effect on the most common cases of AIO.  Unaligned aio will be slower
though, but that's far more acceptable than data corruption.
Signed-off-by: default avatarMark Fasheh <mfasheh@suse.com>
Signed-off-by: default avatarJoel Becker <jlbec@evilplan.org>
      a11f7e63
  7. 25 Jul, 2011 1 commit
    • Sunil Mushran's avatar
      ocfs2: Implement llseek() · 93862d5e
      Sunil Mushran authored 
      ocfs2 implements its own llseek() to provide the SEEK_HOLE/SEEK_DATA
functionality.

SEEK_HOLE sets the file pointer to the start of either a hole or an unwritten
(preallocated) extent, that is greater than or equal to the supplied offset.

SEEK_DATA sets the file pointer to the start of an allocated extent (not
unwritten) that is greater than or equal to the supplied offset.

If the supplied offset is on a desired region, then the file pointer is set
to it. Offsets greater than or equal to the file size return -ENXIO.

Unwritten (preallocated) extents are considered holes because the file system
treats reads to such regions in the same way as it does to holes.
Signed-off-by: default avatarSunil Mushran <sunil.mushran@oracle.com>
      93862d5e
  9. 24 Jul, 2011 34 commits
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