[Ocfs2-devel] [PATCH 1/1] ocfs2: Add extended attribute support v3

[Tiger Yang <tiger.yang@oracle.com>]

Mark Fasheh wrote:
> The thing is, the locking as you have it here isn't protecting against
> racing a data write, which is reading l_count on the extent list (or id_count on
> inline data) and an xattr write which might want to shrink those. You'll
> need at least ip_alloc_sem around those, since ocfs2_page_mkwrite() doesn't
> take i_mutex because it doesn't want to deadlock against the mmap
> semaphore.
Thanks, You point out a potential bug in my patch. I didn't protect
reading/writing xattr against file data.

My patch check l_count/id_count in ocfs2_xattr_has_space_inline() and
may change it in ocfs2_xattr_ibody_set().
is patch attached fix this problem?


> Or are you trying to protect xattr against itself? If that's the case, you
> could push this lock up to the top and take it around entire operations.
Actually I am trying to protect xattr read/write by this semaphore,
since we found a bug about it.
http://oss.oracle.com/bugzilla/show_bug.cgi?id=990

So I need change comment about xattr semaphore.
/* protects extended attribute change on this inode */

Best regards,
tiger

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