From 6d4ade986f9c8df31e68fd30643997f79cc5a5f8 Mon Sep 17 00:00:00 2001 From: Steven Whitehouse Date: Fri, 14 Jun 2013 11:17:15 +0100 Subject: GFS2: Add atomic_open support I've restricted atomic_open to only operate on regular files, although I still don't understand why atomic_open should not be possible also for directories on GFS2. That can always be added in later though, if it makes sense. The ->atomic_open function can be passed negative dentries, which in most cases means either ENOENT (->lookup) or a call to d_instantiate (->create). In the GFS2 case though, we need to actually perform the look up, since we do not know whether there has been a new inode created on another node. The look up calls d_splice_alias which then tries to rehash the dentry - so the solution here is to simply check for that in d_splice_alias. The same issue is likely to affect any other cluster filesystem implementing ->atomic_open Signed-off-by: Steven Whitehouse Cc: Al Viro Cc: "J. Bruce Fields" Cc: Jeff Layton --- fs/dcache.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'fs/dcache.c') diff --git a/fs/dcache.c b/fs/dcache.c index f09b9085f7d8..5a23073138df 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1612,6 +1612,10 @@ EXPORT_SYMBOL(d_obtain_alias); * If a dentry was found and moved, then it is returned. Otherwise NULL * is returned. This matches the expected return value of ->lookup. * + * Cluster filesystems may call this function with a negative, hashed dentry. + * In that case, we know that the inode will be a regular file, and also this + * will only occur during atomic_open. So we need to check for the dentry + * being already hashed only in the final case. */ struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry) { @@ -1636,8 +1640,11 @@ struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry) security_d_instantiate(dentry, inode); d_rehash(dentry); } - } else - d_add(dentry, inode); + } else { + d_instantiate(dentry, inode); + if (d_unhashed(dentry)) + d_rehash(dentry); + } return new; } EXPORT_SYMBOL(d_splice_alias); -- cgit v1.2.3