linux-stable/fs/nfsd
J. Bruce Fields b21996e36c locks: break delegations on unlink
We need to break delegations on any operation that changes the set of
links pointing to an inode.  Start with unlink.

Such operations also hold the i_mutex on a parent directory.  Breaking a
delegation may require waiting for a timeout (by default 90 seconds) in
the case of a unresponsive NFS client.  To avoid blocking all directory
operations, we therefore drop locks before waiting for the delegation.
The logic then looks like:

	acquire locks
	...
	test for delegation; if found:
		take reference on inode
		release locks
		wait for delegation break
		drop reference on inode
		retry

It is possible this could never terminate.  (Even if we take precautions
to prevent another delegation being acquired on the same inode, we could
get a different inode on each retry.)  But this seems very unlikely.

The initial test for a delegation happens after the lock on the target
inode is acquired, but the directory inode may have been acquired
further up the call stack.  We therefore add a "struct inode **"
argument to any intervening functions, which we use to pass the inode
back up to the caller in the case it needs a delegation synchronously
broken.

Cc: David Howells <dhowells@redhat.com>
Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: Dustin Kirkland <dustin.kirkland@gazzang.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-11-09 00:16:42 -05:00
..
acl.h nfsd: Remove declaration of nonexistent nfs4_acl_permisison 2013-02-13 06:15:35 -08:00
auth.c nfsd: Properly compare and initialize kuids and kgids 2013-02-13 06:16:09 -08:00
auth.h nfsd: Remove nfsd_luid, nfsd_lgid, nfsd_ruid and nfsd_rgid 2013-02-13 06:15:51 -08:00
cache.h nfsd: add new reply_cache_stats file in nfsdfs 2013-04-03 11:47:24 -04:00
current_stateid.h
export.c Merge branch 'for-3.9' of git://linux-nfs.org/~bfields/linux 2013-02-28 18:02:55 -08:00
fault_inject.c Merge branch 'for-3.9' of git://linux-nfs.org/~bfields/linux 2013-02-28 18:02:55 -08:00
idmap.h nfsd: Convert idmap to use kuids and kgids 2013-02-13 06:15:49 -08:00
Kconfig NFSD: Server implementation of MAC Labeling 2013-05-15 09:27:02 -04:00
lockd.c
Makefile
netns.h nfsd4: make del_recall_lru per-network-namespace 2013-04-04 13:25:16 -04:00
nfs2acl.c nfsd: handle vfs_getattr errors in acl protocol 2013-02-26 02:46:09 -05:00
nfs3acl.c nfsd4: cleanup: replace rq_resused count by rq_next_page pointer 2012-12-17 22:00:16 -05:00
nfs3proc.c switch vfs_getattr() to struct path 2013-02-26 02:46:08 -05:00
nfs3xdr.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
nfs4acl.c nfsd: Handle kuids and kgids in the nfs4acl to posix_acl conversion 2013-02-13 06:16:06 -08:00
nfs4callback.c nfsd4: check backchannel attributes on create_session 2013-04-09 16:53:56 -04:00
nfs4idmap.c Merge branch 'for-3.9' of git://linux-nfs.org/~bfields/linux 2013-02-28 18:02:55 -08:00
nfs4proc.c nfsd: Fix SP4_MACH_CRED negotiation in EXCHANGE_ID 2013-08-07 12:06:07 -04:00
nfs4recover.c nfsd: switch to %p[dD] 2013-10-24 23:34:51 -04:00
nfs4state.c locks: introduce new FL_DELEG lock flag 2013-11-09 00:16:41 -05:00
nfs4xdr.c nfsd: racy access to ->d_name in nsfd4_encode_path() 2013-09-03 22:50:28 -04:00
nfscache.c fs: convert fs shrinkers to new scan/count API 2013-09-10 18:56:31 -04:00
nfsctl.c Merge branch 'for-3.10' of git://linux-nfs.org/~bfields/linux 2013-05-03 10:59:39 -07:00
nfsd.h nfsd4: fix minorversion support interface 2013-07-12 16:48:52 -04:00
nfsfh.c nfsd: switch to %p[dD] 2013-10-24 23:34:51 -04:00
nfsfh.h nfsd: switch to %p[dD] 2013-10-24 23:34:51 -04:00
nfsproc.c switch vfs_getattr() to struct path 2013-02-26 02:46:08 -05:00
nfssvc.c nfsd4: fix minorversion support interface 2013-07-12 16:48:52 -04:00
nfsxdr.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
state.h nfsd4: implement minimal SP4_MACH_CRED 2013-07-01 17:23:06 -04:00
stats.c
vfs.c locks: break delegations on unlink 2013-11-09 00:16:42 -05:00
vfs.h NFSD: Server implementation of MAC Labeling 2013-05-15 09:27:02 -04:00
xdr.h nfsd: handle vfs_getattr errors in acl protocol 2013-02-26 02:46:09 -05:00
xdr3.h nfsd: handle vfs_getattr errors in acl protocol 2013-02-26 02:46:09 -05:00
xdr4.h NFSD: Server implementation of MAC Labeling 2013-05-15 09:27:02 -04:00
xdr4cb.h nfsd4: check backchannel attributes on create_session 2013-04-09 16:53:56 -04:00