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authorDavid Howells <dhowells@redhat.com>2009-04-03 16:42:42 +0100
committerDavid Howells <dhowells@redhat.com>2009-04-03 16:42:42 +0100
commit08734048b380103f0412f58b84c2f76a2c8b599f (patch)
tree34a65d40e33b12d36f5c82adb686bcdae6eab0fe /include/linux
parent147272813e043fb44bd112527951da70c1e663de (diff)
NFS: Define and create superblock-level objects
Define and create superblock-level cache index objects (as managed by nfs_server structs). Each superblock object is created in a server level index object and is itself an index into which inode-level objects are inserted. Ideally there would be one superblock-level object per server, and the former would be folded into the latter; however, since the "nosharecache" option exists this isn't possible. The superblock object key is a sequence consisting of: (1) Certain superblock s_flags. (2) Various connection parameters that serve to distinguish superblocks for sget(). (3) The volume FSID. (4) The security flavour. (5) The uniquifier length. (6) The uniquifier text. This is normally an empty string, unless the fsc=xyz mount option was used to explicitly specify a uniquifier. The key blob is of variable length, depending on the length of (6). The superblock object is given no coherency data to carry in the auxiliary data permitted by the cache. It is assumed that the superblock is always coherent. This patch also adds uniquification handling such that two otherwise identical superblocks, at least one of which is marked "nosharecache", won't end up trying to share the on-disk cache. It will be possible to manually provide a uniquifier through a mount option with a later patch to avoid the error otherwise produced. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com> Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/nfs_fs_sb.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index 0a374b9c509..6ad75948cbf 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -108,6 +108,11 @@ struct nfs_server {
unsigned long mount_time; /* when this fs was mounted */
dev_t s_dev; /* superblock dev numbers */
+#ifdef CONFIG_NFS_FSCACHE
+ struct nfs_fscache_key *fscache_key; /* unique key for superblock */
+ struct fscache_cookie *fscache; /* superblock cookie */
+#endif
+
#ifdef CONFIG_NFS_V4
u32 attr_bitmask[2];/* V4 bitmask representing the set
of attributes supported on this