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authorTrond Myklebust <Trond.Myklebust@netapp.com>2007-05-16 16:53:28 -0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2007-07-10 23:40:48 -0400
commit75180df2ed467866ada839fe73cf7cc7d75c0a22 (patch)
tree35966d0b22e58cc49ddee5b5f8d0e64c577dc576 /include/linux
parent8007122520f0a3599bdc4df47358a5d83b2574aa (diff)
downloadop-kernel-dev-75180df2ed467866ada839fe73cf7cc7d75c0a22.zip
op-kernel-dev-75180df2ed467866ada839fe73cf7cc7d75c0a22.tar.gz
NFS: Add the mount option "nosharecache"
Prior to David Howell's mount changes in 2.6.18, users who mounted different directories which happened to be from the same filesystem on the server would get different super blocks, and hence could choose different mount options. As long as there were no hard linked files that crossed from one subtree to another, this was quite safe. Post the changes, if the two directories are on the same filesystem (have the same 'fsid'), they will share the same super block, and hence the same mount options. Add a flag to allow users to elect not to share the NFS super block with another mount point, even if the fsids are the same. This will allow users to set different mount options for the two different super blocks, as was previously possible. It is still up to the user to ensure that there are no cache coherency issues when doing this, however the default behaviour will be to share super blocks whenever two paths result in the same fsid. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/nfs4_mount.h3
-rw-r--r--include/linux/nfs_mount.h1
2 files changed, 3 insertions, 1 deletions
diff --git a/include/linux/nfs4_mount.h b/include/linux/nfs4_mount.h
index d8d7480..a0dcf66 100644
--- a/include/linux/nfs4_mount.h
+++ b/include/linux/nfs4_mount.h
@@ -65,6 +65,7 @@ struct nfs4_mount_data {
#define NFS4_MOUNT_NOCTO 0x0010 /* 1 */
#define NFS4_MOUNT_NOAC 0x0020 /* 1 */
#define NFS4_MOUNT_STRICTLOCK 0x1000 /* 1 */
-#define NFS4_MOUNT_FLAGMASK 0x1033
+#define NFS4_MOUNT_UNSHARED 0x8000 /* 1 */
+#define NFS4_MOUNT_FLAGMASK 0x9033
#endif
diff --git a/include/linux/nfs_mount.h b/include/linux/nfs_mount.h
index 0b82a17..a3ade89 100644
--- a/include/linux/nfs_mount.h
+++ b/include/linux/nfs_mount.h
@@ -62,6 +62,7 @@ struct nfs_mount_data {
#define NFS_MOUNT_STRICTLOCK 0x1000 /* reserved for NFSv4 */
#define NFS_MOUNT_SECFLAVOUR 0x2000 /* 5 */
#define NFS_MOUNT_NORDIRPLUS 0x4000 /* 5 */
+#define NFS_MOUNT_UNSHARED 0x8000 /* 5 */
#define NFS_MOUNT_FLAGMASK 0xFFFF
#endif
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