2008-06-12 19:49:25

by Myklebust, Trond

[permalink] [raw]
Subject: [PATCH 09/15] NFS: Remove BKL from NFS lookup code

All dentry-related operations are already BKL-safe, since they are
protected by the VFS locking. No extra locks should be needed in the NFS
code.

In the case of nfs_revalidate_inode(), we're only doing an attribute
update (protected by the inode->i_lock).
In the case of nfs_lookup(), we're instantiating a new dentry, so there
should be no contention possible until after we call d_materialise_unique.

Signed-off-by: Trond Myklebust <[email protected]>
---

fs/nfs/dir.c | 9 +--------
1 files changed, 1 insertions(+), 8 deletions(-)

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index cdcc0c3..c936102 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -777,7 +777,6 @@ static int nfs_lookup_revalidate(struct dentry * dentry, struct nameidata *nd)
struct nfs_fattr fattr;

parent = dget_parent(dentry);
- lock_kernel();
dir = parent->d_inode;
nfs_inc_stats(dir, NFSIOS_DENTRYREVALIDATE);
inode = dentry->d_inode;
@@ -815,7 +814,6 @@ static int nfs_lookup_revalidate(struct dentry * dentry, struct nameidata *nd)

nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
out_valid:
- unlock_kernel();
dput(parent);
dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is valid\n",
__func__, dentry->d_parent->d_name.name,
@@ -834,7 +832,6 @@ out_zap_parent:
shrink_dcache_parent(dentry);
}
d_drop(dentry);
- unlock_kernel();
dput(parent);
dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is invalid\n",
__func__, dentry->d_parent->d_name.name,
@@ -921,8 +918,6 @@ static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, stru
res = ERR_PTR(-ENOMEM);
dentry->d_op = NFS_PROTO(dir)->dentry_ops;

- lock_kernel();
-
/*
* If we're doing an exclusive create, optimize away the lookup
* but don't hash the dentry.
@@ -930,7 +925,7 @@ static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, stru
if (nfs_is_exclusive_create(dir, nd)) {
d_instantiate(dentry, NULL);
res = NULL;
- goto out_unlock;
+ goto out;
}

parent = dentry->d_parent;
@@ -958,8 +953,6 @@ no_entry:
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
out_unblock_sillyrename:
nfs_unblock_sillyrename(parent);
-out_unlock:
- unlock_kernel();
out:
return res;
}