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NFSD: Clean up find_or_add_file()

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Remove the call to find_file_locked() in insert_nfs4_file(). Tracing
shows that over 99% of these calls return NULL. Thus it is not worth
the expense of the extra bucket list traversal. insert_file() already
deals correctly with the case where the item is already in the hash
bucket.

Since nfsd4_file_hash_insert() is now just a wrapper around
insert_file(), move the meat of insert_file() into
nfsd4_file_hash_insert() and get rid of it.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: NeilBrown <neilb@suse.de>
This commit is contained in:
Chuck Lever 2022-10-28 10:47:41 -04:00
parent 3341678f2f
commit 9270fc514b
1 changed files with 30 additions and 38 deletions
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68
fs/nfsd/nfs4state.c
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@ -4698,32 +4698,6 @@ find_file_locked(const struct svc_fh *fh, unsigned int hashval)
return NULL;
}
static struct nfs4_file *insert_file(struct nfs4_file *new, struct svc_fh *fh,
unsigned int hashval)
{
struct nfs4_file *fp;
struct nfs4_file *ret = NULL;
bool alias_found = false;
spin_lock(&state_lock);
hlist_for_each_entry_rcu(fp, &file_hashtbl[hashval], fi_hash,
lockdep_is_held(&state_lock)) {
if (fh_match(&fp->fi_fhandle, &fh->fh_handle)) {
if (refcount_inc_not_zero(&fp->fi_ref))
ret = fp;
} else if (d_inode(fh->fh_dentry) == fp->fi_inode)
fp->fi_aliased = alias_found = true;
}
if (likely(ret == NULL)) {
nfsd4_file_init(fh, new);
hlist_add_head_rcu(&new->fi_hash, &file_hashtbl[hashval]);
new->fi_aliased = alias_found;
ret = new;
}
spin_unlock(&state_lock);
return ret;
}
static struct nfs4_file * find_file(struct svc_fh *fh)
{
struct nfs4_file *fp;
@ -4735,19 +4709,37 @@ static struct nfs4_file * find_file(struct svc_fh *fh)
return fp;
}
static struct nfs4_file *
find_or_add_file(struct nfs4_file *new, struct svc_fh *fh)
/*
* On hash insertion, identify entries with the same inode but
* distinct filehandles. They will all be in the same hash bucket
* because nfs4_file's are hashed by the address in the fi_inode
* field.
*/
static noinline_for_stack struct nfs4_file *
nfsd4_file_hash_insert(struct nfs4_file *new, const struct svc_fh *fhp)
{
struct nfs4_file *fp;
unsigned int hashval = file_hashval(fh);
unsigned int hashval = file_hashval(fhp);
struct nfs4_file *ret = NULL;
bool alias_found = false;
struct nfs4_file *fi;
rcu_read_lock();
fp = find_file_locked(fh, hashval);
rcu_read_unlock();
if (fp)
return fp;
return insert_file(new, fh, hashval);
spin_lock(&state_lock);
hlist_for_each_entry_rcu(fi, &file_hashtbl[hashval], fi_hash,
lockdep_is_held(&state_lock)) {
if (fh_match(&fi->fi_fhandle, &fhp->fh_handle)) {
if (refcount_inc_not_zero(&fi->fi_ref))
ret = fi;
} else if (d_inode(fhp->fh_dentry) == fi->fi_inode)
fi->fi_aliased = alias_found = true;
}
if (likely(ret == NULL)) {
nfsd4_file_init(fhp, new);
hlist_add_head_rcu(&new->fi_hash, &file_hashtbl[hashval]);
new->fi_aliased = alias_found;
ret = new;
}
spin_unlock(&state_lock);
return ret;
}
static noinline_for_stack void nfsd4_file_hash_remove(struct nfs4_file *fi)
@ -5641,7 +5633,7 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf
* and check for delegations in the process of being recalled.
* If not found, create the nfs4_file struct
*/
fp = find_or_add_file(open->op_file, current_fh);
fp = nfsd4_file_hash_insert(open->op_file, current_fh);
if (fp != open->op_file) {
status = nfs4_check_deleg(cl, open, &dp);
if (status)