[PATCH] knfsd: nfsd4: represent nfsv4 acl with array instead of linked list

Simplify the memory management and code a bit by representing acls with an
array instead of a linked list.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 66 insertions, 136 deletions

diff --git a/fs/nfsd/nfs4acl.c b/fs/nfsd/nfs4acl.c
index 6c52658e9a26..2797051cd2b4 100644
--- a/fs/nfsd/nfs4acl.c
+++ b/fs/nfsd/nfs4acl.c
@@ -128,74 +128,58 @@ struct ace_container {
 };
 
 static short ace2type(struct nfs4_ace *);
-static int _posix_to_nfsv4_one(struct posix_acl *, struct nfs4_acl *, unsigned int);
-int nfs4_acl_add_ace(struct nfs4_acl *, u32, u32, u32, int, uid_t);
+static void _posix_to_nfsv4_one(struct posix_acl *, struct nfs4_acl *,
+                                unsigned int);
+void nfs4_acl_add_ace(struct nfs4_acl *, u32, u32, u32, int, uid_t);
 
 struct nfs4_acl *
 nfs4_acl_posix_to_nfsv4(struct posix_acl *pacl, struct posix_acl *dpacl,
                         unsigned int flags)
 {
         struct nfs4_acl *acl;
-        int error = -EINVAL;
+        int size = 0;
 
-        if ((pacl != NULL &&
-                (posix_acl_valid(pacl) < 0 || pacl->a_count == 0)) ||
-            (dpacl != NULL &&
-                (posix_acl_valid(dpacl) < 0 || dpacl->a_count == 0)))
-                goto out_err;
-
-        acl = nfs4_acl_new();
-        if (acl == NULL) {
-                error = -ENOMEM;
-                goto out_err;
+        if (pacl) {
+                if (posix_acl_valid(pacl) < 0)
+                        return ERR_PTR(-EINVAL);
+                size += 2*pacl->a_count;
         }
-
-        if (pacl != NULL) {
-                error = _posix_to_nfsv4_one(pacl, acl,
-                                                flags & ~NFS4_ACL_TYPE_DEFAULT);
-                if (error < 0)
-                        goto out_acl;
+        if (dpacl) {
+                if (posix_acl_valid(dpacl) < 0)
+                        return ERR_PTR(-EINVAL);
+                size += 2*dpacl->a_count;
         }
 
-        if (dpacl != NULL) {
-                error = _posix_to_nfsv4_one(dpacl, acl,
-                                                flags | NFS4_ACL_TYPE_DEFAULT);
-                if (error < 0)
-                        goto out_acl;
-        }
+        /* Allocate for worst case: one (deny, allow) pair each: */
+        acl = nfs4_acl_new(size);
+        if (acl == NULL)
+                return ERR_PTR(-ENOMEM);
 
-        return acl;
+        if (pacl)
+                _posix_to_nfsv4_one(pacl, acl, flags & ~NFS4_ACL_TYPE_DEFAULT);
 
-out_acl:
-        nfs4_acl_free(acl);
-out_err:
-        acl = ERR_PTR(error);
+        if (dpacl)
+                _posix_to_nfsv4_one(dpacl, acl, flags | NFS4_ACL_TYPE_DEFAULT);
 
         return acl;
 }
 
-static int
+static void
 nfs4_acl_add_pair(struct nfs4_acl *acl, int eflag, u32 mask, int whotype,
                 uid_t owner, unsigned int flags)
 {
-        int error;
-
-        error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE,
+        nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE,
                                  eflag, mask, whotype, owner);
-        if (error < 0)
-                return error;
-        error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
+        nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
                                 eflag, deny_mask(mask, flags), whotype, owner);
-        return error;
 }
 
 /* We assume the acl has been verified with posix_acl_valid. */
-static int
+static void
 _posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
                                                 unsigned int flags)
 {
         struct posix_acl_entry *pa, *pe, *group_owner_entry;
-        int error = -EINVAL;
         u32 mask, mask_mask;
         int eflag = ((flags & NFS4_ACL_TYPE_DEFAULT) ?
                                         NFS4_INHERITANCE_FLAGS : 0);
@@ -211,23 +195,16 @@ _posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
         pa = pacl->a_entries;
         BUG_ON(pa->e_tag != ACL_USER_OBJ);
         mask = mask_from_posix(pa->e_perm, flags | NFS4_ACL_OWNER);
-        error = nfs4_acl_add_pair(acl, eflag, mask, NFS4_ACL_WHO_OWNER, 0, flags);
-        if (error < 0)
-                goto out;
+        nfs4_acl_add_pair(acl, eflag, mask, NFS4_ACL_WHO_OWNER, 0, flags);
         pa++;
 
         while (pa->e_tag == ACL_USER) {
                 mask = mask_from_posix(pa->e_perm, flags);
-                error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
+                nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
                                 eflag,  mask_mask, NFS4_ACL_WHO_NAMED, pa->e_id);
-                if (error < 0)
-                        goto out;
 
-
-                error = nfs4_acl_add_pair(acl, eflag, mask,
+                nfs4_acl_add_pair(acl, eflag, mask,
                                 NFS4_ACL_WHO_NAMED, pa->e_id, flags);
-                if (error < 0)
-                        goto out;
                 pa++;
         }
 
@@ -238,34 +215,25 @@ _posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
 
         if (pacl->a_count > 3) {
                 BUG_ON(pa->e_tag != ACL_GROUP_OBJ);
-                error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
+                nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
                                 NFS4_ACE_IDENTIFIER_GROUP | eflag, mask_mask,
                                 NFS4_ACL_WHO_GROUP, 0);
-                if (error < 0)
-                        goto out;
         }
         group_owner_entry = pa;
         mask = mask_from_posix(pa->e_perm, flags);
-        error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE,
+        nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE,
                         NFS4_ACE_IDENTIFIER_GROUP | eflag, mask,
                         NFS4_ACL_WHO_GROUP, 0);
-        if (error < 0)
-                goto out;
         pa++;
 
         while (pa->e_tag == ACL_GROUP) {
                 mask = mask_from_posix(pa->e_perm, flags);
-                error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
+                nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
                                 NFS4_ACE_IDENTIFIER_GROUP | eflag, mask_mask,
                                 NFS4_ACL_WHO_NAMED, pa->e_id);
-                if (error < 0)
-                        goto out;
-
-                error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE,
+                nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE,
                                 NFS4_ACE_IDENTIFIER_GROUP | eflag, mask,
                                 NFS4_ACL_WHO_NAMED, pa->e_id);
-                if (error < 0)
-                        goto out;
                 pa++;
         }
 
@@ -273,19 +241,15 @@ _posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
 
         pa = group_owner_entry;
         mask = mask_from_posix(pa->e_perm, flags);
-        error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
+        nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
                         NFS4_ACE_IDENTIFIER_GROUP | eflag,
                         deny_mask(mask, flags), NFS4_ACL_WHO_GROUP, 0);
-        if (error < 0)
-                goto out;
         pa++;
         while (pa->e_tag == ACL_GROUP) {
                 mask = mask_from_posix(pa->e_perm, flags);
-                error = nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
+                nfs4_acl_add_ace(acl, NFS4_ACE_ACCESS_DENIED_ACE_TYPE,
                                 NFS4_ACE_IDENTIFIER_GROUP | eflag,
                                 deny_mask(mask, flags), NFS4_ACL_WHO_NAMED, pa->e_id);
-                if (error < 0)
-                        goto out;
                 pa++;
         }
 
@@ -293,10 +257,7 @@ _posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
                 pa++;
         BUG_ON(pa->e_tag != ACL_OTHER);
         mask = mask_from_posix(pa->e_perm, flags);
-        error = nfs4_acl_add_pair(acl, eflag, mask, NFS4_ACL_WHO_EVERYONE, 0, flags);
-
-out:
-        return error;
+        nfs4_acl_add_pair(acl, eflag, mask, NFS4_ACL_WHO_EVERYONE, 0, flags);
 }
 
 static void
@@ -640,7 +601,7 @@ int nfs4_acl_nfsv4_to_posix(struct nfs4_acl *acl, struct posix_acl **pacl,
         if (ret)
                 goto out_estate;
         ret = -EINVAL;
-        list_for_each_entry(ace, &acl->ace_head, l_ace) {
+        for (ace = acl->aces; ace < acl->aces + acl->naces; ace++) {
                 if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE &&
                     ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE)
                         goto out_dstate;
@@ -705,48 +666,22 @@ EXPORT_SYMBOL(nfs4_acl_posix_to_nfsv4);
 EXPORT_SYMBOL(nfs4_acl_nfsv4_to_posix);
 
 struct nfs4_acl *
-nfs4_acl_new(void)
+nfs4_acl_new(int n)
 {
         struct nfs4_acl *acl;
 
-        if ((acl = kmalloc(sizeof(*acl), GFP_KERNEL)) == NULL)
+        acl = kmalloc(sizeof(*acl) + n*sizeof(struct nfs4_ace), GFP_KERNEL);
+        if (acl == NULL)
                 return NULL;
-
         acl->naces = 0;
-        INIT_LIST_HEAD(&acl->ace_head);
-
         return acl;
 }
 
 void
-nfs4_acl_free(struct nfs4_acl *acl)
-{
-        struct list_head *h;
-        struct nfs4_ace *ace;
-
-        if (!acl)
-                return;
-
-        while (!list_empty(&acl->ace_head)) {
-                h = acl->ace_head.next;
-                list_del(h);
-                ace = list_entry(h, struct nfs4_ace, l_ace);
-                kfree(ace);
-        }
-
-        kfree(acl);
-
-        return;
-}
-
-int
 nfs4_acl_add_ace(struct nfs4_acl *acl, u32 type, u32 flag, u32 access_mask,
                 int whotype, uid_t who)
 {
-        struct nfs4_ace *ace;
-
-        if ((ace = kmalloc(sizeof(*ace), GFP_KERNEL)) == NULL)
-                return -ENOMEM;
+        struct nfs4_ace *ace = acl->aces + acl->naces;
 
         ace->type = type;
         ace->flag = flag;
@@ -754,10 +689,7 @@ nfs4_acl_add_ace(struct nfs4_acl *acl, u32 type, u32 flag, u32 access_mask,
         ace->whotype = whotype;
         ace->who = who;
 
-        list_add_tail(&ace->l_ace, &acl->ace_head);
         acl->naces++;
-
-        return 0;
 }
 
 static struct {
@@ -811,7 +743,6 @@ nfs4_acl_write_who(int who, char *p)
 }
 
 EXPORT_SYMBOL(nfs4_acl_new);
-EXPORT_SYMBOL(nfs4_acl_free);
 EXPORT_SYMBOL(nfs4_acl_add_ace);
 EXPORT_SYMBOL(nfs4_acl_get_whotype);
 EXPORT_SYMBOL(nfs4_acl_write_who);
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 0efba557fb55..fbb4af969243 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -273,42 +273,42 @@ nfsd4_decode_fattr(struct nfsd4_compoundargs *argp, u32 *bmval, struct iattr *ia
                 iattr->ia_valid |= ATTR_SIZE;
         }
         if (bmval[0] & FATTR4_WORD0_ACL) {
-                int nace, i;
-                struct nfs4_ace ace;
+                int nace;
+                struct nfs4_ace *ace;
 
                 READ_BUF(4); len += 4;
                 READ32(nace);
 
-                *acl = nfs4_acl_new();
+                if (nace > NFS4_ACL_MAX)
+                        return nfserr_resource;
+
+                *acl = nfs4_acl_new(nace);
                 if (*acl == NULL) {
                         host_err = -ENOMEM;
                         goto out_nfserr;
                 }
-                defer_free(argp, (void (*)(const void *))nfs4_acl_free, *acl);
+                defer_free(argp, kfree, *acl);
 
-                for (i = 0; i < nace; i++) {
+                (*acl)->naces = nace;
+                for (ace = (*acl)->aces; ace < (*acl)->aces + nace; ace++) {
                         READ_BUF(16); len += 16;
-                        READ32(ace.type);
-                        READ32(ace.flag);
-                        READ32(ace.access_mask);
+                        READ32(ace->type);
+                        READ32(ace->flag);
+                        READ32(ace->access_mask);
                         READ32(dummy32);
                         READ_BUF(dummy32);
                         len += XDR_QUADLEN(dummy32) << 2;
                         READMEM(buf, dummy32);
-                        ace.whotype = nfs4_acl_get_whotype(buf, dummy32);
+                        ace->whotype = nfs4_acl_get_whotype(buf, dummy32);
                         host_err = 0;
-                        if (ace.whotype != NFS4_ACL_WHO_NAMED)
-                                ace.who = 0;
-                        else if (ace.flag & NFS4_ACE_IDENTIFIER_GROUP)
+                        if (ace->whotype != NFS4_ACL_WHO_NAMED)
+                                ace->who = 0;
+                        else if (ace->flag & NFS4_ACE_IDENTIFIER_GROUP)
                                 host_err = nfsd_map_name_to_gid(argp->rqstp,
-                                                buf, dummy32, &ace.who);
+                                                buf, dummy32, &ace->who);
                         else
                                 host_err = nfsd_map_name_to_uid(argp->rqstp,
-                                                buf, dummy32, &ace.who);
-                        if (host_err)
-                                goto out_nfserr;
-                        host_err = nfs4_acl_add_ace(*acl, ace.type, ace.flag,
-                                 ace.access_mask, ace.whotype, ace.who);
+                                                buf, dummy32, &ace->who);
                         if (host_err)
                                 goto out_nfserr;
                 }
@@ -1596,7 +1596,6 @@ nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp,
         }
         if (bmval0 & FATTR4_WORD0_ACL) {
                 struct nfs4_ace *ace;
-                struct list_head *h;
 
                 if (acl == NULL) {
                         if ((buflen -= 4) < 0)
@@ -1609,9 +1608,7 @@ nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp,
                         goto out_resource;
                 WRITE32(acl->naces);
 
-                list_for_each(h, &acl->ace_head) {
-                        ace = list_entry(h, struct nfs4_ace, l_ace);
-
+                for (ace = acl->aces; ace < acl->aces + acl->naces; ace++) {
                         if ((buflen -= 4*3) < 0)
                                 goto out_resource;
                         WRITE32(ace->type);
@@ -1821,7 +1818,7 @@ out_acl:
         status = nfs_ok;
 
 out:
-        nfs4_acl_free(acl);
+        kfree(acl);
         if (fhp == &tempfh)
                 fh_put(&tempfh);
         return status;
diff --git a/include/linux/nfs4.h b/include/linux/nfs4.h
index db05182ca0e8..1be5be88debe 100644
--- a/include/linux/nfs4.h
+++ b/include/linux/nfs4.h
@@ -105,12 +105,11 @@ struct nfs4_ace {
         uint32_t        access_mask;
         int             whotype;
         uid_t           who;
-        struct list_head l_ace;
 };
 
 struct nfs4_acl {
         uint32_t        naces;
-        struct list_head ace_head;
+        struct nfs4_ace aces[0];
 };
 
 typedef struct { char data[NFS4_VERIFIER_SIZE]; } nfs4_verifier;
diff --git a/include/linux/nfs4_acl.h b/include/linux/nfs4_acl.h
index 22aff4d01f20..409b6e02f337 100644
--- a/include/linux/nfs4_acl.h
+++ b/include/linux/nfs4_acl.h
@@ -39,9 +39,12 @@
 
 #include <linux/posix_acl.h>
 
-struct nfs4_acl *nfs4_acl_new(void);
-void nfs4_acl_free(struct nfs4_acl *);
-int nfs4_acl_add_ace(struct nfs4_acl *, u32, u32, u32, int, uid_t);
+/* Maximum ACL we'll accept from client; chosen (somewhat arbitrarily) to
+ * fit in a page: */
+#define NFS4_ACL_MAX 170
+
+struct nfs4_acl *nfs4_acl_new(int);
+void nfs4_acl_add_ace(struct nfs4_acl *, u32, u32, u32, int, uid_t);
 int nfs4_acl_get_whotype(char *, u32);
 int nfs4_acl_write_who(int who, char *p);
 int nfs4_acl_permission(struct nfs4_acl *acl, uid_t owner, gid_t group,