Btrfs: Add ACL support

Signed-off-by: Chris Mason <chris.mason@oracle.com>

6 files changed, 335 insertions, 48 deletions

diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c
index ff0fcc72848a..b192659b4f5f 100644
--- a/fs/btrfs/acl.c
+++ b/fs/btrfs/acl.c
@@ -20,76 +20,302 @@
 #include <linux/string.h>
 #include <linux/xattr.h>
 #include <linux/posix_acl_xattr.h>
+#include <linux/posix_acl.h>
 #include <linux/sched.h>
+
 #include "ctree.h"
+#include "btrfs_inode.h"
 #include "xattr.h"
-#ifndef is_owner_or_cap
-#define is_owner_or_cap(inode)  \
-        ((current->fsuid == (inode)->i_uid) || capable(CAP_FOWNER))
-#endif
+
+static void btrfs_update_cached_acl(struct inode *inode,
+                                    struct posix_acl **p_acl,
+                                    struct posix_acl *acl)
+{
+        spin_lock(&inode->i_lock);
+        if (*p_acl && *p_acl != BTRFS_ACL_NOT_CACHED)
+                posix_acl_release(*p_acl);
+        *p_acl = posix_acl_dup(acl);
+        spin_unlock(&inode->i_lock);
+}
+
+static struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
+{
+        int size, name_index;
+        char *value = NULL;
+        struct posix_acl *acl = NULL, **p_acl;
+
+        switch (type) {
+        case ACL_TYPE_ACCESS:
+                name_index = BTRFS_XATTR_INDEX_POSIX_ACL_ACCESS;
+                p_acl = &BTRFS_I(inode)->i_acl;
+                break;
+        case ACL_TYPE_DEFAULT:
+                name_index = BTRFS_XATTR_INDEX_POSIX_ACL_DEFAULT;
+                p_acl = &BTRFS_I(inode)->i_default_acl;
+                break;
+        default:
+                return ERR_PTR(-EINVAL);
+        }
+
+        spin_lock(&inode->i_lock);
+        if (*p_acl != BTRFS_ACL_NOT_CACHED)
+                acl = posix_acl_dup(*p_acl);
+        spin_unlock(&inode->i_lock);
+
+        if (acl)
+                return acl;
+
+
+        size = btrfs_xattr_get(inode, name_index, "", NULL, 0);
+        if (size > 0) {
+                value = kzalloc(size, GFP_NOFS);
+                if (!value)
+                        return ERR_PTR(-ENOMEM);
+                size = btrfs_xattr_get(inode, name_index, "", value, size);
+                if (size > 0) {
+                        acl = posix_acl_from_xattr(value, size);
+                        btrfs_update_cached_acl(inode, p_acl, acl);
+                }
+                kfree(value);
+        } else if (size == -ENOENT) {
+                acl = NULL;
+                btrfs_update_cached_acl(inode, p_acl, acl);
+        }
+
+        return acl;
+}
+
+static int btrfs_xattr_get_acl(struct inode *inode, int type,
+                               void *value, size_t size)
+{
+        struct posix_acl *acl;
+        int ret = 0;
+
+        acl = btrfs_get_acl(inode, type);
+
+        if (IS_ERR(acl))
+                return PTR_ERR(acl);
+        if (acl == NULL)
+                return -ENODATA;
+        ret = posix_acl_to_xattr(acl, value, size);
+        posix_acl_release(acl);
+
+        return ret;
+}
+
+/*
+ * Needs to be called with fs_mutex held
+ */
+static int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
+{
+        int ret, name_index = 0, size = 0;
+        struct posix_acl **p_acl;
+        char *value = NULL;
+        mode_t mode;
+
+        if (acl) {
+                ret = posix_acl_valid(acl);
+                if (ret < 0)
+                        return ret;
+                ret = 0;
+        }
+
+        switch (type) {
+        case ACL_TYPE_ACCESS:
+                mode = inode->i_mode;
+                ret = posix_acl_equiv_mode(acl, &mode);
+                if (ret < 0)
+                        return ret;
+                ret = 0;
+                inode->i_mode = mode;
+                name_index = BTRFS_XATTR_INDEX_POSIX_ACL_ACCESS;
+                p_acl = &BTRFS_I(inode)->i_acl;
+                break;
+        case ACL_TYPE_DEFAULT:
+                if (!S_ISDIR(inode->i_mode))
+                        return acl ? -EINVAL : 0;
+                name_index = BTRFS_XATTR_INDEX_POSIX_ACL_DEFAULT;
+                p_acl = &BTRFS_I(inode)->i_default_acl;
+                break;
+        default:
+                return -EINVAL;
+        }
+
+        if (acl) {
+                size = posix_acl_xattr_size(acl->a_count);
+                value = kmalloc(size, GFP_NOFS);
+                if (!value) {
+                        ret = -ENOMEM;
+                        goto out;
+                }
+
+                ret = posix_acl_to_xattr(acl, value, size);
+                if (ret < 0)
+                        goto out;
+        }
+
+        ret = btrfs_xattr_set(inode, name_index, "", value, size, 0);
+
+out:
+        if (value)
+                kfree(value);
+
+        if (!ret)
+                btrfs_update_cached_acl(inode, p_acl, acl);
+
+        return ret;
+}
 
 static int btrfs_xattr_set_acl(struct inode *inode, int type,
                                const void *value, size_t size)
 {
         int ret = 0;
-        struct posix_acl *acl;
+        struct posix_acl *acl = NULL;
 
-        if (!is_owner_or_cap(inode))
-                return -EPERM;
         if (value) {
                 acl = posix_acl_from_xattr(value, size);
                 if (acl == NULL) {
                         value = NULL;
                         size = 0;
                 } else if (IS_ERR(acl)) {
-                        ret = PTR_ERR(acl);
-                } else {
-                        ret = posix_acl_valid(acl);
-                        posix_acl_release(acl);
+                        return PTR_ERR(acl);
                 }
-                if (ret)
-                        return ret;
         }
-        return btrfs_xattr_set(inode, type, "", value, size, 0);
-}
 
-static int btrfs_xattr_get_acl(struct inode *inode, int type,
-                               void *value, size_t size)
-{
-        return btrfs_xattr_get(inode, type, "", value, size);
+        ret = btrfs_set_acl(inode, acl, type);
+
+        posix_acl_release(acl);
+
+        return ret;
 }
+
+
 static int btrfs_xattr_acl_access_get(struct inode *inode, const char *name,
                                       void *value, size_t size)
 {
-        if (*name != '\0')
-               return -EINVAL;
-        return btrfs_xattr_get_acl(inode, BTRFS_XATTR_INDEX_POSIX_ACL_ACCESS,
-                                   value, size);
+        return btrfs_xattr_get_acl(inode, ACL_TYPE_ACCESS, value, size);
 }
+
 static int btrfs_xattr_acl_access_set(struct inode *inode, const char *name,
                                       const void *value, size_t size, int flags)
 {
-        if (*name != '\0')
-               return -EINVAL;
-        return btrfs_xattr_set_acl(inode, BTRFS_XATTR_INDEX_POSIX_ACL_ACCESS,
-                                   value, size);
+        return btrfs_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
 }
+
 static int btrfs_xattr_acl_default_get(struct inode *inode, const char *name,
                                        void *value, size_t size)
 {
-        if (*name != '\0')
-               return -EINVAL;
-        return btrfs_xattr_get_acl(inode, BTRFS_XATTR_INDEX_POSIX_ACL_DEFAULT,
-                                   value, size);
+        return btrfs_xattr_get_acl(inode, ACL_TYPE_DEFAULT, value, size);
 }
+
 static int btrfs_xattr_acl_default_set(struct inode *inode, const char *name,
                                        const void *value, size_t size, int flags)
 {
-        if (*name != '\0')
-               return -EINVAL;
-        return btrfs_xattr_set_acl(inode, BTRFS_XATTR_INDEX_POSIX_ACL_DEFAULT,
-                                   value, size);
+        return btrfs_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
+}
+
+int btrfs_check_acl(struct inode *inode, int mask)
+{
+        struct posix_acl *acl;
+        int error = -EAGAIN;
+
+        acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
+
+        if (IS_ERR(acl))
+                return PTR_ERR(acl);
+        if (acl) {
+                error = posix_acl_permission(inode, acl, mask);
+                posix_acl_release(acl);
+        }
+
+        return error;
+}
+
+/*
+ * btrfs_init_acl is already generally called under fs_mutex, so the locking
+ * stuff has been fixed to work with that.  If the locking stuff changes, we
+ * need to re-evaluate the acl locking stuff.
+ */
+int btrfs_init_acl(struct inode *inode, struct inode *dir)
+{
+        struct posix_acl *acl = NULL;
+        int ret = 0;
+
+        /* this happens with subvols */
+        if (!dir)
+                return 0;
+
+        if (!S_ISLNK(inode->i_mode)) {
+                if (IS_POSIXACL(dir)) {
+                        acl = btrfs_get_acl(dir, ACL_TYPE_DEFAULT);
+                        if (IS_ERR(acl))
+                                return PTR_ERR(acl);
+                }
+
+                if (!acl)
+                        inode->i_mode &= ~current->fs->umask;
+        }
+
+        if (IS_POSIXACL(dir) && acl) {
+                struct posix_acl *clone;
+                mode_t mode;
+
+                if (S_ISDIR(inode->i_mode)) {
+                        ret = btrfs_set_acl(inode, acl, ACL_TYPE_DEFAULT);
+                        if (ret)
+                                goto failed;
+                }
+                clone = posix_acl_clone(acl, GFP_NOFS);
+                ret = -ENOMEM;
+                if (!clone)
+                        goto failed;
+
+                mode = inode->i_mode;
+                ret = posix_acl_create_masq(clone, &mode);
+                if (ret >= 0) {
+                        inode->i_mode = mode;
+                        if (ret > 0) {
+                                /* we need an acl */
+                                ret = btrfs_set_acl(inode, clone,
+                                                    ACL_TYPE_ACCESS);
+                        }
+                }
+        }
+failed:
+        posix_acl_release(acl);
+
+        return ret;
+}
+
+int btrfs_acl_chmod(struct inode *inode)
+{
+        struct posix_acl *acl, *clone;
+        int ret = 0;
+
+        if (S_ISLNK(inode->i_mode))
+                return -EOPNOTSUPP;
+
+        if (!IS_POSIXACL(inode))
+                return 0;
+
+        acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
+        if (IS_ERR(acl) || !acl)
+                return PTR_ERR(acl);
+
+        clone = posix_acl_clone(acl, GFP_KERNEL);
+        posix_acl_release(acl);
+        if (!clone)
+                return -ENOMEM;
+
+        ret = posix_acl_chmod_masq(clone, inode->i_mode);
+        if (!ret)
+                ret = btrfs_set_acl(inode, clone, ACL_TYPE_ACCESS);
+
+        posix_acl_release(clone);
+
+        return ret;
 }
+
 struct xattr_handler btrfs_xattr_acl_default_handler = {
         .prefix = POSIX_ACL_XATTR_DEFAULT,
         .list   = btrfs_xattr_generic_list,
diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index b7bd60e4fdd7..9f2a4ef944a7 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -36,6 +36,9 @@ struct btrfs_inode {
         struct inode vfs_inode;
         struct btrfs_ordered_inode_tree ordered_tree;
 
+        struct posix_acl *i_acl;
+        struct posix_acl *i_default_acl;
+
         /*
          * transid of the trans_handle that last modified this inode
          */
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 53d315bdd16d..f87d7263f2d7 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -42,6 +42,8 @@ struct btrfs_ordered_sum;
 
 #define BTRFS_MAGIC "_B5RfS_M"
 
+#define BTRFS_ACL_NOT_CACHED    ((void *)-1)
+
 #ifdef CONFIG_LOCKDEP
 # define BTRFS_MAX_LEVEL 7
 #else
@@ -1694,4 +1696,9 @@ ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size);
 u64 btrfs_parse_size(char *str);
 int btrfs_parse_options(struct btrfs_root *root, char *options);
 int btrfs_sync_fs(struct super_block *sb, int wait);
+
+/* acl.c */
+int btrfs_check_acl(struct inode *inode, int mask);
+int btrfs_init_acl(struct inode *inode, struct inode *dir);
+int btrfs_acl_chmod(struct inode *inode);
 #endif
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 8d371d6fe551..2d8853543a71 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -36,6 +36,7 @@
 #include <linux/bit_spinlock.h>
 #include <linux/version.h>
 #include <linux/xattr.h>
+#include <linux/posix_acl.h>
 #include "ctree.h"
 #include "disk-io.h"
 #include "transaction.h"
@@ -1478,6 +1479,9 @@ static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
         }
 out:
         err = inode_setattr(inode, attr);
+
+        if (!err && ((attr->ia_valid & ATTR_MODE)))
+                err = btrfs_acl_chmod(inode);
 fail:
         return err;
 }
@@ -2184,6 +2188,12 @@ static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
         if (IS_ERR(inode))
                 goto out_unlock;
 
+        err = btrfs_init_acl(inode, dir);
+        if (err) {
+                drop_inode = 1;
+                goto out_unlock;
+        }
+
         btrfs_set_trans_block_group(trans, inode);
         err = btrfs_add_nondir(trans, dentry, inode, 0);
         if (err)
@@ -2239,6 +2249,12 @@ static int btrfs_create(struct inode *dir, struct dentry *dentry,
         if (IS_ERR(inode))
                 goto out_unlock;
 
+        err = btrfs_init_acl(inode, dir);
+        if (err) {
+                drop_inode = 1;
+                goto out_unlock;
+        }
+
         btrfs_set_trans_block_group(trans, inode);
         err = btrfs_add_nondir(trans, dentry, inode, 0);
         if (err)
@@ -2366,6 +2382,11 @@ static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
         }
 
         drop_on_err = 1;
+
+        err = btrfs_init_acl(inode, dir);
+        if (err)
+                goto out_fail;
+
         inode->i_op = &btrfs_dir_inode_operations;
         inode->i_fop = &btrfs_dir_file_operations;
         btrfs_set_trans_block_group(trans, inode);
@@ -3023,6 +3044,8 @@ struct inode *btrfs_alloc_inode(struct super_block *sb)
                 return NULL;
         ei->last_trans = 0;
         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
+        ei->i_acl = BTRFS_ACL_NOT_CACHED;
+        ei->i_default_acl = BTRFS_ACL_NOT_CACHED;
         return &ei->vfs_inode;
 }
 
@@ -3032,6 +3055,13 @@ void btrfs_destroy_inode(struct inode *inode)
         WARN_ON(!list_empty(&inode->i_dentry));
         WARN_ON(inode->i_data.nrpages);
 
+        if (BTRFS_I(inode)->i_acl &&
+            BTRFS_I(inode)->i_acl != BTRFS_ACL_NOT_CACHED)
+                posix_acl_release(BTRFS_I(inode)->i_acl);
+        if (BTRFS_I(inode)->i_default_acl &&
+            BTRFS_I(inode)->i_default_acl != BTRFS_ACL_NOT_CACHED)
+                posix_acl_release(BTRFS_I(inode)->i_default_acl);
+
         while(1) {
                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
                 if (!ordered)
@@ -3230,6 +3260,12 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
         if (IS_ERR(inode))
                 goto out_unlock;
 
+        err = btrfs_init_acl(inode, dir);
+        if (err) {
+                drop_inode = 1;
+                goto out_unlock;
+        }
+
         btrfs_set_trans_block_group(trans, inode);
         err = btrfs_add_nondir(trans, dentry, inode, 0);
         if (err)
@@ -3310,7 +3346,7 @@ static int btrfs_permission(struct inode *inode, int mask,
 {
         if (btrfs_test_flag(inode, READONLY) && (mask & MAY_WRITE))
                 return -EACCES;
-        return generic_permission(inode, mask, NULL);
+        return generic_permission(inode, mask, btrfs_check_acl);
 }
 
 static struct inode_operations btrfs_dir_inode_operations = {
@@ -3392,6 +3428,10 @@ static struct inode_operations btrfs_special_inode_operations = {
         .getattr        = btrfs_getattr,
         .setattr        = btrfs_setattr,
         .permission     = btrfs_permission,
+        .setxattr       = generic_setxattr,
+        .getxattr       = generic_getxattr,
+        .listxattr      = btrfs_listxattr,
+        .removexattr    = generic_removexattr,
 };
 static struct inode_operations btrfs_symlink_inode_operations = {
         .readlink       = generic_readlink,
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 4cb6aac5122e..a6a418b6894b 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -68,7 +68,7 @@ static void btrfs_put_super (struct super_block * sb)
 enum {
         Opt_degraded, Opt_subvol, Opt_device, Opt_nodatasum, Opt_nodatacow,
         Opt_max_extent, Opt_max_inline, Opt_alloc_start, Opt_nobarrier,
-        Opt_ssd, Opt_thread_pool, Opt_err,
+        Opt_ssd, Opt_thread_pool, Opt_noacl,  Opt_err,
 };
 
 static match_table_t tokens = {
@@ -83,7 +83,8 @@ static match_table_t tokens = {
         {Opt_alloc_start, "alloc_start=%s"},
         {Opt_thread_pool, "thread_pool=%d"},
         {Opt_ssd, "ssd"},
-        {Opt_err, NULL}
+        {Opt_noacl, "noacl"},
+        {Opt_err, NULL},
 };
 
 u64 btrfs_parse_size(char *str)
@@ -215,6 +216,9 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
                                         info->alloc_start);
                         }
                         break;
+                case Opt_noacl:
+                        root->fs_info->sb->s_flags &= ~MS_POSIXACL;
+                        break;
                 default:
                         break;
                 }
@@ -301,6 +305,7 @@ static int btrfs_fill_super(struct super_block * sb,
         sb->s_op = &btrfs_super_ops;
         sb->s_xattr = btrfs_xattr_handlers;
         sb->s_time_gran = 1;
+        sb->s_flags |= MS_POSIXACL;
 
         tree_root = open_ctree(sb, fs_devices, (char *)data);
 
diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c
index 6730b5958844..121c9550314f 100644
--- a/fs/btrfs/xattr.c
+++ b/fs/btrfs/xattr.c
@@ -26,25 +26,27 @@
 #include "transaction.h"
 #include "xattr.h"
 #include "disk-io.h"
+
 static struct xattr_handler *btrfs_xattr_handler_map[] = {
         [BTRFS_XATTR_INDEX_USER]                = &btrfs_xattr_user_handler,
 #ifdef CONFIG_FS_POSIX_ACL
-//      [BTRFS_XATTR_INDEX_POSIX_ACL_ACCESS]    = &btrfs_xattr_acl_access_handler,
-//      [BTRFS_XATTR_INDEX_POSIX_ACL_DEFAULT]   = &btrfs_xattr_acl_default_handler,
+        [BTRFS_XATTR_INDEX_POSIX_ACL_ACCESS]    = &btrfs_xattr_acl_access_handler,
+        [BTRFS_XATTR_INDEX_POSIX_ACL_DEFAULT]   = &btrfs_xattr_acl_default_handler,
 #endif
         [BTRFS_XATTR_INDEX_TRUSTED]             = &btrfs_xattr_trusted_handler,
         [BTRFS_XATTR_INDEX_SECURITY]            = &btrfs_xattr_security_handler,
-//      [BTRFS_XATTR_INDEX_SYSTEM]              = &btrfs_xattr_system_handler,
+        [BTRFS_XATTR_INDEX_SYSTEM]              = &btrfs_xattr_system_handler,
 };
+
 struct xattr_handler *btrfs_xattr_handlers[] = {
         &btrfs_xattr_user_handler,
 #ifdef CONFIG_FS_POSIX_ACL
-//      &btrfs_xattr_acl_access_handler,
-//      &btrfs_xattr_acl_default_handler,
+        &btrfs_xattr_acl_access_handler,
+        &btrfs_xattr_acl_default_handler,
 #endif
         &btrfs_xattr_trusted_handler,
         &btrfs_xattr_security_handler,
-//      &btrfs_xattr_system_handler,
+        &btrfs_xattr_system_handler,
         NULL,
 };
 
@@ -237,10 +239,14 @@ int btrfs_xattr_set(struct inode *inode, int name_index,
                         mod = 1;
                         goto out;
                 }
-        } else if (flags & XATTR_REPLACE) {
-                /* we couldn't find the attr to replace, so error out */
-                ret = -ENODATA;
-                goto out;
+        } else {
+                btrfs_release_path(root, path);
+
+                if (flags & XATTR_REPLACE) {
+                        /* we couldn't find the attr to replace */
+                        ret = -ENODATA;
+                        goto out;
+                }
         }
 
         /* ok we have to create a completely new xattr */