exofs: dir_inode and directory operations

implementation of directory and inode operations.

* A directory is treated as a file, and essentially contains a list
  of <file name, inode #> pairs for files that are found in that
  directory. The object IDs correspond to the files' inode numbers
  and are allocated using a 64bit incrementing global counter.
* Each file's control block (AKA on-disk inode) is stored in its
  object's attributes. This applies to both regular files and other
  types (directories, device files, symlinks, etc.).

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>

1 files changed, 272 insertions, 0 deletions

diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index a3691d8bfb98..7c26ba371e1b 100644
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -843,3 +843,275 @@ int exofs_setattr(struct dentry *dentry, struct iattr *iattr)
         error = inode_setattr(inode, iattr);
         return error;
 }
+
+/*
+ * Read an inode from the OSD, and return it as is.  We also return the size
+ * attribute in the 'sanity' argument if we got compiled with debugging turned
+ * on.
+ */
+static int exofs_get_inode(struct super_block *sb, struct exofs_i_info *oi,
+                    struct exofs_fcb *inode, uint64_t *sanity)
+{
+        struct exofs_sb_info *sbi = sb->s_fs_info;
+        struct osd_request *or;
+        struct osd_attr attr;
+        struct osd_obj_id obj = {sbi->s_pid,
+                                 oi->vfs_inode.i_ino + EXOFS_OBJ_OFF};
+        int ret;
+
+        exofs_make_credential(oi->i_cred, &obj);
+
+        or = osd_start_request(sbi->s_dev, GFP_KERNEL);
+        if (unlikely(!or)) {
+                EXOFS_ERR("exofs_get_inode: osd_start_request failed.\n");
+                return -ENOMEM;
+        }
+        osd_req_get_attributes(or, &obj);
+
+        /* we need the inode attribute */
+        osd_req_add_get_attr_list(or, &g_attr_inode_data, 1);
+
+#ifdef EXOFS_DEBUG_OBJ_ISIZE
+        /* we get the size attributes to do a sanity check */
+        osd_req_add_get_attr_list(or, &g_attr_logical_length, 1);
+#endif
+
+        ret = exofs_sync_op(or, sbi->s_timeout, oi->i_cred);
+        if (ret)
+                goto out;
+
+        attr = g_attr_inode_data;
+        ret = extract_attr_from_req(or, &attr);
+        if (ret) {
+                EXOFS_ERR("exofs_get_inode: extract_attr_from_req failed\n");
+                goto out;
+        }
+
+        WARN_ON(attr.len != EXOFS_INO_ATTR_SIZE);
+        memcpy(inode, attr.val_ptr, EXOFS_INO_ATTR_SIZE);
+
+#ifdef EXOFS_DEBUG_OBJ_ISIZE
+        attr = g_attr_logical_length;
+        ret = extract_attr_from_req(or, &attr);
+        if (ret) {
+                EXOFS_ERR("ERROR: extract attr from or failed\n");
+                goto out;
+        }
+        *sanity = get_unaligned_be64(attr.val_ptr);
+#endif
+
+out:
+        osd_end_request(or);
+        return ret;
+}
+
+/*
+ * Fill in an inode read from the OSD and set it up for use
+ */
+struct inode *exofs_iget(struct super_block *sb, unsigned long ino)
+{
+        struct exofs_i_info *oi;
+        struct exofs_fcb fcb;
+        struct inode *inode;
+        uint64_t uninitialized_var(sanity);
+        int ret;
+
+        inode = iget_locked(sb, ino);
+        if (!inode)
+                return ERR_PTR(-ENOMEM);
+        if (!(inode->i_state & I_NEW))
+                return inode;
+        oi = exofs_i(inode);
+
+        /* read the inode from the osd */
+        ret = exofs_get_inode(sb, oi, &fcb, &sanity);
+        if (ret)
+                goto bad_inode;
+
+        init_waitqueue_head(&oi->i_wq);
+        set_obj_created(oi);
+
+        /* copy stuff from on-disk struct to in-memory struct */
+        inode->i_mode = le16_to_cpu(fcb.i_mode);
+        inode->i_uid = le32_to_cpu(fcb.i_uid);
+        inode->i_gid = le32_to_cpu(fcb.i_gid);
+        inode->i_nlink = le16_to_cpu(fcb.i_links_count);
+        inode->i_ctime.tv_sec = (signed)le32_to_cpu(fcb.i_ctime);
+        inode->i_atime.tv_sec = (signed)le32_to_cpu(fcb.i_atime);
+        inode->i_mtime.tv_sec = (signed)le32_to_cpu(fcb.i_mtime);
+        inode->i_ctime.tv_nsec =
+                inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = 0;
+        oi->i_commit_size = le64_to_cpu(fcb.i_size);
+        i_size_write(inode, oi->i_commit_size);
+        inode->i_blkbits = EXOFS_BLKSHIFT;
+        inode->i_generation = le32_to_cpu(fcb.i_generation);
+
+#ifdef EXOFS_DEBUG_OBJ_ISIZE
+        if ((inode->i_size != sanity) &&
+                (!exofs_inode_is_fast_symlink(inode))) {
+                EXOFS_ERR("WARNING: Size of object from inode and "
+                          "attributes differ (%lld != %llu)\n",
+                          inode->i_size, _LLU(sanity));
+        }
+#endif
+
+        oi->i_dir_start_lookup = 0;
+
+        if ((inode->i_nlink == 0) && (inode->i_mode == 0)) {
+                ret = -ESTALE;
+                goto bad_inode;
+        }
+
+        if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
+                if (fcb.i_data[0])
+                        inode->i_rdev =
+                                old_decode_dev(le32_to_cpu(fcb.i_data[0]));
+                else
+                        inode->i_rdev =
+                                new_decode_dev(le32_to_cpu(fcb.i_data[1]));
+        } else {
+                memcpy(oi->i_data, fcb.i_data, sizeof(fcb.i_data));
+        }
+
+        if (S_ISREG(inode->i_mode)) {
+                inode->i_op = &exofs_file_inode_operations;
+                inode->i_fop = &exofs_file_operations;
+                inode->i_mapping->a_ops = &exofs_aops;
+        } else if (S_ISDIR(inode->i_mode)) {
+                inode->i_op = &exofs_dir_inode_operations;
+                inode->i_fop = &exofs_dir_operations;
+                inode->i_mapping->a_ops = &exofs_aops;
+        } else if (S_ISLNK(inode->i_mode)) {
+                if (exofs_inode_is_fast_symlink(inode))
+                        inode->i_op = &exofs_fast_symlink_inode_operations;
+                else {
+                        inode->i_op = &exofs_symlink_inode_operations;
+                        inode->i_mapping->a_ops = &exofs_aops;
+                }
+        } else {
+                inode->i_op = &exofs_special_inode_operations;
+                if (fcb.i_data[0])
+                        init_special_inode(inode, inode->i_mode,
+                           old_decode_dev(le32_to_cpu(fcb.i_data[0])));
+                else
+                        init_special_inode(inode, inode->i_mode,
+                           new_decode_dev(le32_to_cpu(fcb.i_data[1])));
+        }
+
+        unlock_new_inode(inode);
+        return inode;
+
+bad_inode:
+        iget_failed(inode);
+        return ERR_PTR(ret);
+}
+
+int __exofs_wait_obj_created(struct exofs_i_info *oi)
+{
+        if (!obj_created(oi)) {
+                BUG_ON(!obj_2bcreated(oi));
+                wait_event(oi->i_wq, obj_created(oi));
+        }
+        return unlikely(is_bad_inode(&oi->vfs_inode)) ? -EIO : 0;
+}
+/*
+ * Callback function from exofs_new_inode().  The important thing is that we
+ * set the obj_created flag so that other methods know that the object exists on
+ * the OSD.
+ */
+static void create_done(struct osd_request *or, void *p)
+{
+        struct inode *inode = p;
+        struct exofs_i_info *oi = exofs_i(inode);
+        struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
+        int ret;
+
+        ret = exofs_check_ok(or);
+        osd_end_request(or);
+        atomic_dec(&sbi->s_curr_pending);
+
+        if (unlikely(ret)) {
+                EXOFS_ERR("object=0x%llx creation faild in pid=0x%llx",
+                          _LLU(sbi->s_pid), _LLU(inode->i_ino + EXOFS_OBJ_OFF));
+                make_bad_inode(inode);
+        } else
+                set_obj_created(oi);
+
+        atomic_dec(&inode->i_count);
+        wake_up(&oi->i_wq);
+}
+
+/*
+ * Set up a new inode and create an object for it on the OSD
+ */
+struct inode *exofs_new_inode(struct inode *dir, int mode)
+{
+        struct super_block *sb;
+        struct inode *inode;
+        struct exofs_i_info *oi;
+        struct exofs_sb_info *sbi;
+        struct osd_request *or;
+        struct osd_obj_id obj;
+        int ret;
+
+        sb = dir->i_sb;
+        inode = new_inode(sb);
+        if (!inode)
+                return ERR_PTR(-ENOMEM);
+
+        oi = exofs_i(inode);
+
+        init_waitqueue_head(&oi->i_wq);
+        set_obj_2bcreated(oi);
+
+        sbi = sb->s_fs_info;
+
+        sb->s_dirt = 1;
+        inode->i_uid = current->cred->fsuid;
+        if (dir->i_mode & S_ISGID) {
+                inode->i_gid = dir->i_gid;
+                if (S_ISDIR(mode))
+                        mode |= S_ISGID;
+        } else {
+                inode->i_gid = current->cred->fsgid;
+        }
+        inode->i_mode = mode;
+
+        inode->i_ino = sbi->s_nextid++;
+        inode->i_blkbits = EXOFS_BLKSHIFT;
+        inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
+        oi->i_commit_size = inode->i_size = 0;
+        spin_lock(&sbi->s_next_gen_lock);
+        inode->i_generation = sbi->s_next_generation++;
+        spin_unlock(&sbi->s_next_gen_lock);
+        insert_inode_hash(inode);
+
+        mark_inode_dirty(inode);
+
+        obj.partition = sbi->s_pid;
+        obj.id = inode->i_ino + EXOFS_OBJ_OFF;
+        exofs_make_credential(oi->i_cred, &obj);
+
+        or = osd_start_request(sbi->s_dev, GFP_KERNEL);
+        if (unlikely(!or)) {
+                EXOFS_ERR("exofs_new_inode: osd_start_request failed\n");
+                return ERR_PTR(-ENOMEM);
+        }
+
+        osd_req_create_object(or, &obj);
+
+        /* increment the refcount so that the inode will still be around when we
+         * reach the callback
+         */
+        atomic_inc(&inode->i_count);
+
+        ret = exofs_async_op(or, create_done, inode, oi->i_cred);
+        if (ret) {
+                atomic_dec(&inode->i_count);
+                osd_end_request(or);
+                return ERR_PTR(-EIO);
+        }
+        atomic_inc(&sbi->s_curr_pending);
+
+        return inode;
+}