exofs: Move all operations to an io_engine

In anticipation for multi-device operations, we separate osd operations
into an abstract I/O API. Currently only one device is used but later
when adding more devices, we will drive all devices in parallel according
to a "data_map" that describes how data is arranged on multiple devices.
The file system level operates, like before, as if there is one object
(inode-number) and an i_size. The io engine will split this to the same
object-number but on multiple device.

At first we introduce Mirror (raid 1) layout. But at the final outcome
we intend to fully implement the pNFS-Objects data-map, including
raid 0,4,5,6 over mirrored devices, over multiple device-groups. And
more. See: http://tools.ietf.org/html/draft-ietf-nfsv4-pnfs-obj-12

* Define an io_state based API for accessing osd storage devices
  in an abstract way.
  Usage:
	First a caller allocates an io state with:
		exofs_get_io_state(struct exofs_sb_info *sbi,
				   struct exofs_io_state** ios);

	Then calles one of:
		exofs_sbi_create(struct exofs_io_state *ios);
		exofs_sbi_remove(struct exofs_io_state *ios);
		exofs_sbi_write(struct exofs_io_state *ios);
		exofs_sbi_read(struct exofs_io_state *ios);
		exofs_oi_truncate(struct exofs_i_info *oi, u64 new_len);

	And when done
		exofs_put_io_state(struct exofs_io_state *ios);

* Convert all source files to use this new API
* Convert from bio_alloc to bio_kmalloc
* In io engine we make use of the now fixed osd_req_decode_sense

There are no functional changes or on disk additions after this patch.

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

1 files changed, 43 insertions, 77 deletions

diff --git a/fs/exofs/super.c b/fs/exofs/super.c
index 28add3eac0a4..4cd97f526d49 100644
--- a/fs/exofs/super.c
+++ b/fs/exofs/super.c
@@ -203,49 +203,40 @@ int exofs_sync_fs(struct super_block *sb, int wait)
 {
         struct exofs_sb_info *sbi;
         struct exofs_fscb *fscb;
-        struct osd_request *or;
-        struct osd_obj_id obj;
+        struct exofs_io_state *ios;
         int ret = -ENOMEM;
 
-        fscb = kzalloc(sizeof(struct exofs_fscb), GFP_KERNEL);
-        if (!fscb) {
-                EXOFS_ERR("exofs_write_super: memory allocation failed.\n");
-                return -ENOMEM;
-        }
-
         lock_super(sb);
         sbi = sb->s_fs_info;
+        fscb = &sbi->s_fscb;
+
+        ret = exofs_get_io_state(sbi, &ios);
+        if (ret)
+                goto out;
+
+        ios->length = sizeof(*fscb);
+        memset(fscb, 0, ios->length);
         fscb->s_nextid = cpu_to_le64(sbi->s_nextid);
         fscb->s_numfiles = cpu_to_le32(sbi->s_numfiles);
         fscb->s_magic = cpu_to_le16(sb->s_magic);
         fscb->s_newfs = 0;
 
-        or = osd_start_request(sbi->s_dev, GFP_KERNEL);
-        if (unlikely(!or)) {
-                EXOFS_ERR("exofs_write_super: osd_start_request failed.\n");
-                goto out;
-        }
-
-        obj.partition = sbi->s_pid;
-        obj.id = EXOFS_SUPER_ID;
-        ret = osd_req_write_kern(or, &obj, 0, fscb, sizeof(*fscb));
-        if (unlikely(ret)) {
-                EXOFS_ERR("exofs_write_super: osd_req_write_kern failed.\n");
-                goto out;
-        }
+        ios->obj.id = EXOFS_SUPER_ID;
+        ios->offset = 0;
+        ios->kern_buff = fscb;
+        ios->cred = sbi->s_cred;
 
-        ret = exofs_sync_op(or, sbi->s_timeout, sbi->s_cred);
+        ret = exofs_sbi_write(ios);
         if (unlikely(ret)) {
-                EXOFS_ERR("exofs_write_super: exofs_sync_op failed.\n");
+                EXOFS_ERR("%s: exofs_sbi_write failed.\n", __func__);
                 goto out;
         }
         sb->s_dirt = 0;
 
 out:
-        if (or)
-                osd_end_request(or);
+        EXOFS_DBGMSG("s_nextid=0x%llx ret=%d\n", _LLU(sbi->s_nextid), ret);
+        exofs_put_io_state(ios);
         unlock_super(sb);
-        kfree(fscb);
         return ret;
 }
 
@@ -302,24 +293,23 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
         struct inode *root;
         struct exofs_mountopt *opts = data;
         struct exofs_sb_info *sbi;      /*extended info                  */
+        struct osd_dev *od;             /* Master device                 */
         struct exofs_fscb fscb;         /*on-disk superblock info        */
-        struct osd_request *or = NULL;
         struct osd_obj_id obj;
         int ret;
 
         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
         if (!sbi)
                 return -ENOMEM;
-        sb->s_fs_info = sbi;
 
         /* use mount options to fill superblock */
-        sbi->s_dev = osduld_path_lookup(opts->dev_name);
-        if (IS_ERR(sbi->s_dev)) {
-                ret = PTR_ERR(sbi->s_dev);
-                sbi->s_dev = NULL;
+        od = osduld_path_lookup(opts->dev_name);
+        if (IS_ERR(od)) {
+                ret = PTR_ERR(od);
                 goto free_sbi;
         }
 
+        sbi->s_dev = od;
         sbi->s_pid = opts->pid;
         sbi->s_timeout = opts->timeout;
 
@@ -333,35 +323,13 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
         sb->s_bdev = NULL;
         sb->s_dev = 0;
 
-        /* read data from on-disk superblock object */
         obj.partition = sbi->s_pid;
         obj.id = EXOFS_SUPER_ID;
         exofs_make_credential(sbi->s_cred, &obj);
 
-        or = osd_start_request(sbi->s_dev, GFP_KERNEL);
-        if (unlikely(!or)) {
-                if (!silent)
-                        EXOFS_ERR(
-                               "exofs_fill_super: osd_start_request failed.\n");
-                ret = -ENOMEM;
-                goto free_sbi;
-        }
-        ret = osd_req_read_kern(or, &obj, 0, &fscb, sizeof(fscb));
-        if (unlikely(ret)) {
-                if (!silent)
-                        EXOFS_ERR(
-                               "exofs_fill_super: osd_req_read_kern failed.\n");
-                ret = -ENOMEM;
-                goto free_sbi;
-        }
-
-        ret = exofs_sync_op(or, sbi->s_timeout, sbi->s_cred);
-        if (unlikely(ret)) {
-                if (!silent)
-                        EXOFS_ERR("exofs_fill_super: exofs_sync_op failed.\n");
-                ret = -EIO;
+        ret = exofs_read_kern(od, sbi->s_cred, &obj, 0, &fscb, sizeof(fscb));
+        if (unlikely(ret))
                 goto free_sbi;
-        }
 
         sb->s_magic = le16_to_cpu(fscb.s_magic);
         sbi->s_nextid = le64_to_cpu(fscb.s_nextid);
@@ -380,6 +348,7 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
         spin_lock_init(&sbi->s_next_gen_lock);
 
         /* set up operation vectors */
+        sb->s_fs_info = sbi;
         sb->s_op = &exofs_sops;
         sb->s_export_op = &exofs_export_ops;
         root = exofs_iget(sb, EXOFS_ROOT_ID - EXOFS_OBJ_OFF);
@@ -406,16 +375,14 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
         }
 
         _exofs_print_device("Mounting", opts->dev_name, sbi->s_dev, sbi->s_pid);
-        ret = 0;
-out:
-        if (or)
-                osd_end_request(or);
-        return ret;
+        return 0;
 
 free_sbi:
+        EXOFS_ERR("Unable to mount exofs on %s pid=0x%llx err=%d\n",
+                  opts->dev_name, sbi->s_pid, ret);
         osduld_put_device(sbi->s_dev); /* NULL safe */
         kfree(sbi);
-        goto out;
+        return ret;
 }
 
 /*
@@ -444,7 +411,7 @@ static int exofs_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
         struct super_block *sb = dentry->d_sb;
         struct exofs_sb_info *sbi = sb->s_fs_info;
-        struct osd_obj_id obj = {sbi->s_pid, 0};
+        struct exofs_io_state *ios;
         struct osd_attr attrs[] = {
                 ATTR_DEF(OSD_APAGE_PARTITION_QUOTAS,
                         OSD_ATTR_PQ_CAPACITY_QUOTA, sizeof(__be64)),
@@ -453,26 +420,25 @@ static int exofs_statfs(struct dentry *dentry, struct kstatfs *buf)
         };
         uint64_t capacity = ULLONG_MAX;
         uint64_t used = ULLONG_MAX;
-        struct osd_request *or;
         uint8_t cred_a[OSD_CAP_LEN];
         int ret;
 
-        /* get used/capacity attributes */
-        exofs_make_credential(cred_a, &obj);
-
-        or = osd_start_request(sbi->s_dev, GFP_KERNEL);
-        if (unlikely(!or)) {
-                EXOFS_DBGMSG("exofs_statfs: osd_start_request failed.\n");
-                return -ENOMEM;
+        ret = exofs_get_io_state(sbi, &ios);
+        if (ret) {
+                EXOFS_DBGMSG("exofs_get_io_state failed.\n");
+                return ret;
         }
 
-        osd_req_get_attributes(or, &obj);
-        osd_req_add_get_attr_list(or, attrs, ARRAY_SIZE(attrs));
-        ret = exofs_sync_op(or, sbi->s_timeout, cred_a);
+        exofs_make_credential(cred_a, &ios->obj);
+        ios->cred = sbi->s_cred;
+        ios->in_attr = attrs;
+        ios->in_attr_len = ARRAY_SIZE(attrs);
+
+        ret = exofs_sbi_read(ios);
         if (unlikely(ret))
                 goto out;
 
-        ret = extract_attr_from_req(or, &attrs[0]);
+        ret = extract_attr_from_ios(ios, &attrs[0]);
         if (likely(!ret)) {
                 capacity = get_unaligned_be64(attrs[0].val_ptr);
                 if (unlikely(!capacity))
@@ -480,7 +446,7 @@ static int exofs_statfs(struct dentry *dentry, struct kstatfs *buf)
         } else
                 EXOFS_DBGMSG("exofs_statfs: get capacity failed.\n");
 
-        ret = extract_attr_from_req(or, &attrs[1]);
+        ret = extract_attr_from_ios(ios, &attrs[1]);
         if (likely(!ret))
                 used = get_unaligned_be64(attrs[1].val_ptr);
         else
@@ -497,7 +463,7 @@ static int exofs_statfs(struct dentry *dentry, struct kstatfs *buf)
         buf->f_namelen = EXOFS_NAME_LEN;
 
 out:
-        osd_end_request(or);
+        exofs_put_io_state(ios);
         return ret;
 }