ore/exofs: Change the type of the devices array (API change)

In the pNFS obj-LD the device table at the layout level needs
to point to a device_cache node, where it is possible and likely
that many layouts will point to the same device-nodes.

In Exofs we have a more orderly structure where we have a single
array of devices that repeats twice for a round-robin view of the
device table

This patch moves to a model that can be used by the pNFS obj-LD
where struct ore_components holds an array of ore_dev-pointers.
(ore_dev is newly defined and contains a struct osd_dev *od
 member)

Each pointer in the array of pointers will point to a bigger
user-defined dev_struct. That can be accessed by use of the
container_of macro.

In Exofs an __alloc_dev_table() function allocates the
ore_dev-pointers array as well as an exofs_dev array, in one
allocation and does the addresses dance to set everything pointing
correctly. It still keeps the double allocation trick for the
inodes round-robin view of the table.

The device table is always allocated dynamically, also for the
single device case. So it is unconditionally freed at umount.

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

diff --git a/fs/exofs/exofs.h b/fs/exofs/exofs.h
index 3b2e047..006fd6f 100644 (file)
--- a/fs/exofs/exofs.h
+++ b/fs/exofs/exofs.h
@@ -53,6 +53,10 @@
 /* u64 has problems with printk this will cast it to unsigned long long */
 #define _LLU(x) (unsigned long long)(x)
 
+struct exofs_dev {
+       struct ore_dev ored;
+       unsigned did;
+};
 /*
  * our extension to the in-memory superblock
  */
@@ -69,7 +73,6 @@ struct exofs_sb_info {
        struct ore_layout       layout;         /* Default files layout       */
        struct ore_comp one_comp;               /* id & cred of partition id=0*/
        struct ore_components oc;               /* comps for the partition    */
-       struct osd_dev  *_min_one_dev[1];       /* Place holder for one dev   */
 };
 
 /*
@@ -214,13 +217,14 @@ static inline void exofs_init_comps(struct ore_components *oc,
        one_comp->obj.id = oid;
        exofs_make_credential(one_comp->cred, &one_comp->obj);
 
-       oc->numdevs = sbi->oc.numdevs;
+       oc->numdevs = sbi->layout.group_width * sbi->layout.mirrors_p1 *
+                                                       sbi->layout.group_count;
        oc->single_comp = EC_SINGLE_COMP;
        oc->comps = one_comp;
 
        /* Round robin device view of the table */
        first_dev = (dev_mod * sbi->layout.mirrors_p1) % sbi->oc.numdevs;
-       oc->ods = sbi->oc.ods + first_dev;
+       oc->ods = &sbi->oc.ods[first_dev];
 }
 
 #endif

diff --git a/fs/exofs/ore.c b/fs/exofs/ore.c
index c2b0033..a7d7925 100644 (file)
--- a/fs/exofs/ore.c
+++ b/fs/exofs/ore.c
@@ -59,7 +59,7 @@ static struct osd_obj_id *_ios_obj(struct ore_io_state *ios, unsigned index)
 
 static struct osd_dev *_ios_od(struct ore_io_state *ios, unsigned index)
 {
-       return ios->oc->ods[index];
+       return ore_comp_dev(ios->oc, index);
 }
 
 int  ore_get_rw_state(struct ore_layout *layout, struct ore_components *oc,

diff --git a/fs/exofs/super.c b/fs/exofs/super.c
index 90b4c52..bce3686 100644 (file)
--- a/fs/exofs/super.c
+++ b/fs/exofs/super.c
@@ -431,17 +431,18 @@ static void _exofs_print_device(const char *msg, const char *dev_path,
 
 static void exofs_free_sbi(struct exofs_sb_info *sbi)
 {
-       while (sbi->oc.numdevs) {
-               int i = --sbi->oc.numdevs;
-               struct osd_dev *od = sbi->oc.ods[i];
+       unsigned numdevs = sbi->oc.numdevs;
+
+       while (numdevs) {
+               unsigned i = --numdevs;
+               struct osd_dev *od = ore_comp_dev(&sbi->oc, i);
 
                if (od) {
-                       sbi->oc.ods[i] = NULL;
+                       ore_comp_set_dev(&sbi->oc, i, NULL);
                        osduld_put_device(od);
                }
        }
-       if (sbi->oc.ods != sbi->_min_one_dev)
-               kfree(sbi->oc.ods);
+       kfree(sbi->oc.ods);
        kfree(sbi);
 }
 
@@ -468,7 +469,7 @@ static void exofs_put_super(struct super_block *sb)
                                  msecs_to_jiffies(100));
        }
 
-       _exofs_print_device("Unmounting", NULL, sbi->oc.ods[0],
+       _exofs_print_device("Unmounting", NULL, ore_comp_dev(&sbi->oc, 0),
                            sbi->one_comp.obj.partition);
 
        bdi_destroy(&sbi->bdi);
@@ -592,12 +593,40 @@ static int exofs_devs_2_odi(struct exofs_dt_device_info *dt_dev,
        return !(odi->systemid_len || odi->osdname_len);
 }
 
+int __alloc_dev_table(struct exofs_sb_info *sbi, unsigned numdevs,
+                     struct exofs_dev **peds)
+{
+       struct __alloc_ore_devs_and_exofs_devs {
+               /* Twice bigger table: See exofs_init_comps() and comment at
+                * exofs_read_lookup_dev_table()
+                */
+               struct ore_dev *oreds[numdevs * 2 - 1];
+               struct exofs_dev eds[numdevs];
+       } *aoded;
+       struct exofs_dev *eds;
+       unsigned i;
+
+       aoded = kzalloc(sizeof(*aoded), GFP_KERNEL);
+       if (unlikely(!aoded)) {
+               EXOFS_ERR("ERROR: faild allocating Device array[%d]\n",
+                         numdevs);
+               return -ENOMEM;
+       }
+
+       sbi->oc.ods = aoded->oreds;
+       *peds = eds = aoded->eds;
+       for (i = 0; i < numdevs; ++i)
+               aoded->oreds[i] = &eds[i].ored;
+       return 0;
+}
+
 static int exofs_read_lookup_dev_table(struct exofs_sb_info *sbi,
                                       struct osd_dev *fscb_od,
                                       unsigned table_count)
 {
        struct ore_comp comp;
        struct exofs_device_table *dt;
+       struct exofs_dev *eds;
        unsigned table_bytes = table_count * sizeof(dt->dt_dev_table[0]) +
                                             sizeof(*dt);
        unsigned numdevs, i;
@@ -634,20 +663,16 @@ static int exofs_read_lookup_dev_table(struct exofs_sb_info *sbi,
        if (unlikely(ret))
                goto out;
 
-       if (likely(numdevs > 1)) {
-               unsigned size = numdevs * sizeof(sbi->oc.ods[0]);
-
-               /* Twice bigger table: See exofs_init_comps() and below
-                * comment
-                */
-               sbi->oc.ods = kzalloc(size + size - 1, GFP_KERNEL);
-               if (unlikely(!sbi->oc.ods)) {
-                       EXOFS_ERR("ERROR: faild allocating Device array[%d]\n",
-                                 numdevs);
-                       ret = -ENOMEM;
-                       goto out;
-               }
-       }
+       ret = __alloc_dev_table(sbi, numdevs, &eds);
+       if (unlikely(ret))
+               goto out;
+       /* exofs round-robins the device table view according to inode
+        * number. We hold a: twice bigger table hence inodes can point
+        * to any device and have a sequential view of the table
+        * starting at this device. See exofs_init_comps()
+        */
+       memcpy(&sbi->oc.ods[numdevs], &sbi->oc.ods[0],
+               (numdevs - 1) * sizeof(sbi->oc.ods[0]));
 
        for (i = 0; i < numdevs; i++) {
                struct exofs_fscb fscb;
@@ -663,12 +688,15 @@ static int exofs_read_lookup_dev_table(struct exofs_sb_info *sbi,
                printk(KERN_NOTICE "Add device[%d]: osd_name-%s\n",
                       i, odi.osdname);
 
+               /* the exofs id is currently the table index */
+               eds[i].did = i;
+
                /* On all devices the device table is identical. The user can
                 * specify any one of the participating devices on the command
                 * line. We always keep them in device-table order.
                 */
                if (fscb_od && osduld_device_same(fscb_od, &odi)) {
-                       sbi->oc.ods[i] = fscb_od;
+                       eds[i].ored.od = fscb_od;
                        ++sbi->oc.numdevs;
                        fscb_od = NULL;
                        continue;
@@ -682,7 +710,7 @@ static int exofs_read_lookup_dev_table(struct exofs_sb_info *sbi,
                        goto out;
                }
 
-               sbi->oc.ods[i] = od;
+               eds[i].ored.od = od;
                ++sbi->oc.numdevs;
 
                /* Read the fscb of the other devices to make sure the FS
@@ -705,21 +733,10 @@ static int exofs_read_lookup_dev_table(struct exofs_sb_info *sbi,
 
 out:
        kfree(dt);
-       if (likely(!ret)) {
-               unsigned numdevs = sbi->oc.numdevs;
-
-               if (unlikely(fscb_od)) {
+       if (unlikely(fscb_od && !ret)) {
                        EXOFS_ERR("ERROR: Bad device-table container device not present\n");
                        osduld_put_device(fscb_od);
                        return -EINVAL;
-               }
-               /* exofs round-robins the device table view according to inode
-                * number. We hold a: twice bigger table hence inodes can point
-                * to any device and have a sequential view of the table
-                * starting at this device. See exofs_init_comps()
-                */
-               for (i = 0; i < numdevs - 1; ++i)
-                       sbi->oc.ods[i + numdevs] = sbi->oc.ods[i];
        }
        return ret;
 }
@@ -773,7 +790,6 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
        sbi->oc.numdevs = 1;
        sbi->oc.single_comp = EC_SINGLE_COMP;
        sbi->oc.comps = &sbi->one_comp;
-       sbi->oc.ods = sbi->_min_one_dev;
 
        /* fill in some other data by hand */
        memset(sb->s_id, 0, sizeof(sb->s_id));
@@ -822,7 +838,13 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
                if (unlikely(ret))
                        goto free_sbi;
        } else {
-               sbi->oc.ods[0] = od;
+               struct exofs_dev *eds;
+
+               ret = __alloc_dev_table(sbi, 1, &eds);
+               if (unlikely(ret))
+                       goto free_sbi;
+
+               ore_comp_set_dev(&sbi->oc, 0, od);
        }
 
        __sbi_read_stats(sbi);
@@ -862,7 +884,8 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
                goto free_sbi;
        }
 
-       _exofs_print_device("Mounting", opts->dev_name, sbi->oc.ods[0],
+       _exofs_print_device("Mounting", opts->dev_name,
+                           ore_comp_dev(&sbi->oc, 0),
                            sbi->one_comp.obj.partition);
        return 0;
 

diff --git a/include/scsi/osd_ore.h b/include/scsi/osd_ore.h
index e4d550f..8fefdfb 100644 (file)
--- a/include/scsi/osd_ore.h
+++ b/include/scsi/osd_ore.h
@@ -44,6 +44,10 @@ struct ore_layout {
        unsigned group_count;
 };
 
+struct ore_dev {
+       struct osd_dev *od;
+};
+
 struct ore_components {
        unsigned        numdevs;                /* Num of devices in array    */
        /* If @single_comp == EC_SINGLE_COMP, @comps points to a single
@@ -53,9 +57,29 @@ struct ore_components {
                EC_SINGLE_COMP = 0, EC_MULTPLE_COMPS = 0xffffffff
        }               single_comp;
        struct ore_comp *comps;
-       struct osd_dev  **ods;                  /* osd_dev array              */
+
+       /* Array of pointers to ore_dev-* . User will usually have these pointed
+        * too a bigger struct which contain an "ore_dev ored" member and use
+        * container_of(oc->ods[i], struct foo_dev, ored) to access the bigger
+        * structure.
+        */
+       struct ore_dev  **ods;
 };
 
+/* ore_comp_dev Recievies a logical device index */
+static inline struct osd_dev *ore_comp_dev(
+       const struct ore_components *oc, unsigned i)
+{
+       BUG_ON(oc->numdevs <= i);
+       return oc->ods[i]->od;
+}
+
+static inline void ore_comp_set_dev(
+       struct ore_components *oc, unsigned i, struct osd_dev *od)
+{
+       oc->ods[i]->od = od;
+}
+
 struct ore_striping_info {
        u64 obj_offset;
        u64 group_length;