exofs: Add offset/length to exofs_get_io_state

In future raid code we will need to know the IO offset/length
and if it's a read or write to determine some of the array
sizes we'll need.

So add a new exofs_get_rw_state() API for use when
writeing/reading. All other simple cases are left using the
old way.

The major change to this is that now we need to call
exofs_get_io_state later at inode.c::read_exec and
inode.c::write_exec when we actually know these things. So this
patch is kept separate so I can test things apart from other
changes.

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

1 files changed, 21 insertions, 13 deletions

diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index 8472c098445d..ba9f0bedcbaf 100644
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -110,13 +110,6 @@ static int pcol_try_alloc(struct page_collect *pcol)
 {
         unsigned pages;
 
-        if (!pcol->ios) { /* First time allocate io_state */
-                int ret = exofs_get_io_state(&pcol->sbi->layout, &pcol->ios);
-
-                if (ret)
-                        return ret;
-        }
-
         /* TODO: easily support bio chaining */
         pages =  exofs_max_io_pages(&pcol->sbi->layout, pcol->expected_pages);
 
@@ -269,17 +262,25 @@ static void _unlock_pcol_pages(struct page_collect *pcol, int ret, int rw)
 static int read_exec(struct page_collect *pcol)
 {
         struct exofs_i_info *oi = exofs_i(pcol->inode);
-        struct exofs_io_state *ios = pcol->ios;
+        struct exofs_io_state *ios;
         struct page_collect *pcol_copy = NULL;
         int ret;
 
         if (!pcol->pages)
                 return 0;
 
+        if (!pcol->ios) {
+                int ret = exofs_get_rw_state(&pcol->sbi->layout, true,
+                                             pcol->pg_first << PAGE_CACHE_SHIFT,
+                                             pcol->length, &pcol->ios);
+
+                if (ret)
+                        return ret;
+        }
+
+        ios = pcol->ios;
         ios->pages = pcol->pages;
         ios->nr_pages = pcol->nr_pages;
-        ios->length = pcol->length;
-        ios->offset = pcol->pg_first << PAGE_CACHE_SHIFT;
 
         if (pcol->read_4_write) {
                 exofs_oi_read(oi, pcol->ios);
@@ -507,13 +508,21 @@ static void writepages_done(struct exofs_io_state *ios, void *p)
 static int write_exec(struct page_collect *pcol)
 {
         struct exofs_i_info *oi = exofs_i(pcol->inode);
-        struct exofs_io_state *ios = pcol->ios;
+        struct exofs_io_state *ios;
         struct page_collect *pcol_copy = NULL;
         int ret;
 
         if (!pcol->pages)
                 return 0;
 
+        BUG_ON(pcol->ios);
+        ret = exofs_get_rw_state(&pcol->sbi->layout, false,
+                                 pcol->pg_first << PAGE_CACHE_SHIFT,
+                                 pcol->length, &pcol->ios);
+
+        if (unlikely(ret))
+                goto err;
+
         pcol_copy = kmalloc(sizeof(*pcol_copy), GFP_KERNEL);
         if (!pcol_copy) {
                 EXOFS_ERR("write_exec: Failed to kmalloc(pcol)\n");
@@ -523,10 +532,9 @@ static int write_exec(struct page_collect *pcol)
 
         *pcol_copy = *pcol;
 
+        ios = pcol->ios;
         ios->pages = pcol_copy->pages;
         ios->nr_pages = pcol_copy->nr_pages;
-        ios->offset = pcol_copy->pg_first << PAGE_CACHE_SHIFT;
-        ios->length = pcol_copy->length;
         ios->done = writepages_done;
         ios->private = pcol_copy;