Btrfs: change core code of btrfs to support the device replace operations

This commit contains all the essential changes to the core code
of Btrfs for support of the device replace procedure.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/fs/btrfs/reada.c b/fs/btrfs/reada.c
index 9f363e17ec74..c705a48e676b 100644
--- a/fs/btrfs/reada.c
+++ b/fs/btrfs/reada.c
@@ -27,6 +27,7 @@
 #include "volumes.h"
 #include "disk-io.h"
 #include "transaction.h"
+#include "dev-replace.h"
 
 #undef DEBUG
 
@@ -331,6 +332,7 @@ static struct reada_extent *reada_find_extent(struct btrfs_root *root,
         int nzones = 0;
         int i;
         unsigned long index = logical >> PAGE_CACHE_SHIFT;
+        int dev_replace_is_ongoing;
 
         spin_lock(&fs_info->reada_lock);
         re = radix_tree_lookup(&fs_info->reada_tree, index);
@@ -392,6 +394,7 @@ static struct reada_extent *reada_find_extent(struct btrfs_root *root,
         }
 
         /* insert extent in reada_tree + all per-device trees, all or nothing */
+        btrfs_dev_replace_lock(&fs_info->dev_replace);
         spin_lock(&fs_info->reada_lock);
         ret = radix_tree_insert(&fs_info->reada_tree, index, re);
         if (ret == -EEXIST) {
@@ -399,13 +402,17 @@ static struct reada_extent *reada_find_extent(struct btrfs_root *root,
                 BUG_ON(!re_exist);
                 re_exist->refcnt++;
                 spin_unlock(&fs_info->reada_lock);
+                btrfs_dev_replace_unlock(&fs_info->dev_replace);
                 goto error;
         }
         if (ret) {
                 spin_unlock(&fs_info->reada_lock);
+                btrfs_dev_replace_unlock(&fs_info->dev_replace);
                 goto error;
         }
         prev_dev = NULL;
+        dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing(
+                        &fs_info->dev_replace);
         for (i = 0; i < nzones; ++i) {
                 dev = bbio->stripes[i].dev;
                 if (dev == prev_dev) {
@@ -422,6 +429,14 @@ static struct reada_extent *reada_find_extent(struct btrfs_root *root,
                         /* cannot read ahead on missing device */
                         continue;
                 }
+                if (dev_replace_is_ongoing &&
+                    dev == fs_info->dev_replace.tgtdev) {
+                        /*
+                         * as this device is selected for reading only as
+                         * a last resort, skip it for read ahead.
+                         */
+                        continue;
+                }
                 prev_dev = dev;
                 ret = radix_tree_insert(&dev->reada_extents, index, re);
                 if (ret) {
@@ -434,10 +449,12 @@ static struct reada_extent *reada_find_extent(struct btrfs_root *root,
                         BUG_ON(fs_info == NULL);
                         radix_tree_delete(&fs_info->reada_tree, index);
                         spin_unlock(&fs_info->reada_lock);
+                        btrfs_dev_replace_unlock(&fs_info->dev_replace);
                         goto error;
                 }
         }
         spin_unlock(&fs_info->reada_lock);
+        btrfs_dev_replace_unlock(&fs_info->dev_replace);
 
         kfree(bbio);
         return re;