1 files changed, 110 insertions, 7 deletions

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 33848196550e..030847bf7cec 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -27,10 +27,17 @@
 #include "disk-io.h"
 #include "extent_io.h"
 #include "inode-map.h"
+#include "volumes.h"
 
 #define BITS_PER_BITMAP         (PAGE_CACHE_SIZE * 8)
 #define MAX_CACHE_BYTES_PER_GIG (32 * 1024)
 
+struct btrfs_trim_range {
+        u64 start;
+        u64 bytes;
+        struct list_head list;
+};
+
 static int link_free_space(struct btrfs_free_space_ctl *ctl,
                            struct btrfs_free_space *info);
 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
@@ -881,6 +888,7 @@ int write_cache_extent_entries(struct io_ctl *io_ctl,
         int ret;
         struct btrfs_free_cluster *cluster = NULL;
         struct rb_node *node = rb_first(&ctl->free_space_offset);
+        struct btrfs_trim_range *trim_entry;
 
         /* Get the cluster for this block_group if it exists */
         if (block_group && !list_empty(&block_group->cluster_list)) {
@@ -916,6 +924,21 @@ int write_cache_extent_entries(struct io_ctl *io_ctl,
                         cluster = NULL;
                 }
         }
+
+        /*
+         * Make sure we don't miss any range that was removed from our rbtree
+         * because trimming is running. Otherwise after a umount+mount (or crash
+         * after committing the transaction) we would leak free space and get
+         * an inconsistent free space cache report from fsck.
+         */
+        list_for_each_entry(trim_entry, &ctl->trimming_ranges, list) {
+                ret = io_ctl_add_entry(io_ctl, trim_entry->start,
+                                       trim_entry->bytes, NULL);
+                if (ret)
+                        goto fail;
+                *entries += 1;
+        }
+
         return 0;
 fail:
         return -ENOSPC;
@@ -1135,12 +1158,15 @@ static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
 
         io_ctl_set_generation(&io_ctl, trans->transid);
 
+        mutex_lock(&ctl->cache_writeout_mutex);
         /* Write out the extent entries in the free space cache */
         ret = write_cache_extent_entries(&io_ctl, ctl,
                                          block_group, &entries, &bitmaps,
                                          &bitmap_list);
-        if (ret)
+        if (ret) {
+                mutex_unlock(&ctl->cache_writeout_mutex);
                 goto out_nospc;
+        }
 
         /*
          * Some spaces that are freed in the current transaction are pinned,
@@ -1148,11 +1174,18 @@ static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
          * committed, we shouldn't lose them.
          */
         ret = write_pinned_extent_entries(root, block_group, &io_ctl, &entries);
-        if (ret)
+        if (ret) {
+                mutex_unlock(&ctl->cache_writeout_mutex);
                 goto out_nospc;
+        }
 
-        /* At last, we write out all the bitmaps. */
+        /*
+         * At last, we write out all the bitmaps and keep cache_writeout_mutex
+         * locked while doing it because a concurrent trim can be manipulating
+         * or freeing the bitmap.
+         */
         ret = write_bitmap_entries(&io_ctl, &bitmap_list);
+        mutex_unlock(&ctl->cache_writeout_mutex);
         if (ret)
                 goto out_nospc;
 
@@ -2295,6 +2328,8 @@ void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group)
         ctl->start = block_group->key.objectid;
         ctl->private = block_group;
         ctl->op = &free_space_op;
+        INIT_LIST_HEAD(&ctl->trimming_ranges);
+        mutex_init(&ctl->cache_writeout_mutex);
 
         /*
          * we only want to have 32k of ram per block group for keeping
@@ -2911,10 +2946,12 @@ void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
 
 static int do_trimming(struct btrfs_block_group_cache *block_group,
                        u64 *total_trimmed, u64 start, u64 bytes,
-                       u64 reserved_start, u64 reserved_bytes)
+                       u64 reserved_start, u64 reserved_bytes,
+                       struct btrfs_trim_range *trim_entry)
 {
         struct btrfs_space_info *space_info = block_group->space_info;
         struct btrfs_fs_info *fs_info = block_group->fs_info;
+        struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
         int ret;
         int update = 0;
         u64 trimmed = 0;
@@ -2934,7 +2971,10 @@ static int do_trimming(struct btrfs_block_group_cache *block_group,
         if (!ret)
                 *total_trimmed += trimmed;
 
+        mutex_lock(&ctl->cache_writeout_mutex);
         btrfs_add_free_space(block_group, reserved_start, reserved_bytes);
+        list_del(&trim_entry->list);
+        mutex_unlock(&ctl->cache_writeout_mutex);
 
         if (update) {
                 spin_lock(&space_info->lock);
@@ -2962,16 +3002,21 @@ static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
         u64 bytes;
 
         while (start < end) {
+                struct btrfs_trim_range trim_entry;
+
+                mutex_lock(&ctl->cache_writeout_mutex);
                 spin_lock(&ctl->tree_lock);
 
                 if (ctl->free_space < minlen) {
                         spin_unlock(&ctl->tree_lock);
+                        mutex_unlock(&ctl->cache_writeout_mutex);
                         break;
                 }
 
                 entry = tree_search_offset(ctl, start, 0, 1);
                 if (!entry) {
                         spin_unlock(&ctl->tree_lock);
+                        mutex_unlock(&ctl->cache_writeout_mutex);
                         break;
                 }
 
@@ -2980,6 +3025,7 @@ static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
                         node = rb_next(&entry->offset_index);
                         if (!node) {
                                 spin_unlock(&ctl->tree_lock);
+                                mutex_unlock(&ctl->cache_writeout_mutex);
                                 goto out;
                         }
                         entry = rb_entry(node, struct btrfs_free_space,
@@ -2988,6 +3034,7 @@ static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
 
                 if (entry->offset >= end) {
                         spin_unlock(&ctl->tree_lock);
+                        mutex_unlock(&ctl->cache_writeout_mutex);
                         break;
                 }
 
@@ -2997,6 +3044,7 @@ static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
                 bytes = min(extent_start + extent_bytes, end) - start;
                 if (bytes < minlen) {
                         spin_unlock(&ctl->tree_lock);
+                        mutex_unlock(&ctl->cache_writeout_mutex);
                         goto next;
                 }
 
@@ -3004,9 +3052,13 @@ static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
                 kmem_cache_free(btrfs_free_space_cachep, entry);
 
                 spin_unlock(&ctl->tree_lock);
+                trim_entry.start = extent_start;
+                trim_entry.bytes = extent_bytes;
+                list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
+                mutex_unlock(&ctl->cache_writeout_mutex);
 
                 ret = do_trimming(block_group, total_trimmed, start, bytes,
-                                  extent_start, extent_bytes);
+                                  extent_start, extent_bytes, &trim_entry);
                 if (ret)
                         break;
 next:
@@ -3035,17 +3087,21 @@ static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
 
         while (offset < end) {
                 bool next_bitmap = false;
+                struct btrfs_trim_range trim_entry;
 
+                mutex_lock(&ctl->cache_writeout_mutex);
                 spin_lock(&ctl->tree_lock);
 
                 if (ctl->free_space < minlen) {
                         spin_unlock(&ctl->tree_lock);
+                        mutex_unlock(&ctl->cache_writeout_mutex);
                         break;
                 }
 
                 entry = tree_search_offset(ctl, offset, 1, 0);
                 if (!entry) {
                         spin_unlock(&ctl->tree_lock);
+                        mutex_unlock(&ctl->cache_writeout_mutex);
                         next_bitmap = true;
                         goto next;
                 }
@@ -3054,6 +3110,7 @@ static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
                 ret2 = search_bitmap(ctl, entry, &start, &bytes);
                 if (ret2 || start >= end) {
                         spin_unlock(&ctl->tree_lock);
+                        mutex_unlock(&ctl->cache_writeout_mutex);
                         next_bitmap = true;
                         goto next;
                 }
@@ -3061,6 +3118,7 @@ static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
                 bytes = min(bytes, end - start);
                 if (bytes < minlen) {
                         spin_unlock(&ctl->tree_lock);
+                        mutex_unlock(&ctl->cache_writeout_mutex);
                         goto next;
                 }
 
@@ -3069,9 +3127,13 @@ static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
                         free_bitmap(ctl, entry);
 
                 spin_unlock(&ctl->tree_lock);
+                trim_entry.start = start;
+                trim_entry.bytes = bytes;
+                list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
+                mutex_unlock(&ctl->cache_writeout_mutex);
 
                 ret = do_trimming(block_group, total_trimmed, start, bytes,
-                                  start, bytes);
+                                  start, bytes, &trim_entry);
                 if (ret)
                         break;
 next:
@@ -3101,11 +3163,52 @@ int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
 
         *trimmed = 0;
 
+        spin_lock(&block_group->lock);
+        if (block_group->removed) {
+                spin_unlock(&block_group->lock);
+                return 0;
+        }
+        atomic_inc(&block_group->trimming);
+        spin_unlock(&block_group->lock);
+
         ret = trim_no_bitmap(block_group, trimmed, start, end, minlen);
         if (ret)
-                return ret;
+                goto out;
 
         ret = trim_bitmaps(block_group, trimmed, start, end, minlen);
+out:
+        spin_lock(&block_group->lock);
+        if (atomic_dec_and_test(&block_group->trimming) &&
+            block_group->removed) {
+                struct extent_map_tree *em_tree;
+                struct extent_map *em;
+
+                spin_unlock(&block_group->lock);
+
+                em_tree = &block_group->fs_info->mapping_tree.map_tree;
+                write_lock(&em_tree->lock);
+                em = lookup_extent_mapping(em_tree, block_group->key.objectid,
+                                           1);
+                BUG_ON(!em); /* logic error, can't happen */
+                remove_extent_mapping(em_tree, em);
+                write_unlock(&em_tree->lock);
+
+                lock_chunks(block_group->fs_info->chunk_root);
+                list_del_init(&em->list);
+                unlock_chunks(block_group->fs_info->chunk_root);
+
+                /* once for us and once for the tree */
+                free_extent_map(em);
+                free_extent_map(em);
+
+                /*
+                 * We've left one free space entry and other tasks trimming
+                 * this block group have left 1 entry each one. Free them.
+                 */
+                __btrfs_remove_free_space_cache(block_group->free_space_ctl);
+        } else {
+                spin_unlock(&block_group->lock);
+        }
 
         return ret;
 }