5 files changed, 190 insertions, 1 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index a18b7bc2b22c..93a0191aded6 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2232,6 +2232,7 @@ int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
                                u64 num_bytes, u64 *actual_bytes);
 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
                             struct btrfs_root *root, u64 type);
+int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range);
 
 /* ctree.c */
 int btrfs_bin_search(struct extent_buffer *eb, struct btrfs_key *key,
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index e990d2d1ba4a..1efeda3b2f6f 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -440,7 +440,7 @@ static int cache_block_group(struct btrfs_block_group_cache *cache,
          * allocate blocks for the tree root we can't do the fast caching since
          * we likely hold important locks.
          */
-        if (!trans->transaction->in_commit &&
+        if (trans && (!trans->transaction->in_commit) &&
             (root && root != root->fs_info->tree_root)) {
                 spin_lock(&cache->lock);
                 if (cache->cached != BTRFS_CACHE_NO) {
@@ -8778,3 +8778,51 @@ int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
 {
         return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
 }
+
+int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
+{
+        struct btrfs_fs_info *fs_info = root->fs_info;
+        struct btrfs_block_group_cache *cache = NULL;
+        u64 group_trimmed;
+        u64 start;
+        u64 end;
+        u64 trimmed = 0;
+        int ret = 0;
+
+        cache = btrfs_lookup_block_group(fs_info, range->start);
+
+        while (cache) {
+                if (cache->key.objectid >= (range->start + range->len)) {
+                        btrfs_put_block_group(cache);
+                        break;
+                }
+
+                start = max(range->start, cache->key.objectid);
+                end = min(range->start + range->len,
+                                cache->key.objectid + cache->key.offset);
+
+                if (end - start >= range->minlen) {
+                        if (!block_group_cache_done(cache)) {
+                                ret = cache_block_group(cache, NULL, root, 0);
+                                if (!ret)
+                                        wait_block_group_cache_done(cache);
+                        }
+                        ret = btrfs_trim_block_group(cache,
+                                                     &group_trimmed,
+                                                     start,
+                                                     end,
+                                                     range->minlen);
+
+                        trimmed += group_trimmed;
+                        if (ret) {
+                                btrfs_put_block_group(cache);
+                                break;
+                        }
+                }
+
+                cache = next_block_group(fs_info->tree_root, cache);
+        }
+
+        range->len = trimmed;
+        return ret;
+}
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index f03ef97c3b21..0037427d8a9d 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -2178,3 +2178,95 @@ void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
         cluster->block_group = NULL;
 }
 
+int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
+                           u64 *trimmed, u64 start, u64 end, u64 minlen)
+{
+        struct btrfs_free_space *entry = NULL;
+        struct btrfs_fs_info *fs_info = block_group->fs_info;
+        u64 bytes = 0;
+        u64 actually_trimmed;
+        int ret = 0;
+
+        *trimmed = 0;
+
+        while (start < end) {
+                spin_lock(&block_group->tree_lock);
+
+                if (block_group->free_space < minlen) {
+                        spin_unlock(&block_group->tree_lock);
+                        break;
+                }
+
+                entry = tree_search_offset(block_group, start, 0, 1);
+                if (!entry)
+                        entry = tree_search_offset(block_group,
+                                                   offset_to_bitmap(block_group,
+                                                                    start),
+                                                   1, 1);
+
+                if (!entry || entry->offset >= end) {
+                        spin_unlock(&block_group->tree_lock);
+                        break;
+                }
+
+                if (entry->bitmap) {
+                        ret = search_bitmap(block_group, entry, &start, &bytes);
+                        if (!ret) {
+                                if (start >= end) {
+                                        spin_unlock(&block_group->tree_lock);
+                                        break;
+                                }
+                                bytes = min(bytes, end - start);
+                                bitmap_clear_bits(block_group, entry,
+                                                  start, bytes);
+                                if (entry->bytes == 0)
+                                        free_bitmap(block_group, entry);
+                        } else {
+                                start = entry->offset + BITS_PER_BITMAP *
+                                        block_group->sectorsize;
+                                spin_unlock(&block_group->tree_lock);
+                                ret = 0;
+                                continue;
+                        }
+                } else {
+                        start = entry->offset;
+                        bytes = min(entry->bytes, end - start);
+                        unlink_free_space(block_group, entry);
+                        kfree(entry);
+                }
+
+                spin_unlock(&block_group->tree_lock);
+
+                if (bytes >= minlen) {
+                        int update_ret;
+                        update_ret = btrfs_update_reserved_bytes(block_group,
+                                                                 bytes, 1, 1);
+
+                        ret = btrfs_error_discard_extent(fs_info->extent_root,
+                                                         start,
+                                                         bytes,
+                                                         &actually_trimmed);
+
+                        btrfs_add_free_space(block_group,
+                                             start, bytes);
+                        if (!update_ret)
+                                btrfs_update_reserved_bytes(block_group,
+                                                            bytes, 0, 1);
+
+                        if (ret)
+                                break;
+                        *trimmed += actually_trimmed;
+                }
+                start += bytes;
+                bytes = 0;
+
+                if (fatal_signal_pending(current)) {
+                        ret = -ERESTARTSYS;
+                        break;
+                }
+
+                cond_resched();
+        }
+
+        return ret;
+}
diff --git a/fs/btrfs/free-space-cache.h b/fs/btrfs/free-space-cache.h
index e49ca5c321b5..65c3b935289f 100644
--- a/fs/btrfs/free-space-cache.h
+++ b/fs/btrfs/free-space-cache.h
@@ -68,4 +68,6 @@ u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
 int btrfs_return_cluster_to_free_space(
                                struct btrfs_block_group_cache *block_group,
                                struct btrfs_free_cluster *cluster);
+int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
+                           u64 *trimmed, u64 start, u64 end, u64 minlen);
 #endif
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 32c980ae0f1c..649f47d2afb4 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -40,6 +40,7 @@
 #include <linux/xattr.h>
 #include <linux/vmalloc.h>
 #include <linux/slab.h>
+#include <linux/blkdev.h>
 #include "compat.h"
 #include "ctree.h"
 #include "disk-io.h"
@@ -258,6 +259,49 @@ static int btrfs_ioctl_getversion(struct file *file, int __user *arg)
         return put_user(inode->i_generation, arg);
 }
 
+static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg)
+{
+        struct btrfs_root *root = fdentry(file)->d_sb->s_fs_info;
+        struct btrfs_fs_info *fs_info = root->fs_info;
+        struct btrfs_device *device;
+        struct request_queue *q;
+        struct fstrim_range range;
+        u64 minlen = ULLONG_MAX;
+        u64 num_devices = 0;
+        int ret;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -EPERM;
+
+        mutex_lock(&fs_info->fs_devices->device_list_mutex);
+        list_for_each_entry(device, &fs_info->fs_devices->devices, dev_list) {
+                if (!device->bdev)
+                        continue;
+                q = bdev_get_queue(device->bdev);
+                if (blk_queue_discard(q)) {
+                        num_devices++;
+                        minlen = min((u64)q->limits.discard_granularity,
+                                     minlen);
+                }
+        }
+        mutex_unlock(&fs_info->fs_devices->device_list_mutex);
+        if (!num_devices)
+                return -EOPNOTSUPP;
+
+        if (copy_from_user(&range, arg, sizeof(range)))
+                return -EFAULT;
+
+        range.minlen = max(range.minlen, minlen);
+        ret = btrfs_trim_fs(root, &range);
+        if (ret < 0)
+                return ret;
+
+        if (copy_to_user(arg, &range, sizeof(range)))
+                return -EFAULT;
+
+        return 0;
+}
+
 static noinline int create_subvol(struct btrfs_root *root,
                                   struct dentry *dentry,
                                   char *name, int namelen,
@@ -2426,6 +2470,8 @@ long btrfs_ioctl(struct file *file, unsigned int
                 return btrfs_ioctl_setflags(file, argp);
         case FS_IOC_GETVERSION:
                 return btrfs_ioctl_getversion(file, argp);
+        case FITRIM:
+                return btrfs_ioctl_fitrim(file, argp);
         case BTRFS_IOC_SNAP_CREATE:
                 return btrfs_ioctl_snap_create(file, argp, 0);
         case BTRFS_IOC_SNAP_CREATE_V2: