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authorMiao Xie <miaox@cn.fujitsu.com>2011-07-15 10:34:36 +0000
committerChris Mason <chris.mason@oracle.com>2011-07-27 12:46:45 -0400
commit199c36eaa95077a47ae1bc55532fc0fbeb80cc95 (patch)
treeef4e9a5ff244c842b9b335cb391223d9a4d5f854 /fs/btrfs
parentf7aaa06bff6f5fe049ce9723267e1639c2c3d8b5 (diff)
Btrfs: fix BUG_ON() caused by ENOSPC when relocating space
When we balanced the chunks across the devices, BUG_ON() in __finish_chunk_alloc() was triggered. ------------[ cut here ]------------ kernel BUG at fs/btrfs/volumes.c:2568! [SNIP] Call Trace: [<ffffffffa049525e>] btrfs_alloc_chunk+0x8e/0xa0 [btrfs] [<ffffffffa04546b0>] do_chunk_alloc+0x330/0x3a0 [btrfs] [<ffffffffa045c654>] btrfs_reserve_extent+0xb4/0x1f0 [btrfs] [<ffffffffa045c86b>] btrfs_alloc_free_block+0xdb/0x350 [btrfs] [<ffffffffa048a8d8>] ? read_extent_buffer+0xd8/0x1d0 [btrfs] [<ffffffffa04476fd>] __btrfs_cow_block+0x14d/0x5e0 [btrfs] [<ffffffffa044660d>] ? read_block_for_search+0x14d/0x4d0 [btrfs] [<ffffffffa0447c9b>] btrfs_cow_block+0x10b/0x240 [btrfs] [<ffffffffa044dd5e>] btrfs_search_slot+0x49e/0x7a0 [btrfs] [<ffffffffa044f07d>] btrfs_insert_empty_items+0x8d/0xf0 [btrfs] [<ffffffffa045e973>] insert_with_overflow+0x43/0x110 [btrfs] [<ffffffffa045eb0d>] btrfs_insert_dir_item+0xcd/0x1f0 [btrfs] [<ffffffffa0489bd0>] ? map_extent_buffer+0xb0/0xc0 [btrfs] [<ffffffff812276ad>] ? rb_insert_color+0x9d/0x160 [<ffffffffa046cc40>] ? inode_tree_add+0xf0/0x150 [btrfs] [<ffffffffa0474801>] btrfs_add_link+0xc1/0x1c0 [btrfs] [<ffffffff811dacac>] ? security_inode_init_security+0x1c/0x30 [<ffffffffa04a28aa>] ? btrfs_init_acl+0x4a/0x180 [btrfs] [<ffffffffa047492f>] btrfs_add_nondir+0x2f/0x70 [btrfs] [<ffffffffa046af16>] ? btrfs_init_inode_security+0x46/0x60 [btrfs] [<ffffffffa0474ac0>] btrfs_create+0x150/0x1d0 [btrfs] [<ffffffff81159c63>] ? generic_permission+0x23/0xb0 [<ffffffff8115b415>] vfs_create+0xa5/0xc0 [<ffffffff8115ce6e>] do_last+0x5fe/0x880 [<ffffffff8115dc0d>] path_openat+0xcd/0x3d0 [<ffffffff8115e029>] do_filp_open+0x49/0xa0 [<ffffffff8116a965>] ? alloc_fd+0x95/0x160 [<ffffffff8114f0c7>] do_sys_open+0x107/0x1e0 [<ffffffff810bcc3f>] ? audit_syscall_entry+0x1bf/0x1f0 [<ffffffff8114f1e0>] sys_open+0x20/0x30 [<ffffffff81484ec2>] system_call_fastpath+0x16/0x1b [SNIP] RIP [<ffffffffa049444a>] __finish_chunk_alloc+0x20a/0x220 [btrfs] The reason is: Task1 Space balance task do_chunk_alloc() __finish_chunk_alloc() update device info in the chunk tree alloc system metadata block relocate system metadata block group set system metadata block group readonly, This block group is the only one that can allocate space. So there is no free space that can be allocated now. find no space and don't try to alloc new chunk, and then return ENOSPC BUG_ON() in __finish_chunk_alloc() was triggered. Fix this bug by allocating a new system metadata chunk before relocating the old one if we find there is no free space which can be allocated after setting the old block group to be read-only. Reported-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com> Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Tested-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r--fs/btrfs/extent-tree.c28
1 files changed, 21 insertions, 7 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index d7031e7dfd76..7021dde74d81 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -6526,15 +6526,28 @@ static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
return flags;
}
-static int set_block_group_ro(struct btrfs_block_group_cache *cache)
+static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
{
struct btrfs_space_info *sinfo = cache->space_info;
u64 num_bytes;
+ u64 min_allocable_bytes;
int ret = -ENOSPC;
if (cache->ro)
return 0;
+ /*
+ * We need some metadata space and system metadata space for
+ * allocating chunks in some corner cases until we force to set
+ * it to be readonly.
+ */
+ if ((sinfo->flags &
+ (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
+ !force)
+ min_allocable_bytes = 1 * 1024 * 1024;
+ else
+ min_allocable_bytes = 0;
+
spin_lock(&sinfo->lock);
spin_lock(&cache->lock);
num_bytes = cache->key.offset - cache->reserved - cache->pinned -
@@ -6542,7 +6555,8 @@ static int set_block_group_ro(struct btrfs_block_group_cache *cache)
if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
sinfo->bytes_may_use + sinfo->bytes_readonly +
- cache->reserved_pinned + num_bytes <= sinfo->total_bytes) {
+ cache->reserved_pinned + num_bytes + min_allocable_bytes <=
+ sinfo->total_bytes) {
sinfo->bytes_readonly += num_bytes;
sinfo->bytes_reserved += cache->reserved_pinned;
cache->reserved_pinned = 0;
@@ -6573,7 +6587,7 @@ int btrfs_set_block_group_ro(struct btrfs_root *root,
do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
CHUNK_ALLOC_FORCE);
- ret = set_block_group_ro(cache);
+ ret = set_block_group_ro(cache, 0);
if (!ret)
goto out;
alloc_flags = get_alloc_profile(root, cache->space_info->flags);
@@ -6581,7 +6595,7 @@ int btrfs_set_block_group_ro(struct btrfs_root *root,
CHUNK_ALLOC_FORCE);
if (ret < 0)
goto out;
- ret = set_block_group_ro(cache);
+ ret = set_block_group_ro(cache, 0);
out:
btrfs_end_transaction(trans, root);
return ret;
@@ -7018,7 +7032,7 @@ int btrfs_read_block_groups(struct btrfs_root *root)
set_avail_alloc_bits(root->fs_info, cache->flags);
if (btrfs_chunk_readonly(root, cache->key.objectid))
- set_block_group_ro(cache);
+ set_block_group_ro(cache, 1);
}
list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
@@ -7032,9 +7046,9 @@ int btrfs_read_block_groups(struct btrfs_root *root)
* mirrored block groups.
*/
list_for_each_entry(cache, &space_info->block_groups[3], list)
- set_block_group_ro(cache);
+ set_block_group_ro(cache, 1);
list_for_each_entry(cache, &space_info->block_groups[4], list)
- set_block_group_ro(cache);
+ set_block_group_ro(cache, 1);
}
init_global_block_rsv(info);