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authorLiu Bo <liubo2009@cn.fujitsu.com>2012-03-29 09:57:44 -0400
committerChris Mason <chris.mason@oracle.com>2012-03-29 09:57:44 -0400
commit15d1ff8111aad85d8b40ee396758990d17a2caac (patch)
tree5258905b649150abae0a8aa010bbaa7ef1077e97 /fs/btrfs/extent-tree.c
parent2bcc0328c3a043880796a602c75fbeb1537aa1e1 (diff)
Btrfs: fix deadlock during allocating chunks
This deadlock comes from xfstests 251. We'll hold the chunk_mutex throughout the whole of a chunk allocation. But if we find that we've used up system chunk space, we need to allocate a new system chunk, but this will lead to a recursion of chunk allocation and end up with a deadlock on chunk_mutex. So instead we need to allocate the system chunk first if we find we're in ENOSPC. Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/extent-tree.c')
-rw-r--r--fs/btrfs/extent-tree.c50
1 files changed, 50 insertions, 0 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 7c233407beee..a84420491c11 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3445,6 +3445,50 @@ static int should_alloc_chunk(struct btrfs_root *root,
3445 return 1; 3445 return 1;
3446} 3446}
3447 3447
3448static u64 get_system_chunk_thresh(struct btrfs_root *root, u64 type)
3449{
3450 u64 num_dev;
3451
3452 if (type & BTRFS_BLOCK_GROUP_RAID10 ||
3453 type & BTRFS_BLOCK_GROUP_RAID0)
3454 num_dev = root->fs_info->fs_devices->rw_devices;
3455 else if (type & BTRFS_BLOCK_GROUP_RAID1)
3456 num_dev = 2;
3457 else
3458 num_dev = 1; /* DUP or single */
3459
3460 /* metadata for updaing devices and chunk tree */
3461 return btrfs_calc_trans_metadata_size(root, num_dev + 1);
3462}
3463
3464static void check_system_chunk(struct btrfs_trans_handle *trans,
3465 struct btrfs_root *root, u64 type)
3466{
3467 struct btrfs_space_info *info;
3468 u64 left;
3469 u64 thresh;
3470
3471 info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3472 spin_lock(&info->lock);
3473 left = info->total_bytes - info->bytes_used - info->bytes_pinned -
3474 info->bytes_reserved - info->bytes_readonly;
3475 spin_unlock(&info->lock);
3476
3477 thresh = get_system_chunk_thresh(root, type);
3478 if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) {
3479 printk(KERN_INFO "left=%llu, need=%llu, flags=%llu\n",
3480 left, thresh, type);
3481 dump_space_info(info, 0, 0);
3482 }
3483
3484 if (left < thresh) {
3485 u64 flags;
3486
3487 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
3488 btrfs_alloc_chunk(trans, root, flags);
3489 }
3490}
3491
3448static int do_chunk_alloc(struct btrfs_trans_handle *trans, 3492static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3449 struct btrfs_root *extent_root, u64 alloc_bytes, 3493 struct btrfs_root *extent_root, u64 alloc_bytes,
3450 u64 flags, int force) 3494 u64 flags, int force)
@@ -3515,6 +3559,12 @@ again:
3515 force_metadata_allocation(fs_info); 3559 force_metadata_allocation(fs_info);
3516 } 3560 }
3517 3561
3562 /*
3563 * Check if we have enough space in SYSTEM chunk because we may need
3564 * to update devices.
3565 */
3566 check_system_chunk(trans, extent_root, flags);
3567
3518 ret = btrfs_alloc_chunk(trans, extent_root, flags); 3568 ret = btrfs_alloc_chunk(trans, extent_root, flags);
3519 if (ret < 0 && ret != -ENOSPC) 3569 if (ret < 0 && ret != -ENOSPC)
3520 goto out; 3570 goto out;