From bc42bda22345efdb5d8b578d1b4df2c6eaa85c58 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Mon, 27 Feb 2017 15:10:39 +0800 Subject: [PATCH] btrfs: qgroup: Fix qgroup reserved space underflow by only freeing reserved ranges [BUG] For the following case, btrfs can underflow qgroup reserved space at an error path: (Page size 4K, function name without "btrfs_" prefix) Task A | Task B ---------------------------------------------------------------------- Buffered_write [0, 2K) | |- check_data_free_space() | | |- qgroup_reserve_data() | | Range aligned to page | | range [0, 4K) <<< | | 4K bytes reserved <<< | |- copy pages to page cache | | Buffered_write [2K, 4K) | |- check_data_free_space() | | |- qgroup_reserved_data() | | Range alinged to page | | range [0, 4K) | | Already reserved by A <<< | | 0 bytes reserved <<< | |- delalloc_reserve_metadata() | | And it *FAILED* (Maybe EQUOTA) | |- free_reserved_data_space() |- qgroup_free_data() Range aligned to page range [0, 4K) Freeing 4K (Special thanks to Chandan for the detailed report and analyse) [CAUSE] Above Task B is freeing reserved data range [0, 4K) which is actually reserved by Task A. And at writeback time, page dirty by Task A will go through writeback routine, which will free 4K reserved data space at file extent insert time, causing the qgroup underflow. [FIX] For btrfs_qgroup_free_data(), add @reserved parameter to only free data ranges reserved by previous btrfs_qgroup_reserve_data(). So in above case, Task B will try to free 0 byte, so no underflow. Reported-by: Chandan Rajendra Signed-off-by: Qu Wenruo Reviewed-by: Chandan Rajendra Tested-by: Chandan Rajendra Signed-off-by: David Sterba --- fs/btrfs/ctree.h | 6 ++-- fs/btrfs/extent-tree.c | 12 ++++--- fs/btrfs/file.c | 29 +++++++++-------- fs/btrfs/inode.c | 29 +++++++++-------- fs/btrfs/ioctl.c | 4 +-- fs/btrfs/qgroup.c | 72 +++++++++++++++++++++++++++++++++++++++--- fs/btrfs/qgroup.h | 3 +- fs/btrfs/relocation.c | 8 ++--- 8 files changed, 117 insertions(+), 46 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 1ee4489dc398..5bdd36664421 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -2711,7 +2711,10 @@ enum btrfs_flush_state { int btrfs_alloc_data_chunk_ondemand(struct btrfs_inode *inode, u64 bytes); int btrfs_check_data_free_space(struct inode *inode, struct extent_changeset **reserved, u64 start, u64 len); -void btrfs_free_reserved_data_space(struct inode *inode, u64 start, u64 len); +void btrfs_free_reserved_data_space(struct inode *inode, + struct extent_changeset *reserved, u64 start, u64 len); +void btrfs_delalloc_release_space(struct inode *inode, + struct extent_changeset *reserved, u64 start, u64 len); void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start, u64 len); void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans, @@ -2730,7 +2733,6 @@ int btrfs_delalloc_reserve_metadata(struct btrfs_inode *inode, u64 num_bytes); void btrfs_delalloc_release_metadata(struct btrfs_inode *inode, u64 num_bytes); int btrfs_delalloc_reserve_space(struct inode *inode, struct extent_changeset **reserved, u64 start, u64 len); -void btrfs_delalloc_release_space(struct inode *inode, u64 start, u64 len); void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type); struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_fs_info *fs_info, unsigned short type); diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 70f85cfdbd46..a3339acec28c 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -4389,7 +4389,8 @@ void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start, * This one will handle the per-inode data rsv map for accurate reserved * space framework. */ -void btrfs_free_reserved_data_space(struct inode *inode, u64 start, u64 len) +void btrfs_free_reserved_data_space(struct inode *inode, + struct extent_changeset *reserved, u64 start, u64 len) { struct btrfs_root *root = BTRFS_I(inode)->root; @@ -4399,7 +4400,7 @@ void btrfs_free_reserved_data_space(struct inode *inode, u64 start, u64 len) start = round_down(start, root->fs_info->sectorsize); btrfs_free_reserved_data_space_noquota(inode, start, len); - btrfs_qgroup_free_data(inode, start, len); + btrfs_qgroup_free_data(inode, reserved, start, len); } static void force_metadata_allocation(struct btrfs_fs_info *info) @@ -6204,7 +6205,7 @@ int btrfs_delalloc_reserve_space(struct inode *inode, return ret; ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode), len); if (ret < 0) - btrfs_free_reserved_data_space(inode, start, len); + btrfs_free_reserved_data_space(inode, *reserved, start, len); return ret; } @@ -6223,10 +6224,11 @@ int btrfs_delalloc_reserve_space(struct inode *inode, * list if there are no delalloc bytes left. * Also it will handle the qgroup reserved space. */ -void btrfs_delalloc_release_space(struct inode *inode, u64 start, u64 len) +void btrfs_delalloc_release_space(struct inode *inode, + struct extent_changeset *reserved, u64 start, u64 len) { btrfs_delalloc_release_metadata(BTRFS_I(inode), len); - btrfs_free_reserved_data_space(inode, start, len); + btrfs_free_reserved_data_space(inode, reserved, start, len); } static int update_block_group(struct btrfs_trans_handle *trans, diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 1b5cce51728b..0f102a1b851f 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -1660,8 +1660,9 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file, reserve_bytes); if (ret) { if (!only_release_metadata) - btrfs_free_reserved_data_space(inode, pos, - write_bytes); + btrfs_free_reserved_data_space(inode, + data_reserved, pos, + write_bytes); else btrfs_end_write_no_snapshoting(root); break; @@ -1743,8 +1744,9 @@ again: __pos = round_down(pos, fs_info->sectorsize) + (dirty_pages << PAGE_SHIFT); - btrfs_delalloc_release_space(inode, __pos, - release_bytes); + btrfs_delalloc_release_space(inode, + data_reserved, __pos, + release_bytes); } } @@ -1799,9 +1801,9 @@ again: btrfs_delalloc_release_metadata(BTRFS_I(inode), release_bytes); } else { - btrfs_delalloc_release_space(inode, - round_down(pos, fs_info->sectorsize), - release_bytes); + btrfs_delalloc_release_space(inode, data_reserved, + round_down(pos, fs_info->sectorsize), + release_bytes); } } @@ -2918,8 +2920,8 @@ static long btrfs_fallocate(struct file *file, int mode, * range, free reserved data space first, otherwise * it'll result in false ENOSPC error. */ - btrfs_free_reserved_data_space(inode, cur_offset, - last_byte - cur_offset); + btrfs_free_reserved_data_space(inode, data_reserved, + cur_offset, last_byte - cur_offset); } free_extent_map(em); cur_offset = last_byte; @@ -2938,8 +2940,9 @@ static long btrfs_fallocate(struct file *file, int mode, range->len, i_blocksize(inode), offset + len, &alloc_hint); else - btrfs_free_reserved_data_space(inode, range->start, - range->len); + btrfs_free_reserved_data_space(inode, + data_reserved, range->start, + range->len); list_del(&range->list); kfree(range); } @@ -2977,8 +2980,8 @@ out: inode_unlock(inode); /* Let go of our reservation. */ if (ret != 0) - btrfs_free_reserved_data_space(inode, alloc_start, - alloc_end - cur_offset); + btrfs_free_reserved_data_space(inode, data_reserved, + alloc_start, alloc_end - cur_offset); extent_changeset_free(data_reserved); return ret; } diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index d9cf6df40d5e..5d3c6ac960fd 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -345,7 +345,7 @@ out: * And at reserve time, it's always aligned to page size, so * just free one page here. */ - btrfs_qgroup_free_data(inode, 0, PAGE_SIZE); + btrfs_qgroup_free_data(inode, NULL, 0, PAGE_SIZE); btrfs_free_path(path); btrfs_end_transaction(trans); return ret; @@ -2935,7 +2935,7 @@ static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent) * space for NOCOW range. * As NOCOW won't cause a new delayed ref, just free the space */ - btrfs_qgroup_free_data(inode, ordered_extent->file_offset, + btrfs_qgroup_free_data(inode, NULL, ordered_extent->file_offset, ordered_extent->len); btrfs_ordered_update_i_size(inode, 0, ordered_extent); if (nolock) @@ -4794,7 +4794,7 @@ int btrfs_truncate_block(struct inode *inode, loff_t from, loff_t len, again: page = find_or_create_page(mapping, index, mask); if (!page) { - btrfs_delalloc_release_space(inode, + btrfs_delalloc_release_space(inode, data_reserved, round_down(from, blocksize), blocksize); ret = -ENOMEM; @@ -4866,7 +4866,7 @@ again: out_unlock: if (ret) - btrfs_delalloc_release_space(inode, block_start, + btrfs_delalloc_release_space(inode, data_reserved, block_start, blocksize); unlock_page(page); put_page(page); @@ -5266,7 +5266,7 @@ static void evict_inode_truncate_pages(struct inode *inode) * Note, end is the bytenr of last byte, so we need + 1 here. */ if (state->state & EXTENT_DELALLOC) - btrfs_qgroup_free_data(inode, start, end - start + 1); + btrfs_qgroup_free_data(inode, NULL, start, end - start + 1); clear_extent_bit(io_tree, start, end, EXTENT_LOCKED | EXTENT_DIRTY | @@ -8792,8 +8792,8 @@ static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter) current->journal_info = NULL; if (ret < 0 && ret != -EIOCBQUEUED) { if (dio_data.reserve) - btrfs_delalloc_release_space(inode, offset, - dio_data.reserve); + btrfs_delalloc_release_space(inode, data_reserved, + offset, dio_data.reserve); /* * On error we might have left some ordered extents * without submitting corresponding bios for them, so @@ -8808,8 +8808,8 @@ static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter) dio_data.unsubmitted_oe_range_start, false); } else if (ret >= 0 && (size_t)ret < count) - btrfs_delalloc_release_space(inode, offset, - count - (size_t)ret); + btrfs_delalloc_release_space(inode, data_reserved, + offset, count - (size_t)ret); } out: if (wakeup) @@ -9008,7 +9008,7 @@ again: * free the entire extent. */ if (PageDirty(page)) - btrfs_qgroup_free_data(inode, page_start, PAGE_SIZE); + btrfs_qgroup_free_data(inode, NULL, page_start, PAGE_SIZE); if (!inode_evicting) { clear_extent_bit(tree, page_start, page_end, EXTENT_LOCKED | EXTENT_DIRTY | @@ -9130,8 +9130,8 @@ again: spin_lock(&BTRFS_I(inode)->lock); BTRFS_I(inode)->outstanding_extents++; spin_unlock(&BTRFS_I(inode)->lock); - btrfs_delalloc_release_space(inode, page_start, - PAGE_SIZE - reserved_space); + btrfs_delalloc_release_space(inode, data_reserved, + page_start, PAGE_SIZE - reserved_space); } } @@ -9187,7 +9187,8 @@ out_unlock: } unlock_page(page); out: - btrfs_delalloc_release_space(inode, page_start, reserved_space); + btrfs_delalloc_release_space(inode, data_reserved, page_start, + reserved_space); out_noreserve: sb_end_pagefault(inode->i_sb); extent_changeset_free(data_reserved); @@ -10557,7 +10558,7 @@ next: btrfs_end_transaction(trans); } if (cur_offset < end) - btrfs_free_reserved_data_space(inode, cur_offset, + btrfs_free_reserved_data_space(inode, NULL, cur_offset, end - cur_offset + 1); return ret; } diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index ccee5417d3f6..b4e9941efb60 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -1227,7 +1227,7 @@ again: spin_lock(&BTRFS_I(inode)->lock); BTRFS_I(inode)->outstanding_extents++; spin_unlock(&BTRFS_I(inode)->lock); - btrfs_delalloc_release_space(inode, + btrfs_delalloc_release_space(inode, data_reserved, start_index << PAGE_SHIFT, (page_cnt - i_done) << PAGE_SHIFT); } @@ -1255,7 +1255,7 @@ out: unlock_page(pages[i]); put_page(pages[i]); } - btrfs_delalloc_release_space(inode, + btrfs_delalloc_release_space(inode, data_reserved, start_index << PAGE_SHIFT, page_cnt << PAGE_SHIFT); extent_changeset_free(data_reserved); diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c index 002088937021..fc9dffaa9524 100644 --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -2892,13 +2892,72 @@ cleanup: return ret; } -static int __btrfs_qgroup_release_data(struct inode *inode, u64 start, u64 len, - int free) +/* Free ranges specified by @reserved, normally in error path */ +static int qgroup_free_reserved_data(struct inode *inode, + struct extent_changeset *reserved, u64 start, u64 len) +{ + struct btrfs_root *root = BTRFS_I(inode)->root; + struct ulist_node *unode; + struct ulist_iterator uiter; + struct extent_changeset changeset; + int freed = 0; + int ret; + + extent_changeset_init(&changeset); + len = round_up(start + len, root->fs_info->sectorsize); + start = round_down(start, root->fs_info->sectorsize); + + ULIST_ITER_INIT(&uiter); + while ((unode = ulist_next(&reserved->range_changed, &uiter))) { + u64 range_start = unode->val; + /* unode->aux is the inclusive end */ + u64 range_len = unode->aux - range_start + 1; + u64 free_start; + u64 free_len; + + extent_changeset_release(&changeset); + + /* Only free range in range [start, start + len) */ + if (range_start >= start + len || + range_start + range_len <= start) + continue; + free_start = max(range_start, start); + free_len = min(start + len, range_start + range_len) - + free_start; + /* + * TODO: To also modify reserved->ranges_reserved to reflect + * the modification. + * + * However as long as we free qgroup reserved according to + * EXTENT_QGROUP_RESERVED, we won't double free. + * So not need to rush. + */ + ret = clear_record_extent_bits(&BTRFS_I(inode)->io_failure_tree, + free_start, free_start + free_len - 1, + EXTENT_QGROUP_RESERVED, &changeset); + if (ret < 0) + goto out; + freed += changeset.bytes_changed; + } + btrfs_qgroup_free_refroot(root->fs_info, root->objectid, freed); + ret = freed; +out: + extent_changeset_release(&changeset); + return ret; +} + +static int __btrfs_qgroup_release_data(struct inode *inode, + struct extent_changeset *reserved, u64 start, u64 len, + int free) { struct extent_changeset changeset; int trace_op = QGROUP_RELEASE; int ret; + /* In release case, we shouldn't have @reserved */ + WARN_ON(!free && reserved); + if (free && reserved) + return qgroup_free_reserved_data(inode, reserved, start, len); extent_changeset_init(&changeset); ret = clear_record_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len -1, EXTENT_QGROUP_RESERVED, &changeset); @@ -2924,14 +2983,17 @@ out: * * Should be called when a range of pages get invalidated before reaching disk. * Or for error cleanup case. + * if @reserved is given, only reserved range in [@start, @start + @len) will + * be freed. * * For data written to disk, use btrfs_qgroup_release_data(). * * NOTE: This function may sleep for memory allocation. */ -int btrfs_qgroup_free_data(struct inode *inode, u64 start, u64 len) +int btrfs_qgroup_free_data(struct inode *inode, + struct extent_changeset *reserved, u64 start, u64 len) { - return __btrfs_qgroup_release_data(inode, start, len, 1); + return __btrfs_qgroup_release_data(inode, reserved, start, len, 1); } /* @@ -2951,7 +3013,7 @@ int btrfs_qgroup_free_data(struct inode *inode, u64 start, u64 len) */ int btrfs_qgroup_release_data(struct inode *inode, u64 start, u64 len) { - return __btrfs_qgroup_release_data(inode, start, len, 0); + return __btrfs_qgroup_release_data(inode, NULL, start, len, 0); } int btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes, diff --git a/fs/btrfs/qgroup.h b/fs/btrfs/qgroup.h index 99408e93eb0d..d9984e87cddf 100644 --- a/fs/btrfs/qgroup.h +++ b/fs/btrfs/qgroup.h @@ -245,7 +245,8 @@ int btrfs_verify_qgroup_counts(struct btrfs_fs_info *fs_info, u64 qgroupid, int btrfs_qgroup_reserve_data(struct inode *inode, struct extent_changeset **reserved, u64 start, u64 len); int btrfs_qgroup_release_data(struct inode *inode, u64 start, u64 len); -int btrfs_qgroup_free_data(struct inode *inode, u64 start, u64 len); +int btrfs_qgroup_free_data(struct inode *inode, + struct extent_changeset *reserved, u64 start, u64 len); int btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes, bool enforce); diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index 6407423151ab..dc69b6ba29af 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -3114,8 +3114,8 @@ int prealloc_file_extent_cluster(struct inode *inode, lock_extent(&BTRFS_I(inode)->io_tree, start, end); num_bytes = end + 1 - start; if (cur_offset < start) - btrfs_free_reserved_data_space(inode, cur_offset, - start - cur_offset); + btrfs_free_reserved_data_space(inode, data_reserved, + cur_offset, start - cur_offset); ret = btrfs_prealloc_file_range(inode, 0, start, num_bytes, num_bytes, end + 1, &alloc_hint); @@ -3126,8 +3126,8 @@ int prealloc_file_extent_cluster(struct inode *inode, nr++; } if (cur_offset < prealloc_end) - btrfs_free_reserved_data_space(inode, cur_offset, - prealloc_end + 1 - cur_offset); + btrfs_free_reserved_data_space(inode, data_reserved, + cur_offset, prealloc_end + 1 - cur_offset); out: inode_unlock(inode); extent_changeset_free(data_reserved); -- 2.25.1