From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-97.freemail.mail.aliyun.com (out30-97.freemail.mail.aliyun.com [115.124.30.97]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 354CA307AEB for ; Fri, 12 Dec 2025 07:58:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.97 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765526320; cv=none; b=cPML7mV6dZpkld5ne1PFzRorO3+FRhnNF5YFVI336yHqhxwM8nBbPl+yCFosuHOm5cRRxMb/MBxeUicK1LHOaPd2i/5a8RUOs5L2gvBrl8JHwnidPJ45O4lIhOf5jAxaCCJRxiSrUYdvepb0LnI4AHAprotPuG6vHHgVxW9j6/k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765526320; c=relaxed/simple; bh=3UeYqvg2XEmmhD97o3pxrd0mMHuGCFXgrO9ys983NP0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Bcpe2cH0vXVfkB724QET6fNmcFITmP7m0dq4lcOEQUVqN2CRN5eqtS7PX1Pi23U/8hMXDs/HCYBRfkf1VCb2szaWv8LeRCZewac2w53yIpzNGg7mStx0CNuatWwRCtbpoc30k80rEFH6Mgd4K58VOobcr4gsZAX+9PCbZRQMthQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=cbZr6Anu; arc=none smtp.client-ip=115.124.30.97 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="cbZr6Anu" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1765526314; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=HeWzlKMudGOCXdUEXNJHI/OnEN91mGltNX/toBFKaM0=; b=cbZr6Anu5Zm+NBluMbFgEX/GPDAZhXa4JOBHewTMTK1YkLn+UzGV8qsQN/NxaYHaLM6o9Hg0WQ2dww5LD43jcvjUYz44vieMy2jBq346aI/cw45s9PEeMHLR+oT8Ej1w92B8o1bDbdwCsLpZ0wYZ/I41OVHAxryVzSSwYQrUwjQ= Received: from 30.221.145.122(mailfrom:joseph.qi@linux.alibaba.com fp:SMTPD_---0WudV8bW_1765526313 cluster:ay36) by smtp.aliyun-inc.com; Fri, 12 Dec 2025 15:58:34 +0800 Message-ID: <226c8cb9-ed97-4f0c-ae46-7187418e5ec9@linux.alibaba.com> Date: Fri, 12 Dec 2025 15:58:33 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 1/2] ocfs2: give ocfs2 the ability to reclaim suballocator free bg To: Heming Zhao , mark@fasheh.com, jlbec@evilplan.org, akpm Cc: ocfs2-devel@lists.linux.dev, linux-kernel@vger.kernel.org, glass.su@suse.com References: <20251212074505.25962-1-heming.zhao@suse.com> <20251212074505.25962-2-heming.zhao@suse.com> From: Joseph Qi In-Reply-To: <20251212074505.25962-2-heming.zhao@suse.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 2025/12/12 15:45, Heming Zhao wrote: > The current ocfs2 code can't reclaim suballocator block group space. > In some cases, this causes ocfs2 to hold onto a lot of space. > For example, when creating lots of small files, the space is held/managed > by the '//inode_alloc'. After the user deletes all the small files, > the space never returns to the '//global_bitmap'. This issue prevents > ocfs2 from providing the needed space even when there is enough free > space in a small ocfs2 volume. > > This patch gives ocfs2 the ability to reclaim suballocator free space > when the block group is freed. For performance reasons, this patch keeps > the first suballocator block group active. > > Signed-off-by: Heming Zhao > Reviewed-by: Su Yue Looks good. Reviewed-by: Joseph Qi > --- > fs/ocfs2/suballoc.c | 308 ++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 299 insertions(+), 9 deletions(-) > > diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c > index 6ac4dcd54588..9a19f5230c8c 100644 > --- a/fs/ocfs2/suballoc.c > +++ b/fs/ocfs2/suballoc.c > @@ -294,6 +294,74 @@ static int ocfs2_validate_group_descriptor(struct super_block *sb, > return ocfs2_validate_gd_self(sb, bh, 0); > } > > +/* > + * The hint group descriptor (gd) may already have been released > + * in _ocfs2_free_suballoc_bits(). We first check the gd signature, > + * then perform the standard ocfs2_read_group_descriptor() jobs. > + * > + * If the gd signature is invalid, we return 'rc=0' and set > + * '*released=1'. The caller is expected to handle this specific case. > + * Otherwise, we return the actual error code. > + * > + * We treat gd signature corruption case as a release case. The > + * caller ocfs2_claim_suballoc_bits() will use ocfs2_search_chain() > + * to search each gd block. The code will eventually find this > + * corrupted gd block - Late, but not missed. > + * > + * Note: > + * The caller is responsible for initializing the '*released' status. > + */ > +static int ocfs2_read_hint_group_descriptor(struct inode *inode, > + struct ocfs2_dinode *di, u64 gd_blkno, > + struct buffer_head **bh, int *released) > +{ > + int rc; > + struct buffer_head *tmp = *bh; > + struct ocfs2_group_desc *gd; > + > + rc = ocfs2_read_block(INODE_CACHE(inode), gd_blkno, &tmp, NULL); > + if (rc) > + goto out; > + > + gd = (struct ocfs2_group_desc *) tmp->b_data; > + if (!OCFS2_IS_VALID_GROUP_DESC(gd)) { > + /* > + * Invalid gd cache was set in ocfs2_read_block(), > + * which will affect block_group allocation. > + * Path: > + * ocfs2_reserve_suballoc_bits > + * ocfs2_block_group_alloc > + * ocfs2_block_group_alloc_contig > + * ocfs2_set_new_buffer_uptodate > + */ > + ocfs2_remove_from_cache(INODE_CACHE(inode), tmp); > + *released = 1; /* we return 'rc=0' for this case */ > + goto free_bh; > + } > + > + /* below jobs same with ocfs2_read_group_descriptor() */ > + if (!buffer_jbd(tmp)) { > + rc = ocfs2_validate_group_descriptor(inode->i_sb, tmp); > + if (rc) > + goto free_bh; > + } > + > + rc = ocfs2_validate_gd_parent(inode->i_sb, di, tmp, 0); > + if (rc) > + goto free_bh; > + > + /* If ocfs2_read_block() got us a new bh, pass it up. */ > + if (!*bh) > + *bh = tmp; > + > + return rc; > + > +free_bh: > + brelse(tmp); > +out: > + return rc; > +} > + > int ocfs2_read_group_descriptor(struct inode *inode, struct ocfs2_dinode *di, > u64 gd_blkno, struct buffer_head **bh) > { > @@ -1724,7 +1792,7 @@ static int ocfs2_search_one_group(struct ocfs2_alloc_context *ac, > u32 bits_wanted, > u32 min_bits, > struct ocfs2_suballoc_result *res, > - u16 *bits_left) > + u16 *bits_left, int *released) > { > int ret; > struct buffer_head *group_bh = NULL; > @@ -1732,9 +1800,11 @@ static int ocfs2_search_one_group(struct ocfs2_alloc_context *ac, > struct ocfs2_dinode *di = (struct ocfs2_dinode *)ac->ac_bh->b_data; > struct inode *alloc_inode = ac->ac_inode; > > - ret = ocfs2_read_group_descriptor(alloc_inode, di, > - res->sr_bg_blkno, &group_bh); > - if (ret < 0) { > + ret = ocfs2_read_hint_group_descriptor(alloc_inode, di, > + res->sr_bg_blkno, &group_bh, released); > + if (*released) { > + return 0; > + } else if (ret < 0) { > mlog_errno(ret); > return ret; > } > @@ -1949,6 +2019,7 @@ static int ocfs2_claim_suballoc_bits(struct ocfs2_alloc_context *ac, > struct ocfs2_suballoc_result *res) > { > int status; > + int released = 0; > u16 victim, i; > u16 bits_left = 0; > u64 hint = ac->ac_last_group; > @@ -1975,6 +2046,7 @@ static int ocfs2_claim_suballoc_bits(struct ocfs2_alloc_context *ac, > goto bail; > } > > + /* the hint bg may already be released, we quiet search this group. */ > res->sr_bg_blkno = hint; > if (res->sr_bg_blkno) { > /* Attempt to short-circuit the usual search mechanism > @@ -1982,7 +2054,12 @@ static int ocfs2_claim_suballoc_bits(struct ocfs2_alloc_context *ac, > * allocation group. This helps us maintain some > * contiguousness across allocations. */ > status = ocfs2_search_one_group(ac, handle, bits_wanted, > - min_bits, res, &bits_left); > + min_bits, res, &bits_left, > + &released); > + if (released) { > + res->sr_bg_blkno = 0; > + goto chain_search; > + } > if (!status) > goto set_hint; > if (status < 0 && status != -ENOSPC) { > @@ -1990,7 +2067,7 @@ static int ocfs2_claim_suballoc_bits(struct ocfs2_alloc_context *ac, > goto bail; > } > } > - > +chain_search: > cl = (struct ocfs2_chain_list *) &fe->id2.i_chain; > > victim = ocfs2_find_victim_chain(cl); > @@ -2102,6 +2179,12 @@ int ocfs2_claim_metadata(handle_t *handle, > return status; > } > > +/* > + * after ocfs2 has the ability to release block group unused space, > + * the ->ip_last_used_group may be invalid. so this function returns > + * ac->ac_last_group need to verify. > + * refer the 'hint' in ocfs2_claim_suballoc_bits() for more details. > + */ > static void ocfs2_init_inode_ac_group(struct inode *dir, > struct buffer_head *parent_di_bh, > struct ocfs2_alloc_context *ac) > @@ -2540,6 +2623,198 @@ static int ocfs2_block_group_clear_bits(handle_t *handle, > return status; > } > > +/* > + * Reclaim the suballocator managed space to main bitmap. > + * This function first works on the suballocator to perform the > + * cleanup rec/alloc_inode job, then switches to the main bitmap > + * to reclaim released space. > + * > + * handle: The transaction handle > + * alloc_inode: The suballoc inode > + * alloc_bh: The buffer_head of suballoc inode > + * group_bh: The group descriptor buffer_head of suballocator managed. > + * Caller should release the input group_bh. > + */ > +static int _ocfs2_reclaim_suballoc_to_main(handle_t *handle, > + struct inode *alloc_inode, > + struct buffer_head *alloc_bh, > + struct buffer_head *group_bh) > +{ > + int idx, status = 0; > + int i, next_free_rec, len = 0; > + __le16 old_bg_contig_free_bits = 0; > + u16 start_bit; > + u32 tmp_used; > + u64 bg_blkno, start_blk; > + unsigned int count; > + struct ocfs2_chain_rec *rec; > + struct buffer_head *main_bm_bh = NULL; > + struct inode *main_bm_inode = NULL; > + struct ocfs2_super *osb = OCFS2_SB(alloc_inode->i_sb); > + struct ocfs2_dinode *fe = (struct ocfs2_dinode *) alloc_bh->b_data; > + struct ocfs2_chain_list *cl = &fe->id2.i_chain; > + struct ocfs2_group_desc *group = (struct ocfs2_group_desc *) group_bh->b_data; > + > + idx = le16_to_cpu(group->bg_chain); > + rec = &(cl->cl_recs[idx]); > + > + status = ocfs2_extend_trans(handle, > + ocfs2_calc_group_alloc_credits(osb->sb, > + le16_to_cpu(cl->cl_cpg))); > + if (status) { > + mlog_errno(status); > + goto bail; > + } > + status = ocfs2_journal_access_di(handle, INODE_CACHE(alloc_inode), > + alloc_bh, OCFS2_JOURNAL_ACCESS_WRITE); > + if (status < 0) { > + mlog_errno(status); > + goto bail; > + } > + > + /* > + * Only clear the suballocator rec item in-place. > + * > + * If idx is not the last, we don't compress (remove the empty item) > + * the cl_recs[]. If not, we need to do lots jobs. > + * > + * Compress cl_recs[] code example: > + * if (idx != cl->cl_next_free_rec - 1) > + * memmove(&cl->cl_recs[idx], &cl->cl_recs[idx + 1], > + * sizeof(struct ocfs2_chain_rec) * > + * (cl->cl_next_free_rec - idx - 1)); > + * for(i = idx; i < cl->cl_next_free_rec-1; i++) { > + * group->bg_chain = "later group->bg_chain"; > + * group->bg_blkno = xxx; > + * ... ... > + * } > + */ > + > + tmp_used = le32_to_cpu(fe->id1.bitmap1.i_total); > + fe->id1.bitmap1.i_total = cpu_to_le32(tmp_used - le32_to_cpu(rec->c_total)); > + > + /* Substraction 1 for the block group itself */ > + tmp_used = le32_to_cpu(fe->id1.bitmap1.i_used); > + fe->id1.bitmap1.i_used = cpu_to_le32(tmp_used - 1); > + > + tmp_used = le32_to_cpu(fe->i_clusters); > + fe->i_clusters = cpu_to_le32(tmp_used - le16_to_cpu(cl->cl_cpg)); > + > + spin_lock(&OCFS2_I(alloc_inode)->ip_lock); > + OCFS2_I(alloc_inode)->ip_clusters -= le32_to_cpu(fe->i_clusters); > + fe->i_size = cpu_to_le64(ocfs2_clusters_to_bytes(alloc_inode->i_sb, > + le32_to_cpu(fe->i_clusters))); > + spin_unlock(&OCFS2_I(alloc_inode)->ip_lock); > + i_size_write(alloc_inode, le64_to_cpu(fe->i_size)); > + alloc_inode->i_blocks = ocfs2_inode_sector_count(alloc_inode); > + > + ocfs2_journal_dirty(handle, alloc_bh); > + ocfs2_update_inode_fsync_trans(handle, alloc_inode, 0); > + > + start_blk = le64_to_cpu(rec->c_blkno); > + count = le32_to_cpu(rec->c_total) / le16_to_cpu(cl->cl_bpc); > + > + /* > + * If the rec is the last one, let's compress the chain list by > + * removing the empty cl_recs[] at the end. > + */ > + next_free_rec = le16_to_cpu(cl->cl_next_free_rec); > + if (idx == (next_free_rec - 1)) { > + len++; /* the last item should be counted first */ > + for (i = (next_free_rec - 2); i > 0; i--) { > + if (cl->cl_recs[i].c_free == cl->cl_recs[i].c_total) > + len++; > + else > + break; > + } > + } > + le16_add_cpu(&cl->cl_next_free_rec, -len); > + > + rec->c_free = 0; > + rec->c_total = 0; > + rec->c_blkno = 0; > + ocfs2_remove_from_cache(INODE_CACHE(alloc_inode), group_bh); > + memset(group, 0, sizeof(struct ocfs2_group_desc)); > + > + /* prepare job for reclaim clusters */ > + main_bm_inode = ocfs2_get_system_file_inode(osb, > + GLOBAL_BITMAP_SYSTEM_INODE, > + OCFS2_INVALID_SLOT); > + if (!main_bm_inode) > + goto bail; /* ignore the error in reclaim path */ > + > + inode_lock(main_bm_inode); > + > + status = ocfs2_inode_lock(main_bm_inode, &main_bm_bh, 1); > + if (status < 0) > + goto free_bm_inode; /* ignore the error in reclaim path */ > + > + ocfs2_block_to_cluster_group(main_bm_inode, start_blk, &bg_blkno, > + &start_bit); > + fe = (struct ocfs2_dinode *) main_bm_bh->b_data; > + cl = &fe->id2.i_chain; > + /* reuse group_bh, caller will release the input group_bh */ > + group_bh = NULL; > + > + /* reclaim clusters to global_bitmap */ > + status = ocfs2_read_group_descriptor(main_bm_inode, fe, bg_blkno, > + &group_bh); > + if (status < 0) { > + mlog_errno(status); > + goto free_bm_bh; > + } > + group = (struct ocfs2_group_desc *) group_bh->b_data; > + > + if ((count + start_bit) > le16_to_cpu(group->bg_bits)) { > + ocfs2_error(alloc_inode->i_sb, > + "reclaim length (%d) beyands block group length (%d)", > + count + start_bit, le16_to_cpu(group->bg_bits)); > + goto free_group_bh; > + } > + > + old_bg_contig_free_bits = group->bg_contig_free_bits; > + status = ocfs2_block_group_clear_bits(handle, main_bm_inode, > + group, group_bh, > + start_bit, count, 0, > + _ocfs2_clear_bit); > + if (status < 0) { > + mlog_errno(status); > + goto free_group_bh; > + } > + > + status = ocfs2_journal_access_di(handle, INODE_CACHE(main_bm_inode), > + main_bm_bh, OCFS2_JOURNAL_ACCESS_WRITE); > + if (status < 0) { > + mlog_errno(status); > + ocfs2_block_group_set_bits(handle, main_bm_inode, group, group_bh, > + start_bit, count, > + le16_to_cpu(old_bg_contig_free_bits), 1); > + goto free_group_bh; > + } > + > + idx = le16_to_cpu(group->bg_chain); > + rec = &(cl->cl_recs[idx]); > + > + le32_add_cpu(&rec->c_free, count); > + tmp_used = le32_to_cpu(fe->id1.bitmap1.i_used); > + fe->id1.bitmap1.i_used = cpu_to_le32(tmp_used - count); > + ocfs2_journal_dirty(handle, main_bm_bh); > + > +free_group_bh: > + brelse(group_bh); > + > +free_bm_bh: > + ocfs2_inode_unlock(main_bm_inode, 1); > + brelse(main_bm_bh); > + > +free_bm_inode: > + inode_unlock(main_bm_inode); > + iput(main_bm_inode); > + > +bail: > + return status; > +} > + > /* > * expects the suballoc inode to already be locked. > */ > @@ -2552,12 +2827,13 @@ static int _ocfs2_free_suballoc_bits(handle_t *handle, > void (*undo_fn)(unsigned int bit, > unsigned long *bitmap)) > { > - int status = 0; > + int idx, status = 0; > u32 tmp_used; > struct ocfs2_dinode *fe = (struct ocfs2_dinode *) alloc_bh->b_data; > struct ocfs2_chain_list *cl = &fe->id2.i_chain; > struct buffer_head *group_bh = NULL; > struct ocfs2_group_desc *group; > + struct ocfs2_chain_rec *rec; > __le16 old_bg_contig_free_bits = 0; > > /* The alloc_bh comes from ocfs2_free_dinode() or > @@ -2603,12 +2879,26 @@ static int _ocfs2_free_suballoc_bits(handle_t *handle, > goto bail; > } > > - le32_add_cpu(&cl->cl_recs[le16_to_cpu(group->bg_chain)].c_free, > - count); > + idx = le16_to_cpu(group->bg_chain); > + rec = &(cl->cl_recs[idx]); > + > + le32_add_cpu(&rec->c_free, count); > tmp_used = le32_to_cpu(fe->id1.bitmap1.i_used); > fe->id1.bitmap1.i_used = cpu_to_le32(tmp_used - count); > ocfs2_journal_dirty(handle, alloc_bh); > > + /* > + * Reclaim suballocator free space. > + * Bypass: global_bitmap, non empty rec, first rec in cl_recs[] > + */ > + if (ocfs2_is_cluster_bitmap(alloc_inode) || > + (le32_to_cpu(rec->c_free) != (le32_to_cpu(rec->c_total) - 1)) || > + (le16_to_cpu(cl->cl_next_free_rec) == 1)) { > + goto bail; > + } > + > + _ocfs2_reclaim_suballoc_to_main(handle, alloc_inode, alloc_bh, group_bh); > + > bail: > brelse(group_bh); > return status;