From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 6B8A021353 for ; Tue, 26 Mar 2024 03:53:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711425193; cv=none; b=F3IF4J0ttgwV4XWbhSjzzvn5mAAnxGZyUczSDXpChB99uTXnvlFBZ5K3I3DmM1KVKgzvszlkKI9AuGP9iKXlUaIefF0yQA+VzEMv9BLuXF9qrWgwTvIVwgDXbJUfLy+1nF77l2vJyeHdhQzL4kQ3RNqknUmcqnjmNdJ1KXMLoXU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711425193; c=relaxed/simple; bh=+odALaleD6wDBhoWmHRoKzX3k1iPhWY1BxsjBRpkKAQ=; h=Date:Subject:From:To:Cc:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=a67zDCYI+soQmlR2hTXGnRkOC39jMRU3scTM6q8c/9lqinaihWWOXSpq8I0tokOCaRM35HfmyIgYvcqFCCfTbsudoe//w+621ZSfluTenYj04PpIJo/8D2U0CzIDGGqchajAWxGBfge6vrKTPekQDTi7iJHOCYBiumIieDlWL6M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=j3AvE56k; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="j3AvE56k" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3B469C433F1; Tue, 26 Mar 2024 03:53:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711425193; bh=+odALaleD6wDBhoWmHRoKzX3k1iPhWY1BxsjBRpkKAQ=; h=Date:Subject:From:To:Cc:In-Reply-To:References:From; b=j3AvE56k1jLEhDdZEXBejdSR1BaGIyNjRtj0NVxeaIyD4qeoOprluV8ayiRYe03+i FyosQU7QWOv1aMGjjbPYOhVtbp+KSfQQ6Zq7SuMDAfiRk+93Crsmbq7ubKTaQMG1Ms ThQXB0aj9gGyzy86O3GsUqn4Q/iEN2Twf/B+8XqDihzUGJXxnBXsN1fe3jaGDudz8i hSFrlrTaF+Wbq6SyC+ztkFmpuprXnHIlMbISyiVt6/2Sdp3sUceeah75V7gn6DU64k cbilcB8nglhPEGBDQ9abCteapu62Yqy0z8+cGu7bAcE90IZQ9UwqEJHUBV4sQkCbLU hLHvjkR96Gh6Q== Date: Mon, 25 Mar 2024 20:53:12 -0700 Subject: [PATCH 095/110] xfs: launder in-memory btree buffers before transaction commit From: "Darrick J. Wong" To: cem@kernel.org, djwong@kernel.org Cc: Christoph Hellwig , linux-xfs@vger.kernel.org Message-ID: <171142132748.2215168.7242665357492672168.stgit@frogsfrogsfrogs> In-Reply-To: <171142131228.2215168.2795743548791967397.stgit@frogsfrogsfrogs> References: <171142131228.2215168.2795743548791967397.stgit@frogsfrogsfrogs> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-xfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit From: Darrick J. Wong Source kernel commit: 0dc63c8a1ce39c1ac7da536ee9174cdc714afae2 As we've noted in various places, all current users of in-memory btrees are online fsck. Online fsck only stages a btree long enough to rebuild an ondisk data structure, which means that the in-memory btree is ephemeral. Furthermore, if we encounter /any/ errors while updating an in-memory btree, all we do is tear down all the staged data and return an errno to userspace. In-memory btrees need not be transactional, so their buffers should not be committed to the ondisk log, nor should they be checkpointed by the AIL. That's just as well since the ephemeral nature of the btree means that the buftarg and the buffers may disappear quickly anyway. Therefore, we need a way to launder the btree buffers that get attached to the transaction by the generic btree code. Because the buffers are directly mapped to backing file pages, there's no need to bwrite them back to the tmpfs file. All we need to do is clean enough of the buffer log item state so that the bli can be detached from the buffer, remove the bli from the transaction's log item list, and reset the transaction dirty state as if the laundered items had never been there. For simplicity, create xfbtree transaction commit and cancel helpers that launder the in-memory btree buffers for callers. Once laundered, call the write verifier on non-stale buffers to avoid integrity issues, or punch a hole in the backing file for stale buffers. Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig --- include/xfs_trace.h | 1 include/xfs_trans.h | 1 libxfs/buf_mem.c | 65 +++++++++++++++++++++++++ libxfs/buf_mem.h | 2 + libxfs/libxfs_api_defs.h | 1 libxfs/trans.c | 40 +++++++++++++++ libxfs/xfs_btree_mem.c | 119 ++++++++++++++++++++++++++++++++++++++++++++++ libxfs/xfs_btree_mem.h | 3 + 8 files changed, 232 insertions(+) diff --git a/include/xfs_trace.h b/include/xfs_trace.h index 6c8eeff1e62a..6b9d3358a3ae 100644 --- a/include/xfs_trace.h +++ b/include/xfs_trace.h @@ -211,6 +211,7 @@ #define trace_xfs_trans_cancel(a,b) ((void) 0) #define trace_xfs_trans_brelse(a) ((void) 0) #define trace_xfs_trans_binval(a) ((void) 0) +#define trace_xfs_trans_bdetach(a) ((void) 0) #define trace_xfs_trans_bjoin(a) ((void) 0) #define trace_xfs_trans_bhold(a) ((void) 0) #define trace_xfs_trans_bhold_release(a) ((void) 0) diff --git a/include/xfs_trans.h b/include/xfs_trans.h index ac82c3bc480a..b7f01ff073cd 100644 --- a/include/xfs_trans.h +++ b/include/xfs_trans.h @@ -114,6 +114,7 @@ int libxfs_trans_roll_inode (struct xfs_trans **, struct xfs_inode *); void libxfs_trans_brelse(struct xfs_trans *, struct xfs_buf *); void libxfs_trans_binval(struct xfs_trans *, struct xfs_buf *); void libxfs_trans_bjoin(struct xfs_trans *, struct xfs_buf *); +void libxfs_trans_bdetach(struct xfs_trans *tp, struct xfs_buf *bp); void libxfs_trans_bhold(struct xfs_trans *, struct xfs_buf *); void libxfs_trans_bhold_release(struct xfs_trans *, struct xfs_buf *); void libxfs_trans_dirty_buf(struct xfs_trans *, struct xfs_buf *); diff --git a/libxfs/buf_mem.c b/libxfs/buf_mem.c index 769cce23f3f3..830e793205db 100644 --- a/libxfs/buf_mem.c +++ b/libxfs/buf_mem.c @@ -246,3 +246,68 @@ xmbuf_verify_daddr( return daddr < (xf->partition_bytes >> BBSHIFT); } + +/* Discard the page backing this buffer. */ +static void +xmbuf_stale( + struct xfs_buf *bp) +{ + struct xfile *xf = bp->b_target->bt_xfile; + loff_t pos; + + ASSERT(xfs_buftarg_is_mem(bp->b_target)); + + pos = BBTOB(xfs_buf_daddr(bp)) + xf->partition_pos; + fallocate(xf->fcb->fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, pos, + BBTOB(bp->b_length)); +} + +/* + * Finalize a buffer -- discard the backing page if it's stale, or run the + * write verifier to detect problems. + */ +int +xmbuf_finalize( + struct xfs_buf *bp) +{ + xfs_failaddr_t fa; + int error = 0; + + if (bp->b_flags & LIBXFS_B_STALE) { + xmbuf_stale(bp); + return 0; + } + + /* + * Although this btree is ephemeral, validate the buffer structure so + * that we can detect memory corruption errors and software bugs. + */ + fa = bp->b_ops->verify_struct(bp); + if (fa) { + error = -EFSCORRUPTED; + xfs_verifier_error(bp, error, fa); + } + + return error; +} + +/* + * Detach this xmbuf buffer from the transaction by any means necessary. + * All buffers are direct-mapped, so they do not need bwrite. + */ +void +xmbuf_trans_bdetach( + struct xfs_trans *tp, + struct xfs_buf *bp) +{ + struct xfs_buf_log_item *bli = bp->b_log_item; + + ASSERT(bli != NULL); + + bli->bli_flags &= ~(XFS_BLI_DIRTY | XFS_BLI_ORDERED | + XFS_BLI_STALE); + clear_bit(XFS_LI_DIRTY, &bli->bli_item.li_flags); + + while (bp->b_log_item != NULL) + xfs_trans_bdetach(tp, bp); +} diff --git a/libxfs/buf_mem.h b/libxfs/buf_mem.h index d40f9f9df8f1..3829dd00d7e9 100644 --- a/libxfs/buf_mem.h +++ b/libxfs/buf_mem.h @@ -24,5 +24,7 @@ int xmbuf_map_page(struct xfs_buf *bp); void xmbuf_unmap_page(struct xfs_buf *bp); bool xmbuf_verify_daddr(struct xfs_buftarg *btp, xfs_daddr_t daddr); +void xmbuf_trans_bdetach(struct xfs_trans *tp, struct xfs_buf *bp); +int xmbuf_finalize(struct xfs_buf *bp); #endif /* __XFS_BUF_MEM_H__ */ diff --git a/libxfs/libxfs_api_defs.h b/libxfs/libxfs_api_defs.h index fe8a0dc40269..de37d3050c7e 100644 --- a/libxfs/libxfs_api_defs.h +++ b/libxfs/libxfs_api_defs.h @@ -224,6 +224,7 @@ #define xfs_trans_alloc_empty libxfs_trans_alloc_empty #define xfs_trans_alloc libxfs_trans_alloc #define xfs_trans_alloc_inode libxfs_trans_alloc_inode +#define xfs_trans_bdetach libxfs_trans_bdetach #define xfs_trans_bhold libxfs_trans_bhold #define xfs_trans_bhold_release libxfs_trans_bhold_release #define xfs_trans_binval libxfs_trans_binval diff --git a/libxfs/trans.c b/libxfs/trans.c index 8143a6a99f62..7fec2caff493 100644 --- a/libxfs/trans.c +++ b/libxfs/trans.c @@ -614,6 +614,46 @@ libxfs_trans_brelse( libxfs_buf_relse(bp); } +/* + * Forcibly detach a buffer previously joined to the transaction. The caller + * will retain its locked reference to the buffer after this function returns. + * The buffer must be completely clean and must not be held to the transaction. + */ +void +libxfs_trans_bdetach( + struct xfs_trans *tp, + struct xfs_buf *bp) +{ + struct xfs_buf_log_item *bip = bp->b_log_item; + + ASSERT(tp != NULL); + ASSERT(bp->b_transp == tp); + ASSERT(bip->bli_item.li_type == XFS_LI_BUF); + + trace_xfs_trans_bdetach(bip); + + /* + * Erase all recursion count, since we're removing this buffer from the + * transaction. + */ + bip->bli_recur = 0; + + /* + * The buffer must be completely clean. Specifically, it had better + * not be dirty, stale, logged, ordered, or held to the transaction. + */ + ASSERT(!test_bit(XFS_LI_DIRTY, &bip->bli_item.li_flags)); + ASSERT(!(bip->bli_flags & XFS_BLI_DIRTY)); + ASSERT(!(bip->bli_flags & XFS_BLI_HOLD)); + ASSERT(!(bip->bli_flags & XFS_BLI_ORDERED)); + ASSERT(!(bip->bli_flags & XFS_BLI_STALE)); + + /* Unlink the log item from the transaction and drop the log item. */ + xfs_trans_del_item(&bip->bli_item); + xfs_buf_item_put(bip); + bp->b_transp = NULL; +} + /* * Mark the buffer as not needing to be unlocked when the buf item's * iop_unlock() routine is called. The buffer must already be locked diff --git a/libxfs/xfs_btree_mem.c b/libxfs/xfs_btree_mem.c index 31835e065652..ae9302b9090f 100644 --- a/libxfs/xfs_btree_mem.c +++ b/libxfs/xfs_btree_mem.c @@ -225,3 +225,122 @@ xfbtree_get_maxrecs( return xfbt->maxrecs[level != 0]; } + +/* If this log item is a buffer item that came from the xfbtree, return it. */ +static inline struct xfs_buf * +xfbtree_buf_match( + struct xfbtree *xfbt, + const struct xfs_log_item *lip) +{ + const struct xfs_buf_log_item *bli; + struct xfs_buf *bp; + + if (lip->li_type != XFS_LI_BUF) + return NULL; + + bli = container_of(lip, struct xfs_buf_log_item, bli_item); + bp = bli->bli_buf; + if (bp->b_target != xfbt->target) + return NULL; + + return bp; +} + +/* + * Commit changes to the incore btree immediately by writing all dirty xfbtree + * buffers to the backing xfile. This detaches all xfbtree buffers from the + * transaction, even on failure. The buffer locks are dropped between the + * delwri queue and submit, so the caller must synchronize btree access. + * + * Normally we'd let the buffers commit with the transaction and get written to + * the xfile via the log, but online repair stages ephemeral btrees in memory + * and uses the btree_staging functions to write new btrees to disk atomically. + * The in-memory btree (and its backing store) are discarded at the end of the + * repair phase, which means that xfbtree buffers cannot commit with the rest + * of a transaction. + * + * In other words, online repair only needs the transaction to collect buffer + * pointers and to avoid buffer deadlocks, not to guarantee consistency of + * updates. + */ +int +xfbtree_trans_commit( + struct xfbtree *xfbt, + struct xfs_trans *tp) +{ + struct xfs_log_item *lip, *n; + bool tp_dirty = false; + int error = 0; + + /* + * For each xfbtree buffer attached to the transaction, write the dirty + * buffers to the xfile and release them. + */ + list_for_each_entry_safe(lip, n, &tp->t_items, li_trans) { + struct xfs_buf *bp = xfbtree_buf_match(xfbt, lip); + + if (!bp) { + if (test_bit(XFS_LI_DIRTY, &lip->li_flags)) + tp_dirty |= true; + continue; + } + + trace_xfbtree_trans_commit_buf(xfbt, bp); + + xmbuf_trans_bdetach(tp, bp); + + /* + * If the buffer fails verification, note the failure but + * continue walking the transaction items so that we remove all + * ephemeral btree buffers. + */ + if (!error) + error = xmbuf_finalize(bp); + + xfs_buf_relse(bp); + } + + /* + * Reset the transaction's dirty flag to reflect the dirty state of the + * log items that are still attached. + */ + tp->t_flags = (tp->t_flags & ~XFS_TRANS_DIRTY) | + (tp_dirty ? XFS_TRANS_DIRTY : 0); + + return error; +} + +/* + * Cancel changes to the incore btree by detaching all the xfbtree buffers. + * Changes are not undone, so callers must not access the btree ever again. + */ +void +xfbtree_trans_cancel( + struct xfbtree *xfbt, + struct xfs_trans *tp) +{ + struct xfs_log_item *lip, *n; + bool tp_dirty = false; + + list_for_each_entry_safe(lip, n, &tp->t_items, li_trans) { + struct xfs_buf *bp = xfbtree_buf_match(xfbt, lip); + + if (!bp) { + if (test_bit(XFS_LI_DIRTY, &lip->li_flags)) + tp_dirty |= true; + continue; + } + + trace_xfbtree_trans_cancel_buf(xfbt, bp); + + xmbuf_trans_bdetach(tp, bp); + xfs_buf_relse(bp); + } + + /* + * Reset the transaction's dirty flag to reflect the dirty state of the + * log items that are still attached. + */ + tp->t_flags = (tp->t_flags & ~XFS_TRANS_DIRTY) | + (tp_dirty ? XFS_TRANS_DIRTY : 0); +} diff --git a/libxfs/xfs_btree_mem.h b/libxfs/xfs_btree_mem.h index ecc2ceac3ed4..1c3825786ec8 100644 --- a/libxfs/xfs_btree_mem.h +++ b/libxfs/xfs_btree_mem.h @@ -65,6 +65,9 @@ int xfbtree_free_block(struct xfs_btree_cur *cur, struct xfs_buf *bp); int xfbtree_init(struct xfs_mount *mp, struct xfbtree *xfbt, struct xfs_buftarg *btp, const struct xfs_btree_ops *ops); void xfbtree_destroy(struct xfbtree *xfbt); + +int xfbtree_trans_commit(struct xfbtree *xfbt, struct xfs_trans *tp); +void xfbtree_trans_cancel(struct xfbtree *xfbt, struct xfs_trans *tp); #else # define xfbtree_verify_bno(...) (false) #endif /* CONFIG_XFS_BTREE_IN_MEM */