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f1a6cf44b3
Currently all reads of the fsverity hashes are kicked off from the data I/O completion handler, leading to needlessly dependent I/O. This is worked around a bit by performing readahead on the level 0 nodes, but still fairly ineffective. Switch to a model where the ->read_folio and ->readahead methods instead kick off explicit readahead of the fsverity hashed so they are usually available at I/O completion time. For 64k sequential reads on my test VM this improves read performance from 2.4GB/s - 2.6GB/s to 3.5GB/s - 3.9GB/s. The improvements for random reads are likely to be even bigger. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: David Sterba <dsterba@suse.com> # btrfs Link: https://lore.kernel.org/r/20260202060754.270269-5-hch@lst.de Signed-off-by: Eric Biggers <ebiggers@kernel.org>
58 lines
1.8 KiB
C
58 lines
1.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright 2019 Google LLC
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*/
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#include <linux/export.h>
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#include <linux/fsverity.h>
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#include <linux/pagemap.h>
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/**
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* generic_read_merkle_tree_page - generic ->read_merkle_tree_page helper
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* @inode: inode containing the Merkle tree
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* @index: 0-based index of the Merkle tree page in the inode
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*
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* The caller needs to adjust @index from the Merkle-tree relative index passed
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* to ->read_merkle_tree_page to the actual index where the Merkle tree is
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* stored in the page cache for @inode.
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*/
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struct page *generic_read_merkle_tree_page(struct inode *inode, pgoff_t index)
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{
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struct folio *folio;
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folio = read_mapping_folio(inode->i_mapping, index, NULL);
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if (IS_ERR(folio))
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return ERR_CAST(folio);
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return folio_file_page(folio, index);
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}
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EXPORT_SYMBOL_GPL(generic_read_merkle_tree_page);
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/**
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* generic_readahead_merkle_tree() - generic ->readahead_merkle_tree helper
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* @inode: inode containing the Merkle tree
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* @index: 0-based index of the first Merkle tree page to read ahead in the
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* inode
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* @nr_pages: the number of Merkle tree pages that should be read ahead
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*
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* The caller needs to adjust @index from the Merkle-tree relative index passed
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* to ->read_merkle_tree_page to the actual index where the Merkle tree is
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* stored in the page cache for @inode.
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*/
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void generic_readahead_merkle_tree(struct inode *inode, pgoff_t index,
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unsigned long nr_pages)
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{
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struct folio *folio;
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lockdep_assert_held(&inode->i_mapping->invalidate_lock);
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folio = __filemap_get_folio(inode->i_mapping, index, FGP_ACCESSED, 0);
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if (folio == ERR_PTR(-ENOENT) ||
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(!IS_ERR(folio) && !folio_test_uptodate(folio))) {
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DEFINE_READAHEAD(ractl, NULL, NULL, inode->i_mapping, index);
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page_cache_ra_unbounded(&ractl, nr_pages, 0);
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}
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if (!IS_ERR(folio))
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folio_put(folio);
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}
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EXPORT_SYMBOL_GPL(generic_readahead_merkle_tree);
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