fsverity: start consolidating pagecache code

ext4 and f2fs are largely using the same code to read a page full
of Merkle tree blocks from the page cache, and the upcoming xfs
fsverity support would add another copy.

Move the ext4 code to fs/verity/ and use it in f2fs as well.  For f2fs
this removes the previous f2fs-specific error injection, but otherwise
the behavior remains unchanged.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Link: https://lore.kernel.org/r/20260128152630.627409-7-hch@lst.de
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

diff --git a/fs/ext4/verity.c b/fs/ext4/verity.c
index 2ce4cf8a1e314971b881e1f8c800dfef2fdbbde5..a071860ad36ae5a612c6c821733d62774831bac1 100644 (file)
--- a/fs/ext4/verity.c
+++ b/fs/ext4/verity.c
@@ -361,23 +361,8 @@ static struct page *ext4_read_merkle_tree_page(struct inode *inode,
                                               pgoff_t index,
                                               unsigned long num_ra_pages)
 {
-       struct folio *folio;
-
        index += ext4_verity_metadata_pos(inode) >> PAGE_SHIFT;
-
-       folio = __filemap_get_folio(inode->i_mapping, index, FGP_ACCESSED, 0);
-       if (IS_ERR(folio) || !folio_test_uptodate(folio)) {
-               DEFINE_READAHEAD(ractl, NULL, NULL, inode->i_mapping, index);
-
-               if (!IS_ERR(folio))
-                       folio_put(folio);
-               else if (num_ra_pages > 1)
-                       page_cache_ra_unbounded(&ractl, num_ra_pages, 0);
-               folio = read_mapping_folio(inode->i_mapping, index, NULL);
-               if (IS_ERR(folio))
-                       return ERR_CAST(folio);
-       }
-       return folio_file_page(folio, index);
+       return generic_read_merkle_tree_page(inode, index, num_ra_pages);
 }
 
 static int ext4_write_merkle_tree_block(struct file *file, const void *buf,

diff --git a/fs/f2fs/verity.c b/fs/f2fs/verity.c
index c1c4d80446818ae3182b0d569319ce0b408d0720..d37e584423afe570a929685159a2e4365dff33c4 100644 (file)
--- a/fs/f2fs/verity.c
+++ b/fs/f2fs/verity.c
@@ -259,23 +259,8 @@ static struct page *f2fs_read_merkle_tree_page(struct inode *inode,
                                               pgoff_t index,
                                               unsigned long num_ra_pages)
 {
-       struct folio *folio;
-
        index += f2fs_verity_metadata_pos(inode) >> PAGE_SHIFT;
-
-       folio = f2fs_filemap_get_folio(inode->i_mapping, index, FGP_ACCESSED, 0);
-       if (IS_ERR(folio) || !folio_test_uptodate(folio)) {
-               DEFINE_READAHEAD(ractl, NULL, NULL, inode->i_mapping, index);
-
-               if (!IS_ERR(folio))
-                       folio_put(folio);
-               else if (num_ra_pages > 1)
-                       page_cache_ra_unbounded(&ractl, num_ra_pages, 0);
-               folio = read_mapping_folio(inode->i_mapping, index, NULL);
-               if (IS_ERR(folio))
-                       return ERR_CAST(folio);
-       }
-       return folio_file_page(folio, index);
+       return generic_read_merkle_tree_page(inode, index, num_ra_pages);
 }
 
 static int f2fs_write_merkle_tree_block(struct file *file, const void *buf,

diff --git a/fs/verity/Makefile b/fs/verity/Makefile
index 435559a4fa9eae1d947ef0d90d0945bc14b08ee8..ddb4a88a0d608a1468a9952b33290ba216f8c70f 100644 (file)
--- a/fs/verity/Makefile
+++ b/fs/verity/Makefile
@@ -5,6 +5,7 @@ obj-$(CONFIG_FS_VERITY) += enable.o \
                           init.o \
                           measure.o \
                           open.o \
+                          pagecache.o \
                           read_metadata.o \
                           verify.o
 

diff --git a/fs/verity/pagecache.c b/fs/verity/pagecache.c
new file mode 100644 (file)
index 0000000..01c652b
--- /dev/null
+++ b/fs/verity/pagecache.c
@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 Google LLC
+ */
+
+#include <linux/fsverity.h>
+#include <linux/pagemap.h>
+
+/**
+ * generic_read_merkle_tree_page - generic ->read_merkle_tree_page helper
+ * @inode:     inode containing the Merkle tree
+ * @index:     0-based index of the Merkle tree page in the inode
+ * @num_ra_pages: The number of Merkle tree pages that should be prefetched.
+ *
+ * The caller needs to adjust @index from the Merkle-tree relative index passed
+ * to ->read_merkle_tree_page to the actual index where the Merkle tree is
+ * stored in the page cache for @inode.
+ */
+struct page *generic_read_merkle_tree_page(struct inode *inode, pgoff_t index,
+                                          unsigned long num_ra_pages)
+{
+       struct folio *folio;
+
+       folio = __filemap_get_folio(inode->i_mapping, index, FGP_ACCESSED, 0);
+       if (IS_ERR(folio) || !folio_test_uptodate(folio)) {
+               DEFINE_READAHEAD(ractl, NULL, NULL, inode->i_mapping, index);
+
+               if (!IS_ERR(folio))
+                       folio_put(folio);
+               else if (num_ra_pages > 1)
+                       page_cache_ra_unbounded(&ractl, num_ra_pages, 0);
+               folio = read_mapping_folio(inode->i_mapping, index, NULL);
+               if (IS_ERR(folio))
+                       return ERR_CAST(folio);
+       }
+       return folio_file_page(folio, index);
+}
+EXPORT_SYMBOL_GPL(generic_read_merkle_tree_page);

diff --git a/include/linux/fsverity.h b/include/linux/fsverity.h
index ac5c98fd4602f4cbf37c5de413aa8cbda94f615e..8ddaa87fece3a29e4357725d3a4c2737985f65b1 100644 (file)
--- a/include/linux/fsverity.h
+++ b/include/linux/fsverity.h
@@ -309,4 +309,7 @@ static inline int fsverity_file_open(struct inode *inode, struct file *filp)
 
 void fsverity_cleanup_inode(struct inode *inode);
 
+struct page *generic_read_merkle_tree_page(struct inode *inode, pgoff_t index,
+                                          unsigned long num_ra_pages);
+
 #endif /* _LINUX_FSVERITY_H */