From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/fs/ext4/verity.c | 141 +++++++++++++++++++++-------------------------
1 files changed, 65 insertions(+), 76 deletions(-)
diff --git a/kernel/fs/ext4/verity.c b/kernel/fs/ext4/verity.c
index 0650056..e3019f9 100644
--- a/kernel/fs/ext4/verity.c
+++ b/kernel/fs/ext4/verity.c
@@ -79,8 +79,7 @@
size_t n = min_t(size_t, count,
PAGE_SIZE - offset_in_page(pos));
struct page *page;
- void *fsdata;
- void *addr;
+ void *fsdata = NULL;
int res;
res = pagecache_write_begin(NULL, inode->i_mapping, pos, n, 0,
@@ -88,9 +87,7 @@
if (res)
return res;
- addr = kmap_atomic(page);
- memcpy(addr + offset_in_page(pos), buf, n);
- kunmap_atomic(addr);
+ memcpy_to_page(page, offset_in_page(pos), buf, n);
res = pagecache_write_end(NULL, inode->i_mapping, pos, n, n,
page, fsdata);
@@ -112,6 +109,9 @@
const int credits = 2; /* superblock and inode for ext4_orphan_add() */
handle_t *handle;
int err;
+
+ if (IS_DAX(inode) || ext4_test_inode_flag(inode, EXT4_INODE_DAX))
+ return -EINVAL;
if (ext4_verity_in_progress(inode))
return -EBUSY;
@@ -198,55 +198,76 @@
struct inode *inode = file_inode(filp);
const int credits = 2; /* superblock and inode for ext4_orphan_del() */
handle_t *handle;
+ struct ext4_iloc iloc;
int err = 0;
- int err2;
-
- if (desc != NULL) {
- /* Succeeded; write the verity descriptor. */
- err = ext4_write_verity_descriptor(inode, desc, desc_size,
- merkle_tree_size);
-
- /* Write all pages before clearing VERITY_IN_PROGRESS. */
- if (!err)
- err = filemap_write_and_wait(inode->i_mapping);
- }
-
- /* If we failed, truncate anything we wrote past i_size. */
- if (desc == NULL || err)
- ext4_truncate(inode);
/*
- * We must always clean up by clearing EXT4_STATE_VERITY_IN_PROGRESS and
- * deleting the inode from the orphan list, even if something failed.
- * If everything succeeded, we'll also set the verity bit in the same
- * transaction.
+ * If an error already occurred (which fs/verity/ signals by passing
+ * desc == NULL), then only clean-up is needed.
*/
+ if (desc == NULL)
+ goto cleanup;
- ext4_clear_inode_state(inode, EXT4_STATE_VERITY_IN_PROGRESS);
+ /* Append the verity descriptor. */
+ err = ext4_write_verity_descriptor(inode, desc, desc_size,
+ merkle_tree_size);
+ if (err)
+ goto cleanup;
+
+ /*
+ * Write all pages (both data and verity metadata). Note that this must
+ * happen before clearing EXT4_STATE_VERITY_IN_PROGRESS; otherwise pages
+ * beyond i_size won't be written properly. For crash consistency, this
+ * also must happen before the verity inode flag gets persisted.
+ */
+ err = filemap_write_and_wait(inode->i_mapping);
+ if (err)
+ goto cleanup;
+
+ /*
+ * Finally, set the verity inode flag and remove the inode from the
+ * orphan list (in a single transaction).
+ */
handle = ext4_journal_start(inode, EXT4_HT_INODE, credits);
if (IS_ERR(handle)) {
- ext4_orphan_del(NULL, inode);
- return PTR_ERR(handle);
+ err = PTR_ERR(handle);
+ goto cleanup;
}
- err2 = ext4_orphan_del(handle, inode);
- if (err2)
- goto out_stop;
+ err = ext4_orphan_del(handle, inode);
+ if (err)
+ goto stop_and_cleanup;
- if (desc != NULL && !err) {
- struct ext4_iloc iloc;
+ err = ext4_reserve_inode_write(handle, inode, &iloc);
+ if (err)
+ goto stop_and_cleanup;
- err = ext4_reserve_inode_write(handle, inode, &iloc);
- if (err)
- goto out_stop;
- ext4_set_inode_flag(inode, EXT4_INODE_VERITY);
- ext4_set_inode_flags(inode);
- err = ext4_mark_iloc_dirty(handle, inode, &iloc);
- }
-out_stop:
+ ext4_set_inode_flag(inode, EXT4_INODE_VERITY);
+ ext4_set_inode_flags(inode, false);
+ err = ext4_mark_iloc_dirty(handle, inode, &iloc);
+ if (err)
+ goto stop_and_cleanup;
+
ext4_journal_stop(handle);
- return err ?: err2;
+
+ ext4_clear_inode_state(inode, EXT4_STATE_VERITY_IN_PROGRESS);
+ return 0;
+
+stop_and_cleanup:
+ ext4_journal_stop(handle);
+cleanup:
+ /*
+ * Verity failed to be enabled, so clean up by truncating any verity
+ * metadata that was written beyond i_size (both from cache and from
+ * disk), removing the inode from the orphan list (if it wasn't done
+ * already), and clearing EXT4_STATE_VERITY_IN_PROGRESS.
+ */
+ truncate_inode_pages(inode->i_mapping, inode->i_size);
+ ext4_truncate(inode);
+ ext4_orphan_del(NULL, inode);
+ ext4_clear_inode_state(inode, EXT4_STATE_VERITY_IN_PROGRESS);
+ return err;
}
static int ext4_get_verity_descriptor_location(struct inode *inode,
@@ -342,39 +363,6 @@
return desc_size;
}
-/*
- * Prefetch some pages from the file's Merkle tree.
- *
- * This is basically a stripped-down version of __do_page_cache_readahead()
- * which works on pages past i_size.
- */
-static void ext4_merkle_tree_readahead(struct address_space *mapping,
- pgoff_t start_index, unsigned long count)
-{
- LIST_HEAD(pages);
- unsigned int nr_pages = 0;
- struct page *page;
- pgoff_t index;
- struct blk_plug plug;
-
- for (index = start_index; index < start_index + count; index++) {
- rcu_read_lock();
- page = radix_tree_lookup(&mapping->i_pages, index);
- rcu_read_unlock();
- if (!page || radix_tree_exceptional_entry(page)) {
- page = __page_cache_alloc(readahead_gfp_mask(mapping));
- if (!page)
- break;
- page->index = index;
- list_add(&page->lru, &pages);
- nr_pages++;
- }
- }
- blk_start_plug(&plug);
- ext4_mpage_readpages(mapping, &pages, NULL, nr_pages, true);
- blk_finish_plug(&plug);
-}
-
static struct page *ext4_read_merkle_tree_page(struct inode *inode,
pgoff_t index,
unsigned long num_ra_pages)
@@ -385,11 +373,12 @@
page = find_get_page_flags(inode->i_mapping, index, FGP_ACCESSED);
if (!page || !PageUptodate(page)) {
+ DEFINE_READAHEAD(ractl, NULL, inode->i_mapping, index);
+
if (page)
put_page(page);
else if (num_ra_pages > 1)
- ext4_merkle_tree_readahead(inode->i_mapping, index,
- num_ra_pages);
+ page_cache_ra_unbounded(&ractl, num_ra_pages, 0);
page = read_mapping_page(inode->i_mapping, index, NULL);
}
return page;
--
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