From: Eric Biggers <ebiggers@xxxxxxxxxx>
As a step towards freeing the PG_error flag for other uses, change ext4
and f2fs to stop using PG_error to track verity errors. Instead, if a
verity error occurs, just mark the whole bio as failed. The coarser
granularity isn't really a problem since it isn't any worse than what
the block layer provides, and errors from a multi-page readahead aren't
reported to applications unless a single-page read fails too.
f2fs supports compression, which makes the f2fs changes a bit more
complicated than desired, but the basic premise still works.
Note: there are still a few uses of PageError in f2fs, but they are on
the write path, so they are unrelated and this patch doesn't touch them.
Reviewed-by: Chao Yu <chao@xxxxxxxxxx>
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
---
v4: Added a comment for decompression_attempted, added a paragraph to
the commit message, and added Chao's Reviewed-by.
v3: made a small simplification to the f2fs changes. Also dropped the
fscrypt patch since it is upstream now.
fs/ext4/readpage.c | 8 ++----
fs/f2fs/compress.c | 64 ++++++++++++++++++++++------------------------
fs/f2fs/data.c | 53 +++++++++++++++++++++++---------------
fs/verity/verify.c | 12 ++++-----
4 files changed, 72 insertions(+), 65 deletions(-)
diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
index 3d21eae267fca..e604ea4e102b7 100644
--- a/fs/ext4/readpage.c
+++ b/fs/ext4/readpage.c
@@ -75,14 +75,10 @@ static void __read_end_io(struct bio *bio)
bio_for_each_segment_all(bv, bio, iter_all) {
page = bv->bv_page;
- /* PG_error was set if verity failed. */
- if (bio->bi_status || PageError(page)) {
+ if (bio->bi_status)
ClearPageUptodate(page);
- /* will re-read again later */
- ClearPageError(page);
- } else {
+ else
SetPageUptodate(page);
- }
unlock_page(page);
}
if (bio->bi_private)
diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index d315c2de136f2..2b7a5cc4ed662 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -1711,50 +1711,27 @@ static void f2fs_put_dic(struct decompress_io_ctx *dic, bool in_task)
}
}
-/*
- * Update and unlock the cluster's pagecache pages, and release the reference to
- * the decompress_io_ctx that was being held for I/O completion.
- */
-static void __f2fs_decompress_end_io(struct decompress_io_ctx *dic, bool failed,
- bool in_task)
+static void f2fs_verify_cluster(struct work_struct *work)
{
+ struct decompress_io_ctx *dic =
+ container_of(work, struct decompress_io_ctx, verity_work);
int i;
+ /* Verify, update, and unlock the decompressed pages. */
for (i = 0; i < dic->cluster_size; i++) {
struct page *rpage = dic->rpages[i];
if (!rpage)
continue;
- /* PG_error was set if verity failed. */
- if (failed || PageError(rpage)) {
- ClearPageUptodate(rpage);
- /* will re-read again later */
- ClearPageError(rpage);
- } else {
+ if (fsverity_verify_page(rpage))
SetPageUptodate(rpage);
- }
+ else
+ ClearPageUptodate(rpage);
unlock_page(rpage);
}
- f2fs_put_dic(dic, in_task);
-}
-
-static void f2fs_verify_cluster(struct work_struct *work)
-{
- struct decompress_io_ctx *dic =
- container_of(work, struct decompress_io_ctx, verity_work);
- int i;
-
- /* Verify the cluster's decompressed pages with fs-verity. */
- for (i = 0; i < dic->cluster_size; i++) {
- struct page *rpage = dic->rpages[i];
-
- if (rpage && !fsverity_verify_page(rpage))
- SetPageError(rpage);
- }
-
- __f2fs_decompress_end_io(dic, false, true);
+ f2fs_put_dic(dic, true);
}
/*
@@ -1764,6 +1741,8 @@ static void f2fs_verify_cluster(struct work_struct *work)
void f2fs_decompress_end_io(struct decompress_io_ctx *dic, bool failed,
bool in_task)
{
+ int i;
+
if (!failed && dic->need_verity) {
/*
* Note that to avoid deadlocks, the verity work can't be done
@@ -1773,9 +1752,28 @@ void f2fs_decompress_end_io(struct decompress_io_ctx *dic, bool failed,
*/
INIT_WORK(&dic->verity_work, f2fs_verify_cluster);
fsverity_enqueue_verify_work(&dic->verity_work);
- } else {
- __f2fs_decompress_end_io(dic, failed, in_task);
+ return;
+ }
+
+ /* Update and unlock the cluster's pagecache pages. */
+ for (i = 0; i < dic->cluster_size; i++) {
+ struct page *rpage = dic->rpages[i];
+
+ if (!rpage)
+ continue;
+
+ if (failed)
+ ClearPageUptodate(rpage);
+ else
+ SetPageUptodate(rpage);
+ unlock_page(rpage);
}
+
+ /*
+ * Release the reference to the decompress_io_ctx that was being held
+ * for I/O completion.
+ */
+ f2fs_put_dic(dic, in_task);
}
/*
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index a71e818cd67b4..1ae8da259d6c5 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -116,43 +116,56 @@ struct bio_post_read_ctx {
struct f2fs_sb_info *sbi;
struct work_struct work;
unsigned int enabled_steps;
+ /*
+ * decompression_attempted keeps track of whether
+ * f2fs_end_read_compressed_page() has been called on the pages in the
+ * bio that belong to a compressed cluster yet.
+ */
+ bool decompression_attempted;
block_t fs_blkaddr;
};
+/*
+ * Update and unlock a bio's pages, and free the bio.
+ *
+ * This marks pages up-to-date only if there was no error in the bio (I/O error,
+ * decryption error, or verity error), as indicated by bio->bi_status.
+ *
+ * "Compressed pages" (pagecache pages backed by a compressed cluster on-disk)
+ * aren't marked up-to-date here, as decompression is done on a per-compression-
+ * cluster basis rather than a per-bio basis. Instead, we only must do two
+ * things for each compressed page here: call f2fs_end_read_compressed_page()
+ * with failed=true if an error occurred before it would have normally gotten
+ * called (i.e., I/O error or decryption error, but *not* verity error), and
+ * release the bio's reference to the decompress_io_ctx of the page's cluster.
+ */
static void f2fs_finish_read_bio(struct bio *bio, bool in_task)
{
struct bio_vec *bv;
struct bvec_iter_all iter_all;
+ struct bio_post_read_ctx *ctx = bio->bi_private;
- /*
- * Update and unlock the bio's pagecache pages, and put the
- * decompression context for any compressed pages.
- */
bio_for_each_segment_all(bv, bio, iter_all) {
struct page *page = bv->bv_page;
if (f2fs_is_compressed_page(page)) {
- if (bio->bi_status)
+ if (!ctx->decompression_attempted)
f2fs_end_read_compressed_page(page, true, 0,
in_task);
f2fs_put_page_dic(page, in_task);
continue;
}
- /* PG_error was set if verity failed. */
- if (bio->bi_status || PageError(page)) {
+ if (bio->bi_status)
ClearPageUptodate(page);
- /* will re-read again later */
- ClearPageError(page);
- } else {
+ else
SetPageUptodate(page);
- }
dec_page_count(F2FS_P_SB(page), __read_io_type(page));
unlock_page(page);
}
- if (bio->bi_private)
- mempool_free(bio->bi_private, bio_post_read_ctx_pool);
+ if (ctx)
+ mempool_free(ctx, bio_post_read_ctx_pool);
bio_put(bio);
}
@@ -185,8 +198,10 @@ static void f2fs_verify_bio(struct work_struct *work)
struct page *page = bv->bv_page;
if (!f2fs_is_compressed_page(page) &&
- !fsverity_verify_page(page))
- SetPageError(page);
+ !fsverity_verify_page(page)) {
+ bio->bi_status = BLK_STS_IOERR;
+ break;
+ }
}
} else {
fsverity_verify_bio(bio);
@@ -245,6 +260,8 @@ static void f2fs_handle_step_decompress(struct bio_post_read_ctx *ctx,
blkaddr++;
}
+ ctx->decompression_attempted = true;
+
/*
* Optimization: if all the bio's pages are compressed, then scheduling
* the per-bio verity work is unnecessary, as verity will be fully
@@ -1062,6 +1079,7 @@ static struct bio *f2fs_grab_read_bio(struct inode *inode, block_t blkaddr,
ctx->sbi = sbi;
ctx->enabled_steps = post_read_steps;
ctx->fs_blkaddr = blkaddr;
+ ctx->decompression_attempted = false;
bio->bi_private = ctx;
}
iostat_alloc_and_bind_ctx(sbi, bio, ctx);
@@ -1089,7 +1107,6 @@ static int f2fs_submit_page_read(struct inode *inode, struct page *page,
bio_put(bio);
return -EFAULT;
}
- ClearPageError(page);
inc_page_count(sbi, F2FS_RD_DATA);
f2fs_update_iostat(sbi, NULL, FS_DATA_READ_IO, F2FS_BLKSIZE);
__submit_bio(sbi, bio, DATA);
@@ -2141,7 +2158,6 @@ static int f2fs_read_single_page(struct inode *inode, struct page *page,
inc_page_count(F2FS_I_SB(inode), F2FS_RD_DATA);
f2fs_update_iostat(F2FS_I_SB(inode), NULL, FS_DATA_READ_IO,
F2FS_BLKSIZE);
- ClearPageError(page);
*last_block_in_bio = block_nr;
goto out;
out:
@@ -2289,7 +2305,6 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
inc_page_count(sbi, F2FS_RD_DATA);
f2fs_update_iostat(sbi, inode, FS_DATA_READ_IO, F2FS_BLKSIZE);
- ClearPageError(page);
*last_block_in_bio = blkaddr;
}
@@ -2306,7 +2321,6 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
for (i = 0; i < cc->cluster_size; i++) {
if (cc->rpages[i]) {
ClearPageUptodate(cc->rpages[i]);
- ClearPageError(cc->rpages[i]);
unlock_page(cc->rpages[i]);
}
}
@@ -2403,7 +2417,6 @@ static int f2fs_mpage_readpages(struct inode *inode,
#ifdef CONFIG_F2FS_FS_COMPRESSION
set_error_page:
#endif
- SetPageError(page);
zero_user_segment(page, 0, PAGE_SIZE);
unlock_page(page);
}
diff --git a/fs/verity/verify.c b/fs/verity/verify.c
index bde8c9b7d25f6..961ba248021f9 100644
--- a/fs/verity/verify.c
+++ b/fs/verity/verify.c
@@ -200,9 +200,8 @@ EXPORT_SYMBOL_GPL(fsverity_verify_page);
* @bio: the bio to verify
*
* Verify a set of pages that have just been read from a verity file. The pages
- * must be pagecache pages that are still locked and not yet uptodate. Pages
- * that fail verification are set to the Error state. Verification is skipped
- * for pages already in the Error state, e.g. due to fscrypt decryption failure.
+ * must be pagecache pages that are still locked and not yet uptodate. If a
+ * page fails verification, then bio->bi_status is set to an error status.
*
* This is a helper function for use by the ->readahead() method of filesystems
* that issue bios to read data directly into the page cache. Filesystems that
@@ -244,9 +243,10 @@ void fsverity_verify_bio(struct bio *bio)
unsigned long level0_ra_pages =
min(max_ra_pages, params->level0_blocks - level0_index);
- if (!PageError(page) &&
- !verify_page(inode, vi, req, page, level0_ra_pages))
- SetPageError(page);
+ if (!verify_page(inode, vi, req, page, level0_ra_pages)) {
+ bio->bi_status = BLK_STS_IOERR;
+ break;
+ }
}
fsverity_free_hash_request(params->hash_alg, req);
base-commit: f0c4d9fc9cc9462659728d168387191387e903cc
--
2.38.1
