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fscrypt: stop using PG_error to track error status

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As a step towards freeing the PG_error flag for other uses, change ext4
and f2fs to stop using PG_error to track decryption errors.  Instead, if
a decryption 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.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Chao Yu <chao@kernel.org> # for f2fs part
Link: https://lore.kernel.org/r/20220815235052.86545-2-ebiggers@kernel.org
This commit is contained in:
Eric Biggers 2022-08-15 16:50:51 -07:00
parent 272ac15003
commit 14db0b3c7b
4 changed files with 29 additions and 20 deletions
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16
fs/crypto/bio.c
View File

@ -25,21 +25,25 @@
* then this function isn't applicable. This function may sleep, so it must be
* called from a workqueue rather than from the bio's bi_end_io callback.
*
* This function sets PG_error on any pages that contain any blocks that failed
* to be decrypted. The filesystem must not mark such pages uptodate.
* Return: %true on success; %false on failure. On failure, bio->bi_status is
* also set to an error status.
*/
void fscrypt_decrypt_bio(struct bio *bio)
bool fscrypt_decrypt_bio(struct bio *bio)
{
struct bio_vec *bv;
struct bvec_iter_all iter_all;
bio_for_each_segment_all(bv, bio, iter_all) {
struct page *page = bv->bv_page;
int ret = fscrypt_decrypt_pagecache_blocks(page, bv->bv_len,
int err = fscrypt_decrypt_pagecache_blocks(page, bv->bv_len,
bv->bv_offset);
if (ret)
SetPageError(page);
if (err) {
bio->bi_status = errno_to_blk_status(err);
return false;
}
}
return true;
}
EXPORT_SYMBOL(fscrypt_decrypt_bio);

10
fs/ext4/readpage.c
View File

@ -75,7 +75,7 @@ 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 any post_read step failed */
/* PG_error was set if verity failed. */
if (bio->bi_status || PageError(page)) {
ClearPageUptodate(page);
/* will re-read again later */
@ -96,10 +96,12 @@ static void decrypt_work(struct work_struct *work)
{
struct bio_post_read_ctx *ctx =
container_of(work, struct bio_post_read_ctx, work);
struct bio *bio = ctx->bio;
fscrypt_decrypt_bio(ctx->bio);
bio_post_read_processing(ctx);
if (fscrypt_decrypt_bio(bio))
bio_post_read_processing(ctx);
else
__read_end_io(bio);
}
static void verity_work(struct work_struct *work)

18
fs/f2fs/data.c
View File

@ -139,7 +139,7 @@ static void f2fs_finish_read_bio(struct bio *bio, bool in_task)
continue;
}
/* PG_error was set if decryption or verity failed. */
/* PG_error was set if verity failed. */
if (bio->bi_status || PageError(page)) {
ClearPageUptodate(page);
/* will re-read again later */
@ -185,7 +185,7 @@ static void f2fs_verify_bio(struct work_struct *work)
struct page *page = bv->bv_page;
if (!f2fs_is_compressed_page(page) &&
!PageError(page) && !fsverity_verify_page(page))
!fsverity_verify_page(page))
SetPageError(page);
}
} else {
@ -236,10 +236,9 @@ static void f2fs_handle_step_decompress(struct bio_post_read_ctx *ctx,
bio_for_each_segment_all(bv, ctx->bio, iter_all) {
struct page *page = bv->bv_page;
/* PG_error was set if decryption failed. */
if (f2fs_is_compressed_page(page))
f2fs_end_read_compressed_page(page, PageError(page),
blkaddr, in_task);
f2fs_end_read_compressed_page(page, false, blkaddr,
in_task);
else
all_compressed = false;
@ -259,14 +258,17 @@ static void f2fs_post_read_work(struct work_struct *work)
{
struct bio_post_read_ctx *ctx =
container_of(work, struct bio_post_read_ctx, work);
struct bio *bio = ctx->bio;
if (ctx->enabled_steps & STEP_DECRYPT)
fscrypt_decrypt_bio(ctx->bio);
if ((ctx->enabled_steps & STEP_DECRYPT) && !fscrypt_decrypt_bio(bio)) {
f2fs_finish_read_bio(bio, true);
return;
}
if (ctx->enabled_steps & STEP_DECOMPRESS)
f2fs_handle_step_decompress(ctx, true);
f2fs_verify_and_finish_bio(ctx->bio, true);
f2fs_verify_and_finish_bio(bio, true);
}
static void f2fs_read_end_io(struct bio *bio)

5
include/linux/fscrypt.h
View File

@ -351,7 +351,7 @@ u64 fscrypt_fname_siphash(const struct inode *dir, const struct qstr *name);
int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags);
/* bio.c */
void fscrypt_decrypt_bio(struct bio *bio);
bool fscrypt_decrypt_bio(struct bio *bio);
int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
sector_t pblk, unsigned int len);
@ -644,8 +644,9 @@ static inline int fscrypt_d_revalidate(struct dentry *dentry,
}
/* bio.c */
static inline void fscrypt_decrypt_bio(struct bio *bio)
static inline bool fscrypt_decrypt_bio(struct bio *bio)
{
return true;
}
static inline int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,