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authorMichael Halcrow <mhalcrow@google.com>2015-04-12 06:56:10 +0200
committerTheodore Ts'o <tytso@mit.edu>2015-04-12 06:56:10 +0200
commitc9c7429c2e486f375bddd0c338cc3ad366123717 (patch)
treeb9cc5749676e272856e930f3086e4965839c44ea /fs/ext4/readpage.c
parentext4 crypto: implement the ext4 encryption write path (diff)
downloadlinux-c9c7429c2e486f375bddd0c338cc3ad366123717.tar.xz
linux-c9c7429c2e486f375bddd0c338cc3ad366123717.zip
ext4 crypto: implement the ext4 decryption read path
Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/readpage.c')
-rw-r--r--fs/ext4/readpage.c66
1 files changed, 65 insertions, 1 deletions
diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
index fff9fe6aacf8..171b9ac4b45e 100644
--- a/fs/ext4/readpage.c
+++ b/fs/ext4/readpage.c
@@ -47,6 +47,46 @@
#include "ext4.h"
/*
+ * Call ext4_decrypt on every single page, reusing the encryption
+ * context.
+ */
+static void completion_pages(struct work_struct *work)
+{
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+ struct ext4_crypto_ctx *ctx =
+ container_of(work, struct ext4_crypto_ctx, work);
+ struct bio *bio = ctx->bio;
+ struct bio_vec *bv;
+ int i;
+
+ bio_for_each_segment_all(bv, bio, i) {
+ struct page *page = bv->bv_page;
+
+ int ret = ext4_decrypt(ctx, page);
+ if (ret) {
+ WARN_ON_ONCE(1);
+ SetPageError(page);
+ } else
+ SetPageUptodate(page);
+ unlock_page(page);
+ }
+ ext4_release_crypto_ctx(ctx);
+ bio_put(bio);
+#else
+ BUG();
+#endif
+}
+
+static inline bool ext4_bio_encrypted(struct bio *bio)
+{
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+ return unlikely(bio->bi_private != NULL);
+#else
+ return false;
+#endif
+}
+
+/*
* I/O completion handler for multipage BIOs.
*
* The mpage code never puts partial pages into a BIO (except for end-of-file).
@@ -63,6 +103,18 @@ static void mpage_end_io(struct bio *bio, int err)
struct bio_vec *bv;
int i;
+ if (ext4_bio_encrypted(bio)) {
+ struct ext4_crypto_ctx *ctx = bio->bi_private;
+
+ if (err) {
+ ext4_release_crypto_ctx(ctx);
+ } else {
+ INIT_WORK(&ctx->work, completion_pages);
+ ctx->bio = bio;
+ queue_work(ext4_read_workqueue, &ctx->work);
+ return;
+ }
+ }
bio_for_each_segment_all(bv, bio, i) {
struct page *page = bv->bv_page;
@@ -223,13 +275,25 @@ int ext4_mpage_readpages(struct address_space *mapping,
bio = NULL;
}
if (bio == NULL) {
+ struct ext4_crypto_ctx *ctx = NULL;
+
+ if (ext4_encrypted_inode(inode) &&
+ S_ISREG(inode->i_mode)) {
+ ctx = ext4_get_crypto_ctx(inode);
+ if (IS_ERR(ctx))
+ goto set_error_page;
+ }
bio = bio_alloc(GFP_KERNEL,
min_t(int, nr_pages, bio_get_nr_vecs(bdev)));
- if (!bio)
+ if (!bio) {
+ if (ctx)
+ ext4_release_crypto_ctx(ctx);
goto set_error_page;
+ }
bio->bi_bdev = bdev;
bio->bi_iter.bi_sector = blocks[0] << (blkbits - 9);
bio->bi_end_io = mpage_end_io;
+ bio->bi_private = ctx;
}
length = first_hole << blkbits;