@@ -87,3 +87,62 @@ bool netfs_encrypt(struct netfs_io_request *wreq)
wreq->error = ret;
return false;
}
+
+/*
+ * Decrypt the result of a read request.
+ */
+void netfs_decrypt(struct netfs_io_request *rreq)
+{
+ struct netfs_inode *ctx = netfs_inode(rreq->inode);
+ struct scatterlist source_sg[16], dest_sg[16];
+ unsigned int n_source;
+ size_t n, chunk, bsize = 1UL << ctx->crypto_bshift;
+ loff_t pos;
+ int ret;
+
+ trace_netfs_rreq(rreq, netfs_rreq_trace_decrypt);
+ if (rreq->start >= rreq->i_size)
+ return;
+
+ n = min_t(unsigned long long, rreq->len, rreq->i_size - rreq->start);
+
+ _debug("DECRYPT %llx-%llx f=%lx",
+ rreq->start, rreq->start + n, rreq->flags);
+
+ pos = rreq->start;
+ for (; n > 0; n -= chunk, pos += chunk) {
+ chunk = min(n, bsize);
+
+ ret = netfs_iter_to_sglist(&rreq->io_iter, chunk,
+ source_sg, ARRAY_SIZE(source_sg));
+ if (ret < 0)
+ goto error;
+ n_source = ret;
+
+ if (test_bit(NETFS_RREQ_CRYPT_IN_PLACE, &rreq->flags)) {
+ ret = ctx->ops->decrypt_block(rreq, pos, chunk,
+ source_sg, n_source,
+ source_sg, n_source);
+ } else {
+ ret = netfs_iter_to_sglist(&rreq->iter, chunk,
+ dest_sg, ARRAY_SIZE(dest_sg));
+ if (ret < 0)
+ goto error;
+ ret = ctx->ops->decrypt_block(rreq, pos, chunk,
+ source_sg, n_source,
+ dest_sg, ret);
+ }
+
+ if (ret < 0)
+ goto error_failed;
+ }
+
+ return;
+
+error_failed:
+ trace_netfs_failure(rreq, NULL, ret, netfs_fail_decryption);
+error:
+ rreq->error = ret;
+ set_bit(NETFS_RREQ_FAILED, &rreq->flags);
+ return;
+}
@@ -26,6 +26,7 @@ int netfs_prefetch_for_write(struct file *file, struct folio *folio,
* crypto.c
*/
bool netfs_encrypt(struct netfs_io_request *wreq);
+void netfs_decrypt(struct netfs_io_request *rreq);
/*
* direct_write.c
@@ -398,6 +398,9 @@ static void netfs_rreq_assess(struct netfs_io_request *rreq, bool was_async)
return;
}
+ if (!test_bit(NETFS_RREQ_FAILED, &rreq->flags) &&
+ test_bit(NETFS_RREQ_CONTENT_ENCRYPTION, &rreq->flags))
+ netfs_decrypt(rreq);
if (rreq->origin != NETFS_DIO_READ)
netfs_rreq_unlock_folios(rreq);
else
@@ -427,7 +430,8 @@ static void netfs_rreq_work(struct work_struct *work)
static void netfs_rreq_terminated(struct netfs_io_request *rreq,
bool was_async)
{
- if (test_bit(NETFS_RREQ_INCOMPLETE_IO, &rreq->flags) &&
+ if ((test_bit(NETFS_RREQ_INCOMPLETE_IO, &rreq->flags) ||
+ test_bit(NETFS_RREQ_CONTENT_ENCRYPTION, &rreq->flags)) &&
was_async) {
if (!queue_work(system_unbound_wq, &rreq->work))
BUG();
@@ -327,6 +327,9 @@ struct netfs_request_ops {
int (*encrypt_block)(struct netfs_io_request *wreq, loff_t pos, size_t len,
struct scatterlist *source_sg, unsigned int n_source,
struct scatterlist *dest_sg, unsigned int n_dest);
+ int (*decrypt_block)(struct netfs_io_request *rreq, loff_t pos, size_t len,
+ struct scatterlist *source_sg, unsigned int n_source,
+ struct scatterlist *dest_sg, unsigned int n_dest);
};
/*
@@ -40,6 +40,7 @@
#define netfs_rreq_traces \
EM(netfs_rreq_trace_assess, "ASSESS ") \
EM(netfs_rreq_trace_copy, "COPY ") \
+ EM(netfs_rreq_trace_decrypt, "DECRYPT") \
EM(netfs_rreq_trace_done, "DONE ") \
EM(netfs_rreq_trace_encrypt, "ENCRYPT") \
EM(netfs_rreq_trace_free, "FREE ") \
@@ -75,6 +76,7 @@
#define netfs_failures \
EM(netfs_fail_check_write_begin, "check-write-begin") \
EM(netfs_fail_copy_to_cache, "copy-to-cache") \
+ EM(netfs_fail_decryption, "decryption") \
EM(netfs_fail_dio_read_short, "dio-read-short") \
EM(netfs_fail_dio_read_zero, "dio-read-zero") \
EM(netfs_fail_encryption, "encryption") \
Implement a facility to provide decryption for encrypted content to a whole read-request in one go (which might have been stitched together from disparate sources with divisions that don't match page boundaries). Note that this doesn't necessarily gain the best throughput if the crypto block size is equal to or less than the size of a page (in which case we might be better doing it as pages become read), but it will handle crypto blocks larger than the size of a page. Signed-off-by: David Howells <dhowells@redhat.com> cc: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org --- fs/netfs/crypto.c | 59 ++++++++++++++++++++++++++++++++++++ fs/netfs/internal.h | 1 + fs/netfs/io.c | 6 +++- include/linux/netfs.h | 3 ++ include/trace/events/netfs.h | 2 ++ 5 files changed, 70 insertions(+), 1 deletion(-)