BMC/Intel-BMC/linux.git/fs/ext4/crypto.c, branch dev-4.3

ext4: fix an endianness bug in ext4_encrypted_zeroout()

2016-02-19T22:28:34+00:00

commit e2c9e0b28e146c9a3bce21408f3c02e24ac7ac31 upstream. ex->ee_block is not host-endian (note that accesses of other fields of *ex right next to that line go through the helpers that do proper conversion from little-endian to host-endian; it might make sense to add similar for ->ee_block to avoid reintroducing that kind of bugs...) Signed-off-by: Al Viro Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

ext4 crypto: fix bugs in ext4_encrypted_zeroout()

2015-12-15T05:41:07+00:00

commit 36086d43f6575c081067de9855786a2fc91df77b upstream. Fix multiple bugs in ext4_encrypted_zeroout(), including one that could cause us to write an encrypted zero page to the wrong location on disk, potentially causing data and file system corruption. Fortunately, this tends to only show up in stress tests, but even with these fixes, we are seeing some test failures with generic/127 --- but these are now caused by data failures instead of metadata corruption. Since ext4_encrypted_zeroout() is only used for some optimizations to keep the extent tree from being too fragmented, and ext4_encrypted_zeroout() itself isn't all that optimized from a time or IOPS perspective, disable the extent tree optimization for encrypted inodes for now. This prevents the data corruption issues reported by generic/127 until we can figure out what's going wrong. Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

ext4 crypto: fix ext4_get_crypto_ctx()'s calling convention in ext4_decrypt_one

2015-06-08T15:54:56+00:00

Signed-off-by: Theodore Ts'o

ext4 crypto: allocate bounce pages using GFP_NOWAIT

2015-06-03T13:32:39+00:00

Previously we allocated bounce pages using a combination of alloc_page() and mempool_alloc() with the __GFP_WAIT bit set. Instead, use mempool_alloc() with GFP_NOWAIT. The mempool_alloc() function will try using alloc_pages() initially, and then only use the mempool reserve of pages if alloc_pages() is unable to fulfill the request. This minimizes the the impact on the mm layer when we need to do a large amount of writeback of encrypted files, as Jaeguk Kim had reported that under a heavy fio workload on a system with restricted amounts memory (which unfortunately, includes many mobile handsets), he had observed the the OOM killer getting triggered several times. Using GFP_NOWAIT If the mempool_alloc() function fails, we will retry the page writeback at a later time; the function of the mempool is to ensure that we can writeback at least 32 pages at a time, so we can more efficiently dispatch I/O under high memory pressure situations. In the future we should make this be a tunable so we can determine the best tradeoff between permanently sequestering memory and the ability to quickly launder pages so we can free up memory quickly when necessary. Signed-off-by: Theodore Ts'o

ext4 crypto: handle unexpected lack of encryption keys

2015-05-31T17:35:39+00:00

Fix up attempts by users to try to write to a file when they don't have access to the encryption key. Signed-off-by: Theodore Ts'o

ext4 crypto: fix memory leaks in ext4_encrypted_zeroout

2015-05-31T17:34:24+00:00

ext4_encrypted_zeroout() could end up leaking a bio and bounce page. Fortunately it's not used much. While we're fixing things up, refactor out common code into the static function alloc_bounce_page() and fix up error handling if mempool_alloc() fails. Signed-off-by: Theodore Ts'o

ext4 crypto: use per-inode tfm structure

2015-05-31T17:34:22+00:00

As suggested by Herbert Xu, we shouldn't allocate a new tfm each time we read or write a page. Instead we can use a single tfm hanging off the inode's crypt_info structure for all of our encryption needs for that inode, since the tfm can be used by multiple crypto requests in parallel. Also use cmpxchg() to avoid races that could result in crypt_info structure getting doubly allocated or doubly freed. Signed-off-by: Theodore Ts'o

ext4 crypto: shrink size of the ext4_crypto_ctx structure

2015-05-31T17:31:34+00:00

Some fields are only used when the crypto_ctx is being used on the read path, some are only used on the write path, and some are only used when the structure is on free list. Optimize memory use by using a union. Signed-off-by: Theodore Ts'o

ext4 crypto: get rid of ci_mode from struct ext4_crypt_info

2015-05-18T17:20:47+00:00

The ci_mode field was superfluous, and getting rid of it gets rid of an unused hole in the structure. Signed-off-by: Theodore Ts'o

ext4 crypto: use slab caches

2015-05-18T17:19:47+00:00

Use slab caches the ext4_crypto_ctx and ext4_crypt_info structures for slighly better memory efficiency and debuggability. Signed-off-by: Theodore Ts'o