ext4 crypto: don't let data integrity writebacks fail with ENOMEM

We don't want the writeback triggered from the journal commit (in
data=writeback mode) to cause the journal to abort due to
generic_writepages() returning an ENOMEM error.  In addition, if
fsync() fails with ENOMEM, most applications will probably not do the
right thing.

So if we are doing a data integrity sync, and ext4_encrypt() returns
ENOMEM, we will submit any queued I/O to date, and then retry the
allocation using GFP_NOFAIL.

Google-Bug-Id: 27641567

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o
2016-03-26 16:14:34 -04:00
parent 9e92f48c34
commit c9af28fdd4
4 changed files with 39 additions and 20 deletions

View File

@@ -2282,11 +2282,13 @@ extern struct kmem_cache *ext4_crypt_info_cachep;
bool ext4_valid_contents_enc_mode(uint32_t mode);
uint32_t ext4_validate_encryption_key_size(uint32_t mode, uint32_t size);
extern struct workqueue_struct *ext4_read_workqueue;
struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode);
struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode,
gfp_t gfp_flags);
void ext4_release_crypto_ctx(struct ext4_crypto_ctx *ctx);
void ext4_restore_control_page(struct page *data_page);
struct page *ext4_encrypt(struct inode *inode,
struct page *plaintext_page);
struct page *plaintext_page,
gfp_t gfp_flags);
int ext4_decrypt(struct page *page);
int ext4_encrypted_zeroout(struct inode *inode, ext4_lblk_t lblk,
ext4_fsblk_t pblk, ext4_lblk_t len);