ext4 crypto: implement the ext4 encryption write path
Pulls block_write_begin() into fs/ext4/inode.c because it might need
to do a low-level read of the existing data, in which case we need to
decrypt it.
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>
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index 5687e47..51a5f12 100644
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -67,6 +67,10 @@
bio_for_each_segment_all(bvec, bio, i) {
struct page *page = bvec->bv_page;
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+ struct page *data_page = NULL;
+ struct ext4_crypto_ctx *ctx = NULL;
+#endif
struct buffer_head *bh, *head;
unsigned bio_start = bvec->bv_offset;
unsigned bio_end = bio_start + bvec->bv_len;
@@ -76,6 +80,15 @@
if (!page)
continue;
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+ if (!page->mapping) {
+ /* The bounce data pages are unmapped. */
+ data_page = page;
+ ctx = (struct ext4_crypto_ctx *)page_private(data_page);
+ page = ctx->control_page;
+ }
+#endif
+
if (error) {
SetPageError(page);
set_bit(AS_EIO, &page->mapping->flags);
@@ -100,8 +113,13 @@
} while ((bh = bh->b_this_page) != head);
bit_spin_unlock(BH_Uptodate_Lock, &head->b_state);
local_irq_restore(flags);
- if (!under_io)
+ if (!under_io) {
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+ if (ctx)
+ ext4_restore_control_page(data_page);
+#endif
end_page_writeback(page);
+ }
}
}
@@ -376,6 +394,7 @@
static int io_submit_add_bh(struct ext4_io_submit *io,
struct inode *inode,
+ struct page *page,
struct buffer_head *bh)
{
int ret;
@@ -389,7 +408,7 @@
if (ret)
return ret;
}
- ret = bio_add_page(io->io_bio, bh->b_page, bh->b_size, bh_offset(bh));
+ ret = bio_add_page(io->io_bio, page, bh->b_size, bh_offset(bh));
if (ret != bh->b_size)
goto submit_and_retry;
io->io_next_block++;
@@ -402,6 +421,7 @@
struct writeback_control *wbc,
bool keep_towrite)
{
+ struct page *data_page = NULL;
struct inode *inode = page->mapping->host;
unsigned block_start, blocksize;
struct buffer_head *bh, *head;
@@ -461,19 +481,29 @@
set_buffer_async_write(bh);
} while ((bh = bh->b_this_page) != head);
- /* Now submit buffers to write */
bh = head = page_buffers(page);
+
+ if (ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode)) {
+ data_page = ext4_encrypt(inode, page);
+ if (IS_ERR(data_page)) {
+ ret = PTR_ERR(data_page);
+ data_page = NULL;
+ goto out;
+ }
+ }
+
+ /* Now submit buffers to write */
do {
if (!buffer_async_write(bh))
continue;
- ret = io_submit_add_bh(io, inode, bh);
+ ret = io_submit_add_bh(io, inode,
+ data_page ? data_page : page, bh);
if (ret) {
/*
* We only get here on ENOMEM. Not much else
* we can do but mark the page as dirty, and
* better luck next time.
*/
- redirty_page_for_writepage(wbc, page);
break;
}
nr_submitted++;
@@ -482,6 +512,11 @@
/* Error stopped previous loop? Clean up buffers... */
if (ret) {
+ out:
+ if (data_page)
+ ext4_restore_control_page(data_page);
+ printk_ratelimited(KERN_ERR "%s: ret = %d\n", __func__, ret);
+ redirty_page_for_writepage(wbc, page);
do {
clear_buffer_async_write(bh);
bh = bh->b_this_page;