With subpage sized blocks, ext4_block_write_begin() can have up to two
blocks to decrypt. Hence this commit invokes fscrypt_decrypt_page() for
each of those blocks.
Signed-off-by: Chandan Rajendra <chan...@linux.ibm.com>
---
fs/ext4/inode.c | 33 +++++++++++++++++++++++----------
1 file changed, 23 insertions(+), 10 deletions(-)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 1327e04334df..51744a3c3964 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1156,12 +1156,14 @@ static int ext4_block_write_begin(struct page *page,
loff_t pos, unsigned len,
unsigned to = from + len;
struct inode *inode = page->mapping->host;
unsigned block_start, block_end;
- sector_t block;
+ sector_t block, page_blk_nr;
int err = 0;
unsigned blocksize = inode->i_sb->s_blocksize;
unsigned bbits;
- struct buffer_head *bh, *head, *wait[2], **wait_bh = wait;
+ struct buffer_head *bh, *head, *wait[2];
+ int nr_wait = 0;
bool decrypt = false;
+ int i;
BUG_ON(!PageLocked(page));
BUG_ON(from > PAGE_SIZE);
@@ -1213,25 +1215,36 @@ static int ext4_block_write_begin(struct page *page,
loff_t pos, unsigned len,
!buffer_unwritten(bh) &&
(block_start < from || block_end > to)) {
ll_rw_block(REQ_OP_READ, 0, 1, &bh);
- *wait_bh++ = bh;
+ wait[nr_wait++] = bh;
decrypt = IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode);
}
}
/*
* If we issued read requests, let them complete.
*/
- while (wait_bh > wait) {
- wait_on_buffer(*--wait_bh);
- if (!buffer_uptodate(*wait_bh))
+ for (i = 0; i < nr_wait; i++) {
+ wait_on_buffer(wait[i]);
+ if (!buffer_uptodate(wait[i]))
err = -EIO;
}
if (unlikely(err)) {
page_zero_new_buffers(page, from, to);
} else if (decrypt) {
- err = fscrypt_decrypt_page(page->mapping->host, page,
- PAGE_SIZE, 0, page->index);
- if (err)
- clear_buffer_uptodate(*wait_bh);
+ page_blk_nr = (sector_t)page->index << (PAGE_SHIFT - bbits);
+
+ for (i = 0; i < nr_wait; i++) {
+ int err2;
+
+ block = page_blk_nr + (bh_offset(wait[i]) >> bbits);
+ err2 = fscrypt_decrypt_page(page->mapping->host, page,
+ wait[i]->b_size,
+ bh_offset(wait[i]),
+ block);
+ if (err2) {
+ clear_buffer_uptodate(wait[i]);
+ err = err2;
+ }
+ }
}
return err;
--
2.19.1
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