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| author |   Eric Biggers <ebiggers@google.com> | 2019-05-20 09:29:52 -0700 |
|---|---|---|
| committer | Eric Biggers <ebiggers@google.com> | 2019-05-28 10:27:53 -0700 |
| commit | 6e4b73bcd1519d50680d92ba74887c80c4e59140 (patch) | |
| tree | 36dcd075033712f765fedf4340713b8f23122803 /fs/ext4 | |
| parent | ext4: decrypt only the needed block in __ext4_block_zero_page_range() (diff) | |
| download | linux-dev-6e4b73bcd1519d50680d92ba74887c80c4e59140.tar.xz linux-dev-6e4b73bcd1519d50680d92ba74887c80c4e59140.zip | |
ext4: encrypt only up to last block in ext4_bio_write_page()
As an optimization, don't encrypt blocks fully beyond i_size, since
those definitely won't need to be written out. Also add a comment.
This is in preparation for allowing encryption on ext4 filesystems with
blocksize != PAGE_SIZE.
This is based on work by Chandan Rajendra.
Reviewed-by: Chandan Rajendra <chandan@linux.ibm.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/page-io.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c index 40ee33df5764..a18a47a2a1d1 100644 --- a/fs/ext4/page-io.c +++ b/fs/ext4/page-io.c @@ -467,11 +467,19 @@ int ext4_bio_write_page(struct ext4_io_submit *io, bh = head = page_buffers(page); + /* + * If any blocks are being written to an encrypted file, encrypt them + * into a bounce page. For simplicity, just encrypt until the last + * block which might be needed. This may cause some unneeded blocks + * (e.g. holes) to be unnecessarily encrypted, but this is rare and + * can't happen in the common case of blocksize == PAGE_SIZE. + */ if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode) && nr_to_submit) { gfp_t gfp_flags = GFP_NOFS; + unsigned int enc_bytes = round_up(len, i_blocksize(inode)); retry_encrypt: - bounce_page = fscrypt_encrypt_pagecache_blocks(page, PAGE_SIZE, + bounce_page = fscrypt_encrypt_pagecache_blocks(page, enc_bytes, 0, gfp_flags); if (IS_ERR(bounce_page)) { ret = PTR_ERR(bounce_page); |