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ext4 crypto: fix bugs in ext4_encrypted_zeroout() 

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 <tytso@mit.edu>
Cc: stable@vger.kernel.org
This commit is contained in:
Theodore Ts'o 2015-10-03 10:49:29 -04:00
parent 687c3c36e7
commit 36086d43f6
2 changed files with 22 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
fs/ext4/crypto.c
View File

@ -392,7 +392,13 @@ int ext4_encrypted_zeroout(struct inode *inode, struct ext4_extent *ex)
ext4_lblk_t lblk = ex->ee_block;
ext4_fsblk_t pblk = ext4_ext_pblock(ex);
unsigned int len = ext4_ext_get_actual_len(ex);
int err = 0;
int ret, err = 0;
#if 0
ext4_msg(inode->i_sb, KERN_CRIT,
"ext4_encrypted_zeroout ino %lu lblk %u len %u",
(unsigned long) inode->i_ino, lblk, len);
#endif
BUG_ON(inode->i_sb->s_blocksize != PAGE_CACHE_SIZE);
@ -418,17 +424,26 @@ int ext4_encrypted_zeroout(struct inode *inode, struct ext4_extent *ex)
goto errout;
}
bio->bi_bdev = inode->i_sb->s_bdev;
bio->bi_iter.bi_sector = pblk;
err = bio_add_page(bio, ciphertext_page,
bio->bi_iter.bi_sector =
pblk << (inode->i_sb->s_blocksize_bits - 9);
ret = bio_add_page(bio, ciphertext_page,
inode->i_sb->s_blocksize, 0);
if (err) {
if (ret != inode->i_sb->s_blocksize) {
/* should never happen! */
ext4_msg(inode->i_sb, KERN_ERR,
"bio_add_page failed: %d", ret);
WARN_ON(1);
bio_put(bio);
err = -EIO;
goto errout;
}
err = submit_bio_wait(WRITE, bio);
if ((err == 0) && bio->bi_error)
err = -EIO;
bio_put(bio);
if (err)
goto errout;
lblk++; pblk++;
}
err = 0;
errout:

3
fs/ext4/extents.c
View File

@ -3558,6 +3558,9 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
max_zeroout = sbi->s_extent_max_zeroout_kb >>
(inode->i_sb->s_blocksize_bits - 10);
if (ext4_encrypted_inode(inode))
max_zeroout = 0;
/* If extent is less than s_max_zeroout_kb, zeroout directly */
if (max_zeroout && (ee_len <= max_zeroout)) {
err = ext4_ext_zeroout(inode, ex);