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Date: Thu, 30 Jun 2011 14:22:02 -0700
From: Allison Henderson <achender@...ux.vnet.ibm.com>
To: linux-ext4@...r.kernel.org
Cc: Allison Henderson <achender@...ux.vnet.ibm.com>
Subject: [PATCH 1/2 v3] EXT4: Secure Delete: Zero out file data
The first patch adds a new flag, EXT4_FREE_BLOCKS_ZERO,
to ext4_free_blocks. This flag causes causes blocks to be
zerod before they are freed. Files that have the EXT4_SECRM_FL
attribute flag on will have their blocks zerod when
they are released. The EXT4_SECRM_FL attribute flag can
be enabled useing chattr +s
Signed-off-by: Allison Henderson <achender@...ux.vnet.ibm.com>
---
v1->v2
Removed check for discard mount option and replaced with
check for secure discard and discard_zeroes_data
Added BLKDEV_DISCARD_SECURE to the sb_issue_discard call
v2->v3
Removed code for discard. A seperate patch will
be done to add that code in the block layer
:100644 100644 1921392... 38a4d75... M fs/ext4/ext4.h
:100644 100644 f815cc8... cf178f3... M fs/ext4/extents.c
:100644 100644 62f86e7... 8fdae7d... M fs/ext4/inode.c
:100644 100644 6ed859d... 94872b2... M fs/ext4/mballoc.c
:100644 100644 c757adc... 1ff7532... M fs/ext4/xattr.c
fs/ext4/ext4.h | 1 +
fs/ext4/extents.c | 3 +++
fs/ext4/inode.c | 3 +++
fs/ext4/mballoc.c | 8 ++++++++
fs/ext4/xattr.c | 12 ++++++++----
5 files changed, 23 insertions(+), 4 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 1921392..38a4d75 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -526,6 +526,7 @@ struct ext4_new_group_data {
#define EXT4_FREE_BLOCKS_METADATA 0x0001
#define EXT4_FREE_BLOCKS_FORGET 0x0002
#define EXT4_FREE_BLOCKS_VALIDATED 0x0004
+#define EXT4_FREE_BLOCKS_ZERO 0x0008
/*
* ioctl commands
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index f815cc8..cf178f3 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -2231,6 +2231,9 @@ static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
flags |= EXT4_FREE_BLOCKS_METADATA;
+
+ if (EXT4_I(inode)->i_flags & EXT4_SECRM_FL)
+ flags |= EXT4_FREE_BLOCKS_ZERO;
#ifdef EXTENTS_STATS
{
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 62f86e7..8fdae7d 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4182,6 +4182,9 @@ static int ext4_clear_blocks(handle_t *handle, struct inode *inode,
for (p = first; p < last; p++)
*p = 0;
+ if (EXT4_I(inode)->i_flags & EXT4_SECRM_FL)
+ flags |= EXT4_FREE_BLOCKS_ZERO;
+
ext4_free_blocks(handle, inode, NULL, block_to_free, count, flags);
return 0;
out_err:
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 6ed859d..94872b2 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4485,6 +4485,14 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode,
ext4_debug("freeing block %llu\n", block);
trace_ext4_free_blocks(inode, block, count, flags);
+ if (flags & EXT4_FREE_BLOCKS_ZERO) {
+ err = sb_issue_zeroout(inode->i_sb, block, count, GFP_NOFS);
+ if (err < 0)
+ goto error_return;
+ else
+ err = 0;
+ }
+
if (flags & EXT4_FREE_BLOCKS_FORGET) {
struct buffer_head *tbh = bh;
int i;
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index c757adc..1ff7532 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -471,7 +471,7 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode,
struct buffer_head *bh)
{
struct mb_cache_entry *ce = NULL;
- int error = 0;
+ int free_blocks_flags, error = 0;
ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
error = ext4_journal_get_write_access(handle, bh);
@@ -484,9 +484,13 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode,
if (ce)
mb_cache_entry_free(ce);
get_bh(bh);
- ext4_free_blocks(handle, inode, bh, 0, 1,
- EXT4_FREE_BLOCKS_METADATA |
- EXT4_FREE_BLOCKS_FORGET);
+ free_blocks_flags = EXT4_FREE_BLOCKS_METADATA |
+ EXT4_FREE_BLOCKS_FORGET;
+
+ if (EXT4_I(inode)->i_flags & EXT4_SECRM_FL)
+ free_blocks_flags |= EXT4_FREE_BLOCKS_ZERO;
+
+ ext4_free_blocks(handle, inode, bh, 0, 1, free_blocks_flags);
} else {
le32_add_cpu(&BHDR(bh)->h_refcount, -1);
error = ext4_handle_dirty_metadata(handle, inode, bh);
--
1.7.1
--
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