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 <redacted>
---
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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