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Date: Thu, 12 Jun 2014 19:14:07 -0700
From: JP Abgrall <jpa@...gle.com>
To: linux-ext4@...r.kernel.org
Cc: jpa@...gle.com, gcondra@...gle.com
Subject: [PATCH] ext4: Add support for SFITRIM, an ioctl for secure FITRIM.
This provides an interface for issuing secure trims to parallel
the existing interface for non-secure trim.
Signed-off-by: Geremy Condra <gcondra@...gle.com>
Signed-off-by: JP Abgrall <jpa@...gle.com>
---
fs/ext4/ext4.h | 3 ++-
fs/ext4/ioctl.c | 14 +++++++++++++-
fs/ext4/mballoc.c | 29 +++++++++++++++++++----------
include/uapi/linux/fs.h | 1 +
4 files changed, 35 insertions(+), 12 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 7cc5a0e..cf2ddad 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2082,7 +2082,8 @@ extern int ext4_mb_add_groupinfo(struct super_block *sb,
ext4_group_t i, struct ext4_group_desc *desc);
extern int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
ext4_fsblk_t block, unsigned long count);
-extern int ext4_trim_fs(struct super_block *, struct fstrim_range *);
+extern int ext4_trim_fs(struct super_block *, struct fstrim_range *,
+ bool secure);
/* inode.c */
struct buffer_head *ext4_getblk(handle_t *, struct inode *,
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 0f2252e..0a0b483 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -580,11 +580,13 @@ resizefs_out:
return err;
}
+ case SFITRIM:
case FITRIM:
{
struct request_queue *q = bdev_get_queue(sb->s_bdev);
struct fstrim_range range;
int ret = 0;
+ bool secure_trim = cmd == SFITRIM;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
@@ -592,13 +594,23 @@ resizefs_out:
if (!blk_queue_discard(q))
return -EOPNOTSUPP;
+ if (secure_trim && !blk_queue_secdiscard(q))
+ return -EOPNOTSUPP;
+
+ if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
+ EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
+ ext4_msg(sb, KERN_ERR,
+ "FITRIM not supported with bigalloc");
+ return -EOPNOTSUPP;
+ }
+
if (copy_from_user(&range, (struct fstrim_range __user *)arg,
sizeof(range)))
return -EFAULT;
range.minlen = max((unsigned int)range.minlen,
q->limits.discard_granularity);
- ret = ext4_trim_fs(sb, &range);
+ ret = ext4_trim_fs(sb, &range, secure_trim);
if (ret < 0)
return ret;
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 59e3162..b470efe 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2734,16 +2734,18 @@ int ext4_mb_release(struct super_block *sb)
}
static inline int ext4_issue_discard(struct super_block *sb,
- ext4_group_t block_group, ext4_grpblk_t cluster, int count)
+ ext4_group_t block_group, ext4_grpblk_t cluster, int count,
+ bool secure)
{
ext4_fsblk_t discard_block;
+ unsigned long flags = secure ? BLKDEV_DISCARD_SECURE : 0;
discard_block = (EXT4_C2B(EXT4_SB(sb), cluster) +
ext4_group_first_block_no(sb, block_group));
count = EXT4_C2B(EXT4_SB(sb), count);
trace_ext4_discard_blocks(sb,
(unsigned long long) discard_block, count);
- return sb_issue_discard(sb, discard_block, count, GFP_NOFS, 0);
+ return sb_issue_discard(sb, discard_block, count, GFP_NOFS, flags);
}
/*
@@ -2765,7 +2767,7 @@ static void ext4_free_data_callback(struct super_block *sb,
if (test_opt(sb, DISCARD)) {
err = ext4_issue_discard(sb, entry->efd_group,
entry->efd_start_cluster,
- entry->efd_count);
+ entry->efd_count, 0);
if (err && err != -EOPNOTSUPP)
ext4_msg(sb, KERN_WARNING, "discard request in"
" group:%d block:%d count:%d failed"
@@ -4804,7 +4806,8 @@ do_more:
* them with group lock_held
*/
if (test_opt(sb, DISCARD)) {
- err = ext4_issue_discard(sb, block_group, bit, count);
+ err = ext4_issue_discard(sb, block_group, bit, count,
+ 0);
if (err && err != -EOPNOTSUPP)
ext4_msg(sb, KERN_WARNING, "discard request in"
" group:%d block:%d count:%lu failed"
@@ -5011,13 +5014,15 @@ error_return:
* @count: number of blocks to TRIM
* @group: alloc. group we are working with
* @e4b: ext4 buddy for the group
+ * @secure: false to issue a standard discard, true for secure discard
*
* Trim "count" blocks starting at "start" in the "group". To assure that no
* one will allocate those blocks, mark it as used in buddy bitmap. This must
* be called with under the group lock.
*/
static int ext4_trim_extent(struct super_block *sb, int start, int count,
- ext4_group_t group, struct ext4_buddy *e4b)
+ ext4_group_t group, struct ext4_buddy *e4b,
+ bool secure)
__releases(bitlock)
__acquires(bitlock)
{
@@ -5038,7 +5043,7 @@ __acquires(bitlock)
*/
mb_mark_used(e4b, &ex);
ext4_unlock_group(sb, group);
- ret = ext4_issue_discard(sb, group, start, count);
+ ret = ext4_issue_discard(sb, group, start, count, secure);
ext4_lock_group(sb, group);
mb_free_blocks(NULL, e4b, start, ex.fe_len);
return ret;
@@ -5051,6 +5056,7 @@ __acquires(bitlock)
* @start: first group block to examine
* @max: last group block to examine
* @minblocks: minimum extent block count
+ * @secure: false for standard discard, true for secure discard
*
* ext4_trim_all_free walks through group's buddy bitmap searching for free
* extents. When the free block is found, ext4_trim_extent is called to TRIM
@@ -5065,7 +5071,7 @@ __acquires(bitlock)
static ext4_grpblk_t
ext4_trim_all_free(struct super_block *sb, ext4_group_t group,
ext4_grpblk_t start, ext4_grpblk_t max,
- ext4_grpblk_t minblocks)
+ ext4_grpblk_t minblocks, bool secure)
{
void *bitmap;
ext4_grpblk_t next, count = 0, free_count = 0;
@@ -5098,7 +5104,8 @@ ext4_trim_all_free(struct super_block *sb, ext4_group_t group,
if ((next - start) >= minblocks) {
ret = ext4_trim_extent(sb, start,
- next - start, group, &e4b);
+ next - start, group, &e4b,
+ secure);
if (ret && ret != -EOPNOTSUPP)
break;
ret = 0;
@@ -5140,6 +5147,7 @@ out:
* ext4_trim_fs() -- trim ioctl handle function
* @sb: superblock for filesystem
* @range: fstrim_range structure
+ * @secure: false for standard discard, true for secure discard
*
* start: First Byte to trim
* len: number of Bytes to trim from start
@@ -5148,7 +5156,8 @@ out:
* start to start+len. For each such a group ext4_trim_all_free function
* is invoked to trim all free space.
*/
-int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
+int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range,
+ bool secure)
{
struct ext4_group_info *grp;
ext4_group_t group, first_group, last_group;
@@ -5204,7 +5213,7 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
if (grp->bb_free >= minlen) {
cnt = ext4_trim_all_free(sb, group, first_cluster,
- end, minlen);
+ end, minlen, secure);
if (cnt < 0) {
ret = cnt;
break;
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index ca1a11b..efbd8f8 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -156,6 +156,7 @@ struct inodes_stat_t {
#define FIFREEZE _IOWR('X', 119, int) /* Freeze */
#define FITHAW _IOWR('X', 120, int) /* Thaw */
#define FITRIM _IOWR('X', 121, struct fstrim_range) /* Trim */
+#define SFITRIM _IOWR('X', 122, struct fstrim_range) /* Secure trim */
#define FS_IOC_GETFLAGS _IOR('f', 1, long)
#define FS_IOC_SETFLAGS _IOW('f', 2, long)
--
2.0.0.526.g5318336
--
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