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    SubjectRe: [PATCH V4 4/5] block: Add secure discard
    Hunter Adrian (Nokia-MS/Helsinki) wrote:
    >>From 1cdd5b576bfafcd53857ed4d37830446e96e8206 Mon Sep 17 00:00:00 2001
    > From: Adrian Hunter <adrian.hunter@nokia.com>
    > Date: Wed, 23 Jun 2010 15:41:38 +0300
    > Subject: [PATCH 4/5] block: Add secure discard
    >
    > Secure discard is the same as discard except that all copies
    > of the discarded sectors (perhaps created by garbage collection)
    > must also be erased.
    >
    > Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>

    Christoph will you comment on this patch? Is it doing what you
    asked?

    > ---
    > block/blk-core.c | 5 ++++-
    > block/blk-lib.c | 6 ++++++
    > block/compat_ioctl.c | 1 +
    > block/elevator.c | 6 ++++++
    > block/ioctl.c | 15 ++++++++++-----
    > include/linux/bio.h | 2 ++
    > include/linux/blkdev.h | 7 ++++++-
    > include/linux/fs.h | 2 ++
    > kernel/trace/blktrace.c | 8 ++++++++
    > 9 files changed, 45 insertions(+), 7 deletions(-)
    >
    > diff --git a/block/blk-core.c b/block/blk-core.c
    > index 3c37894..7931081 100644
    > --- a/block/blk-core.c
    > +++ b/block/blk-core.c
    > @@ -1513,7 +1513,10 @@ static inline void __generic_make_request(struct bio *bio)
    > if (bio_check_eod(bio, nr_sectors))
    > goto end_io;
    >
    > - if ((bio->bi_rw & REQ_DISCARD) && !blk_queue_discard(q)) {
    > + if ((bio->bi_rw & REQ_DISCARD) &&
    > + (!blk_queue_discard(q) ||
    > + ((bio->bi_rw & REQ_SECURE) &&
    > + !blk_queue_secdiscard(q)))) {
    > err = -EOPNOTSUPP;
    > goto end_io;
    > }
    > diff --git a/block/blk-lib.c b/block/blk-lib.c
    > index e16185b..ba8c0f9 100644
    > --- a/block/blk-lib.c
    > +++ b/block/blk-lib.c
    > @@ -50,6 +50,12 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
    > if (!blk_queue_discard(q))
    > return -EOPNOTSUPP;
    >
    > + if (flags & BLKDEV_IFL_SECURE) {
    > + if (!blk_queue_secdiscard(q))
    > + return -EOPNOTSUPP;
    > + type |= DISCARD_SECURE;
    > + }
    > +
    > while (nr_sects && !ret) {
    > unsigned int max_discard_sectors =
    > min(q->limits.max_discard_sectors, UINT_MAX >> 9);
    > diff --git a/block/compat_ioctl.c b/block/compat_ioctl.c
    > index f26051f..24a146d 100644
    > --- a/block/compat_ioctl.c
    > +++ b/block/compat_ioctl.c
    > @@ -753,6 +753,7 @@ long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
    > case BLKFLSBUF:
    > case BLKROSET:
    > case BLKDISCARD:
    > + case BLKSECDISCARD:
    > /*
    > * the ones below are implemented in blkdev_locked_ioctl,
    > * but we call blkdev_ioctl, which gets the lock for us
    > diff --git a/block/elevator.c b/block/elevator.c
    > index 816a7c8..ec585c9 100644
    > --- a/block/elevator.c
    > +++ b/block/elevator.c
    > @@ -83,6 +83,12 @@ int elv_rq_merge_ok(struct request *rq, struct bio *bio)
    > return 0;
    >
    > /*
    > + * Don't merge discard requests and secure discard requests
    > + */
    > + if ((bio->bi_rw & REQ_SECURE) != (rq->bio->bi_rw & REQ_SECURE))
    > + return 0;
    > +
    > + /*
    > * different data direction or already started, don't merge
    > */
    > if (bio_data_dir(bio) != rq_data_dir(rq))
    > diff --git a/block/ioctl.c b/block/ioctl.c
    > index 6f3db6f..afcfe48 100644
    > --- a/block/ioctl.c
    > +++ b/block/ioctl.c
    > @@ -114,8 +114,10 @@ static int blkdev_reread_part(struct block_device *bdev)
    > }
    >
    > static int blk_ioctl_discard(struct block_device *bdev, uint64_t start,
    > - uint64_t len)
    > + uint64_t len, int secure)
    > {
    > + unsigned long flags = BLKDEV_IFL_WAIT;
    > +
    > if (start & 511)
    > return -EINVAL;
    > if (len & 511)
    > @@ -125,8 +127,9 @@ static int blk_ioctl_discard(struct block_device *bdev, uint64_t start,
    >
    > if (start + len > (bdev->bd_inode->i_size >> 9))
    > return -EINVAL;
    > - return blkdev_issue_discard(bdev, start, len, GFP_KERNEL,
    > - BLKDEV_IFL_WAIT);
    > + if (secure)
    > + flags |= BLKDEV_IFL_SECURE;
    > + return blkdev_issue_discard(bdev, start, len, GFP_KERNEL, flags);
    > }
    >
    > static int put_ushort(unsigned long arg, unsigned short val)
    > @@ -226,7 +229,8 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
    > unlock_kernel();
    > return 0;
    >
    > - case BLKDISCARD: {
    > + case BLKDISCARD:
    > + case BLKSECDISCARD: {
    > uint64_t range[2];
    >
    > if (!(mode & FMODE_WRITE))
    > @@ -235,7 +239,8 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
    > if (copy_from_user(range, (void __user *)arg, sizeof(range)))
    > return -EFAULT;
    >
    > - return blk_ioctl_discard(bdev, range[0], range[1]);
    > + return blk_ioctl_discard(bdev, range[0], range[1],
    > + cmd == BLKSECDISCARD);
    > }
    >
    > case HDIO_GETGEO: {
    > diff --git a/include/linux/bio.h b/include/linux/bio.h
    > index 4d379c8..147e631 100644
    > --- a/include/linux/bio.h
    > +++ b/include/linux/bio.h
    > @@ -176,6 +176,7 @@ enum rq_flag_bits {
    > __REQ_INTEGRITY, /* integrity metadata has been remapped */
    > __REQ_IO_STAT, /* account I/O stat */
    > __REQ_MIXED_MERGE, /* merge of different types, fail separately */
    > + __REQ_SECURE, /* secure discard (used with __REQ_DISCARD) */
    > __REQ_NR_BITS, /* stops here */
    > };
    >
    > @@ -215,6 +216,7 @@ enum rq_flag_bits {
    > #define REQ_INTEGRITY (1 << __REQ_INTEGRITY)
    > #define REQ_IO_STAT (1 << __REQ_IO_STAT)
    > #define REQ_MIXED_MERGE (1 << __REQ_MIXED_MERGE)
    > +#define REQ_SECURE (1 << __REQ_SECURE)
    >
    > /*
    > * upper 16 bits of bi_rw define the io priority of this bio
    > diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
    > index 204fbe2..da643f4 100644
    > --- a/include/linux/blkdev.h
    > +++ b/include/linux/blkdev.h
    > @@ -404,6 +404,7 @@ struct request_queue
    > #define QUEUE_FLAG_DISCARD 16 /* supports DISCARD */
    > #define QUEUE_FLAG_NOXMERGES 17 /* No extended merges */
    > #define QUEUE_FLAG_ADD_RANDOM 18 /* Contributes to random pool */
    > +#define QUEUE_FLAG_SECDISCARD 19 /* supports SECDISCARD */
    >
    > #define QUEUE_FLAG_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \
    > (1 << QUEUE_FLAG_CLUSTER) | \
    > @@ -539,6 +540,8 @@ enum {
    > #define blk_queue_stackable(q) \
    > test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
    > #define blk_queue_discard(q) test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
    > +#define blk_queue_secdiscard(q) (blk_queue_discard(q) && \
    > + test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags))
    >
    > #define blk_noretry_request(rq) \
    > ((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
    > @@ -931,10 +934,12 @@ static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
    > }
    > enum{
    > BLKDEV_WAIT, /* wait for completion */
    > - BLKDEV_BARRIER, /*issue request with barrier */
    > + BLKDEV_BARRIER, /* issue request with barrier */
    > + BLKDEV_SECURE, /* secure discard */
    > };
    > #define BLKDEV_IFL_WAIT (1 << BLKDEV_WAIT)
    > #define BLKDEV_IFL_BARRIER (1 << BLKDEV_BARRIER)
    > +#define BLKDEV_IFL_SECURE (1 << BLKDEV_SECURE)
    > extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *,
    > unsigned long);
    > extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
    > diff --git a/include/linux/fs.h b/include/linux/fs.h
    > index dc9d185..2f5df1f 100644
    > --- a/include/linux/fs.h
    > +++ b/include/linux/fs.h
    > @@ -176,6 +176,7 @@ struct inodes_stat_t {
    > */
    > #define DISCARD_NOBARRIER (WRITE | REQ_DISCARD)
    > #define DISCARD_BARRIER (WRITE | REQ_DISCARD | REQ_HARDBARRIER)
    > +#define DISCARD_SECURE (DISCARD_NOBARRIER | REQ_SECURE)
    >
    > #define SEL_IN 1
    > #define SEL_OUT 2
    > @@ -318,6 +319,7 @@ struct inodes_stat_t {
    > #define BLKALIGNOFF _IO(0x12,122)
    > #define BLKPBSZGET _IO(0x12,123)
    > #define BLKDISCARDZEROES _IO(0x12,124)
    > +#define BLKSECDISCARD _IO(0x12,125)
    >
    > #define BMAP_IOCTL 1 /* obsolete - kept for compatibility */
    > #define FIBMAP _IO(0x00,1) /* bmap access */
    > diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
    > index 3b4a695..a711b47 100644
    > --- a/kernel/trace/blktrace.c
    > +++ b/kernel/trace/blktrace.c
    > @@ -667,6 +667,9 @@ static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
    > if (rq->cmd_flags & REQ_DISCARD)
    > rw |= REQ_DISCARD;
    >
    > + if (rq->cmd_flags & REQ_SECURE)
    > + rw |= REQ_SECURE;
    > +
    > if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
    > what |= BLK_TC_ACT(BLK_TC_PC);
    > __blk_add_trace(bt, 0, blk_rq_bytes(rq), rw,
    > @@ -1773,6 +1776,8 @@ void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
    > rwbs[i++] = 'S';
    > if (rw & REQ_META)
    > rwbs[i++] = 'M';
    > + if (rw & REQ_SECURE)
    > + rwbs[i++] = 'E';
    >
    > rwbs[i] = '\0';
    > }
    > @@ -1785,6 +1790,9 @@ void blk_fill_rwbs_rq(char *rwbs, struct request *rq)
    > if (rq->cmd_flags & REQ_DISCARD)
    > rw |= REQ_DISCARD;
    >
    > + if (rq->cmd_flags & REQ_SECURE)
    > + rw |= REQ_SECURE;
    > +
    > bytes = blk_rq_bytes(rq);
    >
    > blk_fill_rwbs(rwbs, rw, bytes);



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