The patch titled Subject: nbd: fsync and kill block device on shutdown has been removed from the -mm tree. Its filename was nbd-fsync-and-kill-block-device-on-shutdown.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Paolo Bonzini <pbonzini@xxxxxxxxxx> Subject: nbd: fsync and kill block device on shutdown There are two problems with shutdown in the NBD driver. 1: Receiving the NBD_DISCONNECT ioctl does not sync the filesystem. This patch adds the sync operation into __nbd_ioctl()'s NBD_DISCONNECT handler. This is useful because BLKFLSBUF is restricted to processes that have CAP_SYS_ADMIN, and the NBD client may not possess it (fsync of the block device does not sync the filesystem, either). 2: Once we clear the socket we have no guarantee that later reads will come from the same backing storage. The patch adds calls to kill_bdev() in __nbd_ioctl()'s socket clearing code so the page cache is cleaned, lest reads that hit on the page cache will return stale data from the previously-accessible disk. Example: # qemu-nbd -r -c/dev/nbd0 /dev/sr0 # file -s /dev/nbd0 /dev/stdin: # UDF filesystem data (version 1.5) etc. # qemu-nbd -d /dev/nbd0 # qemu-nbd -r -c/dev/nbd0 /dev/sda # file -s /dev/nbd0 /dev/stdin: # UDF filesystem data (version 1.5) etc. While /dev/sda has: # file -s /dev/sda /dev/sda: x86 boot sector; etc. Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> Acked-by: Paul Clements <Paul.Clements@xxxxxxxxxxxx> Cc: Alex Bligh <alex@xxxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/block/nbd.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff -puN drivers/block/nbd.c~nbd-fsync-and-kill-block-device-on-shutdown drivers/block/nbd.c --- a/drivers/block/nbd.c~nbd-fsync-and-kill-block-device-on-shutdown +++ a/drivers/block/nbd.c @@ -608,12 +608,20 @@ static int __nbd_ioctl(struct block_devi struct request sreq; dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n"); + if (!nbd->sock) + return -EINVAL; + mutex_unlock(&nbd->tx_lock); + fsync_bdev(bdev); + mutex_lock(&nbd->tx_lock); blk_rq_init(NULL, &sreq); sreq.cmd_type = REQ_TYPE_SPECIAL; nbd_cmd(&sreq) = NBD_CMD_DISC; + + /* Check again after getting mutex back. */ if (!nbd->sock) return -EINVAL; + nbd_send_req(nbd, &sreq); return 0; } @@ -627,6 +635,7 @@ static int __nbd_ioctl(struct block_devi nbd_clear_que(nbd); BUG_ON(!list_empty(&nbd->queue_head)); BUG_ON(!list_empty(&nbd->waiting_queue)); + kill_bdev(bdev); if (file) fput(file); return 0; @@ -719,6 +728,7 @@ static int __nbd_ioctl(struct block_devi nbd->file = NULL; nbd_clear_que(nbd); dev_warn(disk_to_dev(nbd->disk), "queue cleared\n"); + kill_bdev(bdev); queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue); if (file) fput(file); _ Patches currently in -mm which might be from pbonzini@xxxxxxxxxx are origin.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html