From: "Ed L. Cashin" When an AoE device is detected, the kernel is informed, and a new block device is created. If the device is unused, the block device corresponding to remote device that is no longer available may be removed from the system by telling the aoe driver to "flush" its list of devices. Without this patch, software like GPFS and LVM may attempt to read from AoE devices that were discovered earlier but are no longer present, blocking until the I/O attempt times out. Signed-off-by: Ed L. Cashin Cc: Greg KH Signed-off-by: Andrew Morton --- Documentation/aoe/mkdevs.sh | 2 Documentation/aoe/udev.txt | 1 drivers/block/aoe/aoe.h | 1 drivers/block/aoe/aoechr.c | 5 + drivers/block/aoe/aoedev.c | 87 ++++++++++++++++++++++++++-------- 5 files changed, 77 insertions(+), 19 deletions(-) diff -puN Documentation/aoe/mkdevs.sh~aoe-user-can-ask-driver-to-forget-previously-detected-devices Documentation/aoe/mkdevs.sh --- a/Documentation/aoe/mkdevs.sh~aoe-user-can-ask-driver-to-forget-previously-detected-devices +++ a/Documentation/aoe/mkdevs.sh @@ -29,6 +29,8 @@ rm -f $dir/interfaces mknod -m 0200 $dir/interfaces c $MAJOR 4 rm -f $dir/revalidate mknod -m 0200 $dir/revalidate c $MAJOR 5 +rm -f $dir/flush +mknod -m 0200 $dir/flush c $MAJOR 6 export n_partitions mkshelf=`echo $0 | sed 's!mkdevs!mkshelf!'` diff -puN Documentation/aoe/udev.txt~aoe-user-can-ask-driver-to-forget-previously-detected-devices Documentation/aoe/udev.txt --- a/Documentation/aoe/udev.txt~aoe-user-can-ask-driver-to-forget-previously-detected-devices +++ a/Documentation/aoe/udev.txt @@ -20,6 +20,7 @@ SUBSYSTEM=="aoe", KERNEL=="discover", NA SUBSYSTEM=="aoe", KERNEL=="err", NAME="etherd/%k", GROUP="disk", MODE="0440" SUBSYSTEM=="aoe", KERNEL=="interfaces", NAME="etherd/%k", GROUP="disk", MODE="0220" SUBSYSTEM=="aoe", KERNEL=="revalidate", NAME="etherd/%k", GROUP="disk", MODE="0220" +SUBSYSTEM=="aoe", KERNEL=="flush", NAME="etherd/%k", GROUP="disk", MODE="0220" # aoe block devices KERNEL=="etherd*", NAME="%k", GROUP="disk" diff -puN drivers/block/aoe/aoe.h~aoe-user-can-ask-driver-to-forget-previously-detected-devices drivers/block/aoe/aoe.h --- a/drivers/block/aoe/aoe.h~aoe-user-can-ask-driver-to-forget-previously-detected-devices +++ a/drivers/block/aoe/aoe.h @@ -191,6 +191,7 @@ struct aoedev *aoedev_by_aoeaddr(int maj struct aoedev *aoedev_by_sysminor_m(ulong sysminor); void aoedev_downdev(struct aoedev *d); int aoedev_isbusy(struct aoedev *d); +int aoedev_flush(const char __user *str, size_t size); int aoenet_init(void); void aoenet_exit(void); diff -puN drivers/block/aoe/aoechr.c~aoe-user-can-ask-driver-to-forget-previously-detected-devices drivers/block/aoe/aoechr.c --- a/drivers/block/aoe/aoechr.c~aoe-user-can-ask-driver-to-forget-previously-detected-devices +++ a/drivers/block/aoe/aoechr.c @@ -15,6 +15,7 @@ enum { MINOR_DISCOVER, MINOR_INTERFACES, MINOR_REVALIDATE, + MINOR_FLUSH, MSGSZ = 2048, NMSG = 100, /* message backlog to retain */ }; @@ -43,6 +44,7 @@ static struct aoe_chardev chardevs[] = { { MINOR_DISCOVER, "discover" }, { MINOR_INTERFACES, "interfaces" }, { MINOR_REVALIDATE, "revalidate" }, + { MINOR_FLUSH, "flush" }, }; static int @@ -158,6 +160,9 @@ aoechr_write(struct file *filp, const ch break; case MINOR_REVALIDATE: ret = revalidate(buf, cnt); + break; + case MINOR_FLUSH: + ret = aoedev_flush(buf, cnt); } if (ret == 0) ret = cnt; diff -puN drivers/block/aoe/aoedev.c~aoe-user-can-ask-driver-to-forget-previously-detected-devices drivers/block/aoe/aoedev.c --- a/drivers/block/aoe/aoedev.c~aoe-user-can-ask-driver-to-forget-previously-detected-devices +++ a/drivers/block/aoe/aoedev.c @@ -9,6 +9,10 @@ #include #include "aoe.h" +static void dummy_timer(ulong); +static void aoedev_freedev(struct aoedev *); +static void freetgt(struct aoetgt *t); + static struct aoedev *devlist; static spinlock_t devlist_lock; @@ -108,6 +112,70 @@ aoedev_downdev(struct aoedev *d) d->flags &= ~DEVFL_UP; } +static void +aoedev_freedev(struct aoedev *d) +{ + struct aoetgt **t, **e; + + if (d->gd) { + aoedisk_rm_sysfs(d); + del_gendisk(d->gd); + put_disk(d->gd); + } + t = d->targets; + e = t + NTARGETS; + for (; t < e && *t; t++) + freetgt(*t); + if (d->bufpool) + mempool_destroy(d->bufpool); + kfree(d); +} + +int +aoedev_flush(const char __user *str, size_t cnt) +{ + ulong flags; + struct aoedev *d, **dd; + struct aoedev *rmd = NULL; + char buf[16]; + int all = 0; + + if (cnt >= 3) { + if (cnt > sizeof buf) + cnt = sizeof buf; + if (copy_from_user(buf, str, cnt)) + return -EFAULT; + all = !strncmp(buf, "all", 3); + } + + flush_scheduled_work(); + spin_lock_irqsave(&devlist_lock, flags); + dd = &devlist; + while ((d = *dd)) { + spin_lock(&d->lock); + if ((!all && (d->flags & DEVFL_UP)) + || (d->flags & (DEVFL_GDALLOC|DEVFL_NEWSIZE)) + || d->nopen) { + spin_unlock(&d->lock); + dd = &d->next; + continue; + } + *dd = d->next; + aoedev_downdev(d); + d->flags |= DEVFL_TKILL; + spin_unlock(&d->lock); + d->next = rmd; + rmd = d; + } + spin_unlock_irqrestore(&devlist_lock, flags); + while ((d = rmd)) { + rmd = d->next; + del_timer_sync(&d->timer); + aoedev_freedev(d); /* must be able to sleep */ + } + return 0; +} + /* find it or malloc it */ struct aoedev * aoedev_by_sysminor_m(ulong sysminor) @@ -161,25 +229,6 @@ freetgt(struct aoetgt *t) kfree(t); } -static void -aoedev_freedev(struct aoedev *d) -{ - struct aoetgt **t, **e; - - if (d->gd) { - aoedisk_rm_sysfs(d); - del_gendisk(d->gd); - put_disk(d->gd); - } - t = d->targets; - e = t + NTARGETS; - for (; t < e && *t; t++) - freetgt(*t); - if (d->bufpool) - mempool_destroy(d->bufpool); - kfree(d); -} - void aoedev_exit(void) { _