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Use a zio flag to prevent recursion of vdev_queue_io_done which can

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cause stack overflow for IO's which return ZIO_PIPELINE_CONTINUE
from the zio_vdev_io_start stage and hence don't suspend and complete
in a different thread.

This prevents double fault panic on slow machines running ZFS on
GELI volumes which return EOPNOTSUPP directly to BIO_DELETE requests.

MFC after:	1 month
X-MFC-With:	r265152
This commit is contained in:
smh 2014-05-04 14:05:14 +00:00
parent 86a85509b8
commit fd5ca87253
2 changed files with 12 additions and 0 deletions
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1
sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio.h
View File

@ -196,6 +196,7 @@ enum zio_flag {
ZIO_FLAG_NOPWRITE = 1 << 25,
ZIO_FLAG_REEXECUTED = 1 << 26,
ZIO_FLAG_DELEGATED = 1 << 27,
ZIO_FLAG_QUEUE_IO_DONE = 1 << 28,
};
#define ZIO_FLAG_MUSTSUCCEED 0

11
sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_queue.c
View File

@ -796,14 +796,25 @@ vdev_queue_io_done(zio_t *zio)
vq->vq_io_complete_ts = gethrtime();
if (zio->io_flags & ZIO_FLAG_QUEUE_IO_DONE) {
/*
* Executing from a previous vdev_queue_io_done so
* to avoid recursion we just unlock and return.
*/
mutex_exit(&vq->vq_lock);
return;
}
while ((nio = vdev_queue_io_to_issue(vq)) != NULL) {
mutex_exit(&vq->vq_lock);
nio->io_flags |= ZIO_FLAG_QUEUE_IO_DONE;
if (nio->io_done == vdev_queue_agg_io_done) {
zio_nowait(nio);
} else {
zio_vdev_io_reissue(nio);
zio_execute(nio);
}
nio->io_flags &= ~ZIO_FLAG_QUEUE_IO_DONE;
mutex_enter(&vq->vq_lock);
}