diff options
Diffstat (limited to 'sys/kern/vfs_bio.c')
| -rw-r--r-- | sys/kern/vfs_bio.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c index 635e394..ba55013 100644 --- a/sys/kern/vfs_bio.c +++ b/sys/kern/vfs_bio.c @@ -758,11 +758,15 @@ bwrite(struct buf * bp) int rtval = bufwait(bp); brelse(bp); return (rtval); - } else { + } else if ((oldflags & B_NOWDRAIN) == 0) { /* * don't allow the async write to saturate the I/O - * system. There is no chance of deadlock here because - * we are blocking on I/O that is already in-progress. + * system. Deadlocks can occur only if a device strategy + * routine (like in MD) turns around and issues another + * high-level write, in which case B_NOWDRAIN is expected + * to be set. Otherwise we will not deadlock here because + * we are blocking waiting for I/O that is already in-progress + * to complete. */ waitrunningbufspace(); } @@ -1286,7 +1290,8 @@ brelse(struct buf * bp) /* unlock */ BUF_UNLOCK(bp); - bp->b_flags &= ~(B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF | B_DIRECT); + bp->b_flags &= ~(B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF | + B_DIRECT | B_NOWDRAIN); bp->b_ioflags &= ~BIO_ORDERED; if ((bp->b_flags & B_DELWRI) == 0 && (bp->b_xflags & BX_VNDIRTY)) panic("brelse: not dirty"); |
