diff options
| -rw-r--r-- | sys/kern/vfs_bio.c | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c index 1dbb1b68fd1f..501febb833a2 100644 --- a/sys/kern/vfs_bio.c +++ b/sys/kern/vfs_bio.c @@ -1053,9 +1053,13 @@ trytofreespace: * Certain layered filesystems can recursively re-enter the vfs_bio * code, due to delayed writes. This helps keep the system from * deadlocking. + * This hack to avoid premature panic is courtesy of alfred + * (alfred@freebsd.org) */ if (writerecursion > 0) { if (writerecursion > 5) { + int loop = 0; +norecurse: bp = TAILQ_FIRST(&bufqueues[QUEUE_AGE]); while (bp) { if ((bp->b_flags & B_DELWRI) == 0) @@ -1070,8 +1074,17 @@ trytofreespace: bp = TAILQ_NEXT(bp, b_freelist); } } - if (bp == NULL) - panic("getnewbuf: cannot get buffer, infinite recursion failure"); + if (bp == NULL) { + needsbuffer |= VFS_BIO_NEED_ANY; + if (tsleep(&needsbuffer, + (PRIBIO + 4) | slpflag, + "nbufhack", slptimeo+1)) + return (NULL); + if (loop++ < 5) + goto norecurse; + else + goto start; + } } else { bremfree(bp); bp->b_flags |= B_BUSY | B_AGE | B_ASYNC; |