diff options
| -rw-r--r-- | sys/kern/vfs_subr.c | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c index 6f1cdf3..9411e81 100644 --- a/sys/kern/vfs_subr.c +++ b/sys/kern/vfs_subr.c @@ -345,7 +345,19 @@ vfs_busy(struct mount *mp, int flags) MNT_ILOCK(mp); MNT_REF(mp); - if (mp->mnt_kern_flag & MNTK_UNMOUNT) { + /* + * If mount point is currenly being unmounted, sleep until the + * mount point fate is decided. If thread doing the unmounting fails, + * it will clear MNTK_UNMOUNT flag before waking us up, indicating + * that this mount point has survived the unmount attempt and vfs_busy + * should retry. Otherwise the unmounter thread will set MNTK_REFEXPIRE + * flag in addition to MNTK_UNMOUNT, indicating that mount point is + * about to be really destroyed. vfs_busy needs to release its + * reference on the mount point in this case and return with ENOENT, + * telling the caller that mount mount it tried to busy is no longer + * valid. + */ + while (mp->mnt_kern_flag & MNTK_UNMOUNT) { if (flags & MBF_NOWAIT || mp->mnt_kern_flag & MNTK_REFEXPIRE) { MNT_REL(mp); MNT_IUNLOCK(mp); @@ -357,12 +369,8 @@ vfs_busy(struct mount *mp, int flags) mtx_unlock(&mountlist_mtx); mp->mnt_kern_flag |= MNTK_MWAIT; msleep(mp, MNT_MTX(mp), PVFS, "vfs_busy", 0); - MNT_REL(mp); - MNT_IUNLOCK(mp); if (flags & MBF_MNTLSTLOCK) mtx_lock(&mountlist_mtx); - CTR1(KTR_VFS, "%s: failed busying after sleep", __func__); - return (ENOENT); } if (flags & MBF_MNTLSTLOCK) mtx_unlock(&mountlist_mtx); |
