diff options
| -rw-r--r-- | usr/src/uts/common/fs/tmpfs/tmp_vfsops.c | 103 |
1 files changed, 68 insertions, 35 deletions
diff --git a/usr/src/uts/common/fs/tmpfs/tmp_vfsops.c b/usr/src/uts/common/fs/tmpfs/tmp_vfsops.c index c724f23dac..01d848f750 100644 --- a/usr/src/uts/common/fs/tmpfs/tmp_vfsops.c +++ b/usr/src/uts/common/fs/tmpfs/tmp_vfsops.c @@ -427,15 +427,16 @@ tmp_unmount(struct vfs *vfsp, int flag, struct cred *cr) mutex_enter(&tm->tm_contents); /* - * If there are no open files, only the root node should have - * a reference count. + * In the normal unmount case (non-forced unmount), if there are no + * open files, only the root node should have a reference count. + * * With tm_contents held, nothing can be added or removed. * There may be some dirty pages. To prevent fsflush from * disrupting the unmount, put a hold on each node while scanning. * If we find a previously referenced node, undo the holds we have * placed and fail EBUSY. * - * However, in the case of a forced umount things are a bit different. + * However, in the case of a forced umount, things are a bit different. * An additional VFS_HOLD is added for each outstanding VN_HOLD to * ensure that the file system is not cleaned up (tmp_freevfs) until * the last vfs hold is dropped. This happens in tmp_inactive as the @@ -454,8 +455,12 @@ tmp_unmount(struct vfs *vfsp, int flag, struct cred *cr) vfsp->vfs_flag |= VFS_UNMOUNTED; /* Extra hold which we rele below when we drop the zone ref */ VFS_HOLD(vfsp); + for (i = 1; i < cnt; i++) VFS_HOLD(vfsp); + + /* drop the mutex now because no one can find this mount */ + mutex_exit(&tm->tm_contents); } else if (cnt > 1) { mutex_exit(&vp->v_lock); mutex_exit(&tm->tm_contents); @@ -471,37 +476,63 @@ tmp_unmount(struct vfs *vfsp, int flag, struct cred *cr) vp = TNTOV(tnp); mutex_enter(&vp->v_lock); cnt = vp->v_count; - if (cnt > 0) { - if (flag & MS_FORCE) { - for (i = 0; i < cnt; i++) - VFS_HOLD(vfsp); - /* - * In the case of a forced umount don't add an - * additional VN_HOLD on the vnode. It already - * has at least one hold and we need - * tmp_inactive to get called when the last - * hold on the node is released. - */ - } else { - /* - * An open file, unwind everything. - */ - mutex_exit(&vp->v_lock); - cancel = tm->tm_rootnode->tn_forw; - while (cancel != tnp) { - vp = TNTOV(cancel); - ASSERT(vp->v_count > 0); - VN_RELE(vp); - cancel = cancel->tn_forw; - } - mutex_exit(&tm->tm_contents); - return (EBUSY); + if (flag & MS_FORCE) { + for (i = 0; i < cnt; i++) + VFS_HOLD(vfsp); + + /* + * In the case of a forced umount don't add an + * additional VN_HOLD on the already held vnodes, like + * we do in the non-forced unmount case. If the + * cnt > 0, then the vnode already has at least one + * hold and we need tmp_inactive to get called when the + * last pre-existing hold on the node is released so + * that we can VFS_RELE the VFS holds we just added. + */ + if (cnt == 0) { + /* directly add VN_HOLD since have the lock */ + vp->v_count++; + } + + mutex_exit(&vp->v_lock); + + /* + * If the tmpnode has any pages associated with it + * (i.e. if it's a normal file with non-zero size), the + * tmpnode could still be discovered by pageout or + * fsflush via the page vnode pointers. To prevent this + * from interfering with the tmp_freevfs, truncate the + * tmpnode now. + */ + if (tnp->tn_size != 0 && tnp->tn_type == VREG) { + rw_enter(&tnp->tn_rwlock, RW_WRITER); + rw_enter(&tnp->tn_contents, RW_WRITER); + + (void) tmpnode_trunc(tm, tnp, 0); + + rw_exit(&tnp->tn_contents); + rw_exit(&tnp->tn_rwlock); + + ASSERT(tnp->tn_size == 0); + ASSERT(tnp->tn_nblocks == 0); } + } else if (cnt > 0) { + /* An open file; unwind the holds we've been adding. */ + mutex_exit(&vp->v_lock); + cancel = tm->tm_rootnode->tn_forw; + while (cancel != tnp) { + vp = TNTOV(cancel); + ASSERT(vp->v_count > 0); + VN_RELE(vp); + cancel = cancel->tn_forw; + } + mutex_exit(&tm->tm_contents); + return (EBUSY); } else { - /* directly add a VN_HOLD but since we have the lock */ + /* directly add a VN_HOLD since we have the lock */ vp->v_count++; + mutex_exit(&vp->v_lock); } - mutex_exit(&vp->v_lock); } if (flag & MS_FORCE) { @@ -516,13 +547,15 @@ tmp_unmount(struct vfs *vfsp, int flag, struct cred *cr) } /* We can now drop the extra hold we added above. */ VFS_RELE(vfsp); + } else { + /* + * For the non-forced case, we can drop the mutex now because + * no one can find this mount anymore + */ + vfsp->vfs_flag |= VFS_UNMOUNTED; + mutex_exit(&tm->tm_contents); } - /* - * We can drop the mutex now because no one can find this mount - */ - mutex_exit(&tm->tm_contents); - return (0); } |