mirror of
https://git.hardenedbsd.org/hardenedbsd/HardenedBSD.git
synced 2025-01-11 17:04:19 +01:00
Need to reorganize the flushing of directory entry (pagedep) dependencies
so that they never try to lock an inode corresponding to ".." as this can lead to deadlock. We observe that any inode with an updated link count is always pushed into its buffer at the time of the link count change, so we do not need to do a VOP_UPDATE, but merely find its buffer and write it. The only time we need to get the inode itself is from the result of a mkdir whose name will never be ".." and hence locking such an inode will never request a lock above us in the filesystem tree. Thanks to Brian Fundakowski Feldman for providing the test program that tickled soft updates into hanging in "inode" sleep. Submitted by: Brian Fundakowski Feldman <green@FreeBSD.org>
This commit is contained in:
Kirk McKusick
parent
4aee48edcc
commit
4c6adb0622
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=56208
@ -52,7 +52,7 @@
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: @(#)ffs_softdep.c 9.54 (McKusick) 1/16/00
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* from: @(#)ffs_softdep.c 9.55 (McKusick) 1/17/00
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* $FreeBSD$
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*/
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@ -4214,87 +4214,86 @@ flush_pagedep_deps(pvp, mp, diraddhdp)
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if (dap != LIST_FIRST(diraddhdp))
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continue;
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if (dap->da_state & MKDIR_PARENT)
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panic("flush_pagedep_deps: MKDIR");
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panic("flush_pagedep_deps: MKDIR_PARENT");
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}
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/*
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* Flush the file on which the directory entry depends.
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* If the inode has already been pushed out of the cache,
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* then all the block dependencies will have been flushed
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* leaving only inode dependencies (e.g., bitmaps). Thus,
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* we do a ufs_ihashget to check for the vnode in the cache.
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* If it is there, we do a full flush. If it is no longer
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* there we need only dispose of any remaining bitmap
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* dependencies and write the inode to disk.
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* A newly allocated directory must have its "." and
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* ".." entries written out before its name can be
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* committed in its parent. We do not want or need
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* the full semantics of a synchronous VOP_FSYNC as
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* that may end up here again, once for each directory
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* level in the filesystem. Instead, we push the blocks
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* and wait for them to clear. We have to fsync twice
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* because the first call may choose to defer blocks
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* that still have dependencies, but deferral will
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* happen at most once.
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*/
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inum = dap->da_newinum;
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FREE_LOCK(&lk);
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if ((vp = ufs_ihashget(ump->um_dev, inum)) == NULL) {
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ACQUIRE_LOCK(&lk);
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if (inodedep_lookup(ump->um_fs, inum, 0, &inodedep) == 0
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&& dap == LIST_FIRST(diraddhdp))
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panic("flush_pagedep_deps: flush 1 failed");
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/*
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* If the inode still has bitmap dependencies,
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* push them to disk.
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*/
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if ((inodedep->id_state & DEPCOMPLETE) == 0) {
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gotit = getdirtybuf(&inodedep->id_buf,MNT_WAIT);
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FREE_LOCK(&lk);
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if (gotit &&
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(error = VOP_BWRITE(inodedep->id_buf->b_vp,
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inodedep->id_buf)) != 0)
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break;
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ACQUIRE_LOCK(&lk);
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}
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if (dap != LIST_FIRST(diraddhdp))
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continue;
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/*
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* If the inode is still sitting in a buffer waiting
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* to be written, push it to disk.
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*/
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if (dap->da_state & MKDIR_BODY) {
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FREE_LOCK(&lk);
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if ((error = bread(ump->um_devvp,
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fsbtodb(ump->um_fs, ino_to_fsba(ump->um_fs, inum)),
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(int)ump->um_fs->fs_bsize, NOCRED, &bp)) != 0)
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if ((error = VFS_VGET(mp, inum, &vp)) != 0)
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break;
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if ((error = VOP_BWRITE(bp->b_vp, bp)) != 0)
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break;
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ACQUIRE_LOCK(&lk);
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if (dap == LIST_FIRST(diraddhdp))
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panic("flush_pagedep_deps: flush 2 failed");
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continue;
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}
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if (vp->v_type == VDIR) {
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/*
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* A newly allocated directory must have its "." and
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* ".." entries written out before its name can be
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* committed in its parent. We do not want or need
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* the full semantics of a synchronous VOP_FSYNC as
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* that may end up here again, once for each directory
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* level in the filesystem. Instead, we push the blocks
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* and wait for them to clear. We have to fsync twice
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* because the first call may choose to defer blocks
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* that still have dependencies, but deferral will
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* happen at most once.
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*/
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if ((error=VOP_FSYNC(vp, p->p_ucred, MNT_NOWAIT, p)) ||
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(error=VOP_FSYNC(vp, p->p_ucred, MNT_NOWAIT, p))) {
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vput(vp);
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break;
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}
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drain_output(vp, 0);
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vput(vp);
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ACQUIRE_LOCK(&lk);
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/*
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* If that cleared dependencies, go on to next.
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*/
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if (dap != LIST_FIRST(diraddhdp))
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continue;
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if (dap->da_state & MKDIR_BODY)
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panic("flush_pagedep_deps: MKDIR_BODY");
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}
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error = UFS_UPDATE(vp, 1);
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vput(vp);
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if (error)
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/*
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* Flush the inode on which the directory entry depends.
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* Having accounted for MKDIR_PARENT and MKDIR_BODY above,
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* the only remaining dependency is that the updated inode
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* count must get pushed to disk. The inode has already
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* been pushed into its inode buffer (via VOP_UPDATE) at
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* the time of the reference count change. So we need only
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* locate that buffer, ensure that there will be no rollback
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* caused by a bitmap dependency, then write the inode buffer.
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*/
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if (inodedep_lookup(ump->um_fs, inum, 0, &inodedep) == 0)
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panic("flush_pagedep_deps: lost inode");
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/*
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* If the inode still has bitmap dependencies,
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* push them to disk.
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*/
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if ((inodedep->id_state & DEPCOMPLETE) == 0) {
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gotit = getdirtybuf(&inodedep->id_buf, MNT_WAIT);
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FREE_LOCK(&lk);
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if (gotit &&
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(error = VOP_BWRITE(inodedep->id_buf->b_vp,
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inodedep->id_buf)) != 0)
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break;
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ACQUIRE_LOCK(&lk);
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if (dap != LIST_FIRST(diraddhdp))
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continue;
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}
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/*
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* If the inode is still sitting in a buffer waiting
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* to be written, push it to disk.
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*/
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FREE_LOCK(&lk);
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if ((error = bread(ump->um_devvp,
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fsbtodb(ump->um_fs, ino_to_fsba(ump->um_fs, inum)),
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(int)ump->um_fs->fs_bsize, NOCRED, &bp)) != 0)
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break;
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if ((error = VOP_BWRITE(bp->b_vp, bp)) != 0)
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break;
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ACQUIRE_LOCK(&lk);
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/*
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* If we have failed to get rid of all the dependencies
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* then something is seriously wrong.
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*/
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if (dap == LIST_FIRST(diraddhdp))
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panic("flush_pagedep_deps: flush 3 failed");
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ACQUIRE_LOCK(&lk);
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panic("flush_pagedep_deps: flush failed");
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}
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if (error)
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ACQUIRE_LOCK(&lk);
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@ -52,7 +52,7 @@
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: @(#)ffs_softdep.c 9.54 (McKusick) 1/16/00
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* from: @(#)ffs_softdep.c 9.55 (McKusick) 1/17/00
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* $FreeBSD$
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*/
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@ -4214,87 +4214,86 @@ flush_pagedep_deps(pvp, mp, diraddhdp)
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if (dap != LIST_FIRST(diraddhdp))
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continue;
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if (dap->da_state & MKDIR_PARENT)
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panic("flush_pagedep_deps: MKDIR");
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panic("flush_pagedep_deps: MKDIR_PARENT");
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}
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/*
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* Flush the file on which the directory entry depends.
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* If the inode has already been pushed out of the cache,
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* then all the block dependencies will have been flushed
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* leaving only inode dependencies (e.g., bitmaps). Thus,
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* we do a ufs_ihashget to check for the vnode in the cache.
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* If it is there, we do a full flush. If it is no longer
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* there we need only dispose of any remaining bitmap
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* dependencies and write the inode to disk.
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* A newly allocated directory must have its "." and
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* ".." entries written out before its name can be
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* committed in its parent. We do not want or need
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* the full semantics of a synchronous VOP_FSYNC as
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* that may end up here again, once for each directory
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* level in the filesystem. Instead, we push the blocks
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* and wait for them to clear. We have to fsync twice
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* because the first call may choose to defer blocks
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* that still have dependencies, but deferral will
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* happen at most once.
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*/
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inum = dap->da_newinum;
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FREE_LOCK(&lk);
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if ((vp = ufs_ihashget(ump->um_dev, inum)) == NULL) {
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ACQUIRE_LOCK(&lk);
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if (inodedep_lookup(ump->um_fs, inum, 0, &inodedep) == 0
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&& dap == LIST_FIRST(diraddhdp))
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panic("flush_pagedep_deps: flush 1 failed");
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/*
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* If the inode still has bitmap dependencies,
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* push them to disk.
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*/
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if ((inodedep->id_state & DEPCOMPLETE) == 0) {
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gotit = getdirtybuf(&inodedep->id_buf,MNT_WAIT);
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FREE_LOCK(&lk);
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if (gotit &&
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(error = VOP_BWRITE(inodedep->id_buf->b_vp,
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inodedep->id_buf)) != 0)
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break;
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ACQUIRE_LOCK(&lk);
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}
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if (dap != LIST_FIRST(diraddhdp))
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continue;
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/*
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* If the inode is still sitting in a buffer waiting
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* to be written, push it to disk.
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*/
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if (dap->da_state & MKDIR_BODY) {
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FREE_LOCK(&lk);
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if ((error = bread(ump->um_devvp,
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fsbtodb(ump->um_fs, ino_to_fsba(ump->um_fs, inum)),
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(int)ump->um_fs->fs_bsize, NOCRED, &bp)) != 0)
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if ((error = VFS_VGET(mp, inum, &vp)) != 0)
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break;
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if ((error = VOP_BWRITE(bp->b_vp, bp)) != 0)
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break;
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ACQUIRE_LOCK(&lk);
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if (dap == LIST_FIRST(diraddhdp))
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panic("flush_pagedep_deps: flush 2 failed");
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continue;
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}
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if (vp->v_type == VDIR) {
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/*
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* A newly allocated directory must have its "." and
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* ".." entries written out before its name can be
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* committed in its parent. We do not want or need
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* the full semantics of a synchronous VOP_FSYNC as
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* that may end up here again, once for each directory
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* level in the filesystem. Instead, we push the blocks
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* and wait for them to clear. We have to fsync twice
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* because the first call may choose to defer blocks
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* that still have dependencies, but deferral will
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* happen at most once.
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*/
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if ((error=VOP_FSYNC(vp, p->p_ucred, MNT_NOWAIT, p)) ||
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(error=VOP_FSYNC(vp, p->p_ucred, MNT_NOWAIT, p))) {
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vput(vp);
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break;
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}
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drain_output(vp, 0);
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vput(vp);
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ACQUIRE_LOCK(&lk);
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/*
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* If that cleared dependencies, go on to next.
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*/
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if (dap != LIST_FIRST(diraddhdp))
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continue;
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if (dap->da_state & MKDIR_BODY)
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panic("flush_pagedep_deps: MKDIR_BODY");
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}
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error = UFS_UPDATE(vp, 1);
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vput(vp);
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if (error)
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/*
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* Flush the inode on which the directory entry depends.
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* Having accounted for MKDIR_PARENT and MKDIR_BODY above,
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* the only remaining dependency is that the updated inode
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* count must get pushed to disk. The inode has already
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* been pushed into its inode buffer (via VOP_UPDATE) at
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* the time of the reference count change. So we need only
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* locate that buffer, ensure that there will be no rollback
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* caused by a bitmap dependency, then write the inode buffer.
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*/
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if (inodedep_lookup(ump->um_fs, inum, 0, &inodedep) == 0)
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panic("flush_pagedep_deps: lost inode");
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/*
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* If the inode still has bitmap dependencies,
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* push them to disk.
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*/
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if ((inodedep->id_state & DEPCOMPLETE) == 0) {
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gotit = getdirtybuf(&inodedep->id_buf, MNT_WAIT);
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FREE_LOCK(&lk);
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if (gotit &&
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(error = VOP_BWRITE(inodedep->id_buf->b_vp,
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inodedep->id_buf)) != 0)
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break;
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ACQUIRE_LOCK(&lk);
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if (dap != LIST_FIRST(diraddhdp))
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continue;
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}
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/*
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* If the inode is still sitting in a buffer waiting
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* to be written, push it to disk.
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*/
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FREE_LOCK(&lk);
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if ((error = bread(ump->um_devvp,
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fsbtodb(ump->um_fs, ino_to_fsba(ump->um_fs, inum)),
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(int)ump->um_fs->fs_bsize, NOCRED, &bp)) != 0)
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break;
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if ((error = VOP_BWRITE(bp->b_vp, bp)) != 0)
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break;
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ACQUIRE_LOCK(&lk);
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/*
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* If we have failed to get rid of all the dependencies
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* then something is seriously wrong.
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*/
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if (dap == LIST_FIRST(diraddhdp))
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panic("flush_pagedep_deps: flush 3 failed");
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ACQUIRE_LOCK(&lk);
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panic("flush_pagedep_deps: flush failed");
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}
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if (error)
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ACQUIRE_LOCK(&lk);
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