diff options
Diffstat (limited to 'sys/ufs/ffs/ffs_snapshot.c')
| -rw-r--r-- | sys/ufs/ffs/ffs_snapshot.c | 83 |
1 files changed, 66 insertions, 17 deletions
diff --git a/sys/ufs/ffs/ffs_snapshot.c b/sys/ufs/ffs/ffs_snapshot.c index 2b09162..0e1e68f 100644 --- a/sys/ufs/ffs/ffs_snapshot.c +++ b/sys/ufs/ffs/ffs_snapshot.c @@ -198,10 +198,14 @@ restart: } /* * Allocate shadow blocks to copy all of the other snapshot inodes - * so that we will be able to expunge them from this snapshot. + * so that we will be able to expunge them from this snapshot. Also + * include a copy of ourselves so that we do not deadlock trying + * to copyonwrite ourselves when VOP_FSYNC'ing below. */ - for (loc = 0, inoblkcnt = 0; loc < snaploc; loc++) { + fs->fs_snapinum[snaploc] = ip->i_number; + for (loc = snaploc, inoblkcnt = 0; loc >= 0; loc--) { blkno = fragstoblks(fs, ino_to_fsba(fs, fs->fs_snapinum[loc])); + fs->fs_snapinum[snaploc] = 0; for (i = 0; i < inoblkcnt; i++) if (inoblks[i] == blkno) break; @@ -652,14 +656,14 @@ ffs_snapremove(vp) ip = VTOI(vp); fs = ip->i_fs; /* - * Delete from incore list. + * If active, delete from incore list (this snapshot may + * already have been in the process of being deleted, so + * would not have been active). + * * Clear copy-on-write flag if last snapshot. */ - devvp = ip->i_devvp; - if (ip->i_nextsnap.tqe_prev == 0) { - printf("ffs_snapremove: lost snapshot vnode %d\n", - ip->i_number); - } else { + if (ip->i_nextsnap.tqe_prev != 0) { + devvp = ip->i_devvp; TAILQ_REMOVE(&devvp->v_rdev->si_snapshots, ip, i_nextsnap); ip->i_nextsnap.tqe_prev = 0; if (TAILQ_FIRST(&devvp->v_rdev->si_snapshots) == 0) { @@ -832,9 +836,10 @@ ffs_snapblkfree(freeip, bno, size) error = VOP_BALLOC(vp, lblktosize(fs, (off_t)lbn), fs->fs_bsize, KERNCRED, 0, &cbp); p->p_flag &= ~P_COWINPROGRESS; - VOP_UNLOCK(vp, 0, p); - if (error) + if (error) { + VOP_UNLOCK(vp, 0, p); break; + } #ifdef DEBUG if (snapdebug) printf("%s%d lbn %d for inum %d size %ld to blkno %d\n", @@ -843,22 +848,44 @@ ffs_snapblkfree(freeip, bno, size) #endif /* * If we have already read the old block contents, then - * simply copy them to the new block. + * simply copy them to the new block. Note that we need + * to synchronously write snapshots that have not been + * unlinked, and hence will be visible after a crash, + * to ensure their integrity. */ if (savedcbp != 0) { bcopy(savedcbp->b_data, cbp->b_data, fs->fs_bsize); bawrite(cbp); + if (ip->i_effnlink > 0) + (void) VOP_FSYNC(vp, KERNCRED, MNT_WAIT, p); + VOP_UNLOCK(vp, 0, p); continue; } /* * Otherwise, read the old block contents into the buffer. */ - if ((error = readblock(cbp, lbn)) != 0) + if ((error = readblock(cbp, lbn)) != 0) { + bzero(cbp->b_data, fs->fs_bsize); + bawrite(cbp); + if (ip->i_effnlink > 0) + (void) VOP_FSYNC(vp, KERNCRED, MNT_WAIT, p); + VOP_UNLOCK(vp, 0, p); break; + } savedcbp = cbp; } - if (savedcbp) + /* + * Note that we need to synchronously write snapshots that + * have not been unlinked, and hence will be visible after + * a crash, to ensure their integrity. + */ + if (savedcbp) { + vp = savedcbp->b_vp; bawrite(savedcbp); + if (VTOI(vp)->i_effnlink > 0) + (void) VOP_FSYNC(vp, KERNCRED, MNT_WAIT, p); + VOP_UNLOCK(vp, 0, p); + } /* * If we have been unable to allocate a block in which to do * the copy, then return non-zero so that the fragment will @@ -1014,8 +1041,8 @@ retry: error = VOP_BALLOC(vp, lblktosize(fs, (off_t)lbn), fs->fs_bsize, KERNCRED, B_NOWAIT, &cbp); p->p_flag &= ~P_COWINPROGRESS; - VOP_UNLOCK(vp, 0, p); if (error) { + VOP_UNLOCK(vp, 0, p); if (error != EWOULDBLOCK) break; tsleep(vp, p->p_pri.pri_user, "nap", 1); @@ -1035,22 +1062,44 @@ retry: #endif /* * If we have already read the old block contents, then - * simply copy them to the new block. + * simply copy them to the new block. Note that we need + * to synchronously write snapshots that have not been + * unlinked, and hence will be visible after a crash, + * to ensure their integrity. */ if (savedcbp != 0) { bcopy(savedcbp->b_data, cbp->b_data, fs->fs_bsize); bawrite(cbp); + if (ip->i_effnlink > 0) + (void) VOP_FSYNC(vp, KERNCRED, MNT_WAIT, p); + VOP_UNLOCK(vp, 0, p); continue; } /* * Otherwise, read the old block contents into the buffer. */ - if ((error = readblock(cbp, lbn)) != 0) + if ((error = readblock(cbp, lbn)) != 0) { + bzero(cbp->b_data, fs->fs_bsize); + bawrite(cbp); + if (ip->i_effnlink > 0) + (void) VOP_FSYNC(vp, KERNCRED, MNT_WAIT, p); + VOP_UNLOCK(vp, 0, p); break; + } savedcbp = cbp; } - if (savedcbp) + /* + * Note that we need to synchronously write snapshots that + * have not been unlinked, and hence will be visible after + * a crash, to ensure their integrity. + */ + if (savedcbp) { + vp = savedcbp->b_vp; bawrite(savedcbp); + if (VTOI(vp)->i_effnlink > 0) + (void) VOP_FSYNC(vp, KERNCRED, MNT_WAIT, p); + VOP_UNLOCK(vp, 0, p); + } return (error); } |
