diff options
| -rw-r--r-- | sys/ufs/ffs/ffs_snapshot.c | 50 |
1 files changed, 43 insertions, 7 deletions
diff --git a/sys/ufs/ffs/ffs_snapshot.c b/sys/ufs/ffs/ffs_snapshot.c index 3bfc1b9..afbea57 100644 --- a/sys/ufs/ffs/ffs_snapshot.c +++ b/sys/ufs/ffs/ffs_snapshot.c @@ -119,16 +119,15 @@ ffs_snapshot(mp, snapfile) struct mount *mp; char *snapfile; { - ufs2_daddr_t numblks, blkno; + ufs2_daddr_t numblks, blkno, *blkp, *snapblklist; int error, cg, snaploc; int i, size, len, loc; int flag = mp->mnt_flag; struct timespec starttime = {0, 0}, endtime; char saved_nice = 0; - long redo = 0, snaplistsize; + long redo = 0, snaplistsize = 0; int32_t *lp; void *space; - daddr_t *snapblklist; struct fs *copy_fs = NULL, *fs = VFSTOUFS(mp)->um_fs; struct snaphead *snaphead; struct thread *td = curthread; @@ -394,7 +393,11 @@ restart: * spec_strategy about writing on a suspended filesystem. * Note that we skip unlinked snapshot files as they will * be handled separately below. + * + * We also calculate the needed size for the snapshot list. */ + snaplistsize = fs->fs_ncg + howmany(fs->fs_cssize, fs->fs_bsize) + + FSMAXSNAP + 1 /* superblock */ + 1 /* last block */ + 1 /* size */; mp->mnt_kern_flag &= ~MNTK_SUSPENDED; mtx_lock(&mntvnode_mtx); loop: @@ -438,6 +441,7 @@ loop: DIP(xp, i_db[loc]) = 0; } } + snaplistsize += 1; if (xp->i_ump->um_fstype == UFS1) error = expunge_ufs1(vp, xp, copy_fs, fullacct_ufs1, BLK_NOCOPY); @@ -487,6 +491,36 @@ loop: transferlockers(&vp->v_lock, vp->v_vnlock); lockmgr(&vp->v_lock, LK_RELEASE, NULL, td); /* + * If this is the first snapshot on this filesystem, then we need + * to allocate the space for the list of preallocated snapshot blocks. + * This list will be refined below, but this preliminary one will + * keep us out of deadlock until the full one is ready. + */ + if (xp == NULL) { + MALLOC(snapblklist, daddr_t *, snaplistsize * sizeof(daddr_t), + M_UFSMNT, M_WAITOK); + blkp = &snapblklist[1]; + *blkp++ = lblkno(fs, fs->fs_sblockloc); + blkno = fragstoblks(fs, fs->fs_csaddr); + for (cg = 0; cg < fs->fs_ncg; cg++) { + if (fragstoblks(fs, cgtod(fs, cg) > blkno)) + break; + *blkp++ = fragstoblks(fs, cgtod(fs, cg)); + } + len = howmany(fs->fs_cssize, fs->fs_bsize); + for (loc = 0; loc < len; loc++) + *blkp++ = blkno + loc; + for (; cg < fs->fs_ncg; cg++) + *blkp++ = fragstoblks(fs, cgtod(fs, cg)); + snapblklist[0] = blkp - snapblklist; + VI_LOCK(devvp); + if (devvp->v_rdev->si_snapblklist != NULL) + panic("ffs_snapshot: non-empty list"); + devvp->v_rdev->si_snapblklist = snapblklist; + devvp->v_rdev->si_snaplistsize = blkp - snapblklist; + VI_UNLOCK(devvp); + } + /* * Record snapshot inode. Since this is the newest snapshot, * it must be placed at the end of the list. */ @@ -535,10 +569,8 @@ out1: } } /* - * Allocate the space for the list of preallocated snapshot blocks. + * Allocate space for the full list of preallocated snapshot blocks. */ - snaplistsize = fs->fs_ncg + howmany(fs->fs_cssize, fs->fs_bsize) + - FSMAXSNAP + 1 /* superblock */ + 1 /* last block */ + 1 /* size */; MALLOC(snapblklist, daddr_t *, snaplistsize * sizeof(daddr_t), M_UFSMNT, M_WAITOK); ip->i_snapblklist = &snapblklist[1]; @@ -556,6 +588,8 @@ out1: FREE(snapblklist, M_UFSMNT); goto done; } + if (snaplistsize < ip->i_snapblklist - snapblklist) + panic("ffs_snapshot: list too small"); snaplistsize = ip->i_snapblklist - snapblklist; snapblklist[0] = snaplistsize; ip->i_snapblklist = 0; @@ -600,9 +634,11 @@ out1: * should replace the previous list. */ VI_LOCK(devvp); - FREE(devvp->v_rdev->si_snapblklist, M_UFSMNT); + space = devvp->v_rdev->si_snapblklist; devvp->v_rdev->si_snapblklist = snapblklist; devvp->v_rdev->si_snaplistsize = snaplistsize; + if (space != NULL) + FREE(space, M_UFSMNT); VI_UNLOCK(devvp); done: free(copy_fs->fs_csp, M_UFSMNT); |
