diff options
Diffstat (limited to 'fs/xfs/scrub/common.c')
| -rw-r--r-- | fs/xfs/scrub/common.c | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/fs/xfs/scrub/common.c b/fs/xfs/scrub/common.c index 82d2a85d6461..de24532fe083 100644 --- a/fs/xfs/scrub/common.c +++ b/fs/xfs/scrub/common.c @@ -1230,3 +1230,155 @@ xchk_fsgates_enable( sc->flags |= scrub_fsgates; } + +/* + * Decide if this is this a cached inode that's also allocated. The caller + * must hold a reference to an AG and the AGI buffer lock to prevent inodes + * from being allocated or freed. + * + * Look up an inode by number in the given file system. If the inode number + * is invalid, return -EINVAL. If the inode is not in cache, return -ENODATA. + * If the inode is being reclaimed, return -ENODATA because we know the inode + * cache cannot be updating the ondisk metadata. + * + * Otherwise, the incore inode is the one we want, and it is either live, + * somewhere in the inactivation machinery, or reclaimable. The inode is + * allocated if i_mode is nonzero. In all three cases, the cached inode will + * be more up to date than the ondisk inode buffer, so we must use the incore + * i_mode. + */ +int +xchk_inode_is_allocated( + struct xfs_scrub *sc, + xfs_agino_t agino, + bool *inuse) +{ + struct xfs_mount *mp = sc->mp; + struct xfs_perag *pag = sc->sa.pag; + xfs_ino_t ino; + struct xfs_inode *ip; + int error; + + /* caller must hold perag reference */ + if (pag == NULL) { + ASSERT(pag != NULL); + return -EINVAL; + } + + /* caller must have AGI buffer */ + if (sc->sa.agi_bp == NULL) { + ASSERT(sc->sa.agi_bp != NULL); + return -EINVAL; + } + + /* reject inode numbers outside existing AGs */ + ino = XFS_AGINO_TO_INO(sc->mp, pag->pag_agno, agino); + if (!xfs_verify_ino(mp, ino)) + return -EINVAL; + + error = -ENODATA; + rcu_read_lock(); + ip = radix_tree_lookup(&pag->pag_ici_root, agino); + if (!ip) { + /* cache miss */ + goto out_rcu; + } + + /* + * If the inode number doesn't match, the incore inode got reused + * during an RCU grace period and the radix tree hasn't been updated. + * This isn't the inode we want. + */ + spin_lock(&ip->i_flags_lock); + if (ip->i_ino != ino) + goto out_skip; + + trace_xchk_inode_is_allocated(ip); + + /* + * We have an incore inode that matches the inode we want, and the + * caller holds the perag structure and the AGI buffer. Let's check + * our assumptions below: + */ + +#ifdef DEBUG + /* + * (1) If the incore inode is live (i.e. referenced from the dcache), + * it will not be INEW, nor will it be in the inactivation or reclaim + * machinery. The ondisk inode had better be allocated. This is the + * most trivial case. + */ + if (!(ip->i_flags & (XFS_NEED_INACTIVE | XFS_INEW | XFS_IRECLAIMABLE | + XFS_INACTIVATING))) { + /* live inode */ + ASSERT(VFS_I(ip)->i_mode != 0); + } + + /* + * If the incore inode is INEW, there are several possibilities: + * + * (2) For a file that is being created, note that we allocate the + * ondisk inode before allocating, initializing, and adding the incore + * inode to the radix tree. + * + * (3) If the incore inode is being recycled, the inode has to be + * allocated because we don't allow freed inodes to be recycled. + * Recycling doesn't touch i_mode. + */ + if (ip->i_flags & XFS_INEW) { + /* created on disk already or recycling */ + ASSERT(VFS_I(ip)->i_mode != 0); + } + + /* + * (4) If the inode is queued for inactivation (NEED_INACTIVE) but + * inactivation has not started (!INACTIVATING), it is still allocated. + */ + if ((ip->i_flags & XFS_NEED_INACTIVE) && + !(ip->i_flags & XFS_INACTIVATING)) { + /* definitely before difree */ + ASSERT(VFS_I(ip)->i_mode != 0); + } +#endif + + /* + * If the incore inode is undergoing inactivation (INACTIVATING), there + * are two possibilities: + * + * (5) It is before the point where it would get freed ondisk, in which + * case i_mode is still nonzero. + * + * (6) It has already been freed, in which case i_mode is zero. + * + * We don't take the ILOCK here, but difree and dialloc update the AGI, + * and we've taken the AGI buffer lock, which prevents that from + * happening. + */ + + /* + * (7) Inodes undergoing inactivation (INACTIVATING) or queued for + * reclaim (IRECLAIMABLE) could be allocated or free. i_mode still + * reflects the ondisk state. + */ + + /* + * (8) If the inode is in IFLUSHING, it's safe to query i_mode because + * the flush code uses i_mode to format the ondisk inode. + */ + + /* + * (9) If the inode is in IRECLAIM and was reachable via the radix + * tree, it still has the same i_mode as it did before it entered + * reclaim. The inode object is still alive because we hold the RCU + * read lock. + */ + + *inuse = VFS_I(ip)->i_mode != 0; + error = 0; + +out_skip: + spin_unlock(&ip->i_flags_lock); +out_rcu: + rcu_read_unlock(); + return error; +} |