diff options
Diffstat (limited to 'fs/xfs/libxfs/xfs_alloc.c')
| -rw-r--r-- | fs/xfs/libxfs/xfs_alloc.c | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c index 8164eeb8db28..516e0c57cf9c 100644 --- a/fs/xfs/libxfs/xfs_alloc.c +++ b/fs/xfs/libxfs/xfs_alloc.c @@ -2057,6 +2057,93 @@ xfs_alloc_space_available( } /* + * Check the agfl fields of the agf for inconsistency or corruption. The purpose + * is to detect an agfl header padding mismatch between current and early v5 + * kernels. This problem manifests as a 1-slot size difference between the + * on-disk flcount and the active [first, last] range of a wrapped agfl. This + * may also catch variants of agfl count corruption unrelated to padding. Either + * way, we'll reset the agfl and warn the user. + * + * Return true if a reset is required before the agfl can be used, false + * otherwise. + */ +static bool +xfs_agfl_needs_reset( + struct xfs_mount *mp, + struct xfs_agf *agf) +{ + uint32_t f = be32_to_cpu(agf->agf_flfirst); + uint32_t l = be32_to_cpu(agf->agf_fllast); + uint32_t c = be32_to_cpu(agf->agf_flcount); + int agfl_size = xfs_agfl_size(mp); + int active; + + /* no agfl header on v4 supers */ + if (!xfs_sb_version_hascrc(&mp->m_sb)) + return false; + + /* + * The agf read verifier catches severe corruption of these fields. + * Repeat some sanity checks to cover a packed -> unpacked mismatch if + * the verifier allows it. + */ + if (f >= agfl_size || l >= agfl_size) + return true; + if (c > agfl_size) + return true; + + /* + * Check consistency between the on-disk count and the active range. An + * agfl padding mismatch manifests as an inconsistent flcount. + */ + if (c && l >= f) + active = l - f + 1; + else if (c) + active = agfl_size - f + l + 1; + else + active = 0; + + return active != c; +} + +/* + * Reset the agfl to an empty state. Ignore/drop any existing blocks since the + * agfl content cannot be trusted. Warn the user that a repair is required to + * recover leaked blocks. + * + * The purpose of this mechanism is to handle filesystems affected by the agfl + * header padding mismatch problem. A reset keeps the filesystem online with a + * relatively minor free space accounting inconsistency rather than suffer the + * inevitable crash from use of an invalid agfl block. + */ +static void +xfs_agfl_reset( + struct xfs_trans *tp, + struct xfs_buf *agbp, + struct xfs_perag *pag) +{ + struct xfs_mount *mp = tp->t_mountp; + struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp); + + ASSERT(pag->pagf_agflreset); + trace_xfs_agfl_reset(mp, agf, 0, _RET_IP_); + + xfs_warn(mp, + "WARNING: Reset corrupted AGFL on AG %u. %d blocks leaked. " + "Please unmount and run xfs_repair.", + pag->pag_agno, pag->pagf_flcount); + + agf->agf_flfirst = 0; + agf->agf_fllast = cpu_to_be32(xfs_agfl_size(mp) - 1); + agf->agf_flcount = 0; + xfs_alloc_log_agf(tp, agbp, XFS_AGF_FLFIRST | XFS_AGF_FLLAST | + XFS_AGF_FLCOUNT); + + pag->pagf_flcount = 0; + pag->pagf_agflreset = false; +} + +/* * Decide whether to use this allocation group for this allocation. * If so, fix up the btree freelist's size. */ @@ -2117,6 +2204,10 @@ xfs_alloc_fix_freelist( } } + /* reset a padding mismatched agfl before final free space check */ + if (pag->pagf_agflreset) + xfs_agfl_reset(tp, agbp, pag); + /* If there isn't enough total space or single-extent, reject it. */ need = xfs_alloc_min_freelist(mp, pag); if (!xfs_alloc_space_available(args, need, flags)) @@ -2273,6 +2364,7 @@ xfs_alloc_get_freelist( agf->agf_flfirst = 0; pag = xfs_perag_get(mp, be32_to_cpu(agf->agf_seqno)); + ASSERT(!pag->pagf_agflreset); be32_add_cpu(&agf->agf_flcount, -1); xfs_trans_agflist_delta(tp, -1); pag->pagf_flcount--; @@ -2384,6 +2476,7 @@ xfs_alloc_put_freelist( agf->agf_fllast = 0; pag = xfs_perag_get(mp, be32_to_cpu(agf->agf_seqno)); + ASSERT(!pag->pagf_agflreset); be32_add_cpu(&agf->agf_flcount, 1); xfs_trans_agflist_delta(tp, 1); pag->pagf_flcount++; @@ -2589,6 +2682,7 @@ xfs_alloc_read_agf( pag->pagb_count = 0; pag->pagb_tree = RB_ROOT; pag->pagf_init = 1; + pag->pagf_agflreset = xfs_agfl_needs_reset(mp, agf); } #ifdef DEBUG else if (!XFS_FORCED_SHUTDOWN(mp)) { |