6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx> [ Upstream commit 8d2517aaeea3ab8651bb517bca8f3c8664d318ea ] Previously, the block size always equaled to PAGE_SIZE, therefore `lclusterbits` couldn't be less than 12. Since sub-page compressed blocks are now considered, `lobits` for a lcluster in each pack cannot always be `lclusterbits` as before. Otherwise, there is no enough room for the special value `Z_EROFS_LI_D0_CBLKCNT`. To support smaller block sizes, `lobits` for each compacted lcluster is now calculated as: lobits = max(lclusterbits, ilog2(Z_EROFS_LI_D0_CBLKCNT) + 1) Reviewed-by: Yue Hu <huyue2@xxxxxxxxxxx> Reviewed-by: Chao Yu <chao@xxxxxxxxxx> Signed-off-by: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20231206091057.87027-4-hsiangkao@xxxxxxxxxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- fs/erofs/zmap.c | 32 ++++++++++++++------------------ 1 file changed, 14 insertions(+), 18 deletions(-) diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c index 7a1a24ae4a2d..e313c936351d 100644 --- a/fs/erofs/zmap.c +++ b/fs/erofs/zmap.c @@ -82,29 +82,26 @@ static int z_erofs_load_full_lcluster(struct z_erofs_maprecorder *m, } static unsigned int decode_compactedbits(unsigned int lobits, - unsigned int lomask, u8 *in, unsigned int pos, u8 *type) { const unsigned int v = get_unaligned_le32(in + pos / 8) >> (pos & 7); - const unsigned int lo = v & lomask; + const unsigned int lo = v & ((1 << lobits) - 1); *type = (v >> lobits) & 3; return lo; } -static int get_compacted_la_distance(unsigned int lclusterbits, +static int get_compacted_la_distance(unsigned int lobits, unsigned int encodebits, unsigned int vcnt, u8 *in, int i) { - const unsigned int lomask = (1 << lclusterbits) - 1; unsigned int lo, d1 = 0; u8 type; DBG_BUGON(i >= vcnt); do { - lo = decode_compactedbits(lclusterbits, lomask, - in, encodebits * i, &type); + lo = decode_compactedbits(lobits, in, encodebits * i, &type); if (type != Z_EROFS_LCLUSTER_TYPE_NONHEAD) return d1; @@ -123,15 +120,14 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m, { struct erofs_inode *const vi = EROFS_I(m->inode); const unsigned int lclusterbits = vi->z_logical_clusterbits; - const unsigned int lomask = (1 << lclusterbits) - 1; - unsigned int vcnt, base, lo, encodebits, nblk, eofs; + unsigned int vcnt, base, lo, lobits, encodebits, nblk, eofs; int i; u8 *in, type; bool big_pcluster; if (1 << amortizedshift == 4 && lclusterbits <= 14) vcnt = 2; - else if (1 << amortizedshift == 2 && lclusterbits == 12) + else if (1 << amortizedshift == 2 && lclusterbits <= 12) vcnt = 16; else return -EOPNOTSUPP; @@ -140,6 +136,7 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m, m->nextpackoff = round_down(pos, vcnt << amortizedshift) + (vcnt << amortizedshift); big_pcluster = vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1; + lobits = max(lclusterbits, ilog2(Z_EROFS_LI_D0_CBLKCNT) + 1U); encodebits = ((vcnt << amortizedshift) - sizeof(__le32)) * 8 / vcnt; eofs = erofs_blkoff(m->inode->i_sb, pos); base = round_down(eofs, vcnt << amortizedshift); @@ -147,15 +144,14 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m, i = (eofs - base) >> amortizedshift; - lo = decode_compactedbits(lclusterbits, lomask, - in, encodebits * i, &type); + lo = decode_compactedbits(lobits, in, encodebits * i, &type); m->type = type; if (type == Z_EROFS_LCLUSTER_TYPE_NONHEAD) { m->clusterofs = 1 << lclusterbits; /* figure out lookahead_distance: delta[1] if needed */ if (lookahead) - m->delta[1] = get_compacted_la_distance(lclusterbits, + m->delta[1] = get_compacted_la_distance(lobits, encodebits, vcnt, in, i); if (lo & Z_EROFS_LI_D0_CBLKCNT) { if (!big_pcluster) { @@ -174,8 +170,8 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m, * of which lo saves delta[1] rather than delta[0]. * Hence, get delta[0] by the previous lcluster indirectly. */ - lo = decode_compactedbits(lclusterbits, lomask, - in, encodebits * (i - 1), &type); + lo = decode_compactedbits(lobits, in, + encodebits * (i - 1), &type); if (type != Z_EROFS_LCLUSTER_TYPE_NONHEAD) lo = 0; else if (lo & Z_EROFS_LI_D0_CBLKCNT) @@ -190,8 +186,8 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m, nblk = 1; while (i > 0) { --i; - lo = decode_compactedbits(lclusterbits, lomask, - in, encodebits * i, &type); + lo = decode_compactedbits(lobits, in, + encodebits * i, &type); if (type == Z_EROFS_LCLUSTER_TYPE_NONHEAD) i -= lo; @@ -202,8 +198,8 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m, nblk = 0; while (i > 0) { --i; - lo = decode_compactedbits(lclusterbits, lomask, - in, encodebits * i, &type); + lo = decode_compactedbits(lobits, in, + encodebits * i, &type); if (type == Z_EROFS_LCLUSTER_TYPE_NONHEAD) { if (lo & Z_EROFS_LI_D0_CBLKCNT) { --i; -- 2.43.0
