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authorGao Xiang <hsiangkao@linux.alibaba.com>2023-12-06 12:10:55 +0300
committerGao Xiang <hsiangkao@linux.alibaba.com>2023-12-14 20:47:19 +0300
commit8d2517aaeea3ab8651bb517bca8f3c8664d318ea (patch)
tree9da0507b31d028d11a506276230dc55d773c0142 /fs/erofs
parent54ed3fdd66055d073cb1cd2c6c65bbc0683c40cf (diff)
downloadlinux-8d2517aaeea3ab8651bb517bca8f3c8664d318ea.tar.xz
erofs: fix up compacted indexes for block size < 4096
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@coolpad.com> Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20231206091057.87027-4-hsiangkao@linux.alibaba.com
Diffstat (limited to 'fs/erofs')
-rw-r--r--fs/erofs/zmap.c32
1 files changed, 14 insertions, 18 deletions
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 7b55111fd533..9753875e41cb 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;