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-rw-r--r--fs/erofs/zmap.c810
1 files changed, 810 insertions, 0 deletions
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
new file mode 100644
index 000000000..0337b70b2
--- /dev/null
+++ b/fs/erofs/zmap.c
@@ -0,0 +1,810 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2018-2019 HUAWEI, Inc.
+ * https://www.huawei.com/
+ */
+#include "internal.h"
+#include <asm/unaligned.h>
+#include <trace/events/erofs.h>
+
+static int z_erofs_do_map_blocks(struct inode *inode,
+ struct erofs_map_blocks *map,
+ int flags);
+
+int z_erofs_fill_inode(struct inode *inode)
+{
+ struct erofs_inode *const vi = EROFS_I(inode);
+ struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
+
+ if (!erofs_sb_has_big_pcluster(sbi) &&
+ !erofs_sb_has_ztailpacking(sbi) && !erofs_sb_has_fragments(sbi) &&
+ vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY) {
+ vi->z_advise = 0;
+ vi->z_algorithmtype[0] = 0;
+ vi->z_algorithmtype[1] = 0;
+ vi->z_logical_clusterbits = LOG_BLOCK_SIZE;
+ set_bit(EROFS_I_Z_INITED_BIT, &vi->flags);
+ }
+ inode->i_mapping->a_ops = &z_erofs_aops;
+ return 0;
+}
+
+static int z_erofs_fill_inode_lazy(struct inode *inode)
+{
+ struct erofs_inode *const vi = EROFS_I(inode);
+ struct super_block *const sb = inode->i_sb;
+ int err, headnr;
+ erofs_off_t pos;
+ struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+ void *kaddr;
+ struct z_erofs_map_header *h;
+
+ if (test_bit(EROFS_I_Z_INITED_BIT, &vi->flags)) {
+ /*
+ * paired with smp_mb() at the end of the function to ensure
+ * fields will only be observed after the bit is set.
+ */
+ smp_mb();
+ return 0;
+ }
+
+ if (wait_on_bit_lock(&vi->flags, EROFS_I_BL_Z_BIT, TASK_KILLABLE))
+ return -ERESTARTSYS;
+
+ err = 0;
+ if (test_bit(EROFS_I_Z_INITED_BIT, &vi->flags))
+ goto out_unlock;
+
+ pos = ALIGN(erofs_iloc(inode) + vi->inode_isize + vi->xattr_isize, 8);
+ kaddr = erofs_read_metabuf(&buf, sb, erofs_blknr(pos), EROFS_KMAP);
+ if (IS_ERR(kaddr)) {
+ err = PTR_ERR(kaddr);
+ goto out_unlock;
+ }
+
+ h = kaddr + erofs_blkoff(pos);
+ /*
+ * if the highest bit of the 8-byte map header is set, the whole file
+ * is stored in the packed inode. The rest bits keeps z_fragmentoff.
+ */
+ if (h->h_clusterbits >> Z_EROFS_FRAGMENT_INODE_BIT) {
+ vi->z_advise = Z_EROFS_ADVISE_FRAGMENT_PCLUSTER;
+ vi->z_fragmentoff = le64_to_cpu(*(__le64 *)h) ^ (1ULL << 63);
+ vi->z_tailextent_headlcn = 0;
+ goto done;
+ }
+ vi->z_advise = le16_to_cpu(h->h_advise);
+ vi->z_algorithmtype[0] = h->h_algorithmtype & 15;
+ vi->z_algorithmtype[1] = h->h_algorithmtype >> 4;
+
+ headnr = 0;
+ if (vi->z_algorithmtype[0] >= Z_EROFS_COMPRESSION_MAX ||
+ vi->z_algorithmtype[++headnr] >= Z_EROFS_COMPRESSION_MAX) {
+ erofs_err(sb, "unknown HEAD%u format %u for nid %llu, please upgrade kernel",
+ headnr + 1, vi->z_algorithmtype[headnr], vi->nid);
+ err = -EOPNOTSUPP;
+ goto out_put_metabuf;
+ }
+
+ vi->z_logical_clusterbits = LOG_BLOCK_SIZE + (h->h_clusterbits & 7);
+ if (!erofs_sb_has_big_pcluster(EROFS_SB(sb)) &&
+ vi->z_advise & (Z_EROFS_ADVISE_BIG_PCLUSTER_1 |
+ Z_EROFS_ADVISE_BIG_PCLUSTER_2)) {
+ erofs_err(sb, "per-inode big pcluster without sb feature for nid %llu",
+ vi->nid);
+ err = -EFSCORRUPTED;
+ goto out_put_metabuf;
+ }
+ if (vi->datalayout == EROFS_INODE_FLAT_COMPRESSION &&
+ !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1) ^
+ !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_2)) {
+ erofs_err(sb, "big pcluster head1/2 of compact indexes should be consistent for nid %llu",
+ vi->nid);
+ err = -EFSCORRUPTED;
+ goto out_put_metabuf;
+ }
+
+ if (vi->z_advise & Z_EROFS_ADVISE_INLINE_PCLUSTER) {
+ struct erofs_map_blocks map = {
+ .buf = __EROFS_BUF_INITIALIZER
+ };
+
+ vi->z_idata_size = le16_to_cpu(h->h_idata_size);
+ err = z_erofs_do_map_blocks(inode, &map,
+ EROFS_GET_BLOCKS_FINDTAIL);
+ erofs_put_metabuf(&map.buf);
+
+ if (!map.m_plen ||
+ erofs_blkoff(map.m_pa) + map.m_plen > EROFS_BLKSIZ) {
+ erofs_err(sb, "invalid tail-packing pclustersize %llu",
+ map.m_plen);
+ err = -EFSCORRUPTED;
+ }
+ if (err < 0)
+ goto out_put_metabuf;
+ }
+
+ if (vi->z_advise & Z_EROFS_ADVISE_FRAGMENT_PCLUSTER &&
+ !(h->h_clusterbits >> Z_EROFS_FRAGMENT_INODE_BIT)) {
+ struct erofs_map_blocks map = {
+ .buf = __EROFS_BUF_INITIALIZER
+ };
+
+ vi->z_fragmentoff = le32_to_cpu(h->h_fragmentoff);
+ err = z_erofs_do_map_blocks(inode, &map,
+ EROFS_GET_BLOCKS_FINDTAIL);
+ erofs_put_metabuf(&map.buf);
+ if (err < 0)
+ goto out_put_metabuf;
+ }
+done:
+ /* paired with smp_mb() at the beginning of the function */
+ smp_mb();
+ set_bit(EROFS_I_Z_INITED_BIT, &vi->flags);
+out_put_metabuf:
+ erofs_put_metabuf(&buf);
+out_unlock:
+ clear_and_wake_up_bit(EROFS_I_BL_Z_BIT, &vi->flags);
+ return err;
+}
+
+struct z_erofs_maprecorder {
+ struct inode *inode;
+ struct erofs_map_blocks *map;
+ void *kaddr;
+
+ unsigned long lcn;
+ /* compression extent information gathered */
+ u8 type, headtype;
+ u16 clusterofs;
+ u16 delta[2];
+ erofs_blk_t pblk, compressedblks;
+ erofs_off_t nextpackoff;
+ bool partialref;
+};
+
+static int legacy_load_cluster_from_disk(struct z_erofs_maprecorder *m,
+ unsigned long lcn)
+{
+ struct inode *const inode = m->inode;
+ struct erofs_inode *const vi = EROFS_I(inode);
+ const erofs_off_t pos =
+ Z_EROFS_VLE_LEGACY_INDEX_ALIGN(erofs_iloc(inode) +
+ vi->inode_isize + vi->xattr_isize) +
+ lcn * sizeof(struct z_erofs_vle_decompressed_index);
+ struct z_erofs_vle_decompressed_index *di;
+ unsigned int advise, type;
+
+ m->kaddr = erofs_read_metabuf(&m->map->buf, inode->i_sb,
+ erofs_blknr(pos), EROFS_KMAP_ATOMIC);
+ if (IS_ERR(m->kaddr))
+ return PTR_ERR(m->kaddr);
+
+ m->nextpackoff = pos + sizeof(struct z_erofs_vle_decompressed_index);
+ m->lcn = lcn;
+ di = m->kaddr + erofs_blkoff(pos);
+
+ advise = le16_to_cpu(di->di_advise);
+ type = (advise >> Z_EROFS_VLE_DI_CLUSTER_TYPE_BIT) &
+ ((1 << Z_EROFS_VLE_DI_CLUSTER_TYPE_BITS) - 1);
+ switch (type) {
+ case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
+ m->clusterofs = 1 << vi->z_logical_clusterbits;
+ m->delta[0] = le16_to_cpu(di->di_u.delta[0]);
+ if (m->delta[0] & Z_EROFS_VLE_DI_D0_CBLKCNT) {
+ if (!(vi->z_advise & (Z_EROFS_ADVISE_BIG_PCLUSTER_1 |
+ Z_EROFS_ADVISE_BIG_PCLUSTER_2))) {
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+ }
+ m->compressedblks = m->delta[0] &
+ ~Z_EROFS_VLE_DI_D0_CBLKCNT;
+ m->delta[0] = 1;
+ }
+ m->delta[1] = le16_to_cpu(di->di_u.delta[1]);
+ break;
+ case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
+ case Z_EROFS_VLE_CLUSTER_TYPE_HEAD1:
+ case Z_EROFS_VLE_CLUSTER_TYPE_HEAD2:
+ if (advise & Z_EROFS_VLE_DI_PARTIAL_REF)
+ m->partialref = true;
+ m->clusterofs = le16_to_cpu(di->di_clusterofs);
+ if (m->clusterofs >= 1 << vi->z_logical_clusterbits) {
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+ }
+ m->pblk = le32_to_cpu(di->di_u.blkaddr);
+ break;
+ default:
+ DBG_BUGON(1);
+ return -EOPNOTSUPP;
+ }
+ m->type = type;
+ return 0;
+}
+
+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;
+
+ *type = (v >> lobits) & 3;
+ return lo;
+}
+
+static int get_compacted_la_distance(unsigned int lclusterbits,
+ 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);
+
+ if (type != Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD)
+ return d1;
+ ++d1;
+ } while (++i < vcnt);
+
+ /* vcnt - 1 (Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) item */
+ if (!(lo & Z_EROFS_VLE_DI_D0_CBLKCNT))
+ d1 += lo - 1;
+ return d1;
+}
+
+static int unpack_compacted_index(struct z_erofs_maprecorder *m,
+ unsigned int amortizedshift,
+ erofs_off_t pos, bool lookahead)
+{
+ 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;
+ int i;
+ u8 *in, type;
+ bool big_pcluster;
+
+ if (1 << amortizedshift == 4 && lclusterbits <= 14)
+ vcnt = 2;
+ else if (1 << amortizedshift == 2 && lclusterbits == 12)
+ vcnt = 16;
+ else
+ return -EOPNOTSUPP;
+
+ /* it doesn't equal to round_up(..) */
+ m->nextpackoff = round_down(pos, vcnt << amortizedshift) +
+ (vcnt << amortizedshift);
+ big_pcluster = vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1;
+ encodebits = ((vcnt << amortizedshift) - sizeof(__le32)) * 8 / vcnt;
+ eofs = erofs_blkoff(pos);
+ base = round_down(eofs, vcnt << amortizedshift);
+ in = m->kaddr + base;
+
+ i = (eofs - base) >> amortizedshift;
+
+ lo = decode_compactedbits(lclusterbits, lomask,
+ in, encodebits * i, &type);
+ m->type = type;
+ if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) {
+ m->clusterofs = 1 << lclusterbits;
+
+ /* figure out lookahead_distance: delta[1] if needed */
+ if (lookahead)
+ m->delta[1] = get_compacted_la_distance(lclusterbits,
+ encodebits, vcnt, in, i);
+ if (lo & Z_EROFS_VLE_DI_D0_CBLKCNT) {
+ if (!big_pcluster) {
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+ }
+ m->compressedblks = lo & ~Z_EROFS_VLE_DI_D0_CBLKCNT;
+ m->delta[0] = 1;
+ return 0;
+ } else if (i + 1 != (int)vcnt) {
+ m->delta[0] = lo;
+ return 0;
+ }
+ /*
+ * since the last lcluster in the pack is special,
+ * 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);
+ if (type != Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD)
+ lo = 0;
+ else if (lo & Z_EROFS_VLE_DI_D0_CBLKCNT)
+ lo = 1;
+ m->delta[0] = lo + 1;
+ return 0;
+ }
+ m->clusterofs = lo;
+ m->delta[0] = 0;
+ /* figout out blkaddr (pblk) for HEAD lclusters */
+ if (!big_pcluster) {
+ nblk = 1;
+ while (i > 0) {
+ --i;
+ lo = decode_compactedbits(lclusterbits, lomask,
+ in, encodebits * i, &type);
+ if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD)
+ i -= lo;
+
+ if (i >= 0)
+ ++nblk;
+ }
+ } else {
+ nblk = 0;
+ while (i > 0) {
+ --i;
+ lo = decode_compactedbits(lclusterbits, lomask,
+ in, encodebits * i, &type);
+ if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) {
+ if (lo & Z_EROFS_VLE_DI_D0_CBLKCNT) {
+ --i;
+ nblk += lo & ~Z_EROFS_VLE_DI_D0_CBLKCNT;
+ continue;
+ }
+ /* bigpcluster shouldn't have plain d0 == 1 */
+ if (lo <= 1) {
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+ }
+ i -= lo - 2;
+ continue;
+ }
+ ++nblk;
+ }
+ }
+ in += (vcnt << amortizedshift) - sizeof(__le32);
+ m->pblk = le32_to_cpu(*(__le32 *)in) + nblk;
+ return 0;
+}
+
+static int compacted_load_cluster_from_disk(struct z_erofs_maprecorder *m,
+ unsigned long lcn, bool lookahead)
+{
+ struct inode *const inode = m->inode;
+ struct erofs_inode *const vi = EROFS_I(inode);
+ const erofs_off_t ebase = sizeof(struct z_erofs_map_header) +
+ ALIGN(erofs_iloc(inode) + vi->inode_isize + vi->xattr_isize, 8);
+ const unsigned int totalidx = DIV_ROUND_UP(inode->i_size, EROFS_BLKSIZ);
+ unsigned int compacted_4b_initial, compacted_2b;
+ unsigned int amortizedshift;
+ erofs_off_t pos;
+
+ if (lcn >= totalidx)
+ return -EINVAL;
+
+ m->lcn = lcn;
+ /* used to align to 32-byte (compacted_2b) alignment */
+ compacted_4b_initial = (32 - ebase % 32) / 4;
+ if (compacted_4b_initial == 32 / 4)
+ compacted_4b_initial = 0;
+
+ if ((vi->z_advise & Z_EROFS_ADVISE_COMPACTED_2B) &&
+ compacted_4b_initial < totalidx)
+ compacted_2b = rounddown(totalidx - compacted_4b_initial, 16);
+ else
+ compacted_2b = 0;
+
+ pos = ebase;
+ if (lcn < compacted_4b_initial) {
+ amortizedshift = 2;
+ goto out;
+ }
+ pos += compacted_4b_initial * 4;
+ lcn -= compacted_4b_initial;
+
+ if (lcn < compacted_2b) {
+ amortizedshift = 1;
+ goto out;
+ }
+ pos += compacted_2b * 2;
+ lcn -= compacted_2b;
+ amortizedshift = 2;
+out:
+ pos += lcn * (1 << amortizedshift);
+ m->kaddr = erofs_read_metabuf(&m->map->buf, inode->i_sb,
+ erofs_blknr(pos), EROFS_KMAP_ATOMIC);
+ if (IS_ERR(m->kaddr))
+ return PTR_ERR(m->kaddr);
+ return unpack_compacted_index(m, amortizedshift, pos, lookahead);
+}
+
+static int z_erofs_load_cluster_from_disk(struct z_erofs_maprecorder *m,
+ unsigned int lcn, bool lookahead)
+{
+ const unsigned int datamode = EROFS_I(m->inode)->datalayout;
+
+ if (datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY)
+ return legacy_load_cluster_from_disk(m, lcn);
+
+ if (datamode == EROFS_INODE_FLAT_COMPRESSION)
+ return compacted_load_cluster_from_disk(m, lcn, lookahead);
+
+ return -EINVAL;
+}
+
+static int z_erofs_extent_lookback(struct z_erofs_maprecorder *m,
+ unsigned int lookback_distance)
+{
+ struct erofs_inode *const vi = EROFS_I(m->inode);
+ const unsigned int lclusterbits = vi->z_logical_clusterbits;
+
+ while (m->lcn >= lookback_distance) {
+ unsigned long lcn = m->lcn - lookback_distance;
+ int err;
+
+ /* load extent head logical cluster if needed */
+ err = z_erofs_load_cluster_from_disk(m, lcn, false);
+ if (err)
+ return err;
+
+ switch (m->type) {
+ case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
+ if (!m->delta[0]) {
+ erofs_err(m->inode->i_sb,
+ "invalid lookback distance 0 @ nid %llu",
+ vi->nid);
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+ }
+ lookback_distance = m->delta[0];
+ continue;
+ case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
+ case Z_EROFS_VLE_CLUSTER_TYPE_HEAD1:
+ case Z_EROFS_VLE_CLUSTER_TYPE_HEAD2:
+ m->headtype = m->type;
+ m->map->m_la = (lcn << lclusterbits) | m->clusterofs;
+ return 0;
+ default:
+ erofs_err(m->inode->i_sb,
+ "unknown type %u @ lcn %lu of nid %llu",
+ m->type, lcn, vi->nid);
+ DBG_BUGON(1);
+ return -EOPNOTSUPP;
+ }
+ }
+
+ erofs_err(m->inode->i_sb, "bogus lookback distance @ nid %llu",
+ vi->nid);
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+}
+
+static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m,
+ unsigned int initial_lcn)
+{
+ struct erofs_inode *const vi = EROFS_I(m->inode);
+ struct erofs_map_blocks *const map = m->map;
+ const unsigned int lclusterbits = vi->z_logical_clusterbits;
+ unsigned long lcn;
+ int err;
+
+ DBG_BUGON(m->type != Z_EROFS_VLE_CLUSTER_TYPE_PLAIN &&
+ m->type != Z_EROFS_VLE_CLUSTER_TYPE_HEAD1 &&
+ m->type != Z_EROFS_VLE_CLUSTER_TYPE_HEAD2);
+ DBG_BUGON(m->type != m->headtype);
+
+ if (m->headtype == Z_EROFS_VLE_CLUSTER_TYPE_PLAIN ||
+ ((m->headtype == Z_EROFS_VLE_CLUSTER_TYPE_HEAD1) &&
+ !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1)) ||
+ ((m->headtype == Z_EROFS_VLE_CLUSTER_TYPE_HEAD2) &&
+ !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_2))) {
+ map->m_plen = 1ULL << lclusterbits;
+ return 0;
+ }
+ lcn = m->lcn + 1;
+ if (m->compressedblks)
+ goto out;
+
+ err = z_erofs_load_cluster_from_disk(m, lcn, false);
+ if (err)
+ return err;
+
+ /*
+ * If the 1st NONHEAD lcluster has already been handled initially w/o
+ * valid compressedblks, which means at least it mustn't be CBLKCNT, or
+ * an internal implemenatation error is detected.
+ *
+ * The following code can also handle it properly anyway, but let's
+ * BUG_ON in the debugging mode only for developers to notice that.
+ */
+ DBG_BUGON(lcn == initial_lcn &&
+ m->type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD);
+
+ switch (m->type) {
+ case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
+ case Z_EROFS_VLE_CLUSTER_TYPE_HEAD1:
+ case Z_EROFS_VLE_CLUSTER_TYPE_HEAD2:
+ /*
+ * if the 1st NONHEAD lcluster is actually PLAIN or HEAD type
+ * rather than CBLKCNT, it's a 1 lcluster-sized pcluster.
+ */
+ m->compressedblks = 1 << (lclusterbits - LOG_BLOCK_SIZE);
+ break;
+ case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
+ if (m->delta[0] != 1)
+ goto err_bonus_cblkcnt;
+ if (m->compressedblks)
+ break;
+ fallthrough;
+ default:
+ erofs_err(m->inode->i_sb,
+ "cannot found CBLKCNT @ lcn %lu of nid %llu",
+ lcn, vi->nid);
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+ }
+out:
+ map->m_plen = (u64)m->compressedblks << LOG_BLOCK_SIZE;
+ return 0;
+err_bonus_cblkcnt:
+ erofs_err(m->inode->i_sb,
+ "bogus CBLKCNT @ lcn %lu of nid %llu",
+ lcn, vi->nid);
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+}
+
+static int z_erofs_get_extent_decompressedlen(struct z_erofs_maprecorder *m)
+{
+ struct inode *inode = m->inode;
+ struct erofs_inode *vi = EROFS_I(inode);
+ struct erofs_map_blocks *map = m->map;
+ unsigned int lclusterbits = vi->z_logical_clusterbits;
+ u64 lcn = m->lcn, headlcn = map->m_la >> lclusterbits;
+ int err;
+
+ do {
+ /* handle the last EOF pcluster (no next HEAD lcluster) */
+ if ((lcn << lclusterbits) >= inode->i_size) {
+ map->m_llen = inode->i_size - map->m_la;
+ return 0;
+ }
+
+ err = z_erofs_load_cluster_from_disk(m, lcn, true);
+ if (err)
+ return err;
+
+ if (m->type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) {
+ DBG_BUGON(!m->delta[1] &&
+ m->clusterofs != 1 << lclusterbits);
+ } else if (m->type == Z_EROFS_VLE_CLUSTER_TYPE_PLAIN ||
+ m->type == Z_EROFS_VLE_CLUSTER_TYPE_HEAD1 ||
+ m->type == Z_EROFS_VLE_CLUSTER_TYPE_HEAD2) {
+ /* go on until the next HEAD lcluster */
+ if (lcn != headlcn)
+ break;
+ m->delta[1] = 1;
+ } else {
+ erofs_err(inode->i_sb, "unknown type %u @ lcn %llu of nid %llu",
+ m->type, lcn, vi->nid);
+ DBG_BUGON(1);
+ return -EOPNOTSUPP;
+ }
+ lcn += m->delta[1];
+ } while (m->delta[1]);
+
+ map->m_llen = (lcn << lclusterbits) + m->clusterofs - map->m_la;
+ return 0;
+}
+
+static int z_erofs_do_map_blocks(struct inode *inode,
+ struct erofs_map_blocks *map,
+ int flags)
+{
+ struct erofs_inode *const vi = EROFS_I(inode);
+ bool ztailpacking = vi->z_advise & Z_EROFS_ADVISE_INLINE_PCLUSTER;
+ bool fragment = vi->z_advise & Z_EROFS_ADVISE_FRAGMENT_PCLUSTER;
+ struct z_erofs_maprecorder m = {
+ .inode = inode,
+ .map = map,
+ };
+ int err = 0;
+ unsigned int lclusterbits, endoff;
+ unsigned long initial_lcn;
+ unsigned long long ofs, end;
+
+ lclusterbits = vi->z_logical_clusterbits;
+ ofs = flags & EROFS_GET_BLOCKS_FINDTAIL ? inode->i_size - 1 : map->m_la;
+ initial_lcn = ofs >> lclusterbits;
+ endoff = ofs & ((1 << lclusterbits) - 1);
+
+ err = z_erofs_load_cluster_from_disk(&m, initial_lcn, false);
+ if (err)
+ goto unmap_out;
+
+ if (ztailpacking && (flags & EROFS_GET_BLOCKS_FINDTAIL))
+ vi->z_idataoff = m.nextpackoff;
+
+ map->m_flags = EROFS_MAP_MAPPED | EROFS_MAP_ENCODED;
+ end = (m.lcn + 1ULL) << lclusterbits;
+
+ switch (m.type) {
+ case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
+ case Z_EROFS_VLE_CLUSTER_TYPE_HEAD1:
+ case Z_EROFS_VLE_CLUSTER_TYPE_HEAD2:
+ if (endoff >= m.clusterofs) {
+ m.headtype = m.type;
+ map->m_la = (m.lcn << lclusterbits) | m.clusterofs;
+ /*
+ * For ztailpacking files, in order to inline data more
+ * effectively, special EOF lclusters are now supported
+ * which can have three parts at most.
+ */
+ if (ztailpacking && end > inode->i_size)
+ end = inode->i_size;
+ break;
+ }
+ /* m.lcn should be >= 1 if endoff < m.clusterofs */
+ if (!m.lcn) {
+ erofs_err(inode->i_sb,
+ "invalid logical cluster 0 at nid %llu",
+ vi->nid);
+ err = -EFSCORRUPTED;
+ goto unmap_out;
+ }
+ end = (m.lcn << lclusterbits) | m.clusterofs;
+ map->m_flags |= EROFS_MAP_FULL_MAPPED;
+ m.delta[0] = 1;
+ fallthrough;
+ case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
+ /* get the corresponding first chunk */
+ err = z_erofs_extent_lookback(&m, m.delta[0]);
+ if (err)
+ goto unmap_out;
+ break;
+ default:
+ erofs_err(inode->i_sb,
+ "unknown type %u @ offset %llu of nid %llu",
+ m.type, ofs, vi->nid);
+ err = -EOPNOTSUPP;
+ goto unmap_out;
+ }
+ if (m.partialref)
+ map->m_flags |= EROFS_MAP_PARTIAL_REF;
+ map->m_llen = end - map->m_la;
+
+ if (flags & EROFS_GET_BLOCKS_FINDTAIL) {
+ vi->z_tailextent_headlcn = m.lcn;
+ /* for non-compact indexes, fragmentoff is 64 bits */
+ if (fragment &&
+ vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY)
+ vi->z_fragmentoff |= (u64)m.pblk << 32;
+ }
+ if (ztailpacking && m.lcn == vi->z_tailextent_headlcn) {
+ map->m_flags |= EROFS_MAP_META;
+ map->m_pa = vi->z_idataoff;
+ map->m_plen = vi->z_idata_size;
+ } else if (fragment && m.lcn == vi->z_tailextent_headlcn) {
+ map->m_flags |= EROFS_MAP_FRAGMENT;
+ } else {
+ map->m_pa = blknr_to_addr(m.pblk);
+ err = z_erofs_get_extent_compressedlen(&m, initial_lcn);
+ if (err)
+ goto unmap_out;
+ }
+
+ if (m.headtype == Z_EROFS_VLE_CLUSTER_TYPE_PLAIN) {
+ if (map->m_llen > map->m_plen) {
+ DBG_BUGON(1);
+ err = -EFSCORRUPTED;
+ goto unmap_out;
+ }
+ if (vi->z_advise & Z_EROFS_ADVISE_INTERLACED_PCLUSTER)
+ map->m_algorithmformat =
+ Z_EROFS_COMPRESSION_INTERLACED;
+ else
+ map->m_algorithmformat =
+ Z_EROFS_COMPRESSION_SHIFTED;
+ } else if (m.headtype == Z_EROFS_VLE_CLUSTER_TYPE_HEAD2) {
+ map->m_algorithmformat = vi->z_algorithmtype[1];
+ } else {
+ map->m_algorithmformat = vi->z_algorithmtype[0];
+ }
+
+ if ((flags & EROFS_GET_BLOCKS_FIEMAP) ||
+ ((flags & EROFS_GET_BLOCKS_READMORE) &&
+ map->m_algorithmformat == Z_EROFS_COMPRESSION_LZMA &&
+ map->m_llen >= EROFS_BLKSIZ)) {
+ err = z_erofs_get_extent_decompressedlen(&m);
+ if (!err)
+ map->m_flags |= EROFS_MAP_FULL_MAPPED;
+ }
+
+unmap_out:
+ erofs_unmap_metabuf(&m.map->buf);
+ erofs_dbg("%s, m_la %llu m_pa %llu m_llen %llu m_plen %llu m_flags 0%o",
+ __func__, map->m_la, map->m_pa,
+ map->m_llen, map->m_plen, map->m_flags);
+ return err;
+}
+
+int z_erofs_map_blocks_iter(struct inode *inode, struct erofs_map_blocks *map,
+ int flags)
+{
+ struct erofs_inode *const vi = EROFS_I(inode);
+ int err = 0;
+
+ trace_z_erofs_map_blocks_iter_enter(inode, map, flags);
+
+ /* when trying to read beyond EOF, leave it unmapped */
+ if (map->m_la >= inode->i_size) {
+ map->m_llen = map->m_la + 1 - inode->i_size;
+ map->m_la = inode->i_size;
+ map->m_flags = 0;
+ goto out;
+ }
+
+ err = z_erofs_fill_inode_lazy(inode);
+ if (err)
+ goto out;
+
+ if ((vi->z_advise & Z_EROFS_ADVISE_FRAGMENT_PCLUSTER) &&
+ !vi->z_tailextent_headlcn) {
+ map->m_la = 0;
+ map->m_llen = inode->i_size;
+ map->m_flags = EROFS_MAP_MAPPED | EROFS_MAP_FULL_MAPPED |
+ EROFS_MAP_FRAGMENT;
+ goto out;
+ }
+
+ err = z_erofs_do_map_blocks(inode, map, flags);
+out:
+ trace_z_erofs_map_blocks_iter_exit(inode, map, flags, err);
+
+ /* aggressively BUG_ON iff CONFIG_EROFS_FS_DEBUG is on */
+ DBG_BUGON(err < 0 && err != -ENOMEM);
+ return err;
+}
+
+static int z_erofs_iomap_begin_report(struct inode *inode, loff_t offset,
+ loff_t length, unsigned int flags,
+ struct iomap *iomap, struct iomap *srcmap)
+{
+ int ret;
+ struct erofs_map_blocks map = { .m_la = offset };
+
+ ret = z_erofs_map_blocks_iter(inode, &map, EROFS_GET_BLOCKS_FIEMAP);
+ erofs_put_metabuf(&map.buf);
+ if (ret < 0)
+ return ret;
+
+ iomap->bdev = inode->i_sb->s_bdev;
+ iomap->offset = map.m_la;
+ iomap->length = map.m_llen;
+ if (map.m_flags & EROFS_MAP_MAPPED) {
+ iomap->type = IOMAP_MAPPED;
+ iomap->addr = map.m_flags & EROFS_MAP_FRAGMENT ?
+ IOMAP_NULL_ADDR : map.m_pa;
+ } else {
+ iomap->type = IOMAP_HOLE;
+ iomap->addr = IOMAP_NULL_ADDR;
+ /*
+ * No strict rule on how to describe extents for post EOF, yet
+ * we need to do like below. Otherwise, iomap itself will get
+ * into an endless loop on post EOF.
+ *
+ * Calculate the effective offset by subtracting extent start
+ * (map.m_la) from the requested offset, and add it to length.
+ * (NB: offset >= map.m_la always)
+ */
+ if (iomap->offset >= inode->i_size)
+ iomap->length = length + offset - map.m_la;
+ }
+ iomap->flags = 0;
+ return 0;
+}
+
+const struct iomap_ops z_erofs_iomap_report_ops = {
+ .iomap_begin = z_erofs_iomap_begin_report,
+};