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-rw-r--r--fs/erofs/internal.h5
-rw-r--r--fs/erofs/zmap.c95
2 files changed, 92 insertions, 8 deletions
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 25b094085ca6..a9fc5245015b 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -356,6 +356,11 @@ struct erofs_map_blocks {
/* Flags used by erofs_map_blocks_flatmode() */
#define EROFS_GET_BLOCKS_RAW 0x0001
+/*
+ * Used to get the exact decompressed length, e.g. fiemap (consider lookback
+ * approach instead if possible since it's more metadata lightweight.)
+ */
+#define EROFS_GET_BLOCKS_FIEMAP 0x0002
/* zmap.c */
#ifdef CONFIG_EROFS_FS_ZIP
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index f68aea4baed7..c2a31810abeb 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -212,9 +212,34 @@ static unsigned int decode_compactedbits(unsigned int lobits,
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,
- unsigned int eofs)
+ unsigned int eofs, bool lookahead)
{
struct erofs_inode *const vi = EROFS_I(m->inode);
const unsigned int lclusterbits = vi->z_logical_clusterbits;
@@ -243,6 +268,11 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m,
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);
@@ -313,7 +343,7 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m,
}
static int compacted_load_cluster_from_disk(struct z_erofs_maprecorder *m,
- unsigned long lcn)
+ unsigned long lcn, bool lookahead)
{
struct inode *const inode = m->inode;
struct erofs_inode *const vi = EROFS_I(inode);
@@ -364,11 +394,12 @@ out:
err = z_erofs_reload_indexes(m, erofs_blknr(pos));
if (err)
return err;
- return unpack_compacted_index(m, amortizedshift, erofs_blkoff(pos));
+ return unpack_compacted_index(m, amortizedshift, erofs_blkoff(pos),
+ lookahead);
}
static int z_erofs_load_cluster_from_disk(struct z_erofs_maprecorder *m,
- unsigned int lcn)
+ unsigned int lcn, bool lookahead)
{
const unsigned int datamode = EROFS_I(m->inode)->datalayout;
@@ -376,7 +407,7 @@ static int z_erofs_load_cluster_from_disk(struct z_erofs_maprecorder *m,
return legacy_load_cluster_from_disk(m, lcn);
if (datamode == EROFS_INODE_FLAT_COMPRESSION)
- return compacted_load_cluster_from_disk(m, lcn);
+ return compacted_load_cluster_from_disk(m, lcn, lookahead);
return -EINVAL;
}
@@ -399,7 +430,7 @@ static int z_erofs_extent_lookback(struct z_erofs_maprecorder *m,
/* load extent head logical cluster if needed */
lcn -= lookback_distance;
- err = z_erofs_load_cluster_from_disk(m, lcn);
+ err = z_erofs_load_cluster_from_disk(m, lcn, false);
if (err)
return err;
@@ -450,7 +481,7 @@ static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m,
if (m->compressedlcs)
goto out;
- err = z_erofs_load_cluster_from_disk(m, lcn);
+ err = z_erofs_load_cluster_from_disk(m, lcn, false);
if (err)
return err;
@@ -498,6 +529,48 @@ err_bonus_cblkcnt:
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_HEAD) {
+ /* 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;
+}
+
int z_erofs_map_blocks_iter(struct inode *inode,
struct erofs_map_blocks *map,
int flags)
@@ -531,7 +604,7 @@ int z_erofs_map_blocks_iter(struct inode *inode,
initial_lcn = ofs >> lclusterbits;
endoff = ofs & ((1 << lclusterbits) - 1);
- err = z_erofs_load_cluster_from_disk(&m, initial_lcn);
+ err = z_erofs_load_cluster_from_disk(&m, initial_lcn, false);
if (err)
goto unmap_out;
@@ -581,6 +654,12 @@ int z_erofs_map_blocks_iter(struct inode *inode,
err = z_erofs_get_extent_compressedlen(&m, initial_lcn);
if (err)
goto out;
+
+ if (flags & EROFS_GET_BLOCKS_FIEMAP) {
+ err = z_erofs_get_extent_decompressedlen(&m);
+ if (!err)
+ map->m_flags |= EROFS_MAP_FULL_MAPPED;
+ }
unmap_out:
if (m.kaddr)
kunmap_atomic(m.kaddr);
generated by cgit (git 2.34.1) at 2024-06-07 21:16:16 +0000