[PATCH 03/10] erofs: add 48-bit block addressing on-disk support
From: Gao Xiang
Date: Mon Mar 10 2025 - 05:55:42 EST
The current 32-bit block addressing limits EROFS to a 16TiB maximum
volume size with 4KiB blocks. However, several new use cases now
require larger capacity support:
- Massive datasets for model training in order to boost random
sampling performance for each epoch;
- Object storage clients using EROFS direct passthrough.
This extends core on-disk structures to support 48-bit block addressing,
such as inodes, device slots, and inode chunks.
Additionally:
- Expand superblock root NID to 8-byte `rootnid_8b` to enable full
out-of-place update incremental builds;
- Introduce `epoch` field in the superblock as well as add `mtime`
field to 32-byte compact inodes for basic timestamp support.
Signed-off-by: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx>
---
fs/erofs/data.c | 15 ++++----
fs/erofs/erofs_fs.h | 91 +++++++++++++++++++++------------------------
fs/erofs/inode.c | 6 +--
fs/erofs/internal.h | 6 +--
fs/erofs/super.c | 12 +++---
5 files changed, 61 insertions(+), 69 deletions(-)
diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 2f45e39ce8c7..3c4a4eaffe8c 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -95,7 +95,7 @@ int erofs_map_blocks(struct inode *inode, struct erofs_map_blocks *map)
map->m_flags = EROFS_MAP_MAPPED;
if (map->m_la < pos) {
- map->m_pa = erofs_pos(sb, vi->raw_blkaddr) + map->m_la;
+ map->m_pa = erofs_pos(sb, vi->startblk) + map->m_la;
map->m_llen = pos - map->m_la;
} else {
map->m_pa = erofs_iloc(inode) + vi->inode_isize +
@@ -124,7 +124,7 @@ int erofs_map_blocks(struct inode *inode, struct erofs_map_blocks *map)
map->m_llen = min_t(erofs_off_t, 1UL << vi->chunkbits,
round_up(inode->i_size - map->m_la, blksz));
if (vi->chunkformat & EROFS_CHUNK_FORMAT_INDEXES) {
- startblk = le32_to_cpu(idx->blkaddr);
+ startblk = le32_to_cpu(idx->startblk_lo);
if (startblk != EROFS_NULL_ADDR) {
map->m_deviceid = le16_to_cpu(idx->device_id) &
EROFS_SB(sb)->device_id_mask;
@@ -168,7 +168,7 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
{
struct erofs_dev_context *devs = EROFS_SB(sb)->devs;
struct erofs_device_info *dif;
- erofs_off_t startoff, length;
+ erofs_off_t startoff;
int id;
erofs_fill_from_devinfo(map, sb, &EROFS_SB(sb)->dif0);
@@ -181,7 +181,7 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
return -ENODEV;
}
if (devs->flatdev) {
- map->m_pa += erofs_pos(sb, dif->mapped_blkaddr);
+ map->m_pa += erofs_pos(sb, dif->uniaddr);
up_read(&devs->rwsem);
return 0;
}
@@ -190,13 +190,12 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
} else if (devs->extra_devices && !devs->flatdev) {
down_read(&devs->rwsem);
idr_for_each_entry(&devs->tree, dif, id) {
- if (!dif->mapped_blkaddr)
+ if (!dif->uniaddr)
continue;
- startoff = erofs_pos(sb, dif->mapped_blkaddr);
- length = erofs_pos(sb, dif->blocks);
+ startoff = erofs_pos(sb, dif->uniaddr);
if (map->m_pa >= startoff &&
- map->m_pa < startoff + length) {
+ map->m_pa < startoff + erofs_pos(sb, dif->blocks)) {
map->m_pa -= startoff;
erofs_fill_from_devinfo(map, sb, dif);
break;
diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index 199395ed1c1f..8330ca3b18d3 100644
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -30,25 +30,19 @@
#define EROFS_FEATURE_INCOMPAT_FRAGMENTS 0x00000020
#define EROFS_FEATURE_INCOMPAT_DEDUPE 0x00000020
#define EROFS_FEATURE_INCOMPAT_XATTR_PREFIXES 0x00000040
+#define EROFS_FEATURE_INCOMPAT_48BIT 0x00000080
#define EROFS_ALL_FEATURE_INCOMPAT \
- (EROFS_FEATURE_INCOMPAT_ZERO_PADDING | \
- EROFS_FEATURE_INCOMPAT_COMPR_CFGS | \
- EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER | \
- EROFS_FEATURE_INCOMPAT_CHUNKED_FILE | \
- EROFS_FEATURE_INCOMPAT_DEVICE_TABLE | \
- EROFS_FEATURE_INCOMPAT_COMPR_HEAD2 | \
- EROFS_FEATURE_INCOMPAT_ZTAILPACKING | \
- EROFS_FEATURE_INCOMPAT_FRAGMENTS | \
- EROFS_FEATURE_INCOMPAT_DEDUPE | \
- EROFS_FEATURE_INCOMPAT_XATTR_PREFIXES)
+ ((EROFS_FEATURE_INCOMPAT_XATTR_PREFIXES << 1) - 1)
#define EROFS_SB_EXTSLOT_SIZE 16
struct erofs_deviceslot {
u8 tag[64]; /* digest(sha256), etc. */
- __le32 blocks; /* total fs blocks of this device */
- __le32 mapped_blkaddr; /* map starting at mapped_blkaddr */
- u8 reserved[56];
+ __le32 blocks_lo; /* total blocks count of this device */
+ __le32 uniaddr_lo; /* unified starting block of this device */
+ __le32 blocks_hi; /* total blocks count MSB */
+ __le16 uniaddr_hi; /* unified starting block MSB */
+ u8 reserved[50];
};
#define EROFS_DEVT_SLOT_SIZE sizeof(struct erofs_deviceslot)
@@ -59,13 +53,14 @@ struct erofs_super_block {
__le32 feature_compat;
__u8 blkszbits; /* filesystem block size in bit shift */
__u8 sb_extslots; /* superblock size = 128 + sb_extslots * 16 */
-
- __le16 root_nid; /* nid of root directory */
+ union {
+ __le16 rootnid_2b; /* nid of root directory */
+ __le16 blocks_hi; /* (48BIT on) blocks count MSB */
+ } rb;
__le64 inos; /* total valid ino # (== f_files - f_favail) */
-
- __le64 build_time; /* compact inode time derivation */
- __le32 build_time_nsec; /* compact inode time derivation in ns scale */
- __le32 blocks; /* used for statfs */
+ __le64 epoch; /* base seconds used for compact inodes */
+ __le32 fixed_nsec; /* fixed nanoseconds for compact inodes */
+ __le32 blocks_lo; /* blocks count LSB */
__le32 meta_blkaddr; /* start block address of metadata area */
__le32 xattr_blkaddr; /* start block address of shared xattr area */
__u8 uuid[16]; /* 128-bit uuid for volume */
@@ -84,7 +79,10 @@ struct erofs_super_block {
__le32 xattr_prefix_start; /* start of long xattr prefixes */
__le64 packed_nid; /* nid of the special packed inode */
__u8 xattr_filter_reserved; /* reserved for xattr name filter */
- __u8 reserved2[23];
+ __u8 reserved[3];
+ __le32 build_time; /* seconds added to epoch for mkfs time */
+ __le64 rootnid_8b; /* (48BIT on) nid of root directory */
+ __u8 reserved2[8];
};
/*
@@ -115,19 +113,18 @@ static inline bool erofs_inode_is_data_compressed(unsigned int datamode)
#define EROFS_I_VERSION_MASK 0x01
#define EROFS_I_DATALAYOUT_MASK 0x07
-#define EROFS_I_VERSION_BIT 0
-#define EROFS_I_DATALAYOUT_BIT 1
-#define EROFS_I_ALL_BIT 4
-
-#define EROFS_I_ALL ((1 << EROFS_I_ALL_BIT) - 1)
+#define EROFS_I_VERSION_BIT 0
+#define EROFS_I_DATALAYOUT_BIT 1
+#define EROFS_I_NLINK_1_BIT 4 /* non-directory compact inodes only */
+#define EROFS_I_ALL ((1 << (EROFS_I_NLINK_1_BIT + 1)) - 1)
/* indicate chunk blkbits, thus 'chunksize = blocksize << chunk blkbits' */
#define EROFS_CHUNK_FORMAT_BLKBITS_MASK 0x001F
-/* with chunk indexes or just a 4-byte blkaddr array */
+/* with chunk indexes or just a 4-byte block array */
#define EROFS_CHUNK_FORMAT_INDEXES 0x0020
+#define EROFS_CHUNK_FORMAT_48BIT 0x0040
-#define EROFS_CHUNK_FORMAT_ALL \
- (EROFS_CHUNK_FORMAT_BLKBITS_MASK | EROFS_CHUNK_FORMAT_INDEXES)
+#define EROFS_CHUNK_FORMAT_ALL ((EROFS_CHUNK_FORMAT_48BIT << 1) - 1)
/* 32-byte on-disk inode */
#define EROFS_INODE_LAYOUT_COMPACT 0
@@ -140,45 +137,40 @@ struct erofs_inode_chunk_info {
};
union erofs_inode_i_u {
- /* total compressed blocks for compressed inodes */
- __le32 compressed_blocks;
-
- /* block address for uncompressed flat inodes */
- __le32 raw_blkaddr;
-
- /* for device files, used to indicate old/new device # */
- __le32 rdev;
-
- /* for chunk-based files, it contains the summary info */
+ __le32 blocks_lo; /* total blocks count (if compressed inodes) */
+ __le32 startblk_lo; /* starting block number (if flat inodes) */
+ __le32 rdev; /* device ID (if special inodes) */
struct erofs_inode_chunk_info c;
};
+union erofs_inode_i_nb {
+ __le16 nlink; /* if EROFS_I_NLINK_1_BIT is unset */
+ __le16 blocks_hi; /* total blocks count MSB */
+ __le16 startblk_hi; /* starting block number MSB */
+};
+
/* 32-byte reduced form of an ondisk inode */
struct erofs_inode_compact {
__le16 i_format; /* inode format hints */
-
-/* 1 header + n-1 * 4 bytes inline xattr to keep continuity */
__le16 i_xattr_icount;
__le16 i_mode;
- __le16 i_nlink;
+ union erofs_inode_i_nb i_nb;
__le32 i_size;
- __le32 i_reserved;
+ __le32 i_mtime;
union erofs_inode_i_u i_u;
__le32 i_ino; /* only used for 32-bit stat compatibility */
__le16 i_uid;
__le16 i_gid;
- __le32 i_reserved2;
+ __le32 i_reserved;
};
/* 64-byte complete form of an ondisk inode */
struct erofs_inode_extended {
__le16 i_format; /* inode format hints */
-
-/* 1 header + n-1 * 4 bytes inline xattr to keep continuity */
__le16 i_xattr_icount;
__le16 i_mode;
- __le16 i_reserved;
+ union erofs_inode_i_nb i_nb;
__le64 i_size;
union erofs_inode_i_u i_u;
@@ -248,6 +240,7 @@ static inline unsigned int erofs_xattr_ibody_size(__le16 i_xattr_icount)
if (!i_xattr_icount)
return 0;
+ /* 1 header + n-1 * 4 bytes inline xattr to keep continuity */
return sizeof(struct erofs_xattr_ibody_header) +
sizeof(__u32) * (le16_to_cpu(i_xattr_icount) - 1);
}
@@ -266,11 +259,11 @@ static inline unsigned int erofs_xattr_entry_size(struct erofs_xattr_entry *e)
/* 4-byte block address array */
#define EROFS_BLOCK_MAP_ENTRY_SIZE sizeof(__le32)
-/* 8-byte inode chunk indexes */
+/* 8-byte inode chunk index */
struct erofs_inode_chunk_index {
- __le16 advise; /* always 0, don't care for now */
+ __le16 startblk_hi; /* starting block number MSB */
__le16 device_id; /* back-end storage id (with bits masked) */
- __le32 blkaddr; /* start block address of this inode chunk */
+ __le32 startblk_lo; /* starting block number of this chunk */
};
/* dirent sorts in alphabet order, thus we can do binary search */
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index c8ede541c239..e74c0c00aa26 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -108,7 +108,7 @@ static int erofs_read_inode(struct inode *inode)
iu = dic->i_u;
i_uid_write(inode, le16_to_cpu(dic->i_uid));
i_gid_write(inode, le16_to_cpu(dic->i_gid));
- set_nlink(inode, le16_to_cpu(dic->i_nlink));
+ set_nlink(inode, le16_to_cpu(dic->i_nb.nlink));
inode_set_mtime(inode, sbi->build_time, sbi->build_time_nsec);
inode->i_size = le32_to_cpu(dic->i_size);
@@ -129,7 +129,7 @@ static int erofs_read_inode(struct inode *inode)
case S_IFREG:
case S_IFDIR:
case S_IFLNK:
- vi->raw_blkaddr = le32_to_cpu(iu.raw_blkaddr);
+ vi->startblk = le32_to_cpu(iu.startblk_lo);
if(S_ISLNK(inode->i_mode)) {
err = erofs_fill_symlink(inode, ptr, ofs);
if (err)
@@ -152,7 +152,7 @@ static int erofs_read_inode(struct inode *inode)
}
if (erofs_inode_is_data_compressed(vi->datalayout))
- inode->i_blocks = le32_to_cpu(iu.compressed_blocks) <<
+ inode->i_blocks = le32_to_cpu(iu.blocks_lo) <<
(sb->s_blocksize_bits - 9);
else
inode->i_blocks = round_up(inode->i_size, sb->s_blocksize) >> 9;
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index b357cbbce764..58e401131c75 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -47,8 +47,8 @@ struct erofs_device_info {
struct dax_device *dax_dev;
u64 dax_part_off;
- u32 blocks;
- u32 mapped_blkaddr;
+ erofs_blk_t blocks;
+ erofs_blk_t uniaddr;
};
enum {
@@ -252,7 +252,7 @@ struct erofs_inode {
unsigned int *xattr_shared_xattrs;
union {
- erofs_blk_t raw_blkaddr;
+ erofs_blk_t startblk;
struct {
unsigned short chunkformat;
unsigned char chunkbits;
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 19e52ffa34c5..a64f9765e95e 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -178,8 +178,8 @@ static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb,
dif->file = file;
}
- dif->blocks = le32_to_cpu(dis->blocks);
- dif->mapped_blkaddr = le32_to_cpu(dis->mapped_blkaddr);
+ dif->blocks = le32_to_cpu(dis->blocks_lo);
+ dif->uniaddr = le32_to_cpu(dis->uniaddr_lo);
sbi->total_blocks += dif->blocks;
*pos += EROFS_DEVT_SLOT_SIZE;
return 0;
@@ -299,7 +299,7 @@ static int erofs_read_superblock(struct super_block *sb)
sbi->sb_size);
goto out;
}
- sbi->dif0.blocks = le32_to_cpu(dsb->blocks);
+ sbi->dif0.blocks = le32_to_cpu(dsb->blocks_lo);
sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
#ifdef CONFIG_EROFS_FS_XATTR
sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
@@ -308,12 +308,12 @@ static int erofs_read_superblock(struct super_block *sb)
sbi->xattr_filter_reserved = dsb->xattr_filter_reserved;
#endif
sbi->islotbits = ilog2(sizeof(struct erofs_inode_compact));
- sbi->root_nid = le16_to_cpu(dsb->root_nid);
+ sbi->root_nid = le16_to_cpu(dsb->rb.rootnid_2b);
sbi->packed_nid = le64_to_cpu(dsb->packed_nid);
sbi->inos = le64_to_cpu(dsb->inos);
- sbi->build_time = le64_to_cpu(dsb->build_time);
- sbi->build_time_nsec = le32_to_cpu(dsb->build_time_nsec);
+ sbi->build_time = le64_to_cpu(dsb->epoch);
+ sbi->build_time_nsec = le32_to_cpu(dsb->fixed_nsec);
super_set_uuid(sb, (void *)dsb->uuid, sizeof(dsb->uuid));
--
2.43.5