fs/erofs: add erofs filesystem support
This patch mainly deals with uncompressed files.
Signed-off-by: Huang Jianan <jnhuang95@gmail.com>
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
new file mode 100644
index 0000000..4af7c91
--- /dev/null
+++ b/fs/erofs/internal.h
@@ -0,0 +1,313 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+#ifndef __EROFS_INTERNAL_H
+#define __EROFS_INTERNAL_H
+
+#define __packed __attribute__((__packed__))
+
+#include <linux/stat.h>
+#include <linux/bug.h>
+#include <linux/err.h>
+#include <linux/printk.h>
+#include <linux/log2.h>
+#include <inttypes.h>
+#include "erofs_fs.h"
+
+#define erofs_err(fmt, ...) \
+ pr_err(fmt "\n", ##__VA_ARGS__)
+
+#define erofs_info(fmt, ...) \
+ pr_info(fmt "\n", ##__VA_ARGS__)
+
+#define erofs_dbg(fmt, ...) \
+ pr_debug(fmt "\n", ##__VA_ARGS__)
+
+#define DBG_BUGON(condition) BUG_ON(condition)
+
+/* no obvious reason to support explicit PAGE_SIZE != 4096 for now */
+#if PAGE_SIZE != 4096
+#error incompatible PAGE_SIZE is already defined
+#endif
+
+#define PAGE_MASK (~(PAGE_SIZE - 1))
+
+#define LOG_BLOCK_SIZE (12)
+#define EROFS_BLKSIZ (1U << LOG_BLOCK_SIZE)
+
+#define EROFS_ISLOTBITS 5
+#define EROFS_SLOTSIZE (1U << EROFS_ISLOTBITS)
+
+typedef u64 erofs_off_t;
+typedef u64 erofs_nid_t;
+/* data type for filesystem-wide blocks number */
+typedef u32 erofs_blk_t;
+
+#define NULL_ADDR ((unsigned int)-1)
+#define NULL_ADDR_UL ((unsigned long)-1)
+
+#define erofs_blknr(addr) ((addr) / EROFS_BLKSIZ)
+#define erofs_blkoff(addr) ((addr) % EROFS_BLKSIZ)
+#define blknr_to_addr(nr) ((erofs_off_t)(nr) * EROFS_BLKSIZ)
+
+#define BLK_ROUND_UP(addr) DIV_ROUND_UP(addr, EROFS_BLKSIZ)
+
+struct erofs_buffer_head;
+
+struct erofs_device_info {
+ u32 blocks;
+ u32 mapped_blkaddr;
+};
+
+struct erofs_sb_info {
+ struct erofs_device_info *devs;
+
+ u64 total_blocks;
+ u64 primarydevice_blocks;
+
+ erofs_blk_t meta_blkaddr;
+ erofs_blk_t xattr_blkaddr;
+
+ u32 feature_compat;
+ u32 feature_incompat;
+ u64 build_time;
+ u32 build_time_nsec;
+
+ unsigned char islotbits;
+
+ /* what we really care is nid, rather than ino.. */
+ erofs_nid_t root_nid;
+ /* used for statfs, f_files - f_favail */
+ u64 inos;
+
+ u8 uuid[16];
+
+ u16 available_compr_algs;
+ u16 lz4_max_distance;
+ u32 checksum;
+ u16 extra_devices;
+ union {
+ u16 devt_slotoff; /* used for mkfs */
+ u16 device_id_mask; /* used for others */
+ };
+};
+
+/* global sbi */
+extern struct erofs_sb_info sbi;
+
+static inline erofs_off_t iloc(erofs_nid_t nid)
+{
+ return blknr_to_addr(sbi.meta_blkaddr) + (nid << sbi.islotbits);
+}
+
+#define EROFS_FEATURE_FUNCS(name, compat, feature) \
+static inline bool erofs_sb_has_##name(void) \
+{ \
+ return sbi.feature_##compat & EROFS_FEATURE_##feature; \
+} \
+static inline void erofs_sb_set_##name(void) \
+{ \
+ sbi.feature_##compat |= EROFS_FEATURE_##feature; \
+} \
+static inline void erofs_sb_clear_##name(void) \
+{ \
+ sbi.feature_##compat &= ~EROFS_FEATURE_##feature; \
+}
+
+EROFS_FEATURE_FUNCS(lz4_0padding, incompat, INCOMPAT_LZ4_0PADDING)
+EROFS_FEATURE_FUNCS(compr_cfgs, incompat, INCOMPAT_COMPR_CFGS)
+EROFS_FEATURE_FUNCS(big_pcluster, incompat, INCOMPAT_BIG_PCLUSTER)
+EROFS_FEATURE_FUNCS(chunked_file, incompat, INCOMPAT_CHUNKED_FILE)
+EROFS_FEATURE_FUNCS(device_table, incompat, INCOMPAT_DEVICE_TABLE)
+EROFS_FEATURE_FUNCS(sb_chksum, compat, COMPAT_SB_CHKSUM)
+
+#define EROFS_I_EA_INITED (1 << 0)
+#define EROFS_I_Z_INITED (1 << 1)
+
+struct erofs_inode {
+ struct list_head i_hash, i_subdirs, i_xattrs;
+
+ union {
+ /* (erofsfuse) runtime flags */
+ unsigned int flags;
+ /* (mkfs.erofs) device ID containing source file */
+ u32 dev;
+ };
+ unsigned int i_count;
+ struct erofs_inode *i_parent;
+
+ umode_t i_mode;
+ erofs_off_t i_size;
+
+ u64 i_ino[2];
+ u32 i_uid;
+ u32 i_gid;
+ u64 i_ctime;
+ u32 i_ctime_nsec;
+ u32 i_nlink;
+
+ union {
+ u32 i_blkaddr;
+ u32 i_blocks;
+ u32 i_rdev;
+ struct {
+ unsigned short chunkformat;
+ unsigned char chunkbits;
+ };
+ } u;
+
+ unsigned char datalayout;
+ unsigned char inode_isize;
+ /* inline tail-end packing size */
+ unsigned short idata_size;
+
+ unsigned int xattr_isize;
+ unsigned int extent_isize;
+
+ erofs_nid_t nid;
+ struct erofs_buffer_head *bh;
+ struct erofs_buffer_head *bh_inline, *bh_data;
+
+ void *idata;
+
+ union {
+ void *compressmeta;
+ void *chunkindexes;
+ struct {
+ uint16_t z_advise;
+ uint8_t z_algorithmtype[2];
+ uint8_t z_logical_clusterbits;
+ uint8_t z_physical_clusterblks;
+ };
+ };
+};
+
+static inline bool is_inode_layout_compression(struct erofs_inode *inode)
+{
+ return erofs_inode_is_data_compressed(inode->datalayout);
+}
+
+static inline unsigned int erofs_bitrange(unsigned int value, unsigned int bit,
+ unsigned int bits)
+{
+ return (value >> bit) & ((1 << bits) - 1);
+}
+
+static inline unsigned int erofs_inode_version(unsigned int value)
+{
+ return erofs_bitrange(value, EROFS_I_VERSION_BIT,
+ EROFS_I_VERSION_BITS);
+}
+
+static inline unsigned int erofs_inode_datalayout(unsigned int value)
+{
+ return erofs_bitrange(value, EROFS_I_DATALAYOUT_BIT,
+ EROFS_I_DATALAYOUT_BITS);
+}
+
+#define IS_ROOT(x) ((x) == (x)->i_parent)
+
+struct erofs_dentry {
+ struct list_head d_child; /* child of parent list */
+
+ unsigned int type;
+ char name[EROFS_NAME_LEN];
+ union {
+ struct erofs_inode *inode;
+ erofs_nid_t nid;
+ };
+};
+
+static inline bool is_dot_dotdot(const char *name)
+{
+ if (name[0] != '.')
+ return false;
+
+ return name[1] == '\0' || (name[1] == '.' && name[2] == '\0');
+}
+
+enum {
+ BH_Meta,
+ BH_Mapped,
+ BH_Encoded,
+ BH_FullMapped,
+};
+
+/* Has a disk mapping */
+#define EROFS_MAP_MAPPED (1 << BH_Mapped)
+/* Located in metadata (could be copied from bd_inode) */
+#define EROFS_MAP_META (1 << BH_Meta)
+/* The extent is encoded */
+#define EROFS_MAP_ENCODED (1 << BH_Encoded)
+/* The length of extent is full */
+#define EROFS_MAP_FULL_MAPPED (1 << BH_FullMapped)
+
+struct erofs_map_blocks {
+ char mpage[EROFS_BLKSIZ];
+
+ erofs_off_t m_pa, m_la;
+ u64 m_plen, m_llen;
+
+ unsigned short m_deviceid;
+ char m_algorithmformat;
+ unsigned int m_flags;
+ erofs_blk_t index;
+};
+
+/*
+ * 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
+
+enum {
+ Z_EROFS_COMPRESSION_SHIFTED = Z_EROFS_COMPRESSION_MAX,
+ Z_EROFS_COMPRESSION_RUNTIME_MAX
+};
+
+struct erofs_map_dev {
+ erofs_off_t m_pa;
+ unsigned int m_deviceid;
+};
+
+/* fs.c */
+int erofs_blk_read(void *buf, erofs_blk_t start, u32 nblocks);
+int erofs_dev_read(int device_id, void *buf, u64 offset, size_t len);
+
+/* super.c */
+int erofs_read_superblock(void);
+
+/* namei.c */
+int erofs_read_inode_from_disk(struct erofs_inode *vi);
+int erofs_ilookup(const char *path, struct erofs_inode *vi);
+int erofs_read_inode_from_disk(struct erofs_inode *vi);
+
+/* data.c */
+int erofs_pread(struct erofs_inode *inode, char *buf,
+ erofs_off_t count, erofs_off_t offset);
+int erofs_map_blocks(struct erofs_inode *inode,
+ struct erofs_map_blocks *map, int flags);
+int erofs_map_dev(struct erofs_sb_info *sbi, struct erofs_map_dev *map);
+/* zmap.c */
+int z_erofs_fill_inode(struct erofs_inode *vi);
+int z_erofs_map_blocks_iter(struct erofs_inode *vi,
+ struct erofs_map_blocks *map, int flags);
+
+#ifdef EUCLEAN
+#define EFSCORRUPTED EUCLEAN /* Filesystem is corrupted */
+#else
+#define EFSCORRUPTED EIO
+#endif
+
+#define CRC32C_POLY_LE 0x82F63B78
+static inline u32 erofs_crc32c(u32 crc, const u8 *in, size_t len)
+{
+ int i;
+
+ while (len--) {
+ crc ^= *in++;
+ for (i = 0; i < 8; i++)
+ crc = (crc >> 1) ^ ((crc & 1) ? CRC32C_POLY_LE : 0);
+ }
+ return crc;
+}
+
+#endif