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Diffstat (limited to 'fs/xfs/libxfs/xfs_da_format.h')
| -rw-r--r-- | fs/xfs/libxfs/xfs_da_format.h | 862 |
1 files changed, 862 insertions, 0 deletions
diff --git a/fs/xfs/libxfs/xfs_da_format.h b/fs/xfs/libxfs/xfs_da_format.h new file mode 100644 index 000000000..f9015f88e --- /dev/null +++ b/fs/xfs/libxfs/xfs_da_format.h @@ -0,0 +1,862 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc. + * Copyright (c) 2013 Red Hat, Inc. + * All Rights Reserved. + */ +#ifndef __XFS_DA_FORMAT_H__ +#define __XFS_DA_FORMAT_H__ + +/* + * This structure is common to both leaf nodes and non-leaf nodes in the Btree. + * + * It is used to manage a doubly linked list of all blocks at the same + * level in the Btree, and to identify which type of block this is. + */ +#define XFS_DA_NODE_MAGIC 0xfebe /* magic number: non-leaf blocks */ +#define XFS_ATTR_LEAF_MAGIC 0xfbee /* magic number: attribute leaf blks */ +#define XFS_DIR2_LEAF1_MAGIC 0xd2f1 /* magic number: v2 dirlf single blks */ +#define XFS_DIR2_LEAFN_MAGIC 0xd2ff /* magic number: v2 dirlf multi blks */ + +typedef struct xfs_da_blkinfo { + __be32 forw; /* previous block in list */ + __be32 back; /* following block in list */ + __be16 magic; /* validity check on block */ + __be16 pad; /* unused */ +} xfs_da_blkinfo_t; + +/* + * CRC enabled directory structure types + * + * The headers change size for the additional verification information, but + * otherwise the tree layouts and contents are unchanged. Hence the da btree + * code can use the struct xfs_da_blkinfo for manipulating the tree links and + * magic numbers without modification for both v2 and v3 nodes. + */ +#define XFS_DA3_NODE_MAGIC 0x3ebe /* magic number: non-leaf blocks */ +#define XFS_ATTR3_LEAF_MAGIC 0x3bee /* magic number: attribute leaf blks */ +#define XFS_DIR3_LEAF1_MAGIC 0x3df1 /* magic number: v3 dirlf single blks */ +#define XFS_DIR3_LEAFN_MAGIC 0x3dff /* magic number: v3 dirlf multi blks */ + +struct xfs_da3_blkinfo { + /* + * the node link manipulation code relies on the fact that the first + * element of this structure is the struct xfs_da_blkinfo so it can + * ignore the differences in the rest of the structures. + */ + struct xfs_da_blkinfo hdr; + __be32 crc; /* CRC of block */ + __be64 blkno; /* first block of the buffer */ + __be64 lsn; /* sequence number of last write */ + uuid_t uuid; /* filesystem we belong to */ + __be64 owner; /* inode that owns the block */ +}; + +/* + * This is the structure of the root and intermediate nodes in the Btree. + * The leaf nodes are defined above. + * + * Entries are not packed. + * + * Since we have duplicate keys, use a binary search but always follow + * all match in the block, not just the first match found. + */ +#define XFS_DA_NODE_MAXDEPTH 5 /* max depth of Btree */ + +typedef struct xfs_da_node_hdr { + struct xfs_da_blkinfo info; /* block type, links, etc. */ + __be16 __count; /* count of active entries */ + __be16 __level; /* level above leaves (leaf == 0) */ +} xfs_da_node_hdr_t; + +struct xfs_da3_node_hdr { + struct xfs_da3_blkinfo info; /* block type, links, etc. */ + __be16 __count; /* count of active entries */ + __be16 __level; /* level above leaves (leaf == 0) */ + __be32 __pad32; +}; + +#define XFS_DA3_NODE_CRC_OFF (offsetof(struct xfs_da3_node_hdr, info.crc)) + +typedef struct xfs_da_node_entry { + __be32 hashval; /* hash value for this descendant */ + __be32 before; /* Btree block before this key */ +} xfs_da_node_entry_t; + +typedef struct xfs_da_intnode { + struct xfs_da_node_hdr hdr; + struct xfs_da_node_entry __btree[]; +} xfs_da_intnode_t; + +struct xfs_da3_intnode { + struct xfs_da3_node_hdr hdr; + struct xfs_da_node_entry __btree[]; +}; + +/* + * Directory version 2. + * + * There are 4 possible formats: + * - shortform - embedded into the inode + * - single block - data with embedded leaf at the end + * - multiple data blocks, single leaf+freeindex block + * - data blocks, node and leaf blocks (btree), freeindex blocks + * + * Note: many node blocks structures and constants are shared with the attr + * code and defined in xfs_da_btree.h. + */ + +#define XFS_DIR2_BLOCK_MAGIC 0x58443242 /* XD2B: single block dirs */ +#define XFS_DIR2_DATA_MAGIC 0x58443244 /* XD2D: multiblock dirs */ +#define XFS_DIR2_FREE_MAGIC 0x58443246 /* XD2F: free index blocks */ + +/* + * Directory Version 3 With CRCs. + * + * The tree formats are the same as for version 2 directories. The difference + * is in the block header and dirent formats. In many cases the v3 structures + * use v2 definitions as they are no different and this makes code sharing much + * easier. + * + * Also, the xfs_dir3_*() functions handle both v2 and v3 formats - if the + * format is v2 then they switch to the existing v2 code, or the format is v3 + * they implement the v3 functionality. This means the existing dir2 is a mix of + * xfs_dir2/xfs_dir3 calls and functions. The xfs_dir3 functions are called + * where there is a difference in the formats, otherwise the code is unchanged. + * + * Where it is possible, the code decides what to do based on the magic numbers + * in the blocks rather than feature bits in the superblock. This means the code + * is as independent of the external XFS code as possible as doesn't require + * passing struct xfs_mount pointers into places where it isn't really + * necessary. + * + * Version 3 includes: + * + * - a larger block header for CRC and identification purposes and so the + * offsets of all the structures inside the blocks are different. + * + * - new magic numbers to be able to detect the v2/v3 types on the fly. + */ + +#define XFS_DIR3_BLOCK_MAGIC 0x58444233 /* XDB3: single block dirs */ +#define XFS_DIR3_DATA_MAGIC 0x58444433 /* XDD3: multiblock dirs */ +#define XFS_DIR3_FREE_MAGIC 0x58444633 /* XDF3: free index blocks */ + +/* + * Dirents in version 3 directories have a file type field. Additions to this + * list are an on-disk format change, requiring feature bits. Valid values + * are as follows: + */ +#define XFS_DIR3_FT_UNKNOWN 0 +#define XFS_DIR3_FT_REG_FILE 1 +#define XFS_DIR3_FT_DIR 2 +#define XFS_DIR3_FT_CHRDEV 3 +#define XFS_DIR3_FT_BLKDEV 4 +#define XFS_DIR3_FT_FIFO 5 +#define XFS_DIR3_FT_SOCK 6 +#define XFS_DIR3_FT_SYMLINK 7 +#define XFS_DIR3_FT_WHT 8 + +#define XFS_DIR3_FT_MAX 9 + +/* + * Byte offset in data block and shortform entry. + */ +typedef uint16_t xfs_dir2_data_off_t; +#define NULLDATAOFF 0xffffU +typedef uint xfs_dir2_data_aoff_t; /* argument form */ + +/* + * Offset in data space of a data entry. + */ +typedef uint32_t xfs_dir2_dataptr_t; +#define XFS_DIR2_MAX_DATAPTR ((xfs_dir2_dataptr_t)0xffffffff) +#define XFS_DIR2_NULL_DATAPTR ((xfs_dir2_dataptr_t)0) + +/* + * Byte offset in a directory. + */ +typedef xfs_off_t xfs_dir2_off_t; + +/* + * Directory block number (logical dirblk in file) + */ +typedef uint32_t xfs_dir2_db_t; + +#define XFS_INO32_SIZE 4 +#define XFS_INO64_SIZE 8 +#define XFS_INO64_DIFF (XFS_INO64_SIZE - XFS_INO32_SIZE) + +#define XFS_DIR2_MAX_SHORT_INUM ((xfs_ino_t)0xffffffffULL) + +/* + * Directory layout when stored internal to an inode. + * + * Small directories are packed as tightly as possible so as to fit into the + * literal area of the inode. These "shortform" directories consist of a + * single xfs_dir2_sf_hdr header followed by zero or more xfs_dir2_sf_entry + * structures. Due the different inode number storage size and the variable + * length name field in the xfs_dir2_sf_entry all these structure are + * variable length, and the accessors in this file should be used to iterate + * over them. + */ +typedef struct xfs_dir2_sf_hdr { + uint8_t count; /* count of entries */ + uint8_t i8count; /* count of 8-byte inode #s */ + uint8_t parent[8]; /* parent dir inode number */ +} __packed xfs_dir2_sf_hdr_t; + +typedef struct xfs_dir2_sf_entry { + __u8 namelen; /* actual name length */ + __u8 offset[2]; /* saved offset */ + __u8 name[]; /* name, variable size */ + /* + * A single byte containing the file type field follows the inode + * number for version 3 directory entries. + * + * A 64-bit or 32-bit inode number follows here, at a variable offset + * after the name. + */ +} __packed xfs_dir2_sf_entry_t; + +static inline int xfs_dir2_sf_hdr_size(int i8count) +{ + return sizeof(struct xfs_dir2_sf_hdr) - + (i8count == 0) * XFS_INO64_DIFF; +} + +static inline xfs_dir2_data_aoff_t +xfs_dir2_sf_get_offset(xfs_dir2_sf_entry_t *sfep) +{ + return get_unaligned_be16(sfep->offset); +} + +static inline void +xfs_dir2_sf_put_offset(xfs_dir2_sf_entry_t *sfep, xfs_dir2_data_aoff_t off) +{ + put_unaligned_be16(off, sfep->offset); +} + +static inline struct xfs_dir2_sf_entry * +xfs_dir2_sf_firstentry(struct xfs_dir2_sf_hdr *hdr) +{ + return (struct xfs_dir2_sf_entry *) + ((char *)hdr + xfs_dir2_sf_hdr_size(hdr->i8count)); +} + +/* + * Data block structures. + * + * A pure data block looks like the following drawing on disk: + * + * +-------------------------------------------------+ + * | xfs_dir2_data_hdr_t | + * +-------------------------------------------------+ + * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | + * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | + * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | + * | ... | + * +-------------------------------------------------+ + * | unused space | + * +-------------------------------------------------+ + * + * As all the entries are variable size structures the accessors below should + * be used to iterate over them. + * + * In addition to the pure data blocks for the data and node formats, + * most structures are also used for the combined data/freespace "block" + * format below. + */ + +#define XFS_DIR2_DATA_ALIGN_LOG 3 /* i.e., 8 bytes */ +#define XFS_DIR2_DATA_ALIGN (1 << XFS_DIR2_DATA_ALIGN_LOG) +#define XFS_DIR2_DATA_FREE_TAG 0xffff +#define XFS_DIR2_DATA_FD_COUNT 3 + +/* + * Directory address space divided into sections, + * spaces separated by 32GB. + */ +#define XFS_DIR2_MAX_SPACES 3 +#define XFS_DIR2_SPACE_SIZE (1ULL << (32 + XFS_DIR2_DATA_ALIGN_LOG)) +#define XFS_DIR2_DATA_SPACE 0 +#define XFS_DIR2_DATA_OFFSET (XFS_DIR2_DATA_SPACE * XFS_DIR2_SPACE_SIZE) + +/* + * Describe a free area in the data block. + * + * The freespace will be formatted as a xfs_dir2_data_unused_t. + */ +typedef struct xfs_dir2_data_free { + __be16 offset; /* start of freespace */ + __be16 length; /* length of freespace */ +} xfs_dir2_data_free_t; + +/* + * Header for the data blocks. + * + * The code knows that XFS_DIR2_DATA_FD_COUNT is 3. + */ +typedef struct xfs_dir2_data_hdr { + __be32 magic; /* XFS_DIR2_DATA_MAGIC or */ + /* XFS_DIR2_BLOCK_MAGIC */ + xfs_dir2_data_free_t bestfree[XFS_DIR2_DATA_FD_COUNT]; +} xfs_dir2_data_hdr_t; + +/* + * define a structure for all the verification fields we are adding to the + * directory block structures. This will be used in several structures. + * The magic number must be the first entry to align with all the dir2 + * structures so we determine how to decode them just by the magic number. + */ +struct xfs_dir3_blk_hdr { + __be32 magic; /* magic number */ + __be32 crc; /* CRC of block */ + __be64 blkno; /* first block of the buffer */ + __be64 lsn; /* sequence number of last write */ + uuid_t uuid; /* filesystem we belong to */ + __be64 owner; /* inode that owns the block */ +}; + +struct xfs_dir3_data_hdr { + struct xfs_dir3_blk_hdr hdr; + xfs_dir2_data_free_t best_free[XFS_DIR2_DATA_FD_COUNT]; + __be32 pad; /* 64 bit alignment */ +}; + +#define XFS_DIR3_DATA_CRC_OFF offsetof(struct xfs_dir3_data_hdr, hdr.crc) + +/* + * Active entry in a data block. + * + * Aligned to 8 bytes. After the variable length name field there is a + * 2 byte tag field, which can be accessed using xfs_dir3_data_entry_tag_p. + * + * For dir3 structures, there is file type field between the name and the tag. + * This can only be manipulated by helper functions. It is packed hard against + * the end of the name so any padding for rounding is between the file type and + * the tag. + */ +typedef struct xfs_dir2_data_entry { + __be64 inumber; /* inode number */ + __u8 namelen; /* name length */ + __u8 name[]; /* name bytes, no null */ + /* __u8 filetype; */ /* type of inode we point to */ + /* __be16 tag; */ /* starting offset of us */ +} xfs_dir2_data_entry_t; + +/* + * Unused entry in a data block. + * + * Aligned to 8 bytes. Tag appears as the last 2 bytes and must be accessed + * using xfs_dir2_data_unused_tag_p. + */ +typedef struct xfs_dir2_data_unused { + __be16 freetag; /* XFS_DIR2_DATA_FREE_TAG */ + __be16 length; /* total free length */ + /* variable offset */ + __be16 tag; /* starting offset of us */ +} xfs_dir2_data_unused_t; + +/* + * Pointer to a freespace's tag word. + */ +static inline __be16 * +xfs_dir2_data_unused_tag_p(struct xfs_dir2_data_unused *dup) +{ + return (__be16 *)((char *)dup + + be16_to_cpu(dup->length) - sizeof(__be16)); +} + +/* + * Leaf block structures. + * + * A pure leaf block looks like the following drawing on disk: + * + * +---------------------------+ + * | xfs_dir2_leaf_hdr_t | + * +---------------------------+ + * | xfs_dir2_leaf_entry_t | + * | xfs_dir2_leaf_entry_t | + * | xfs_dir2_leaf_entry_t | + * | xfs_dir2_leaf_entry_t | + * | ... | + * +---------------------------+ + * | xfs_dir2_data_off_t | + * | xfs_dir2_data_off_t | + * | xfs_dir2_data_off_t | + * | ... | + * +---------------------------+ + * | xfs_dir2_leaf_tail_t | + * +---------------------------+ + * + * The xfs_dir2_data_off_t members (bests) and tail are at the end of the block + * for single-leaf (magic = XFS_DIR2_LEAF1_MAGIC) blocks only, but not present + * for directories with separate leaf nodes and free space blocks + * (magic = XFS_DIR2_LEAFN_MAGIC). + * + * As all the entries are variable size structures the accessors below should + * be used to iterate over them. + */ + +/* + * Offset of the leaf/node space. First block in this space + * is the btree root. + */ +#define XFS_DIR2_LEAF_SPACE 1 +#define XFS_DIR2_LEAF_OFFSET (XFS_DIR2_LEAF_SPACE * XFS_DIR2_SPACE_SIZE) + +/* + * Leaf block header. + */ +typedef struct xfs_dir2_leaf_hdr { + xfs_da_blkinfo_t info; /* header for da routines */ + __be16 count; /* count of entries */ + __be16 stale; /* count of stale entries */ +} xfs_dir2_leaf_hdr_t; + +struct xfs_dir3_leaf_hdr { + struct xfs_da3_blkinfo info; /* header for da routines */ + __be16 count; /* count of entries */ + __be16 stale; /* count of stale entries */ + __be32 pad; /* 64 bit alignment */ +}; + +/* + * Leaf block entry. + */ +typedef struct xfs_dir2_leaf_entry { + __be32 hashval; /* hash value of name */ + __be32 address; /* address of data entry */ +} xfs_dir2_leaf_entry_t; + +/* + * Leaf block tail. + */ +typedef struct xfs_dir2_leaf_tail { + __be32 bestcount; +} xfs_dir2_leaf_tail_t; + +/* + * Leaf block. + */ +typedef struct xfs_dir2_leaf { + xfs_dir2_leaf_hdr_t hdr; /* leaf header */ + xfs_dir2_leaf_entry_t __ents[]; /* entries */ +} xfs_dir2_leaf_t; + +struct xfs_dir3_leaf { + struct xfs_dir3_leaf_hdr hdr; /* leaf header */ + struct xfs_dir2_leaf_entry __ents[]; /* entries */ +}; + +#define XFS_DIR3_LEAF_CRC_OFF offsetof(struct xfs_dir3_leaf_hdr, info.crc) + +/* + * Get address of the bests array in the single-leaf block. + */ +static inline __be16 * +xfs_dir2_leaf_bests_p(struct xfs_dir2_leaf_tail *ltp) +{ + return (__be16 *)ltp - be32_to_cpu(ltp->bestcount); +} + +/* + * Free space block definitions for the node format. + */ + +/* + * Offset of the freespace index. + */ +#define XFS_DIR2_FREE_SPACE 2 +#define XFS_DIR2_FREE_OFFSET (XFS_DIR2_FREE_SPACE * XFS_DIR2_SPACE_SIZE) + +typedef struct xfs_dir2_free_hdr { + __be32 magic; /* XFS_DIR2_FREE_MAGIC */ + __be32 firstdb; /* db of first entry */ + __be32 nvalid; /* count of valid entries */ + __be32 nused; /* count of used entries */ +} xfs_dir2_free_hdr_t; + +typedef struct xfs_dir2_free { + xfs_dir2_free_hdr_t hdr; /* block header */ + __be16 bests[]; /* best free counts */ + /* unused entries are -1 */ +} xfs_dir2_free_t; + +struct xfs_dir3_free_hdr { + struct xfs_dir3_blk_hdr hdr; + __be32 firstdb; /* db of first entry */ + __be32 nvalid; /* count of valid entries */ + __be32 nused; /* count of used entries */ + __be32 pad; /* 64 bit alignment */ +}; + +struct xfs_dir3_free { + struct xfs_dir3_free_hdr hdr; + __be16 bests[]; /* best free counts */ + /* unused entries are -1 */ +}; + +#define XFS_DIR3_FREE_CRC_OFF offsetof(struct xfs_dir3_free, hdr.hdr.crc) + +/* + * Single block format. + * + * The single block format looks like the following drawing on disk: + * + * +-------------------------------------------------+ + * | xfs_dir2_data_hdr_t | + * +-------------------------------------------------+ + * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | + * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | + * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t : + * | ... | + * +-------------------------------------------------+ + * | unused space | + * +-------------------------------------------------+ + * | ... | + * | xfs_dir2_leaf_entry_t | + * | xfs_dir2_leaf_entry_t | + * +-------------------------------------------------+ + * | xfs_dir2_block_tail_t | + * +-------------------------------------------------+ + * + * As all the entries are variable size structures the accessors below should + * be used to iterate over them. + */ + +typedef struct xfs_dir2_block_tail { + __be32 count; /* count of leaf entries */ + __be32 stale; /* count of stale lf entries */ +} xfs_dir2_block_tail_t; + +/* + * Pointer to the leaf entries embedded in a data block (1-block format) + */ +static inline struct xfs_dir2_leaf_entry * +xfs_dir2_block_leaf_p(struct xfs_dir2_block_tail *btp) +{ + return ((struct xfs_dir2_leaf_entry *)btp) - be32_to_cpu(btp->count); +} + + +/* + * Attribute storage layout + * + * Attribute lists are structured around Btrees where all the data + * elements are in the leaf nodes. Attribute names are hashed into an int, + * then that int is used as the index into the Btree. Since the hashval + * of an attribute name may not be unique, we may have duplicate keys. The + * internal links in the Btree are logical block offsets into the file. + * + * Struct leaf_entry's are packed from the top. Name/values grow from the + * bottom but are not packed. The freemap contains run-length-encoded entries + * for the free bytes after the leaf_entry's, but only the N largest such, + * smaller runs are dropped. When the freemap doesn't show enough space + * for an allocation, we compact the name/value area and try again. If we + * still don't have enough space, then we have to split the block. The + * name/value structs (both local and remote versions) must be 32bit aligned. + * + * Since we have duplicate hash keys, for each key that matches, compare + * the actual name string. The root and intermediate node search always + * takes the first-in-the-block key match found, so we should only have + * to work "forw"ard. If none matches, continue with the "forw"ard leaf + * nodes until the hash key changes or the attribute name is found. + * + * We store the fact that an attribute is a ROOT/USER/SECURE attribute in + * the leaf_entry. The namespaces are independent only because we also look + * at the namespace bit when we are looking for a matching attribute name. + * + * We also store an "incomplete" bit in the leaf_entry. It shows that an + * attribute is in the middle of being created and should not be shown to + * the user if we crash during the time that the bit is set. We clear the + * bit when we have finished setting up the attribute. We do this because + * we cannot create some large attributes inside a single transaction, and we + * need some indication that we weren't finished if we crash in the middle. + */ +#define XFS_ATTR_LEAF_MAPSIZE 3 /* how many freespace slots */ + +/* + * Entries are packed toward the top as tight as possible. + */ +struct xfs_attr_shortform { + struct xfs_attr_sf_hdr { /* constant-structure header block */ + __be16 totsize; /* total bytes in shortform list */ + __u8 count; /* count of active entries */ + __u8 padding; + } hdr; + struct xfs_attr_sf_entry { + uint8_t namelen; /* actual length of name (no NULL) */ + uint8_t valuelen; /* actual length of value (no NULL) */ + uint8_t flags; /* flags bits (see xfs_attr_leaf.h) */ + uint8_t nameval[]; /* name & value bytes concatenated */ + } list[]; /* variable sized array */ +}; + +typedef struct xfs_attr_leaf_map { /* RLE map of free bytes */ + __be16 base; /* base of free region */ + __be16 size; /* length of free region */ +} xfs_attr_leaf_map_t; + +typedef struct xfs_attr_leaf_hdr { /* constant-structure header block */ + xfs_da_blkinfo_t info; /* block type, links, etc. */ + __be16 count; /* count of active leaf_entry's */ + __be16 usedbytes; /* num bytes of names/values stored */ + __be16 firstused; /* first used byte in name area */ + __u8 holes; /* != 0 if blk needs compaction */ + __u8 pad1; + xfs_attr_leaf_map_t freemap[XFS_ATTR_LEAF_MAPSIZE]; + /* N largest free regions */ +} xfs_attr_leaf_hdr_t; + +typedef struct xfs_attr_leaf_entry { /* sorted on key, not name */ + __be32 hashval; /* hash value of name */ + __be16 nameidx; /* index into buffer of name/value */ + __u8 flags; /* LOCAL/ROOT/SECURE/INCOMPLETE flag */ + __u8 pad2; /* unused pad byte */ +} xfs_attr_leaf_entry_t; + +typedef struct xfs_attr_leaf_name_local { + __be16 valuelen; /* number of bytes in value */ + __u8 namelen; /* length of name bytes */ + /* + * In Linux 6.5 this flex array was converted from nameval[1] to + * nameval[]. Be very careful here about extra padding at the end; + * see xfs_attr_leaf_entsize_local() for details. + */ + __u8 nameval[]; /* name/value bytes */ +} xfs_attr_leaf_name_local_t; + +typedef struct xfs_attr_leaf_name_remote { + __be32 valueblk; /* block number of value bytes */ + __be32 valuelen; /* number of bytes in value */ + __u8 namelen; /* length of name bytes */ + /* + * In Linux 6.5 this flex array was converted from name[1] to name[]. + * Be very careful here about extra padding at the end; see + * xfs_attr_leaf_entsize_remote() for details. + */ + __u8 name[]; /* name bytes */ +} xfs_attr_leaf_name_remote_t; + +typedef struct xfs_attr_leafblock { + xfs_attr_leaf_hdr_t hdr; /* constant-structure header block */ + xfs_attr_leaf_entry_t entries[]; /* sorted on key, not name */ + /* + * The rest of the block contains the following structures after the + * leaf entries, growing from the bottom up. The variables are never + * referenced and definining them can actually make gcc optimize away + * accesses to the 'entries' array above index 0 so don't do that. + * + * xfs_attr_leaf_name_local_t namelist; + * xfs_attr_leaf_name_remote_t valuelist; + */ +} xfs_attr_leafblock_t; + +/* + * CRC enabled leaf structures. Called "version 3" structures to match the + * version number of the directory and dablk structures for this feature, and + * attr2 is already taken by the variable inode attribute fork size feature. + */ +struct xfs_attr3_leaf_hdr { + struct xfs_da3_blkinfo info; + __be16 count; + __be16 usedbytes; + __be16 firstused; + __u8 holes; + __u8 pad1; + struct xfs_attr_leaf_map freemap[XFS_ATTR_LEAF_MAPSIZE]; + __be32 pad2; /* 64 bit alignment */ +}; + +#define XFS_ATTR3_LEAF_CRC_OFF (offsetof(struct xfs_attr3_leaf_hdr, info.crc)) + +struct xfs_attr3_leafblock { + struct xfs_attr3_leaf_hdr hdr; + struct xfs_attr_leaf_entry entries[]; + + /* + * The rest of the block contains the following structures after the + * leaf entries, growing from the bottom up. The variables are never + * referenced, the locations accessed purely from helper functions. + * + * struct xfs_attr_leaf_name_local + * struct xfs_attr_leaf_name_remote + */ +}; + +/* + * Special value to represent fs block size in the leaf header firstused field. + * Only used when block size overflows the 2-bytes available on disk. + */ +#define XFS_ATTR3_LEAF_NULLOFF 0 + +/* + * Flags used in the leaf_entry[i].flags field. + */ +#define XFS_ATTR_LOCAL_BIT 0 /* attr is stored locally */ +#define XFS_ATTR_ROOT_BIT 1 /* limit access to trusted attrs */ +#define XFS_ATTR_SECURE_BIT 2 /* limit access to secure attrs */ +#define XFS_ATTR_INCOMPLETE_BIT 7 /* attr in middle of create/delete */ +#define XFS_ATTR_LOCAL (1u << XFS_ATTR_LOCAL_BIT) +#define XFS_ATTR_ROOT (1u << XFS_ATTR_ROOT_BIT) +#define XFS_ATTR_SECURE (1u << XFS_ATTR_SECURE_BIT) +#define XFS_ATTR_INCOMPLETE (1u << XFS_ATTR_INCOMPLETE_BIT) +#define XFS_ATTR_NSP_ONDISK_MASK (XFS_ATTR_ROOT | XFS_ATTR_SECURE) + +/* + * Alignment for namelist and valuelist entries (since they are mixed + * there can be only one alignment value) + */ +#define XFS_ATTR_LEAF_NAME_ALIGN ((uint)sizeof(xfs_dablk_t)) + +static inline int +xfs_attr3_leaf_hdr_size(struct xfs_attr_leafblock *leafp) +{ + if (leafp->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC)) + return sizeof(struct xfs_attr3_leaf_hdr); + return sizeof(struct xfs_attr_leaf_hdr); +} + +static inline struct xfs_attr_leaf_entry * +xfs_attr3_leaf_entryp(xfs_attr_leafblock_t *leafp) +{ + if (leafp->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC)) + return &((struct xfs_attr3_leafblock *)leafp)->entries[0]; + return &leafp->entries[0]; +} + +/* + * Cast typed pointers for "local" and "remote" name/value structs. + */ +static inline char * +xfs_attr3_leaf_name(xfs_attr_leafblock_t *leafp, int idx) +{ + struct xfs_attr_leaf_entry *entries = xfs_attr3_leaf_entryp(leafp); + + return &((char *)leafp)[be16_to_cpu(entries[idx].nameidx)]; +} + +static inline xfs_attr_leaf_name_remote_t * +xfs_attr3_leaf_name_remote(xfs_attr_leafblock_t *leafp, int idx) +{ + return (xfs_attr_leaf_name_remote_t *)xfs_attr3_leaf_name(leafp, idx); +} + +static inline xfs_attr_leaf_name_local_t * +xfs_attr3_leaf_name_local(xfs_attr_leafblock_t *leafp, int idx) +{ + return (xfs_attr_leaf_name_local_t *)xfs_attr3_leaf_name(leafp, idx); +} + +/* + * Calculate total bytes used (including trailing pad for alignment) for + * a "local" name/value structure, a "remote" name/value structure, and + * a pointer which might be either. + */ +static inline int xfs_attr_leaf_entsize_remote(int nlen) +{ + /* + * Prior to Linux 6.5, struct xfs_attr_leaf_name_remote ended with + * name[1], which was used as a flexarray. The layout of this struct + * is 9 bytes of fixed-length fields followed by a __u8 flex array at + * offset 9. + * + * On most architectures, struct xfs_attr_leaf_name_remote had two + * bytes of implicit padding at the end of the struct to make the + * struct length 12. After converting name[1] to name[], there are + * three implicit padding bytes and the struct size remains 12. + * However, there are compiler configurations that do not add implicit + * padding at all (m68k) and have been broken for years. + * + * This entsize computation historically added (the xattr name length) + * to (the padded struct length - 1) and rounded that sum up to the + * nearest multiple of 4 (NAME_ALIGN). IOWs, round_up(11 + nlen, 4). + * This is encoded in the ondisk format, so we cannot change this. + * + * Compute the entsize from offsetof of the flexarray and manually + * adding bytes for the implicit padding. + */ + const size_t remotesize = + offsetof(struct xfs_attr_leaf_name_remote, name) + 2; + + return round_up(remotesize + nlen, XFS_ATTR_LEAF_NAME_ALIGN); +} + +static inline int xfs_attr_leaf_entsize_local(int nlen, int vlen) +{ + /* + * Prior to Linux 6.5, struct xfs_attr_leaf_name_local ended with + * nameval[1], which was used as a flexarray. The layout of this + * struct is 3 bytes of fixed-length fields followed by a __u8 flex + * array at offset 3. + * + * struct xfs_attr_leaf_name_local had zero bytes of implicit padding + * at the end of the struct to make the struct length 4. On most + * architectures, after converting nameval[1] to nameval[], there is + * one implicit padding byte and the struct size remains 4. However, + * there are compiler configurations that do not add implicit padding + * at all (m68k) and would break. + * + * This entsize computation historically added (the xattr name and + * value length) to (the padded struct length - 1) and rounded that sum + * up to the nearest multiple of 4 (NAME_ALIGN). IOWs, the formula is + * round_up(3 + nlen + vlen, 4). This is encoded in the ondisk format, + * so we cannot change this. + * + * Compute the entsize from offsetof of the flexarray and manually + * adding bytes for the implicit padding. + */ + const size_t localsize = + offsetof(struct xfs_attr_leaf_name_local, nameval); + + return round_up(localsize + nlen + vlen, XFS_ATTR_LEAF_NAME_ALIGN); +} + +static inline int xfs_attr_leaf_entsize_local_max(int bsize) +{ + return (((bsize) >> 1) + ((bsize) >> 2)); +} + + + +/* + * Remote attribute block format definition + * + * There is one of these headers per filesystem block in a remote attribute. + * This is done to ensure there is a 1:1 mapping between the attribute value + * length and the number of blocks needed to store the attribute. This makes the + * verification of a buffer a little more complex, but greatly simplifies the + * allocation, reading and writing of these attributes as we don't have to guess + * the number of blocks needed to store the attribute data. + */ +#define XFS_ATTR3_RMT_MAGIC 0x5841524d /* XARM */ + +struct xfs_attr3_rmt_hdr { + __be32 rm_magic; + __be32 rm_offset; + __be32 rm_bytes; + __be32 rm_crc; + uuid_t rm_uuid; + __be64 rm_owner; + __be64 rm_blkno; + __be64 rm_lsn; +}; + +#define XFS_ATTR3_RMT_CRC_OFF offsetof(struct xfs_attr3_rmt_hdr, rm_crc) + +#define XFS_ATTR3_RMT_BUF_SPACE(mp, bufsize) \ + ((bufsize) - (xfs_has_crc((mp)) ? \ + sizeof(struct xfs_attr3_rmt_hdr) : 0)) + +/* Number of bytes in a directory block. */ +static inline unsigned int xfs_dir2_dirblock_bytes(struct xfs_sb *sbp) +{ + return 1 << (sbp->sb_blocklog + sbp->sb_dirblklog); +} + +xfs_failaddr_t xfs_da3_blkinfo_verify(struct xfs_buf *bp, + struct xfs_da3_blkinfo *hdr3); + +#endif /* __XFS_DA_FORMAT_H__ */ |