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linux/fs/xfs/xfs_dir2_format.h
Dave Chinner 8a1fd2950e xfs: fix implicit padding in directory and attr CRC formats 
Michael L. Semon has been testing CRC patches on a 32 bit system and
been seeing assert failures in the directory code from xfs/080.
Thanks to Michael's heroic efforts with printk debugging, we found
that the problem was that the last free space being left in the
directory structure was too small to fit a unused tag structure and
it was being corrupted and attempting to log a region out of bounds.
Hence the assert failure looked something like:

.....
#5 calling xfs_dir2_data_log_unused() 36 32
#1 4092 4095 4096
#2 8182 8183 4096
XFS: Assertion failed: first <= last && last < BBTOB(bp->b_length), file: fs/xfs/xfs_trans_buf.c, line: 568

Where #1 showed the first region of the dup being logged (i.e. the
last 4 bytes of a directory buffer) and #2 shows the corrupt values
being calculated from the length of the dup entry which overflowed
the size of the buffer.

It turns out that the problem was not in the logging code, nor in
the freespace handling code. It is an initial condition bug that
only shows up on 32 bit systems. When a new buffer is initialised,
where's the freespace that is set up:

[  172.316249] calling xfs_dir2_leaf_addname() from xfs_dir_createname()
[  172.316346] #9 calling xfs_dir2_data_log_unused()
[  172.316351] #1 calling xfs_trans_log_buf() 60 63 4096
[  172.316353] #2 calling xfs_trans_log_buf() 4094 4095 4096

Note the offset of the first region being logged? It's 60 bytes into
the buffer. Once I saw that, I pretty much knew that the bug was
going to be caused by this.

Essentially, all direct entries are rounded to 8 bytes in length,
and all entries start with an 8 byte alignment. This means that we
can decode inplace as variables are naturally aligned. With the
directory data supposedly starting on a 8 byte boundary, and all
entries padded to 8 bytes, the minimum freespace in a directory
block is supposed to be 8 bytes, which is large enough to fit a
unused data entry structure (6 bytes in size). The fact we only have
4 bytes of free space indicates a directory data block alignment
problem.

And what do you know - there's an implicit hole in the directory
data block header for the CRC format, which means the header is 60
byte on 32 bit intel systems and 64 bytes on 64 bit systems. Needs
padding. And while looking at the structures, I found the same
problem in the attr leaf header. Fix them both.

Note that this only affects 32 bit systems with CRCs enabled.
Everything else is just fine. Note that CRC enabled filesystems created
before this fix on such systems will not be readable with this fix
applied.

Reported-by: Michael L. Semon <mlsemon35@gmail.com>
Debugged-by: Michael L. Semon <mlsemon35@gmail.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-06-13 10:30:03 -05:00

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/*
* Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
* Copyright (c) 2013 Red Hat, Inc.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef __XFS_DIR2_FORMAT_H__
#define __XFS_DIR2_FORMAT_H__
/*
* 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 */
/*
* 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 */
/*
* Normalized offset (in a data block) of the entry, really xfs_dir2_data_off_t.
* Only need 16 bits, this is the byte offset into the single block form.
*/
typedef struct { __uint8_t i[2]; } __arch_pack xfs_dir2_sf_off_t;
/*
* 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;
/*
* Inode number stored as 8 8-bit values.
*/
typedef struct { __uint8_t i[8]; } xfs_dir2_ino8_t;
/*
* Inode number stored as 4 8-bit values.
* Works a lot of the time, when all the inode numbers in a directory
* fit in 32 bits.
*/
typedef struct { __uint8_t i[4]; } xfs_dir2_ino4_t;
typedef union {
xfs_dir2_ino8_t i8;
xfs_dir2_ino4_t i4;
} xfs_dir2_inou_t;
#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 */
xfs_dir2_inou_t parent; /* parent dir inode number */
} __arch_pack xfs_dir2_sf_hdr_t;
typedef struct xfs_dir2_sf_entry {
__u8 namelen; /* actual name length */
xfs_dir2_sf_off_t offset; /* saved offset */
__u8 name[]; /* name, variable size */
/*
* A xfs_dir2_ino8_t or xfs_dir2_ino4_t follows here, at a
* variable offset after the name.
*/
} __arch_pack xfs_dir2_sf_entry_t;
static inline int xfs_dir2_sf_hdr_size(int i8count)
{
return sizeof(struct xfs_dir2_sf_hdr) -
(i8count == 0) *
(sizeof(xfs_dir2_ino8_t) - sizeof(xfs_dir2_ino4_t));
}
static inline xfs_dir2_data_aoff_t
xfs_dir2_sf_get_offset(xfs_dir2_sf_entry_t *sfep)
{
return get_unaligned_be16(&sfep->offset.i);
}
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.i);
}
static inline int
xfs_dir2_sf_entsize(struct xfs_dir2_sf_hdr *hdr, int len)
{
return sizeof(struct xfs_dir2_sf_entry) + /* namelen + offset */
len + /* name */
(hdr->i8count ? /* ino */
sizeof(xfs_dir2_ino8_t) :
sizeof(xfs_dir2_ino4_t));
}
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));
}
static inline struct xfs_dir2_sf_entry *
xfs_dir2_sf_nextentry(struct xfs_dir2_sf_hdr *hdr,
struct xfs_dir2_sf_entry *sfep)
{
return (struct xfs_dir2_sf_entry *)
((char *)sfep + xfs_dir2_sf_entsize(hdr, sfep->namelen));
}
/*
* 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_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)
#define XFS_DIR2_DATA_FIRSTDB(mp) \
xfs_dir2_byte_to_db(mp, XFS_DIR2_DATA_OFFSET)
/*
* 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)
static inline struct xfs_dir2_data_free *
xfs_dir3_data_bestfree_p(struct xfs_dir2_data_hdr *hdr)
{
if (hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
struct xfs_dir3_data_hdr *hdr3 = (struct xfs_dir3_data_hdr *)hdr;
return hdr3->best_free;
}
return hdr->bestfree;
}
/*
* 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_dir2_data_entry_tag_p.
*/
typedef struct xfs_dir2_data_entry {
__be64 inumber; /* inode number */
__u8 namelen; /* name length */
__u8 name[]; /* name bytes, no null */
/* __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;
/*
* Size of a data entry.
*/
static inline int xfs_dir2_data_entsize(int n)
{
return (int)roundup(offsetof(struct xfs_dir2_data_entry, name[0]) + n +
(uint)sizeof(xfs_dir2_data_off_t), XFS_DIR2_DATA_ALIGN);
}
/*
* Pointer to an entry's tag word.
*/
static inline __be16 *
xfs_dir2_data_entry_tag_p(struct xfs_dir2_data_entry *dep)
{
return (__be16 *)((char *)dep +
xfs_dir2_data_entsize(dep->namelen) - sizeof(__be16));
}
/*
* 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));
}
static inline size_t
xfs_dir3_data_hdr_size(bool dir3)
{
if (dir3)
return sizeof(struct xfs_dir3_data_hdr);
return sizeof(struct xfs_dir2_data_hdr);
}
static inline size_t
xfs_dir3_data_entry_offset(struct xfs_dir2_data_hdr *hdr)
{
bool dir3 = hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC);
return xfs_dir3_data_hdr_size(dir3);
}
static inline struct xfs_dir2_data_entry *
xfs_dir3_data_entry_p(struct xfs_dir2_data_hdr *hdr)
{
return (struct xfs_dir2_data_entry *)
((char *)hdr + xfs_dir3_data_entry_offset(hdr));
}
static inline struct xfs_dir2_data_unused *
xfs_dir3_data_unused_p(struct xfs_dir2_data_hdr *hdr)
{
return (struct xfs_dir2_data_unused *)
((char *)hdr + xfs_dir3_data_entry_offset(hdr));
}
/*
* Offsets of . and .. in data space (always block 0)
*
* The macros are used for shortform directories as they have no headers to read
* the magic number out of. Shortform directories need to know the size of the
* data block header because the sfe embeds the block offset of the entry into
* it so that it doesn't change when format conversion occurs. Bad Things Happen
* if we don't follow this rule.
*/
#define XFS_DIR3_DATA_DOT_OFFSET(mp) \
xfs_dir3_data_hdr_size(xfs_sb_version_hascrc(&(mp)->m_sb))
#define XFS_DIR3_DATA_DOTDOT_OFFSET(mp) \
(XFS_DIR3_DATA_DOT_OFFSET(mp) + xfs_dir2_data_entsize(1))
#define XFS_DIR3_DATA_FIRST_OFFSET(mp) \
(XFS_DIR3_DATA_DOTDOT_OFFSET(mp) + xfs_dir2_data_entsize(2))
static inline xfs_dir2_data_aoff_t
xfs_dir3_data_dot_offset(struct xfs_dir2_data_hdr *hdr)
{
return xfs_dir3_data_entry_offset(hdr);
}
static inline xfs_dir2_data_aoff_t
xfs_dir3_data_dotdot_offset(struct xfs_dir2_data_hdr *hdr)
{
return xfs_dir3_data_dot_offset(hdr) + xfs_dir2_data_entsize(1);
}
static inline xfs_dir2_data_aoff_t
xfs_dir3_data_first_offset(struct xfs_dir2_data_hdr *hdr)
{
return xfs_dir3_data_dotdot_offset(hdr) + xfs_dir2_data_entsize(2);
}
/*
* location of . and .. in data space (always block 0)
*/
static inline struct xfs_dir2_data_entry *
xfs_dir3_data_dot_entry_p(struct xfs_dir2_data_hdr *hdr)
{
return (struct xfs_dir2_data_entry *)
((char *)hdr + xfs_dir3_data_dot_offset(hdr));
}
static inline struct xfs_dir2_data_entry *
xfs_dir3_data_dotdot_entry_p(struct xfs_dir2_data_hdr *hdr)
{
return (struct xfs_dir2_data_entry *)
((char *)hdr + xfs_dir3_data_dotdot_offset(hdr));
}
static inline struct xfs_dir2_data_entry *
xfs_dir3_data_first_entry_p(struct xfs_dir2_data_hdr *hdr)
{
return (struct xfs_dir2_data_entry *)
((char *)hdr + xfs_dir3_data_first_offset(hdr));
}
/*
* 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)
#define XFS_DIR2_LEAF_FIRSTDB(mp) \
xfs_dir2_byte_to_db(mp, XFS_DIR2_LEAF_OFFSET)
/*
* 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 */
};
struct xfs_dir3_icleaf_hdr {
__uint32_t forw;
__uint32_t back;
__uint16_t magic;
__uint16_t count;
__uint16_t stale;
};
/*
* 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)
static inline int
xfs_dir3_leaf_hdr_size(struct xfs_dir2_leaf *lp)
{
if (lp->hdr.info.magic == cpu_to_be16(XFS_DIR3_LEAF1_MAGIC) ||
lp->hdr.info.magic == cpu_to_be16(XFS_DIR3_LEAFN_MAGIC))
return sizeof(struct xfs_dir3_leaf_hdr);
return sizeof(struct xfs_dir2_leaf_hdr);
}
static inline int
xfs_dir3_max_leaf_ents(struct xfs_mount *mp, struct xfs_dir2_leaf *lp)
{
return (mp->m_dirblksize - xfs_dir3_leaf_hdr_size(lp)) /
(uint)sizeof(struct xfs_dir2_leaf_entry);
}
/*
* Get address of the bestcount field in the single-leaf block.
*/
static inline struct xfs_dir2_leaf_entry *
xfs_dir3_leaf_ents_p(struct xfs_dir2_leaf *lp)
{
if (lp->hdr.info.magic == cpu_to_be16(XFS_DIR3_LEAF1_MAGIC) ||
lp->hdr.info.magic == cpu_to_be16(XFS_DIR3_LEAFN_MAGIC)) {
struct xfs_dir3_leaf *lp3 = (struct xfs_dir3_leaf *)lp;
return lp3->__ents;
}
return lp->__ents;
}
/*
* Get address of the bestcount field in the single-leaf block.
*/
static inline struct xfs_dir2_leaf_tail *
xfs_dir2_leaf_tail_p(struct xfs_mount *mp, struct xfs_dir2_leaf *lp)
{
return (struct xfs_dir2_leaf_tail *)
((char *)lp + mp->m_dirblksize -
sizeof(struct xfs_dir2_leaf_tail));
}
/*
* 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);
}
/*
* DB blocks here are logical directory block numbers, not filesystem blocks.
*/
/*
* Convert dataptr to byte in file space
*/
static inline xfs_dir2_off_t
xfs_dir2_dataptr_to_byte(struct xfs_mount *mp, xfs_dir2_dataptr_t dp)
{
return (xfs_dir2_off_t)dp << XFS_DIR2_DATA_ALIGN_LOG;
}
/*
* Convert byte in file space to dataptr. It had better be aligned.
*/
static inline xfs_dir2_dataptr_t
xfs_dir2_byte_to_dataptr(struct xfs_mount *mp, xfs_dir2_off_t by)
{
return (xfs_dir2_dataptr_t)(by >> XFS_DIR2_DATA_ALIGN_LOG);
}
/*
* Convert byte in space to (DB) block
*/
static inline xfs_dir2_db_t
xfs_dir2_byte_to_db(struct xfs_mount *mp, xfs_dir2_off_t by)
{
return (xfs_dir2_db_t)
(by >> (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog));
}
/*
* Convert dataptr to a block number
*/
static inline xfs_dir2_db_t
xfs_dir2_dataptr_to_db(struct xfs_mount *mp, xfs_dir2_dataptr_t dp)
{
return xfs_dir2_byte_to_db(mp, xfs_dir2_dataptr_to_byte(mp, dp));
}
/*
* Convert byte in space to offset in a block
*/
static inline xfs_dir2_data_aoff_t
xfs_dir2_byte_to_off(struct xfs_mount *mp, xfs_dir2_off_t by)
{
return (xfs_dir2_data_aoff_t)(by &
((1 << (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) - 1));
}
/*
* Convert dataptr to a byte offset in a block
*/
static inline xfs_dir2_data_aoff_t
xfs_dir2_dataptr_to_off(struct xfs_mount *mp, xfs_dir2_dataptr_t dp)
{
return xfs_dir2_byte_to_off(mp, xfs_dir2_dataptr_to_byte(mp, dp));
}
/*
* Convert block and offset to byte in space
*/
static inline xfs_dir2_off_t
xfs_dir2_db_off_to_byte(struct xfs_mount *mp, xfs_dir2_db_t db,
xfs_dir2_data_aoff_t o)
{
return ((xfs_dir2_off_t)db <<
(mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) + o;
}
/*
* Convert block (DB) to block (dablk)
*/
static inline xfs_dablk_t
xfs_dir2_db_to_da(struct xfs_mount *mp, xfs_dir2_db_t db)
{
return (xfs_dablk_t)(db << mp->m_sb.sb_dirblklog);
}
/*
* Convert byte in space to (DA) block
*/
static inline xfs_dablk_t
xfs_dir2_byte_to_da(struct xfs_mount *mp, xfs_dir2_off_t by)
{
return xfs_dir2_db_to_da(mp, xfs_dir2_byte_to_db(mp, by));
}
/*
* Convert block and offset to dataptr
*/
static inline xfs_dir2_dataptr_t
xfs_dir2_db_off_to_dataptr(struct xfs_mount *mp, xfs_dir2_db_t db,
xfs_dir2_data_aoff_t o)
{
return xfs_dir2_byte_to_dataptr(mp, xfs_dir2_db_off_to_byte(mp, db, o));
}
/*
* Convert block (dablk) to block (DB)
*/
static inline xfs_dir2_db_t
xfs_dir2_da_to_db(struct xfs_mount *mp, xfs_dablk_t da)
{
return (xfs_dir2_db_t)(da >> mp->m_sb.sb_dirblklog);
}
/*
* Convert block (dablk) to byte offset in space
*/
static inline xfs_dir2_off_t
xfs_dir2_da_to_byte(struct xfs_mount *mp, xfs_dablk_t da)
{
return xfs_dir2_db_off_to_byte(mp, xfs_dir2_da_to_db(mp, da), 0);
}
/*
* Free space block defintions 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)
#define XFS_DIR2_FREE_FIRSTDB(mp) \
xfs_dir2_byte_to_db(mp, XFS_DIR2_FREE_OFFSET)
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)
/*
* In core version of the free block header, abstracted away from on-disk format
* differences. Use this in the code, and convert to/from the disk version using
* xfs_dir3_free_hdr_from_disk/xfs_dir3_free_hdr_to_disk.
*/
struct xfs_dir3_icfree_hdr {
__uint32_t magic;
__uint32_t firstdb;
__uint32_t nvalid;
__uint32_t nused;
};
void xfs_dir3_free_hdr_from_disk(struct xfs_dir3_icfree_hdr *to,
struct xfs_dir2_free *from);
static inline int
xfs_dir3_free_hdr_size(struct xfs_mount *mp)
{
if (xfs_sb_version_hascrc(&mp->m_sb))
return sizeof(struct xfs_dir3_free_hdr);
return sizeof(struct xfs_dir2_free_hdr);
}
static inline int
xfs_dir3_free_max_bests(struct xfs_mount *mp)
{
return (mp->m_dirblksize - xfs_dir3_free_hdr_size(mp)) /
sizeof(xfs_dir2_data_off_t);
}
static inline __be16 *
xfs_dir3_free_bests_p(struct xfs_mount *mp, struct xfs_dir2_free *free)
{
return (__be16 *)((char *)free + xfs_dir3_free_hdr_size(mp));
}
/*
* Convert data space db to the corresponding free db.
*/
static inline xfs_dir2_db_t
xfs_dir2_db_to_fdb(struct xfs_mount *mp, xfs_dir2_db_t db)
{
return XFS_DIR2_FREE_FIRSTDB(mp) + db / xfs_dir3_free_max_bests(mp);
}
/*
* Convert data space db to the corresponding index in a free db.
*/
static inline int
xfs_dir2_db_to_fdindex(struct xfs_mount *mp, xfs_dir2_db_t db)
{
return db % xfs_dir3_free_max_bests(mp);
}
/*
* 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 header embedded in a data block (1-block format)
*/
static inline struct xfs_dir2_block_tail *
xfs_dir2_block_tail_p(struct xfs_mount *mp, struct xfs_dir2_data_hdr *hdr)
{
return ((struct xfs_dir2_block_tail *)
((char *)hdr + mp->m_dirblksize)) - 1;
}
/*
* 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);
}
#endif /* __XFS_DIR2_FORMAT_H__ */
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