0ba9cd84ef
Remove the confusing xfs_dir2_data structure. It is supposed to describe an XFS dir2 data btree block, but due to the variable sized nature of almost all elements in it it can't actuall do anything close to that job. In addition to accessing the fixed offset header structure it was only used to get a pointer to the first dir or unused entry after it, which can be trivially replaced by pointer arithmetics on the header pointer. For most users that is actually more natural anyway, as they don't use a typed pointer but rather a character pointer for further arithmetics. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Alex Elder <aelder@sgi.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
181 lines
5.7 KiB
C
181 lines
5.7 KiB
C
/*
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* Copyright (c) 2000,2005 Silicon Graphics, Inc.
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* All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it would be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef __XFS_DIR2_DATA_H__
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#define __XFS_DIR2_DATA_H__
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/*
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* Directory format 2, data block structures.
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*
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* A pure data block looks like the following drawing on disk:
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*
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* +-------------------------------------------------+
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* | xfs_dir2_data_hdr_t |
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* +-------------------------------------------------+
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* | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
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* | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
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* | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
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* | ... |
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* +-------------------------------------------------+
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* | unused space |
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* +-------------------------------------------------+
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*
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* As all the entries are variable size structures the accessors in this
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* file should be used to iterate over them.
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*/
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struct xfs_dabuf;
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struct xfs_da_args;
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struct xfs_inode;
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struct xfs_trans;
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/*
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* Constants.
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*/
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#define XFS_DIR2_DATA_MAGIC 0x58443244 /* XD2D: for multiblock dirs */
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#define XFS_DIR2_DATA_ALIGN_LOG 3 /* i.e., 8 bytes */
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#define XFS_DIR2_DATA_ALIGN (1 << XFS_DIR2_DATA_ALIGN_LOG)
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#define XFS_DIR2_DATA_FREE_TAG 0xffff
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#define XFS_DIR2_DATA_FD_COUNT 3
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/*
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* Directory address space divided into sections,
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* spaces separated by 32GB.
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*/
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#define XFS_DIR2_SPACE_SIZE (1ULL << (32 + XFS_DIR2_DATA_ALIGN_LOG))
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#define XFS_DIR2_DATA_SPACE 0
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#define XFS_DIR2_DATA_OFFSET (XFS_DIR2_DATA_SPACE * XFS_DIR2_SPACE_SIZE)
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#define XFS_DIR2_DATA_FIRSTDB(mp) \
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xfs_dir2_byte_to_db(mp, XFS_DIR2_DATA_OFFSET)
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/*
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* Offsets of . and .. in data space (always block 0)
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*/
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#define XFS_DIR2_DATA_DOT_OFFSET \
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((xfs_dir2_data_aoff_t)sizeof(xfs_dir2_data_hdr_t))
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#define XFS_DIR2_DATA_DOTDOT_OFFSET \
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(XFS_DIR2_DATA_DOT_OFFSET + xfs_dir2_data_entsize(1))
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#define XFS_DIR2_DATA_FIRST_OFFSET \
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(XFS_DIR2_DATA_DOTDOT_OFFSET + xfs_dir2_data_entsize(2))
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/*
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* Structures.
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*/
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/*
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* Describe a free area in the data block.
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* The freespace will be formatted as a xfs_dir2_data_unused_t.
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*/
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typedef struct xfs_dir2_data_free {
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__be16 offset; /* start of freespace */
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__be16 length; /* length of freespace */
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} xfs_dir2_data_free_t;
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/*
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* Header for the data blocks.
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* Always at the beginning of a directory-sized block.
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* The code knows that XFS_DIR2_DATA_FD_COUNT is 3.
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*/
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typedef struct xfs_dir2_data_hdr {
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__be32 magic; /* XFS_DIR2_DATA_MAGIC */
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/* or XFS_DIR2_BLOCK_MAGIC */
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xfs_dir2_data_free_t bestfree[XFS_DIR2_DATA_FD_COUNT];
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} xfs_dir2_data_hdr_t;
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/*
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* Active entry in a data block. Aligned to 8 bytes.
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* Tag appears as the last 2 bytes.
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*/
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typedef struct xfs_dir2_data_entry {
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__be64 inumber; /* inode number */
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__u8 namelen; /* name length */
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__u8 name[1]; /* name bytes, no null */
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/* variable offset */
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__be16 tag; /* starting offset of us */
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} xfs_dir2_data_entry_t;
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/*
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* Unused entry in a data block. Aligned to 8 bytes.
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* Tag appears as the last 2 bytes.
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*/
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typedef struct xfs_dir2_data_unused {
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__be16 freetag; /* XFS_DIR2_DATA_FREE_TAG */
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__be16 length; /* total free length */
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/* variable offset */
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__be16 tag; /* starting offset of us */
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} xfs_dir2_data_unused_t;
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/*
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* Size of a data entry.
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*/
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static inline int xfs_dir2_data_entsize(int n)
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{
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return (int)roundup(offsetof(xfs_dir2_data_entry_t, name[0]) + (n) + \
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(uint)sizeof(xfs_dir2_data_off_t), XFS_DIR2_DATA_ALIGN);
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}
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/*
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* Pointer to an entry's tag word.
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*/
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static inline __be16 *
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xfs_dir2_data_entry_tag_p(xfs_dir2_data_entry_t *dep)
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{
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return (__be16 *)((char *)dep +
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xfs_dir2_data_entsize(dep->namelen) - sizeof(__be16));
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}
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/*
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* Pointer to a freespace's tag word.
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*/
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static inline __be16 *
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xfs_dir2_data_unused_tag_p(xfs_dir2_data_unused_t *dup)
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{
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return (__be16 *)((char *)dup +
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be16_to_cpu(dup->length) - sizeof(__be16));
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}
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/*
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* Function declarations.
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*/
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#ifdef DEBUG
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extern void xfs_dir2_data_check(struct xfs_inode *dp, struct xfs_dabuf *bp);
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#else
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#define xfs_dir2_data_check(dp,bp)
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#endif
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extern xfs_dir2_data_free_t *xfs_dir2_data_freeinsert(xfs_dir2_data_hdr_t *hdr,
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xfs_dir2_data_unused_t *dup, int *loghead);
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extern void xfs_dir2_data_freescan(struct xfs_mount *mp,
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xfs_dir2_data_hdr_t *hdr, int *loghead);
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extern int xfs_dir2_data_init(struct xfs_da_args *args, xfs_dir2_db_t blkno,
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struct xfs_dabuf **bpp);
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extern void xfs_dir2_data_log_entry(struct xfs_trans *tp, struct xfs_dabuf *bp,
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xfs_dir2_data_entry_t *dep);
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extern void xfs_dir2_data_log_header(struct xfs_trans *tp,
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struct xfs_dabuf *bp);
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extern void xfs_dir2_data_log_unused(struct xfs_trans *tp, struct xfs_dabuf *bp,
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xfs_dir2_data_unused_t *dup);
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extern void xfs_dir2_data_make_free(struct xfs_trans *tp, struct xfs_dabuf *bp,
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xfs_dir2_data_aoff_t offset,
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xfs_dir2_data_aoff_t len, int *needlogp,
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int *needscanp);
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extern void xfs_dir2_data_use_free(struct xfs_trans *tp, struct xfs_dabuf *bp,
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xfs_dir2_data_unused_t *dup,
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xfs_dir2_data_aoff_t offset,
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xfs_dir2_data_aoff_t len, int *needlogp,
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int *needscanp);
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#endif /* __XFS_DIR2_DATA_H__ */
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