266 lines
10 KiB
C
266 lines
10 KiB
C
/*
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* Copyright (c) 2000,2002-2003,2005 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_ATTR_LEAF_H__
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#define __XFS_ATTR_LEAF_H__
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/*
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* Attribute storage layout, internal structure, access macros, etc.
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*
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* Attribute lists are structured around Btrees where all the data
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* elements are in the leaf nodes. Attribute names are hashed into an int,
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* then that int is used as the index into the Btree. Since the hashval
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* of an attribute name may not be unique, we may have duplicate keys. The
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* internal links in the Btree are logical block offsets into the file.
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*/
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struct attrlist;
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struct attrlist_cursor_kern;
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struct xfs_attr_list_context;
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struct xfs_dabuf;
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struct xfs_da_args;
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struct xfs_da_state;
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struct xfs_da_state_blk;
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struct xfs_inode;
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struct xfs_trans;
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/*========================================================================
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* Attribute structure when equal to XFS_LBSIZE(mp) bytes.
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*========================================================================*/
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/*
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* This is the structure of the leaf nodes in the Btree.
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*
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* Struct leaf_entry's are packed from the top. Name/values grow from the
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* bottom but are not packed. The freemap contains run-length-encoded entries
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* for the free bytes after the leaf_entry's, but only the N largest such,
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* smaller runs are dropped. When the freemap doesn't show enough space
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* for an allocation, we compact the name/value area and try again. If we
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* still don't have enough space, then we have to split the block. The
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* name/value structs (both local and remote versions) must be 32bit aligned.
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*
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* Since we have duplicate hash keys, for each key that matches, compare
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* the actual name string. The root and intermediate node search always
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* takes the first-in-the-block key match found, so we should only have
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* to work "forw"ard. If none matches, continue with the "forw"ard leaf
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* nodes until the hash key changes or the attribute name is found.
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*
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* We store the fact that an attribute is a ROOT/USER/SECURE attribute in
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* the leaf_entry. The namespaces are independent only because we also look
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* at the namespace bit when we are looking for a matching attribute name.
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*
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* We also store an "incomplete" bit in the leaf_entry. It shows that an
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* attribute is in the middle of being created and should not be shown to
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* the user if we crash during the time that the bit is set. We clear the
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* bit when we have finished setting up the attribute. We do this because
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* we cannot create some large attributes inside a single transaction, and we
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* need some indication that we weren't finished if we crash in the middle.
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*/
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#define XFS_ATTR_LEAF_MAPSIZE 3 /* how many freespace slots */
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typedef struct xfs_attr_leaf_map { /* RLE map of free bytes */
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__be16 base; /* base of free region */
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__be16 size; /* length of free region */
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} xfs_attr_leaf_map_t;
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typedef struct xfs_attr_leaf_hdr { /* constant-structure header block */
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xfs_da_blkinfo_t info; /* block type, links, etc. */
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__be16 count; /* count of active leaf_entry's */
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__be16 usedbytes; /* num bytes of names/values stored */
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__be16 firstused; /* first used byte in name area */
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__u8 holes; /* != 0 if blk needs compaction */
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__u8 pad1;
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xfs_attr_leaf_map_t freemap[XFS_ATTR_LEAF_MAPSIZE];
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/* N largest free regions */
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} xfs_attr_leaf_hdr_t;
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typedef struct xfs_attr_leaf_entry { /* sorted on key, not name */
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__be32 hashval; /* hash value of name */
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__be16 nameidx; /* index into buffer of name/value */
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__u8 flags; /* LOCAL/ROOT/SECURE/INCOMPLETE flag */
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__u8 pad2; /* unused pad byte */
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} xfs_attr_leaf_entry_t;
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typedef struct xfs_attr_leaf_name_local {
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__be16 valuelen; /* number of bytes in value */
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__u8 namelen; /* length of name bytes */
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__u8 nameval[1]; /* name/value bytes */
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} xfs_attr_leaf_name_local_t;
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typedef struct xfs_attr_leaf_name_remote {
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__be32 valueblk; /* block number of value bytes */
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__be32 valuelen; /* number of bytes in value */
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__u8 namelen; /* length of name bytes */
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__u8 name[1]; /* name bytes */
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} xfs_attr_leaf_name_remote_t;
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typedef struct xfs_attr_leafblock {
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xfs_attr_leaf_hdr_t hdr; /* constant-structure header block */
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xfs_attr_leaf_entry_t entries[1]; /* sorted on key, not name */
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xfs_attr_leaf_name_local_t namelist; /* grows from bottom of buf */
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xfs_attr_leaf_name_remote_t valuelist; /* grows from bottom of buf */
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} xfs_attr_leafblock_t;
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/*
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* Flags used in the leaf_entry[i].flags field.
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* NOTE: the INCOMPLETE bit must not collide with the flags bits specified
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* on the system call, they are "or"ed together for various operations.
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*/
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#define XFS_ATTR_LOCAL_BIT 0 /* attr is stored locally */
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#define XFS_ATTR_ROOT_BIT 1 /* limit access to trusted attrs */
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#define XFS_ATTR_SECURE_BIT 2 /* limit access to secure attrs */
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#define XFS_ATTR_INCOMPLETE_BIT 7 /* attr in middle of create/delete */
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#define XFS_ATTR_LOCAL (1 << XFS_ATTR_LOCAL_BIT)
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#define XFS_ATTR_ROOT (1 << XFS_ATTR_ROOT_BIT)
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#define XFS_ATTR_SECURE (1 << XFS_ATTR_SECURE_BIT)
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#define XFS_ATTR_INCOMPLETE (1 << XFS_ATTR_INCOMPLETE_BIT)
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/*
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* Conversion macros for converting namespace bits from argument flags
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* to ondisk flags.
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*/
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#define XFS_ATTR_NSP_ARGS_MASK (ATTR_ROOT | ATTR_SECURE)
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#define XFS_ATTR_NSP_ONDISK_MASK (XFS_ATTR_ROOT | XFS_ATTR_SECURE)
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#define XFS_ATTR_NSP_ONDISK(flags) ((flags) & XFS_ATTR_NSP_ONDISK_MASK)
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#define XFS_ATTR_NSP_ARGS(flags) ((flags) & XFS_ATTR_NSP_ARGS_MASK)
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#define XFS_ATTR_NSP_ARGS_TO_ONDISK(x) (((x) & ATTR_ROOT ? XFS_ATTR_ROOT : 0) |\
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((x) & ATTR_SECURE ? XFS_ATTR_SECURE : 0))
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#define XFS_ATTR_NSP_ONDISK_TO_ARGS(x) (((x) & XFS_ATTR_ROOT ? ATTR_ROOT : 0) |\
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((x) & XFS_ATTR_SECURE ? ATTR_SECURE : 0))
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/*
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* Alignment for namelist and valuelist entries (since they are mixed
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* there can be only one alignment value)
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*/
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#define XFS_ATTR_LEAF_NAME_ALIGN ((uint)sizeof(xfs_dablk_t))
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/*
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* Cast typed pointers for "local" and "remote" name/value structs.
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*/
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static inline xfs_attr_leaf_name_remote_t *
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xfs_attr_leaf_name_remote(xfs_attr_leafblock_t *leafp, int idx)
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{
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return (xfs_attr_leaf_name_remote_t *)
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&((char *)leafp)[be16_to_cpu(leafp->entries[idx].nameidx)];
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}
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static inline xfs_attr_leaf_name_local_t *
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xfs_attr_leaf_name_local(xfs_attr_leafblock_t *leafp, int idx)
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{
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return (xfs_attr_leaf_name_local_t *)
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&((char *)leafp)[be16_to_cpu(leafp->entries[idx].nameidx)];
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}
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static inline char *xfs_attr_leaf_name(xfs_attr_leafblock_t *leafp, int idx)
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{
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return &((char *)leafp)[be16_to_cpu(leafp->entries[idx].nameidx)];
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}
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/*
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* Calculate total bytes used (including trailing pad for alignment) for
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* a "local" name/value structure, a "remote" name/value structure, and
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* a pointer which might be either.
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*/
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static inline int xfs_attr_leaf_entsize_remote(int nlen)
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{
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return ((uint)sizeof(xfs_attr_leaf_name_remote_t) - 1 + (nlen) + \
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XFS_ATTR_LEAF_NAME_ALIGN - 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN - 1);
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}
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static inline int xfs_attr_leaf_entsize_local(int nlen, int vlen)
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{
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return ((uint)sizeof(xfs_attr_leaf_name_local_t) - 1 + (nlen) + (vlen) +
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XFS_ATTR_LEAF_NAME_ALIGN - 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN - 1);
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}
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static inline int xfs_attr_leaf_entsize_local_max(int bsize)
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{
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return (((bsize) >> 1) + ((bsize) >> 2));
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}
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/*
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* Used to keep a list of "remote value" extents when unlinking an inode.
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*/
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typedef struct xfs_attr_inactive_list {
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xfs_dablk_t valueblk; /* block number of value bytes */
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int valuelen; /* number of bytes in value */
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} xfs_attr_inactive_list_t;
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/*========================================================================
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* Function prototypes for the kernel.
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*========================================================================*/
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/*
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* Internal routines when attribute fork size < XFS_LITINO(mp).
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*/
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void xfs_attr_shortform_create(struct xfs_da_args *args);
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void xfs_attr_shortform_add(struct xfs_da_args *args, int forkoff);
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int xfs_attr_shortform_lookup(struct xfs_da_args *args);
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int xfs_attr_shortform_getvalue(struct xfs_da_args *args);
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int xfs_attr_shortform_to_leaf(struct xfs_da_args *args);
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int xfs_attr_shortform_remove(struct xfs_da_args *args);
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int xfs_attr_shortform_list(struct xfs_attr_list_context *context);
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int xfs_attr_shortform_allfit(struct xfs_dabuf *bp, struct xfs_inode *dp);
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int xfs_attr_shortform_bytesfit(xfs_inode_t *dp, int bytes);
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/*
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* Internal routines when attribute fork size == XFS_LBSIZE(mp).
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*/
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int xfs_attr_leaf_to_node(struct xfs_da_args *args);
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int xfs_attr_leaf_to_shortform(struct xfs_dabuf *bp,
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struct xfs_da_args *args, int forkoff);
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int xfs_attr_leaf_clearflag(struct xfs_da_args *args);
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int xfs_attr_leaf_setflag(struct xfs_da_args *args);
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int xfs_attr_leaf_flipflags(xfs_da_args_t *args);
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/*
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* Routines used for growing the Btree.
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*/
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int xfs_attr_leaf_split(struct xfs_da_state *state,
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struct xfs_da_state_blk *oldblk,
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struct xfs_da_state_blk *newblk);
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int xfs_attr_leaf_lookup_int(struct xfs_dabuf *leaf,
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struct xfs_da_args *args);
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int xfs_attr_leaf_getvalue(struct xfs_dabuf *bp, struct xfs_da_args *args);
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int xfs_attr_leaf_add(struct xfs_dabuf *leaf_buffer,
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struct xfs_da_args *args);
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int xfs_attr_leaf_remove(struct xfs_dabuf *leaf_buffer,
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struct xfs_da_args *args);
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int xfs_attr_leaf_list_int(struct xfs_dabuf *bp,
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struct xfs_attr_list_context *context);
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/*
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* Routines used for shrinking the Btree.
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*/
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int xfs_attr_leaf_toosmall(struct xfs_da_state *state, int *retval);
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void xfs_attr_leaf_unbalance(struct xfs_da_state *state,
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struct xfs_da_state_blk *drop_blk,
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struct xfs_da_state_blk *save_blk);
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int xfs_attr_root_inactive(struct xfs_trans **trans, struct xfs_inode *dp);
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/*
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* Utility routines.
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*/
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xfs_dahash_t xfs_attr_leaf_lasthash(struct xfs_dabuf *bp, int *count);
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int xfs_attr_leaf_order(struct xfs_dabuf *leaf1_bp,
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struct xfs_dabuf *leaf2_bp);
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int xfs_attr_leaf_newentsize(int namelen, int valuelen, int blocksize,
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int *local);
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#endif /* __XFS_ATTR_LEAF_H__ */
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