xfs_attr_leaf.h revision 180208
150276Speter/* 2176187Srafan * Copyright (c) 2000,2002-2003,2005 Silicon Graphics, Inc. 350276Speter * All Rights Reserved. 450276Speter * 550276Speter * This program is free software; you can redistribute it and/or 650276Speter * modify it under the terms of the GNU General Public License as 750276Speter * published by the Free Software Foundation. 850276Speter * 950276Speter * This program is distributed in the hope that it would be useful, 1050276Speter * but WITHOUT ANY WARRANTY; without even the implied warranty of 1150276Speter * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 1250276Speter * GNU General Public License for more details. 1350276Speter * 1450276Speter * You should have received a copy of the GNU General Public License 1550276Speter * along with this program; if not, write the Free Software Foundation, 1650276Speter * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 1750276Speter */ 1850276Speter#ifndef __XFS_ATTR_LEAF_H__ 1950276Speter#define __XFS_ATTR_LEAF_H__ 2050276Speter 2150276Speter/* 2250276Speter * Attribute storage layout, internal structure, access macros, etc. 2350276Speter * 2450276Speter * Attribute lists are structured around Btrees where all the data 2550276Speter * elements are in the leaf nodes. Attribute names are hashed into an int, 2650276Speter * then that int is used as the index into the Btree. Since the hashval 2750276Speter * of an attribute name may not be unique, we may have duplicate keys. The 2850276Speter * internal links in the Btree are logical block offsets into the file. 2950276Speter */ 3050276Speter 3150276Speterstruct attrlist; 32166124Srafanstruct attrlist_cursor_kern; 3350276Speterstruct attrnames; 3450276Speterstruct xfs_dabuf; 3550276Speterstruct xfs_da_args; 3650276Speterstruct xfs_da_state; 3750276Speterstruct xfs_da_state_blk; 3850276Speterstruct xfs_inode; 3950276Speterstruct xfs_trans; 4050276Speter 4150276Speter/*======================================================================== 4250276Speter * Attribute structure when equal to XFS_LBSIZE(mp) bytes. 4350276Speter *========================================================================*/ 44184989Srafan 4550276Speter/* 4650276Speter * This is the structure of the leaf nodes in the Btree. 4750276Speter * 48174993Srafan * Struct leaf_entry's are packed from the top. Name/values grow from the 49178866Srafan * bottom but are not packed. The freemap contains run-length-encoded entries 50174993Srafan * for the free bytes after the leaf_entry's, but only the N largest such, 51174993Srafan * smaller runs are dropped. When the freemap doesn't show enough space 52174993Srafan * for an allocation, we compact the name/value area and try again. If we 53178866Srafan * still don't have enough space, then we have to split the block. The 54174993Srafan * name/value structs (both local and remote versions) must be 32bit aligned. 55174993Srafan * 56178866Srafan * Since we have duplicate hash keys, for each key that matches, compare 5776726Speter * the actual name string. The root and intermediate node search always 5876726Speter * takes the first-in-the-block key match found, so we should only have 59174993Srafan * to work "forw"ard. If none matches, continue with the "forw"ard leaf 6050276Speter * nodes until the hash key changes or the attribute name is found. 61176187Srafan * 62176187Srafan * We store the fact that an attribute is a ROOT/USER/SECURE attribute in 63176187Srafan * the leaf_entry. The namespaces are independent only because we also look 64176187Srafan * at the namespace bit when we are looking for a matching attribute name. 65176187Srafan * 66176187Srafan * We also store an "incomplete" bit in the leaf_entry. It shows that an 67176187Srafan * attribute is in the middle of being created and should not be shown to 68176187Srafan * the user if we crash during the time that the bit is set. We clear the 69176187Srafan * bit when we have finished setting up the attribute. We do this because 70176187Srafan * we cannot create some large attributes inside a single transaction, and we 71176187Srafan * need some indication that we weren't finished if we crash in the middle. 72176187Srafan */ 73176187Srafan#define XFS_ATTR_LEAF_MAPSIZE 3 /* how many freespace slots */ 74176187Srafan 75176187Srafantypedef struct xfs_attr_leaf_map { /* RLE map of free bytes */ 76176187Srafan __be16 base; /* base of free region */ 77176187Srafan __be16 size; /* length of free region */ 78176187Srafan} xfs_attr_leaf_map_t; 79184989Srafan 80184989Srafantypedef struct xfs_attr_leaf_hdr { /* constant-structure header block */ 81184989Srafan xfs_da_blkinfo_t info; /* block type, links, etc. */ 82184989Srafan __be16 count; /* count of active leaf_entry's */ 83184989Srafan __be16 usedbytes; /* num bytes of names/values stored */ 84184989Srafan __be16 firstused; /* first used byte in name area */ 85184989Srafan __u8 holes; /* != 0 if blk needs compaction */ 86166124Srafan __u8 pad1; 87166124Srafan xfs_attr_leaf_map_t freemap[XFS_ATTR_LEAF_MAPSIZE]; 88166124Srafan /* N largest free regions */ 89166124Srafan} xfs_attr_leaf_hdr_t; 90166124Srafan 91166124Srafantypedef struct xfs_attr_leaf_entry { /* sorted on key, not name */ 92166124Srafan __be32 hashval; /* hash value of name */ 93166124Srafan __be16 nameidx; /* index into buffer of name/value */ 94166124Srafan __u8 flags; /* LOCAL/ROOT/SECURE/INCOMPLETE flag */ 95166124Srafan __u8 pad2; /* unused pad byte */ 96178866Srafan} xfs_attr_leaf_entry_t; 97166124Srafan 98166124Srafantypedef struct xfs_attr_leaf_name_local { 99166124Srafan __be16 valuelen; /* number of bytes in value */ 100166124Srafan __u8 namelen; /* length of name bytes */ 101178866Srafan __u8 nameval[1]; /* name/value bytes */ 102178866Srafan} xfs_attr_leaf_name_local_t; 103166124Srafan 104166124Srafantypedef struct xfs_attr_leaf_name_remote { 105166124Srafan __be32 valueblk; /* block number of value bytes */ 106178866Srafan __be32 valuelen; /* number of bytes in value */ 107166124Srafan __u8 namelen; /* length of name bytes */ 108178866Srafan __u8 name[1]; /* name bytes */ 109178866Srafan} xfs_attr_leaf_name_remote_t; 110166124Srafan 111166124Srafantypedef struct xfs_attr_leafblock { 112166124Srafan xfs_attr_leaf_hdr_t hdr; /* constant-structure header block */ 113166124Srafan xfs_attr_leaf_entry_t entries[1]; /* sorted on key, not name */ 114166124Srafan xfs_attr_leaf_name_local_t namelist; /* grows from bottom of buf */ 115166124Srafan xfs_attr_leaf_name_remote_t valuelist; /* grows from bottom of buf */ 116166124Srafan} xfs_attr_leafblock_t; 117166124Srafan 118166124Srafan/* 119178866Srafan * Flags used in the leaf_entry[i].flags field. 12050276Speter * NOTE: the INCOMPLETE bit must not collide with the flags bits specified 121178866Srafan * on the system call, they are "or"ed together for various operations. 12266963Speter */ 12350276Speter#define XFS_ATTR_LOCAL_BIT 0 /* attr is stored locally */ 12462449Speter#define XFS_ATTR_ROOT_BIT 1 /* limit access to trusted attrs */ 12562449Speter#define XFS_ATTR_SECURE_BIT 2 /* limit access to secure attrs */ 12650276Speter#define XFS_ATTR_INCOMPLETE_BIT 7 /* attr in middle of create/delete */ 12750276Speter#define XFS_ATTR_LOCAL (1 << XFS_ATTR_LOCAL_BIT) 128166124Srafan#define XFS_ATTR_ROOT (1 << XFS_ATTR_ROOT_BIT) 129178866Srafan#define XFS_ATTR_SECURE (1 << XFS_ATTR_SECURE_BIT) 13050276Speter#define XFS_ATTR_INCOMPLETE (1 << XFS_ATTR_INCOMPLETE_BIT) 13162449Speter 132178866Srafan/* 133184989Srafan * Alignment for namelist and valuelist entries (since they are mixed 13450276Speter * there can be only one alignment value) 13562449Speter */ 13662449Speter#define XFS_ATTR_LEAF_NAME_ALIGN ((uint)sizeof(xfs_dablk_t)) 13762449Speter 13862449Speter/* 13962449Speter * Cast typed pointers for "local" and "remote" name/value structs. 14050276Speter */ 14150276Speter#define XFS_ATTR_LEAF_NAME_REMOTE(leafp,idx) \ 142174993Srafan xfs_attr_leaf_name_remote(leafp,idx) 143178866Srafanstatic inline xfs_attr_leaf_name_remote_t * 144174993Srafanxfs_attr_leaf_name_remote(xfs_attr_leafblock_t *leafp, int idx) 145174993Srafan{ 14650276Speter return (xfs_attr_leaf_name_remote_t *) 14762449Speter &((char *)leafp)[be16_to_cpu(leafp->entries[idx].nameidx)]; 14850276Speter} 14950276Speter 150166124Srafan#define XFS_ATTR_LEAF_NAME_LOCAL(leafp,idx) \ 151178866Srafan xfs_attr_leaf_name_local(leafp,idx) 15250276Speterstatic inline xfs_attr_leaf_name_local_t * 15362449Speterxfs_attr_leaf_name_local(xfs_attr_leafblock_t *leafp, int idx) 154166124Srafan{ 155166124Srafan return (xfs_attr_leaf_name_local_t *) 15650276Speter &((char *)leafp)[be16_to_cpu(leafp->entries[idx].nameidx)]; 157166124Srafan} 15862449Speter 15962449Speter#define XFS_ATTR_LEAF_NAME(leafp,idx) \ 16050276Speter xfs_attr_leaf_name(leafp,idx) 16150276Speterstatic inline char *xfs_attr_leaf_name(xfs_attr_leafblock_t *leafp, int idx) 16262449Speter{ 16362449Speter return &((char *)leafp)[be16_to_cpu(leafp->entries[idx].nameidx)]; 16450276Speter} 16550276Speter 166166124Srafan/* 167166124Srafan * Calculate total bytes used (including trailing pad for alignment) for 168166124Srafan * a "local" name/value structure, a "remote" name/value structure, and 169178866Srafan * a pointer which might be either. 170166124Srafan */ 171166124Srafan#define XFS_ATTR_LEAF_ENTSIZE_REMOTE(nlen) \ 172178866Srafan xfs_attr_leaf_entsize_remote(nlen) 173166124Srafanstatic inline int xfs_attr_leaf_entsize_remote(int nlen) 174166124Srafan{ 175166124Srafan return ((uint)sizeof(xfs_attr_leaf_name_remote_t) - 1 + (nlen) + \ 176166124Srafan XFS_ATTR_LEAF_NAME_ALIGN - 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN - 1); 177166124Srafan} 178178866Srafan 179166124Srafan#define XFS_ATTR_LEAF_ENTSIZE_LOCAL(nlen,vlen) \ 180166124Srafan xfs_attr_leaf_entsize_local(nlen,vlen) 181166124Srafanstatic inline int xfs_attr_leaf_entsize_local(int nlen, int vlen) 182178866Srafan{ 183178866Srafan return ((uint)sizeof(xfs_attr_leaf_name_local_t) - 1 + (nlen) + (vlen) + 184166124Srafan XFS_ATTR_LEAF_NAME_ALIGN - 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN - 1); 185166124Srafan} 186166124Srafan 187166124Srafan#define XFS_ATTR_LEAF_ENTSIZE_LOCAL_MAX(bsize) \ 188178866Srafan xfs_attr_leaf_entsize_local_max(bsize) 189178866Srafanstatic inline int xfs_attr_leaf_entsize_local_max(int bsize) 19062449Speter{ 19162449Speter return (((bsize) >> 1) + ((bsize) >> 2)); 19262449Speter} 19350276Speter 194166124Srafan 195178866Srafan/*======================================================================== 196178866Srafan * Structure used to pass context around among the routines. 197178866Srafan *========================================================================*/ 198166124Srafan 199166124Srafantypedef struct xfs_attr_list_context { 200178866Srafan struct xfs_inode *dp; /* inode */ 201166124Srafan struct attrlist_cursor_kern *cursor;/* position in list */ 202178866Srafan struct attrlist *alist; /* output buffer */ 203166124Srafan int count; /* num used entries */ 204166124Srafan int dupcnt; /* count dup hashvals seen */ 205166124Srafan int bufsize;/* total buffer size */ 206166124Srafan int firstu; /* first used byte in buffer */ 207166124Srafan int flags; /* from VOP call */ 20862449Speter int resynch;/* T/F: resynch with cursor */ 209178866Srafan} xfs_attr_list_context_t; 21097049Speter 21162449Speter/* 21250276Speter * Used to keep a list of "remote value" extents when unlinking an inode. 21350276Speter */ 21462449Spetertypedef struct xfs_attr_inactive_list { 21562449Speter xfs_dablk_t valueblk; /* block number of value bytes */ 21662449Speter int valuelen; /* number of bytes in value */ 21762449Speter} xfs_attr_inactive_list_t; 21862449Speter 21962449Speter 22062449Speter/*======================================================================== 22162449Speter * Function prototypes for the kernel. 22262449Speter *========================================================================*/ 22362449Speter 22462449Speter/* 22550276Speter * Internal routines when attribute fork size < XFS_LITINO(mp). 22650276Speter */ 22762449Spetervoid xfs_attr_shortform_create(struct xfs_da_args *args); 228178866Srafanvoid xfs_attr_shortform_add(struct xfs_da_args *args, int forkoff); 22966963Speterint xfs_attr_shortform_lookup(struct xfs_da_args *args); 23062449Speterint xfs_attr_shortform_to_leaf(struct xfs_da_args *args); 23166963Speterint xfs_attr_shortform_remove(struct xfs_da_args *args); 23250276Speterint xfs_attr_shortform_list(struct xfs_attr_list_context *context); 233178866Srafanint xfs_attr_shortform_allfit(struct xfs_dabuf *bp, struct xfs_inode *dp); 234178866Srafanint xfs_attr_shortform_bytesfit(xfs_inode_t *dp, int bytes); 23562449Speter 23662449Speter 23762449Speter/* 238184989Srafan * Internal routines when attribute fork size == XFS_LBSIZE(mp). 23950276Speter */ 240174993Srafanint xfs_attr_leaf_to_node(struct xfs_da_args *args); 241178866Srafanint xfs_attr_leaf_to_shortform(struct xfs_dabuf *bp, 242174993Srafan struct xfs_da_args *args, int forkoff); 243174993Srafanint xfs_attr_leaf_clearflag(struct xfs_da_args *args); 24450276Speterint xfs_attr_leaf_setflag(struct xfs_da_args *args); 24562449Speterint xfs_attr_leaf_flipflags(xfs_da_args_t *args); 24650276Speter 24750276Speter/* 248166124Srafan * Routines used for growing the Btree. 249178866Srafan */ 25050276Speterint xfs_attr_leaf_split(struct xfs_da_state *state, 251178866Srafan struct xfs_da_state_blk *oldblk, 25262449Speter struct xfs_da_state_blk *newblk); 25362449Speterint xfs_attr_leaf_lookup_int(struct xfs_dabuf *leaf, 25450276Speter struct xfs_da_args *args); 25550276Speterint xfs_attr_leaf_getvalue(struct xfs_dabuf *bp, struct xfs_da_args *args); 256178866Srafanint xfs_attr_leaf_add(struct xfs_dabuf *leaf_buffer, 25750276Speter struct xfs_da_args *args); 258184989Srafanint xfs_attr_leaf_remove(struct xfs_dabuf *leaf_buffer, 259184989Srafan struct xfs_da_args *args); 260184989Srafanint xfs_attr_leaf_list_int(struct xfs_dabuf *bp, 261184989Srafan struct xfs_attr_list_context *context); 262184989Srafan 263184989Srafan/* 264184989Srafan * Routines used for shrinking the Btree. 26550276Speter */ 266184989Srafanint xfs_attr_leaf_toosmall(struct xfs_da_state *state, int *retval); 267184989Srafanvoid xfs_attr_leaf_unbalance(struct xfs_da_state *state, 268184989Srafan struct xfs_da_state_blk *drop_blk, 269184989Srafan struct xfs_da_state_blk *save_blk); 270184989Srafanint xfs_attr_root_inactive(struct xfs_trans **trans, struct xfs_inode *dp); 271184989Srafan 272184989Srafan/* 273184989Srafan * Utility routines. 274184989Srafan */ 275184989Srafanxfs_dahash_t xfs_attr_leaf_lasthash(struct xfs_dabuf *bp, int *count); 276184989Srafanint xfs_attr_leaf_order(struct xfs_dabuf *leaf1_bp, 277184989Srafan struct xfs_dabuf *leaf2_bp); 278184989Srafanint xfs_attr_leaf_newentsize(int namelen, int valuelen, int blocksize, 279184989Srafan int *local); 280184989Srafanint xfs_attr_rolltrans(struct xfs_trans **transp, struct xfs_inode *dp); 281184989Srafan 282184989Srafan#endif /* __XFS_ATTR_LEAF_H__ */ 283184989Srafan