patch-2.4.25 linux-2.4.25/fs/xfs/xfs_dir_leaf.h

• Lines: 254
• Date: 2004-02-18 05:36:32.000000000 -0800
• Orig file: linux-2.4.24/fs/xfs/xfs_dir_leaf.h
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.24/fs/xfs/xfs_dir_leaf.h linux-2.4.25/fs/xfs/xfs_dir_leaf.h
@@ -0,0 +1,253 @@
+/*
+ * Copyright (c) 2000-2001 Silicon Graphics, Inc.  All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2 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.
+ *
+ * Further, this software is distributed without any warranty that it is
+ * free of the rightful claim of any third person regarding infringement
+ * or the like.  Any license provided herein, whether implied or
+ * otherwise, applies only to this software file.  Patent licenses, if
+ * any, provided herein do not apply to combinations of this program with
+ * other software, or any other product whatsoever.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write the Free Software Foundation, Inc., 59
+ * Temple Place - Suite 330, Boston MA 02111-1307, USA.
+ *
+ * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
+ * Mountain View, CA  94043, or:
+ *
+ * http://www.sgi.com
+ *
+ * For further information regarding this notice, see:
+ *
+ * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
+ */
+#ifndef __XFS_DIR_LEAF_H__
+#define	__XFS_DIR_LEAF_H__
+
+/*
+ * Directory layout, internal structure, access macros, etc.
+ *
+ * Large directories are structured around Btrees where all the data
+ * elements are in the leaf nodes.  Filenames are hashed into an int,
+ * then that int is used as the index into the Btree.  Since the hashval
+ * of a filename may not be unique, we may have duplicate keys.  The
+ * internal links in the Btree are logical block offsets into the file.
+ */
+
+struct uio;
+struct xfs_bmap_free;
+struct xfs_dabuf;
+struct xfs_da_args;
+struct xfs_da_state;
+struct xfs_da_state_blk;
+struct xfs_dir_put_args;
+struct xfs_inode;
+struct xfs_mount;
+struct xfs_trans;
+
+/*========================================================================
+ * Directory Structure when equal to XFS_LBSIZE(mp) bytes.
+ *========================================================================*/
+
+/*
+ * This is the structure of the leaf nodes in the Btree.
+ *
+ * Struct leaf_entry's are packed from the top.  Names 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 namelist area and try again.  If we
+ * still don't have enough space, then we have to split the block.
+ *
+ * Since we have duplicate hash keys, for each key that matches, compare
+ * the actual 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 filename is found.
+ *
+ * The parent directory and the self-pointer are explicitly represented
+ * (ie: there are entries for "." and "..").
+ *
+ * Note that the count being a __uint16_t limits us to something like a
+ * blocksize of 1.3MB in the face of worst case (short) filenames.
+ */
+#define XFS_DIR_LEAF_MAPSIZE	3	/* how many freespace slots */
+
+typedef struct xfs_dir_leafblock {
+	struct xfs_dir_leaf_hdr {	/* constant-structure header block */
+		xfs_da_blkinfo_t info;	/* block type, links, etc. */
+		__uint16_t count;	/* count of active leaf_entry's */
+		__uint16_t namebytes;	/* num bytes of name strings stored */
+		__uint16_t firstused;	/* first used byte in name area */
+		__uint8_t  holes;	/* != 0 if blk needs compaction */
+		__uint8_t  pad1;
+		struct xfs_dir_leaf_map {/* RLE map of free bytes */
+			__uint16_t base; /* base of free region */
+			__uint16_t size; /* run length of free region */
+		} freemap[XFS_DIR_LEAF_MAPSIZE]; /* N largest free regions */
+	} hdr;
+	struct xfs_dir_leaf_entry {	/* sorted on key, not name */
+		xfs_dahash_t hashval;	/* hash value of name */
+		__uint16_t nameidx;	/* index into buffer of name */
+		__uint8_t namelen;	/* length of name string */
+		__uint8_t pad2;
+	} entries[1];			/* var sized array */
+	struct xfs_dir_leaf_name {
+		xfs_dir_ino_t inumber;	/* inode number for this key */
+		__uint8_t name[1];	/* name string itself */
+	} namelist[1];			/* grows from bottom of buf */
+} xfs_dir_leafblock_t;
+typedef struct xfs_dir_leaf_hdr xfs_dir_leaf_hdr_t;
+typedef struct xfs_dir_leaf_map xfs_dir_leaf_map_t;
+typedef struct xfs_dir_leaf_entry xfs_dir_leaf_entry_t;
+typedef struct xfs_dir_leaf_name xfs_dir_leaf_name_t;
+
+/*
+ * Length of name for which a 512-byte block filesystem
+ * can get a double split.
+ */
+#define	XFS_DIR_LEAF_CAN_DOUBLE_SPLIT_LEN	\
+	(512 - (uint)sizeof(xfs_dir_leaf_hdr_t) - \
+	 (uint)sizeof(xfs_dir_leaf_entry_t) * 2 - \
+	 (uint)sizeof(xfs_dir_leaf_name_t) * 2 - (MAXNAMELEN - 2) + 1 + 1)
+
+typedef int (*xfs_dir_put_t)(struct xfs_dir_put_args *pa);
+
+typedef union {
+	xfs_off_t		o;		/* offset (cookie) */
+	/*
+	 * Watch the order here (endian-ness dependent).
+	 */
+	struct {
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+		xfs_dahash_t	h;	/* hash value */
+		__uint32_t	be;	/* block and entry */
+#else	/* __BYTE_ORDER == __BIG_ENDIAN */
+		__uint32_t	be;	/* block and entry */
+		xfs_dahash_t	h;	/* hash value */
+#endif	/* __BYTE_ORDER == __BIG_ENDIAN */
+	} s;
+} xfs_dircook_t;
+
+#define	XFS_PUT_COOKIE(c,mp,bno,entry,hash)	\
+	((c).s.be = XFS_DA_MAKE_BNOENTRY(mp, bno, entry), (c).s.h = (hash))
+
+#define	XFS_GET_DIR_INO_ARCH(mp,di,arch) \
+    DIRINO_GET_ARCH(&(di),arch)
+#define	XFS_GET_DIR_INO(mp,di) \
+    XFS_GET_DIR_INO_ARCH(mp,di,ARCH_NOCONVERT)
+
+typedef struct xfs_dir_put_args
+{
+	xfs_dircook_t	cook;		/* cookie of (next) entry */
+	xfs_intino_t	ino;		/* inode number */
+	struct xfs_dirent	*dbp;		/* buffer pointer */
+	char		*name;		/* directory entry name */
+	int		namelen;	/* length of name */
+	int		done;		/* output: set if value was stored */
+	xfs_dir_put_t	put;		/* put function ptr (i/o) */
+	struct uio	*uio;		/* uio control structure */
+} xfs_dir_put_args_t;
+
+#if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_DIR_LEAF_ENTSIZE_BYNAME)
+int xfs_dir_leaf_entsize_byname(int len);
+#define XFS_DIR_LEAF_ENTSIZE_BYNAME(len)	xfs_dir_leaf_entsize_byname(len)
+#else
+#define XFS_DIR_LEAF_ENTSIZE_BYNAME(len)	/* space a name will use */ \
+	((uint)sizeof(xfs_dir_leaf_name_t)-1 + len)
+#endif
+#if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_DIR_LEAF_ENTSIZE_BYENTRY)
+int xfs_dir_leaf_entsize_byentry(xfs_dir_leaf_entry_t *entry);
+#define XFS_DIR_LEAF_ENTSIZE_BYENTRY(entry)	\
+	xfs_dir_leaf_entsize_byentry(entry)
+#else
+#define XFS_DIR_LEAF_ENTSIZE_BYENTRY(entry)	/* space an entry will use */ \
+	((uint)sizeof(xfs_dir_leaf_name_t)-1 + (entry)->namelen)
+#endif
+#if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_DIR_LEAF_NAMESTRUCT)
+xfs_dir_leaf_name_t *
+xfs_dir_leaf_namestruct(xfs_dir_leafblock_t *leafp, int offset);
+#define XFS_DIR_LEAF_NAMESTRUCT(leafp,offset)	\
+	xfs_dir_leaf_namestruct(leafp,offset)
+#else
+#define XFS_DIR_LEAF_NAMESTRUCT(leafp,offset)	/* point to name struct */ \
+	((xfs_dir_leaf_name_t *)&((char *)(leafp))[offset])
+#endif
+
+/*========================================================================
+ * Function prototypes for the kernel.
+ *========================================================================*/
+
+/*
+ * Internal routines when dirsize < XFS_LITINO(mp).
+ */
+int xfs_dir_shortform_create(struct xfs_da_args *args, xfs_ino_t parent);
+int xfs_dir_shortform_addname(struct xfs_da_args *args);
+int xfs_dir_shortform_lookup(struct xfs_da_args *args);
+int xfs_dir_shortform_to_leaf(struct xfs_da_args *args);
+int xfs_dir_shortform_removename(struct xfs_da_args *args);
+int xfs_dir_shortform_getdents(struct xfs_inode *dp, struct uio *uio, int *eofp,
+				      struct xfs_dirent *dbp, xfs_dir_put_t put);
+int xfs_dir_shortform_replace(struct xfs_da_args *args);
+
+/*
+ * Internal routines when dirsize == XFS_LBSIZE(mp).
+ */
+int xfs_dir_leaf_to_node(struct xfs_da_args *args);
+int xfs_dir_leaf_to_shortform(struct xfs_da_args *args);
+
+/*
+ * Routines used for growing the Btree.
+ */
+int	xfs_dir_leaf_create(struct xfs_da_args *args, xfs_dablk_t which_block,
+				   struct xfs_dabuf **bpp);
+int	xfs_dir_leaf_split(struct xfs_da_state *state,
+				  struct xfs_da_state_blk *oldblk,
+				  struct xfs_da_state_blk *newblk);
+int	xfs_dir_leaf_add(struct xfs_dabuf *leaf_buffer,
+				struct xfs_da_args *args, int insertion_index);
+int	xfs_dir_leaf_addname(struct xfs_da_args *args);
+int	xfs_dir_leaf_lookup_int(struct xfs_dabuf *leaf_buffer,
+				       struct xfs_da_args *args,
+				       int *index_found_at);
+int	xfs_dir_leaf_remove(struct xfs_trans *trans,
+				   struct xfs_dabuf *leaf_buffer,
+				   int index_to_remove);
+int	xfs_dir_leaf_getdents_int(struct xfs_dabuf *bp, struct xfs_inode *dp,
+					 xfs_dablk_t bno, struct uio *uio,
+					 int *eobp, struct xfs_dirent *dbp,
+					 xfs_dir_put_t put, xfs_daddr_t nextda);
+
+/*
+ * Routines used for shrinking the Btree.
+ */
+int	xfs_dir_leaf_toosmall(struct xfs_da_state *state, int *retval);
+void	xfs_dir_leaf_unbalance(struct xfs_da_state *state,
+					     struct xfs_da_state_blk *drop_blk,
+					     struct xfs_da_state_blk *save_blk);
+
+/*
+ * Utility routines.
+ */
+uint	xfs_dir_leaf_lasthash(struct xfs_dabuf *bp, int *count);
+int	xfs_dir_leaf_order(struct xfs_dabuf *leaf1_bp,
+				  struct xfs_dabuf *leaf2_bp);
+int	xfs_dir_put_dirent64_direct(xfs_dir_put_args_t *pa);
+int	xfs_dir_put_dirent64_uio(xfs_dir_put_args_t *pa);
+int	xfs_dir_ino_validate(struct xfs_mount *mp, xfs_ino_t ino);
+
+
+/*
+ * Global data.
+ */
+extern xfs_dahash_t	xfs_dir_hash_dot, xfs_dir_hash_dotdot;
+
+#endif /* __XFS_DIR_LEAF_H__ */