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

• Lines: 310
• Date: 2004-02-18 05:36:32.000000000 -0800
• Orig file: linux-2.4.24/fs/xfs/xfs_attr_leaf.h
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.24/fs/xfs/xfs_attr_leaf.h linux-2.4.25/fs/xfs/xfs_attr_leaf.h
@@ -0,0 +1,309 @@
+/*
+ * Copyright (c) 2000, 2002-2003 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_ATTR_LEAF_H__
+#define	__XFS_ATTR_LEAF_H__
+
+/*
+ * Attribute storage layout, internal structure, access macros, etc.
+ *
+ * Attribute lists are structured around Btrees where all the data
+ * elements are in the leaf nodes.  Attribute names are hashed into an int,
+ * then that int is used as the index into the Btree.  Since the hashval
+ * of an attribute name may not be unique, we may have duplicate keys.  The
+ * internal links in the Btree are logical block offsets into the file.
+ */
+
+struct attrlist;
+struct attrlist_cursor_kern;
+struct attrnames;
+struct xfs_dabuf;
+struct xfs_da_args;
+struct xfs_da_state;
+struct xfs_da_state_blk;
+struct xfs_inode;
+struct xfs_trans;
+
+/*========================================================================
+ * Attribute 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.  Name/values 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 name/value area and try again.  If we
+ * still don't have enough space, then we have to split the block.  The
+ * name/value structs (both local and remote versions) must be 32bit aligned.
+ *
+ * Since we have duplicate hash keys, for each key that matches, compare
+ * the actual name 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 attribute name is found.
+ *
+ * We store the fact that an attribute is a ROOT/USER/SECURE attribute in
+ * the leaf_entry.  The namespaces are independent only because we also look
+ * at the namespace bit when we are looking for a matching attribute name.
+ *
+ * We also store a "incomplete" bit in the leaf_entry.  It shows that an
+ * attribute is in the middle of being created and should not be shown to
+ * the user if we crash during the time that the bit is set.  We clear the
+ * bit when we have finished setting up the attribute.  We do this because
+ * we cannot create some large attributes inside a single transaction, and we
+ * need some indication that we weren't finished if we crash in the middle.
+ */
+#define XFS_ATTR_LEAF_MAPSIZE	3	/* how many freespace slots */
+
+typedef struct xfs_attr_leafblock {
+	struct xfs_attr_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 usedbytes;	/* num bytes of names/values stored */
+		__uint16_t firstused;	/* first used byte in name area */
+		__uint8_t  holes;	/* != 0 if blk needs compaction */
+		__uint8_t  pad1;
+		struct xfs_attr_leaf_map {	  /* RLE map of free bytes */
+			__uint16_t base;	  /* base of free region */
+			__uint16_t size;	  /* length of free region */
+		} freemap[XFS_ATTR_LEAF_MAPSIZE]; /* N largest free regions */
+	} hdr;
+	struct xfs_attr_leaf_entry {	/* sorted on key, not name */
+		xfs_dahash_t hashval;	/* hash value of name */
+		__uint16_t nameidx;	/* index into buffer of name/value */
+		__uint8_t flags;	/* LOCAL/ROOT/SECURE/INCOMPLETE flag */
+		__uint8_t pad2;		/* unused pad byte */
+	} entries[1];			/* variable sized array */
+	struct xfs_attr_leaf_name_local {
+		__uint16_t valuelen;	/* number of bytes in value */
+		__uint8_t namelen;	/* length of name bytes */
+		__uint8_t nameval[1];	/* name/value bytes */
+	} namelist;			/* grows from bottom of buf */
+	struct xfs_attr_leaf_name_remote {
+		xfs_dablk_t valueblk;	/* block number of value bytes */
+		__uint32_t valuelen;	/* number of bytes in value */
+		__uint8_t namelen;	/* length of name bytes */
+		__uint8_t name[1];	/* name bytes */
+	} valuelist;			/* grows from bottom of buf */
+} xfs_attr_leafblock_t;
+typedef struct xfs_attr_leaf_hdr xfs_attr_leaf_hdr_t;
+typedef struct xfs_attr_leaf_map xfs_attr_leaf_map_t;
+typedef struct xfs_attr_leaf_entry xfs_attr_leaf_entry_t;
+typedef struct xfs_attr_leaf_name_local xfs_attr_leaf_name_local_t;
+typedef struct xfs_attr_leaf_name_remote xfs_attr_leaf_name_remote_t;
+
+/*
+ * Flags used in the leaf_entry[i].flags field.
+ * NOTE: the INCOMPLETE bit must not collide with the flags bits specified
+ * on the system call, they are "or"ed together for various operations.
+ */
+#define	XFS_ATTR_LOCAL_BIT	0	/* attr is stored locally */
+#define	XFS_ATTR_ROOT_BIT	1	/* limit access to trusted attrs */
+#define	XFS_ATTR_SECURE_BIT	2	/* limit access to secure attrs */
+#define	XFS_ATTR_INCOMPLETE_BIT	7	/* attr in middle of create/delete */
+#define XFS_ATTR_LOCAL		(1 << XFS_ATTR_LOCAL_BIT)
+#define XFS_ATTR_ROOT		(1 << XFS_ATTR_ROOT_BIT)
+#define XFS_ATTR_SECURE		(1 << XFS_ATTR_SECURE_BIT)
+#define XFS_ATTR_INCOMPLETE	(1 << XFS_ATTR_INCOMPLETE_BIT)
+
+/*
+ * Alignment for namelist and valuelist entries (since they are mixed
+ * there can be only one alignment value)
+ */
+#define	XFS_ATTR_LEAF_NAME_ALIGN	((uint)sizeof(xfs_dablk_t))
+
+/*
+ * Cast typed pointers for "local" and "remote" name/value structs.
+ */
+#if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_NAME_REMOTE)
+xfs_attr_leaf_name_remote_t *
+xfs_attr_leaf_name_remote(xfs_attr_leafblock_t *leafp, int idx);
+#define XFS_ATTR_LEAF_NAME_REMOTE(leafp,idx)	\
+	xfs_attr_leaf_name_remote(leafp,idx)
+#else
+#define XFS_ATTR_LEAF_NAME_REMOTE(leafp,idx)	/* remote name struct ptr */ \
+	((xfs_attr_leaf_name_remote_t *)		\
+	 &((char *)(leafp))[ INT_GET((leafp)->entries[idx].nameidx, ARCH_CONVERT) ])
+#endif
+#if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_NAME_LOCAL)
+xfs_attr_leaf_name_local_t *
+xfs_attr_leaf_name_local(xfs_attr_leafblock_t *leafp, int idx);
+#define XFS_ATTR_LEAF_NAME_LOCAL(leafp,idx)	\
+	xfs_attr_leaf_name_local(leafp,idx)
+#else
+#define XFS_ATTR_LEAF_NAME_LOCAL(leafp,idx)	/* local name struct ptr */ \
+	((xfs_attr_leaf_name_local_t *)		\
+	 &((char *)(leafp))[ INT_GET((leafp)->entries[idx].nameidx, ARCH_CONVERT) ])
+#endif
+#if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_NAME)
+char *xfs_attr_leaf_name(xfs_attr_leafblock_t *leafp, int idx);
+#define XFS_ATTR_LEAF_NAME(leafp,idx)		xfs_attr_leaf_name(leafp,idx)
+#else
+#define XFS_ATTR_LEAF_NAME(leafp,idx)		/* generic name struct ptr */ \
+	(&((char *)(leafp))[ INT_GET((leafp)->entries[idx].nameidx, ARCH_CONVERT) ])
+#endif
+
+/*
+ * Calculate total bytes used (including trailing pad for alignment) for
+ * a "local" name/value structure, a "remote" name/value structure, and
+ * a pointer which might be either.
+ */
+#if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_ENTSIZE_REMOTE)
+int xfs_attr_leaf_entsize_remote(int nlen);
+#define XFS_ATTR_LEAF_ENTSIZE_REMOTE(nlen)	\
+	xfs_attr_leaf_entsize_remote(nlen)
+#else
+#define XFS_ATTR_LEAF_ENTSIZE_REMOTE(nlen)	/* space for remote struct */ \
+	(((uint)sizeof(xfs_attr_leaf_name_remote_t) - 1 + (nlen) + \
+	  XFS_ATTR_LEAF_NAME_ALIGN - 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN - 1))
+#endif
+#if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_ENTSIZE_LOCAL)
+int xfs_attr_leaf_entsize_local(int nlen, int vlen);
+#define XFS_ATTR_LEAF_ENTSIZE_LOCAL(nlen,vlen)	\
+	xfs_attr_leaf_entsize_local(nlen,vlen)
+#else
+#define XFS_ATTR_LEAF_ENTSIZE_LOCAL(nlen,vlen)	/* space for local struct */ \
+	(((uint)sizeof(xfs_attr_leaf_name_local_t) - 1 + (nlen) + (vlen) + \
+	  XFS_ATTR_LEAF_NAME_ALIGN - 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN - 1))
+#endif
+#if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_ATTR_LEAF_ENTSIZE_LOCAL_MAX)
+int xfs_attr_leaf_entsize_local_max(int bsize);
+#define XFS_ATTR_LEAF_ENTSIZE_LOCAL_MAX(bsize)	\
+	xfs_attr_leaf_entsize_local_max(bsize)
+#else
+#define XFS_ATTR_LEAF_ENTSIZE_LOCAL_MAX(bsize)	/* max local struct size */ \
+	(((bsize) >> 1) + ((bsize) >> 2))
+#endif
+
+
+/*========================================================================
+ * Structure used to pass context around among the routines.
+ *========================================================================*/
+
+typedef struct xfs_attr_list_context {
+	struct xfs_inode		*dp;	/* inode */
+	struct attrlist_cursor_kern	*cursor;/* position in list */
+	struct attrlist			*alist;	/* output buffer */
+	int				count;	/* num used entries */
+	int				dupcnt;	/* count dup hashvals seen */
+	int				bufsize;/* total buffer size */
+	int				firstu;	/* first used byte in buffer */
+	int				flags;	/* from VOP call */
+	int				resynch;/* T/F: resynch with cursor */
+} xfs_attr_list_context_t;
+
+/*
+ * Used to keep a list of "remote value" extents when unlinking an inode.
+ */
+typedef struct xfs_attr_inactive_list {
+	xfs_dablk_t	valueblk;	/* block number of value bytes */
+	int		valuelen;	/* number of bytes in value */
+} xfs_attr_inactive_list_t;
+
+
+/*========================================================================
+ * Function prototypes for the kernel.
+ *========================================================================*/
+
+/*
+ * Internal routines when dirsize < XFS_LITINO(mp).
+ */
+int	xfs_attr_shortform_create(struct xfs_da_args *args);
+int	xfs_attr_shortform_add(struct xfs_da_args *add);
+int	xfs_attr_shortform_lookup(struct xfs_da_args *args);
+int	xfs_attr_shortform_getvalue(struct xfs_da_args *args);
+int	xfs_attr_shortform_to_leaf(struct xfs_da_args *args);
+int	xfs_attr_shortform_remove(struct xfs_da_args *remove);
+int	xfs_attr_shortform_list(struct xfs_attr_list_context *context);
+int	xfs_attr_shortform_replace(struct xfs_da_args *args);
+int	xfs_attr_shortform_allfit(struct xfs_dabuf *bp, struct xfs_inode *dp);
+
+/*
+ * Internal routines when dirsize == XFS_LBSIZE(mp).
+ */
+int	xfs_attr_leaf_to_node(struct xfs_da_args *args);
+int	xfs_attr_leaf_to_shortform(struct xfs_dabuf *bp,
+					  struct xfs_da_args *args);
+int	xfs_attr_leaf_clearflag(struct xfs_da_args *args);
+int	xfs_attr_leaf_setflag(struct xfs_da_args *args);
+int	xfs_attr_leaf_flipflags(xfs_da_args_t *args);
+
+/*
+ * Routines used for growing the Btree.
+ */
+int	xfs_attr_leaf_create(struct xfs_da_args *args, xfs_dablk_t which_block,
+				    struct xfs_dabuf **bpp);
+int	xfs_attr_leaf_split(struct xfs_da_state *state,
+				   struct xfs_da_state_blk *oldblk,
+				   struct xfs_da_state_blk *newblk);
+int	xfs_attr_leaf_lookup_int(struct xfs_dabuf *leaf,
+					struct xfs_da_args *args);
+int	xfs_attr_leaf_getvalue(struct xfs_dabuf *bp, struct xfs_da_args *args);
+int	xfs_attr_leaf_add(struct xfs_dabuf *leaf_buffer,
+				 struct xfs_da_args *args);
+int	xfs_attr_leaf_remove(struct xfs_dabuf *leaf_buffer,
+				    struct xfs_da_args *args);
+int	xfs_attr_leaf_list_int(struct xfs_dabuf *bp,
+				      struct xfs_attr_list_context *context);
+
+/*
+ * Routines used for shrinking the Btree.
+ */
+int	xfs_attr_leaf_toosmall(struct xfs_da_state *state, int *retval);
+void	xfs_attr_leaf_unbalance(struct xfs_da_state *state,
+				       struct xfs_da_state_blk *drop_blk,
+				       struct xfs_da_state_blk *save_blk);
+int	xfs_attr_root_inactive(struct xfs_trans **trans, struct xfs_inode *dp);
+int	xfs_attr_node_inactive(struct xfs_trans **trans, struct xfs_inode *dp,
+				      struct xfs_dabuf *bp, int level);
+int	xfs_attr_leaf_inactive(struct xfs_trans **trans, struct xfs_inode *dp,
+				      struct xfs_dabuf *bp);
+int	xfs_attr_leaf_freextent(struct xfs_trans **trans, struct xfs_inode *dp,
+				       xfs_dablk_t blkno, int blkcnt);
+
+/*
+ * Utility routines.
+ */
+xfs_dahash_t	xfs_attr_leaf_lasthash(struct xfs_dabuf *bp, int *count);
+int	xfs_attr_leaf_order(struct xfs_dabuf *leaf1_bp,
+				   struct xfs_dabuf *leaf2_bp);
+int	xfs_attr_leaf_newentsize(struct xfs_da_args *args, int blocksize,
+					int *local);
+int	xfs_attr_leaf_entsize(struct xfs_attr_leafblock *leaf, int index);
+int	xfs_attr_put_listent(struct xfs_attr_list_context *context,
+			     struct attrnames *, char *name, int namelen,
+			     int valuelen);
+int	xfs_attr_rolltrans(struct xfs_trans **transp, struct xfs_inode *dp);
+
+#endif	/* __XFS_ATTR_LEAF_H__ */