xfs_attr_leaf.c

linux 内核源代码

/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms 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.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_da_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_alloc.h"
#include "xfs_btree.h"
#include "xfs_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_inode_item.h"
#include "xfs_bmap.h"
#include "xfs_attr.h"
#include "xfs_attr_leaf.h"
#include "xfs_error.h"

/*
 * xfs_attr_leaf.c
 *
 * Routines to implement leaf blocks of attributes as Btrees of hashed names.
 */

/*========================================================================
 * Function prototypes for the kernel.
 *========================================================================*/

/*
 * Routines used for growing the Btree.
 */
STATIC int xfs_attr_leaf_create(xfs_da_args_t *args, xfs_dablk_t which_block,
				    xfs_dabuf_t **bpp);
STATIC int xfs_attr_leaf_add_work(xfs_dabuf_t *leaf_buffer, xfs_da_args_t *args,
					      int freemap_index);
STATIC void xfs_attr_leaf_compact(xfs_trans_t *trans, xfs_dabuf_t *leaf_buffer);
STATIC void xfs_attr_leaf_rebalance(xfs_da_state_t *state,
						   xfs_da_state_blk_t *blk1,
						   xfs_da_state_blk_t *blk2);
STATIC int xfs_attr_leaf_figure_balance(xfs_da_state_t *state,
					   xfs_da_state_blk_t *leaf_blk_1,
					   xfs_da_state_blk_t *leaf_blk_2,
					   int *number_entries_in_blk1,
					   int *number_usedbytes_in_blk1);

/*
 * Routines used for shrinking the Btree.
 */
STATIC int xfs_attr_node_inactive(xfs_trans_t **trans, xfs_inode_t *dp,
				  xfs_dabuf_t *bp, int level);
STATIC int xfs_attr_leaf_inactive(xfs_trans_t **trans, xfs_inode_t *dp,
				  xfs_dabuf_t *bp);
STATIC int xfs_attr_leaf_freextent(xfs_trans_t **trans, xfs_inode_t *dp,
				   xfs_dablk_t blkno, int blkcnt);

/*
 * Utility routines.
 */
STATIC void xfs_attr_leaf_moveents(xfs_attr_leafblock_t *src_leaf,
					 int src_start,
					 xfs_attr_leafblock_t *dst_leaf,
					 int dst_start, int move_count,
					 xfs_mount_t *mp);
STATIC int xfs_attr_leaf_entsize(xfs_attr_leafblock_t *leaf, int index);

/*========================================================================
 * Namespace helper routines
 *========================================================================*/

STATIC_INLINE attrnames_t *
xfs_attr_flags_namesp(int flags)
{
	return ((flags & XFS_ATTR_SECURE) ? &attr_secure:
		  ((flags & XFS_ATTR_ROOT) ? &attr_trusted : &attr_user));
}

/*
 * If namespace bits don't match return 0.
 * If all match then return 1.
 */
STATIC_INLINE int
xfs_attr_namesp_match(int arg_flags, int ondisk_flags)
{
	return XFS_ATTR_NSP_ONDISK(ondisk_flags) == XFS_ATTR_NSP_ARGS_TO_ONDISK(arg_flags);
}

/*
 * If namespace bits don't match and we don't have an override for it
 * then return 0.
 * If all match or are overridable then return 1.
 */
STATIC_INLINE int
xfs_attr_namesp_match_overrides(int arg_flags, int ondisk_flags)
{
	if (((arg_flags & ATTR_SECURE) == 0) !=
	    ((ondisk_flags & XFS_ATTR_SECURE) == 0) &&
	    !(arg_flags & ATTR_KERNORMALS))
		return 0;
	if (((arg_flags & ATTR_ROOT) == 0) !=
	    ((ondisk_flags & XFS_ATTR_ROOT) == 0) &&
	    !(arg_flags & ATTR_KERNROOTLS))
		return 0;
	return 1;
}


/*========================================================================
 * External routines when attribute fork size < XFS_LITINO(mp).
 *========================================================================*/

/*
 * Query whether the requested number of additional bytes of extended
 * attribute space will be able to fit inline.
 * Returns zero if not, else the di_forkoff fork offset to be used in the
 * literal area for attribute data once the new bytes have been added.
 *
 * di_forkoff must be 8 byte aligned, hence is stored as a >>3 value;
 * special case for dev/uuid inodes, they have fixed size data forks.
 */
int
xfs_attr_shortform_bytesfit(xfs_inode_t *dp, int bytes)
{
	int offset;
	int minforkoff;	/* lower limit on valid forkoff locations */
	int maxforkoff;	/* upper limit on valid forkoff locations */
	int dsize;	
	xfs_mount_t *mp = dp->i_mount;

	offset = (XFS_LITINO(mp) - bytes) >> 3; /* rounded down */

	switch (dp->i_d.di_format) {
	case XFS_DINODE_FMT_DEV:
		minforkoff = roundup(sizeof(xfs_dev_t), 8) >> 3;
		return (offset >= minforkoff) ? minforkoff : 0;
	case XFS_DINODE_FMT_UUID:
		minforkoff = roundup(sizeof(uuid_t), 8) >> 3;
		return (offset >= minforkoff) ? minforkoff : 0;
	}

	if (!(mp->m_flags & XFS_MOUNT_ATTR2)) {
		if (bytes <= XFS_IFORK_ASIZE(dp))
			return mp->m_attroffset >> 3;
		return 0;
	}

	dsize = dp->i_df.if_bytes;
	
	switch (dp->i_d.di_format) {
	case XFS_DINODE_FMT_EXTENTS:
		/* 
		 * If there is no attr fork and the data fork is extents, 
		 * determine if creating the default attr fork will result 
		 * in the extents form migrating to btree. If so, the 
		 * minimum offset only needs to be the space required for 
		 * the btree root.
		 */ 
		if (!dp->i_d.di_forkoff && dp->i_df.if_bytes > mp->m_attroffset)
			dsize = XFS_BMDR_SPACE_CALC(MINDBTPTRS);
		break;
		
	case XFS_DINODE_FMT_BTREE:
		/*
		 * If have data btree then keep forkoff if we have one,
		 * otherwise we are adding a new attr, so then we set 
		 * minforkoff to where the btree root can finish so we have 
		 * plenty of room for attrs
		 */
		if (dp->i_d.di_forkoff) {
			if (offset < dp->i_d.di_forkoff) 
				return 0;
			else 
				return dp->i_d.di_forkoff;
		} else
			dsize = XFS_BMAP_BROOT_SPACE(dp->i_df.if_broot);
		break;
	}
	
	/* 
	 * A data fork btree root must have space for at least 
	 * MINDBTPTRS key/ptr pairs if the data fork is small or empty.
	 */
	minforkoff = MAX(dsize, XFS_BMDR_SPACE_CALC(MINDBTPTRS));
	minforkoff = roundup(minforkoff, 8) >> 3;

	/* attr fork btree root can have at least this many key/ptr pairs */
	maxforkoff = XFS_LITINO(mp) - XFS_BMDR_SPACE_CALC(MINABTPTRS);
	maxforkoff = maxforkoff >> 3;	/* rounded down */

	if (offset >= minforkoff && offset < maxforkoff)
		return offset;
	if (offset >= maxforkoff)
		return maxforkoff;
	return 0;
}

/*
 * Switch on the ATTR2 superblock bit (implies also FEATURES2)
 */
STATIC void
xfs_sbversion_add_attr2(xfs_mount_t *mp, xfs_trans_t *tp)
{
	unsigned long s;

	if ((mp->m_flags & XFS_MOUNT_ATTR2) &&
	    !(XFS_SB_VERSION_HASATTR2(&mp->m_sb))) {
		s = XFS_SB_LOCK(mp);
		if (!XFS_SB_VERSION_HASATTR2(&mp->m_sb)) {
			XFS_SB_VERSION_ADDATTR2(&mp->m_sb);
			XFS_SB_UNLOCK(mp, s);
			xfs_mod_sb(tp, XFS_SB_VERSIONNUM | XFS_SB_FEATURES2);
		} else
			XFS_SB_UNLOCK(mp, s);
	}
}

/*
 * Create the initial contents of a shortform attribute list.
 */
void
xfs_attr_shortform_create(xfs_da_args_t *args)
{
	xfs_attr_sf_hdr_t *hdr;
	xfs_inode_t *dp;
	xfs_ifork_t *ifp;

	dp = args->dp;
	ASSERT(dp != NULL);
	ifp = dp->i_afp;
	ASSERT(ifp != NULL);
	ASSERT(ifp->if_bytes == 0);
	if (dp->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS) {
		ifp->if_flags &= ~XFS_IFEXTENTS;	/* just in case */
		dp->i_d.di_aformat = XFS_DINODE_FMT_LOCAL;
		ifp->if_flags |= XFS_IFINLINE;
	} else {
		ASSERT(ifp->if_flags & XFS_IFINLINE);
	}
	xfs_idata_realloc(dp, sizeof(*hdr), XFS_ATTR_FORK);
	hdr = (xfs_attr_sf_hdr_t *)ifp->if_u1.if_data;
	hdr->count = 0;
	hdr->totsize = cpu_to_be16(sizeof(*hdr));
	xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE | XFS_ILOG_ADATA);
}

/*
 * Add a name/value pair to the shortform attribute list.
 * Overflow from the inode has already been checked for.
 */
void
xfs_attr_shortform_add(xfs_da_args_t *args, int forkoff)
{
	xfs_attr_shortform_t *sf;
	xfs_attr_sf_entry_t *sfe;
	int i, offset, size;
	xfs_mount_t *mp;
	xfs_inode_t *dp;
	xfs_ifork_t *ifp;

	dp = args->dp;
	mp = dp->i_mount;
	dp->i_d.di_forkoff = forkoff;
	dp->i_df.if_ext_max =
		XFS_IFORK_DSIZE(dp) / (uint)sizeof(xfs_bmbt_rec_t);
	dp->i_afp->if_ext_max =
		XFS_IFORK_ASIZE(dp) / (uint)sizeof(xfs_bmbt_rec_t);

	ifp = dp->i_afp;
	ASSERT(ifp->if_flags & XFS_IFINLINE);
	sf = (xfs_attr_shortform_t *)ifp->if_u1.if_data;
	sfe = &sf->list[0];
	for (i = 0; i < sf->hdr.count; sfe = XFS_ATTR_SF_NEXTENTRY(sfe), i++) {
#ifdef DEBUG
		if (sfe->namelen != args->namelen)
			continue;
		if (memcmp(args->name, sfe->nameval, args->namelen) != 0)
			continue;
		if (!xfs_attr_namesp_match(args->flags, sfe->flags))
			continue;
		ASSERT(0);
#endif
	}

	offset = (char *)sfe - (char *)sf;
	size = XFS_ATTR_SF_ENTSIZE_BYNAME(args->namelen, args->valuelen);
	xfs_idata_realloc(dp, size, XFS_ATTR_FORK);
	sf = (xfs_attr_shortform_t *)ifp->if_u1.if_data;
	sfe = (xfs_attr_sf_entry_t *)((char *)sf + offset);

	sfe->namelen = args->namelen;
	sfe->valuelen = args->valuelen;
	sfe->flags = XFS_ATTR_NSP_ARGS_TO_ONDISK(args->flags);
	memcpy(sfe->nameval, args->name, args->namelen);
	memcpy(&sfe->nameval[args->namelen], args->value, args->valuelen);
	sf->hdr.count++;
	be16_add(&sf->hdr.totsize, size);
	xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE | XFS_ILOG_ADATA);

	xfs_sbversion_add_attr2(mp, args->trans);
}

/*
 * Remove an attribute from the shortform attribute list structure.
 */
int
xfs_attr_shortform_remove(xfs_da_args_t *args)
{
	xfs_attr_shortform_t *sf;
	xfs_attr_sf_entry_t *sfe;
	int base, size=0, end, totsize, i;
	xfs_mount_t *mp;
	xfs_inode_t *dp;

	dp = args->dp;
	mp = dp->i_mount;
	base = sizeof(xfs_attr_sf_hdr_t);
	sf = (xfs_attr_shortform_t *)dp->i_afp->if_u1.if_data;
	sfe = &sf->list[0];
	end = sf->hdr.count;
	for (i = 0; i < end; sfe = XFS_ATTR_SF_NEXTENTRY(sfe),
					base += size, i++) {
		size = XFS_ATTR_SF_ENTSIZE(sfe);
		if (sfe->namelen != args->namelen)
			continue;
		if (memcmp(sfe->nameval, args->name, args->namelen) != 0)
			continue;
		if (!xfs_attr_namesp_match(args->flags, sfe->flags))
			continue;
		break;
	}
	if (i == end)
		return(XFS_ERROR(ENOATTR));

	/*
	 * Fix up the attribute fork data, covering the hole
	 */
	end = base + size;
	totsize = be16_to_cpu(sf->hdr.totsize);
	if (end != totsize)
		memmove(&((char *)sf)[base], &((char *)sf)[end], totsize - end);
	sf->hdr.count--;
	be16_add(&sf->hdr.totsize, -size);

	/*
	 * Fix up the start offset of the attribute fork
	 */
	totsize -= size;
	if (totsize == sizeof(xfs_attr_sf_hdr_t) && !args->addname &&
	    (mp->m_flags & XFS_MOUNT_ATTR2) && 
	    (dp->i_d.di_format != XFS_DINODE_FMT_BTREE)) {
		/*
		 * Last attribute now removed, revert to original
		 * inode format making all literal area available
		 * to the data fork once more.
		 */
		xfs_idestroy_fork(dp, XFS_ATTR_FORK);
		dp->i_d.di_forkoff = 0;
		dp->i_d.di_aformat = XFS_DINODE_FMT_EXTENTS;
		ASSERT(dp->i_d.di_anextents == 0);
		ASSERT(dp->i_afp == NULL);
		dp->i_df.if_ext_max =
			XFS_IFORK_DSIZE(dp) / (uint)sizeof(xfs_bmbt_rec_t);
		xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE);
	} else {
		xfs_idata_realloc(dp, -size, XFS_ATTR_FORK);
		dp->i_d.di_forkoff = xfs_attr_shortform_bytesfit(dp, totsize);
		ASSERT(dp->i_d.di_forkoff);
		ASSERT(totsize > sizeof(xfs_attr_sf_hdr_t) || args->addname ||
			!(mp->m_flags & XFS_MOUNT_ATTR2) ||
			dp->i_d.di_format == XFS_DINODE_FMT_BTREE);
		dp->i_afp->if_ext_max =
			XFS_IFORK_ASIZE(dp) / (uint)sizeof(xfs_bmbt_rec_t);
		dp->i_df.if_ext_max =
			XFS_IFORK_DSIZE(dp) / (uint)sizeof(xfs_bmbt_rec_t);
		xfs_trans_log_inode(args->trans, dp,
					XFS_ILOG_CORE | XFS_ILOG_ADATA);
	}

	xfs_sbversion_add_attr2(mp, args->trans);

	return(0);
}

/*
 * Look up a name in a shortform attribute list structure.
 */
/*ARGSUSED*/
int
xfs_attr_shortform_lookup(xfs_da_args_t *args)
{
	xfs_attr_shortform_t *sf;
	xfs_attr_sf_entry_t *sfe;
	int i;
	xfs_ifork_t *ifp;

	ifp = args->dp->i_afp;
	ASSERT(ifp->if_flags & XFS_IFINLINE);
	sf = (xfs_attr_shortform_t *)ifp->if_u1.if_data;
	sfe = &sf->list[0];
	for (i = 0; i < sf->hdr.count;
				sfe = XFS_ATTR_SF_NEXTENTRY(sfe), i++) {
		if (sfe->namelen != args->namelen)
			continue;
		if (memcmp(args->name, sfe->nameval, args->namelen) != 0)
			continue;
		if (!xfs_attr_namesp_match(args->flags, sfe->flags))
			continue;
		return(XFS_ERROR(EEXIST));
	}
	return(XFS_ERROR(ENOATTR));
}

/*
 * Look up a name in a shortform attribute list structure.
 */
/*ARGSUSED*/
int