xfs_attr.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 <linux/capability.h>

#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_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_alloc.h"
#include "xfs_btree.h"
#include "xfs_inode_item.h"
#include "xfs_bmap.h"
#include "xfs_attr.h"
#include "xfs_attr_leaf.h"
#include "xfs_error.h"
#include "xfs_quota.h"
#include "xfs_trans_space.h"
#include "xfs_acl.h"
#include "xfs_rw.h"
#include "xfs_vnodeops.h"

/*
 * xfs_attr.c
 *
 * Provide the external interfaces to manage attribute lists.
 */

#define ATTR_SYSCOUNT	2
static struct attrnames posix_acl_access;
static struct attrnames posix_acl_default;
static struct attrnames *attr_system_names[ATTR_SYSCOUNT];

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

/*
 * Internal routines when attribute list fits inside the inode.
 */
STATIC int xfs_attr_shortform_addname(xfs_da_args_t *args);

/*
 * Internal routines when attribute list is one block.
 */
STATIC int xfs_attr_leaf_get(xfs_da_args_t *args);
STATIC int xfs_attr_leaf_addname(xfs_da_args_t *args);
STATIC int xfs_attr_leaf_removename(xfs_da_args_t *args);
STATIC int xfs_attr_leaf_list(xfs_attr_list_context_t *context);

/*
 * Internal routines when attribute list is more than one block.
 */
STATIC int xfs_attr_node_get(xfs_da_args_t *args);
STATIC int xfs_attr_node_addname(xfs_da_args_t *args);
STATIC int xfs_attr_node_removename(xfs_da_args_t *args);
STATIC int xfs_attr_node_list(xfs_attr_list_context_t *context);
STATIC int xfs_attr_fillstate(xfs_da_state_t *state);
STATIC int xfs_attr_refillstate(xfs_da_state_t *state);

/*
 * Routines to manipulate out-of-line attribute values.
 */
STATIC int xfs_attr_rmtval_set(xfs_da_args_t *args);
STATIC int xfs_attr_rmtval_remove(xfs_da_args_t *args);

#define ATTR_RMTVALUE_MAPSIZE	1	/* # of map entries at once */

#if defined(XFS_ATTR_TRACE)
ktrace_t *xfs_attr_trace_buf;
#endif


/*========================================================================
 * Overall external interface routines.
 *========================================================================*/

int
xfs_attr_fetch(xfs_inode_t *ip, const char *name, int namelen,
	       char *value, int *valuelenp, int flags, struct cred *cred)
{
	xfs_da_args_t   args;
	int             error;

	if ((XFS_IFORK_Q(ip) == 0) ||
	    (ip->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS &&
	     ip->i_d.di_anextents == 0))
		return(ENOATTR);

	/*
	 * Fill in the arg structure for this request.
	 */
	memset((char *)&args, 0, sizeof(args));
	args.name = name;
	args.namelen = namelen;
	args.value = value;
	args.valuelen = *valuelenp;
	args.flags = flags;
	args.hashval = xfs_da_hashname(args.name, args.namelen);
	args.dp = ip;
	args.whichfork = XFS_ATTR_FORK;

	/*
	 * Decide on what work routines to call based on the inode size.
	 */
	if (XFS_IFORK_Q(ip) == 0 ||
	    (ip->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS &&
	     ip->i_d.di_anextents == 0)) {
		error = XFS_ERROR(ENOATTR);
	} else if (ip->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
		error = xfs_attr_shortform_getvalue(&args);
	} else if (xfs_bmap_one_block(ip, XFS_ATTR_FORK)) {
		error = xfs_attr_leaf_get(&args);
	} else {
		error = xfs_attr_node_get(&args);
	}

	/*
	 * Return the number of bytes in the value to the caller.
	 */
	*valuelenp = args.valuelen;

	if (error == EEXIST)
		error = 0;
	return(error);
}

int
xfs_attr_get(
	xfs_inode_t	*ip,
	const char	*name,
	char		*value,
	int		*valuelenp,
	int		flags,
	cred_t		*cred)
{
	int		error, namelen;

	XFS_STATS_INC(xs_attr_get);

	if (!name)
		return(EINVAL);
	namelen = strlen(name);
	if (namelen >= MAXNAMELEN)
		return(EFAULT);		/* match IRIX behaviour */

	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
		return(EIO);

	xfs_ilock(ip, XFS_ILOCK_SHARED);
	error = xfs_attr_fetch(ip, name, namelen, value, valuelenp, flags, cred);
	xfs_iunlock(ip, XFS_ILOCK_SHARED);
	return(error);
}

int
xfs_attr_set_int(xfs_inode_t *dp, const char *name, int namelen,
		 char *value, int valuelen, int flags)
{
	xfs_da_args_t	args;
	xfs_fsblock_t	firstblock;
	xfs_bmap_free_t flist;
	int		error, err2, committed;
	int		local, size;
	uint		nblks;
	xfs_mount_t	*mp = dp->i_mount;
	int             rsvd = (flags & ATTR_ROOT) != 0;

	/*
	 * Attach the dquots to the inode.
	 */
	if ((error = XFS_QM_DQATTACH(mp, dp, 0)))
		return (error);

	/*
	 * If the inode doesn't have an attribute fork, add one.
	 * (inode must not be locked when we call this routine)
	 */
	if (XFS_IFORK_Q(dp) == 0) {
		int sf_size = sizeof(xfs_attr_sf_hdr_t) +
			      XFS_ATTR_SF_ENTSIZE_BYNAME(namelen, valuelen);

		if ((error = xfs_bmap_add_attrfork(dp, sf_size, rsvd)))
			return(error);
	}

	/*
	 * Fill in the arg structure for this request.
	 */
	memset((char *)&args, 0, sizeof(args));
	args.name = name;
	args.namelen = namelen;
	args.value = value;
	args.valuelen = valuelen;
	args.flags = flags;
	args.hashval = xfs_da_hashname(args.name, args.namelen);
	args.dp = dp;
	args.firstblock = &firstblock;
	args.flist = &flist;
	args.whichfork = XFS_ATTR_FORK;
	args.addname = 1;
	args.oknoent = 1;

	/*
	 * Determine space new attribute will use, and if it would be
	 * "local" or "remote" (note: local != inline).
	 */
	size = xfs_attr_leaf_newentsize(namelen, valuelen,
					mp->m_sb.sb_blocksize, &local);

	nblks = XFS_DAENTER_SPACE_RES(mp, XFS_ATTR_FORK);
	if (local) {
		if (size > (mp->m_sb.sb_blocksize >> 1)) {
			/* Double split possible */
			nblks <<= 1;
		}
	} else {
		uint	dblocks = XFS_B_TO_FSB(mp, valuelen);
		/* Out of line attribute, cannot double split, but make
		 * room for the attribute value itself.
		 */
		nblks += dblocks;
		nblks += XFS_NEXTENTADD_SPACE_RES(mp, dblocks, XFS_ATTR_FORK);
	}

	/* Size is now blocks for attribute data */
	args.total = nblks;

	/*
	 * Start our first transaction of the day.
	 *
	 * All future transactions during this code must be "chained" off
	 * this one via the trans_dup() call.  All transactions will contain
	 * the inode, and the inode will always be marked with trans_ihold().
	 * Since the inode will be locked in all transactions, we must log
	 * the inode in every transaction to let it float upward through
	 * the log.
	 */
	args.trans = xfs_trans_alloc(mp, XFS_TRANS_ATTR_SET);

	/*
	 * Root fork attributes can use reserved data blocks for this
	 * operation if necessary
	 */

	if (rsvd)
		args.trans->t_flags |= XFS_TRANS_RESERVE;

	if ((error = xfs_trans_reserve(args.trans, (uint) nblks,
				      XFS_ATTRSET_LOG_RES(mp, nblks),
				      0, XFS_TRANS_PERM_LOG_RES,
				      XFS_ATTRSET_LOG_COUNT))) {
		xfs_trans_cancel(args.trans, 0);
		return(error);
	}
	xfs_ilock(dp, XFS_ILOCK_EXCL);

	error = XFS_TRANS_RESERVE_QUOTA_NBLKS(mp, args.trans, dp, nblks, 0,
			 rsvd ? XFS_QMOPT_RES_REGBLKS | XFS_QMOPT_FORCE_RES :
				XFS_QMOPT_RES_REGBLKS);
	if (error) {
		xfs_iunlock(dp, XFS_ILOCK_EXCL);
		xfs_trans_cancel(args.trans, XFS_TRANS_RELEASE_LOG_RES);
		return (error);
	}

	xfs_trans_ijoin(args.trans, dp, XFS_ILOCK_EXCL);
	xfs_trans_ihold(args.trans, dp);

	/*
	 * If the attribute list is non-existent or a shortform list,
	 * upgrade it to a single-leaf-block attribute list.
	 */
	if ((dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) ||
	    ((dp->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS) &&
	     (dp->i_d.di_anextents == 0))) {

		/*
		 * Build initial attribute list (if required).
		 */
		if (dp->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS)
			xfs_attr_shortform_create(&args);

		/*
		 * Try to add the attr to the attribute list in
		 * the inode.
		 */
		error = xfs_attr_shortform_addname(&args);
		if (error != ENOSPC) {
			/*
			 * Commit the shortform mods, and we're done.
			 * NOTE: this is also the error path (EEXIST, etc).
			 */
			ASSERT(args.trans != NULL);

			/*
			 * If this is a synchronous mount, make sure that
			 * the transaction goes to disk before returning
			 * to the user.
			 */
			if (mp->m_flags & XFS_MOUNT_WSYNC) {
				xfs_trans_set_sync(args.trans);
			}
			err2 = xfs_trans_commit(args.trans,
						 XFS_TRANS_RELEASE_LOG_RES);
			xfs_iunlock(dp, XFS_ILOCK_EXCL);

			/*
			 * Hit the inode change time.
			 */
			if (!error && (flags & ATTR_KERNOTIME) == 0) {
				xfs_ichgtime(dp, XFS_ICHGTIME_CHG);
			}
			return(error == 0 ? err2 : error);
		}

		/*
		 * It won't fit in the shortform, transform to a leaf block.
		 * GROT: another possible req'mt for a double-split btree op.
		 */
		XFS_BMAP_INIT(args.flist, args.firstblock);
		error = xfs_attr_shortform_to_leaf(&args);
		if (!error) {
			error = xfs_bmap_finish(&args.trans, args.flist,
						&committed);
		}
		if (error) {
			ASSERT(committed);
			args.trans = NULL;
			xfs_bmap_cancel(&flist);
			goto out;
		}

		/*
		 * bmap_finish() may have committed the last trans and started
		 * a new one.  We need the inode to be in all transactions.
		 */
		if (committed) {
			xfs_trans_ijoin(args.trans, dp, XFS_ILOCK_EXCL);
			xfs_trans_ihold(args.trans, dp);
		}

		/*
		 * Commit the leaf transformation.  We'll need another (linked)
		 * transaction to add the new attribute to the leaf.
		 */
		if ((error = xfs_attr_rolltrans(&args.trans, dp)))
			goto out;

	}

	if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
		error = xfs_attr_leaf_addname(&args);
	} else {
		error = xfs_attr_node_addname(&args);
	}
	if (error) {
		goto out;
	}

	/*
	 * If this is a synchronous mount, make sure that the
	 * transaction goes to disk before returning to the user.
	 */
	if (mp->m_flags & XFS_MOUNT_WSYNC) {
		xfs_trans_set_sync(args.trans);
	}

	/*
	 * Commit the last in the sequence of transactions.
	 */
	xfs_trans_log_inode(args.trans, dp, XFS_ILOG_CORE);
	error = xfs_trans_commit(args.trans, XFS_TRANS_RELEASE_LOG_RES);
	xfs_iunlock(dp, XFS_ILOCK_EXCL);

	/*
	 * Hit the inode change time.
	 */
	if (!error && (flags & ATTR_KERNOTIME) == 0) {
		xfs_ichgtime(dp, XFS_ICHGTIME_CHG);
	}

	return(error);

out:
	if (args.trans)
		xfs_trans_cancel(args.trans,
			XFS_TRANS_RELEASE_LOG_RES|XFS_TRANS_ABORT);
	xfs_iunlock(dp, XFS_ILOCK_EXCL);
	return(error);
}

int
xfs_attr_set(
	xfs_inode_t	*dp,
	const char	*name,
	char		*value,
	int		valuelen,
	int		flags)
{
	int             namelen;

	namelen = strlen(name);
	if (namelen >= MAXNAMELEN)
		return EFAULT;		/* match IRIX behaviour */

	XFS_STATS_INC(xs_attr_set);

	if (XFS_FORCED_SHUTDOWN(dp->i_mount))
		return (EIO);

	return xfs_attr_set_int(dp, name, namelen, value, valuelen, flags);
}

/*
 * Generic handler routine to remove a name from an attribute list.
 * Transitions attribute list from Btree to shortform as necessary.
 */
int
xfs_attr_remove_int(xfs_inode_t *dp, const char *name, int namelen, int flags)
{
	xfs_da_args_t	args;
	xfs_fsblock_t	firstblock;
	xfs_bmap_free_t	flist;
	int		error;
	xfs_mount_t	*mp = dp->i_mount;

	/*
	 * Fill in the arg structure for this request.
	 */
	memset((char *)&args, 0, sizeof(args));
	args.name = name;
	args.namelen = namelen;
	args.flags = flags;
	args.hashval = xfs_da_hashname(args.name, args.namelen);
	args.dp = dp;
	args.firstblock = &firstblock;
	args.flist = &flist;
	args.total = 0;
	args.whichfork = XFS_ATTR_FORK;

	/*
	 * Attach the dquots to the inode.
	 */
	if ((error = XFS_QM_DQATTACH(mp, dp, 0)))
		return (error);

	/*
	 * Start our first transaction of the day.
	 *
	 * All future transactions during this code must be "chained" off
	 * this one via the trans_dup() call.  All transactions will contain
	 * the inode, and the inode will always be marked with trans_ihold().
	 * Since the inode will be locked in all transactions, we must log
	 * the inode in every transaction to let it float upward through
	 * the log.
	 */
	args.trans = xfs_trans_alloc(mp, XFS_TRANS_ATTR_RM);

	/*
	 * Root fork attributes can use reserved data blocks for this
	 * operation if necessary
	 */

	if (flags & ATTR_ROOT)
		args.trans->t_flags |= XFS_TRANS_RESERVE;