patch-2.4.25 linux-2.4.25/fs/xfs/xfs_rename.c

• Lines: 674
• Date: 2004-02-18 05:36:32.000000000 -0800
• Orig file: linux-2.4.24/fs/xfs/xfs_rename.c
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.24/fs/xfs/xfs_rename.c linux-2.4.25/fs/xfs/xfs_rename.c
@@ -0,0 +1,673 @@
+/*
+ * Copyright (c) 2000-2003 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/
+ */
+
+#include "xfs.h"
+#include "xfs_macros.h"
+#include "xfs_types.h"
+#include "xfs_inum.h"
+#include "xfs_log.h"
+#include "xfs_trans.h"
+#include "xfs_sb.h"
+#include "xfs_dir.h"
+#include "xfs_dir2.h"
+#include "xfs_dmapi.h"
+#include "xfs_mount.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_attr_sf.h"
+#include "xfs_dir_sf.h"
+#include "xfs_dir2_sf.h"
+#include "xfs_dinode.h"
+#include "xfs_inode_item.h"
+#include "xfs_inode.h"
+#include "xfs_bmap.h"
+#include "xfs_error.h"
+#include "xfs_quota.h"
+#include "xfs_refcache.h"
+#include "xfs_utils.h"
+#include "xfs_trans_space.h"
+#include "xfs_da_btree.h"
+#include "xfs_dir_leaf.h"
+
+
+/*
+ * Given an array of up to 4 inode pointers, unlock the pointed to inodes.
+ * If there are fewer than 4 entries in the array, the empty entries will
+ * be at the end and will have NULL pointers in them.
+ */
+STATIC void
+xfs_rename_unlock4(
+	xfs_inode_t	**i_tab,
+	uint		lock_mode)
+{
+	int	i;
+
+	xfs_iunlock(i_tab[0], lock_mode);
+	for (i = 1; i < 4; i++) {
+		if (i_tab[i] == NULL) {
+			break;
+		}
+		/*
+		 * Watch out for duplicate entries in the table.
+		 */
+		if (i_tab[i] != i_tab[i-1]) {
+			xfs_iunlock(i_tab[i], lock_mode);
+		}
+	}
+}
+
+#ifdef DEBUG
+int xfs_rename_skip, xfs_rename_nskip;
+#endif
+
+/*
+ * The following routine will acquire the locks required for a rename
+ * operation. The code understands the semantics of renames and will
+ * validate that name1 exists under dp1 & that name2 may or may not
+ * exist under dp2.
+ *
+ * We are renaming dp1/name1 to dp2/name2.
+ *
+ * Return ENOENT if dp1 does not exist, other lookup errors, or 0 for success.
+ */
+STATIC int
+xfs_lock_for_rename(
+	xfs_inode_t	*dp1,	/* old (source) directory inode */
+	xfs_inode_t	*dp2,	/* new (target) directory inode */
+	vname_t		*vname1,/* old entry name */
+	vname_t		*vname2,/* new entry name */
+	xfs_inode_t	**ipp1,	/* inode of old entry */
+	xfs_inode_t	**ipp2,	/* inode of new entry, if it
+				   already exists, NULL otherwise. */
+	xfs_inode_t	**i_tab,/* array of inode returned, sorted */
+	int		*num_inodes)  /* number of inodes in array */
+{
+	xfs_inode_t		*ip1, *ip2, *temp;
+	xfs_ino_t		inum1, inum2;
+	int			error;
+	int			i, j;
+	uint			lock_mode;
+	int			diff_dirs = (dp1 != dp2);
+
+	ip2 = NULL;
+
+	/*
+	 * First, find out the current inums of the entries so that we
+	 * can determine the initial locking order.  We'll have to
+	 * sanity check stuff after all the locks have been acquired
+	 * to see if we still have the right inodes, directories, etc.
+	 */
+	lock_mode = xfs_ilock_map_shared(dp1);
+	error = xfs_get_dir_entry(vname1, &ip1);
+	if (error) {
+		xfs_iunlock_map_shared(dp1, lock_mode);
+		return error;
+	}
+
+	inum1 = ip1->i_ino;
+
+	ASSERT(ip1);
+	ITRACE(ip1);
+
+	/*
+	 * Unlock dp1 and lock dp2 if they are different.
+	 */
+
+	if (diff_dirs) {
+		xfs_iunlock_map_shared(dp1, lock_mode);
+		lock_mode = xfs_ilock_map_shared(dp2);
+	}
+
+	error = xfs_dir_lookup_int(XFS_ITOBHV(dp2), lock_mode,
+				   vname2, &inum2, &ip2);
+	if (error == ENOENT) {		/* target does not need to exist. */
+		inum2 = 0;
+	} else if (error) {
+		/*
+		 * If dp2 and dp1 are the same, the next line unlocks dp1.
+		 * Got it?
+		 */
+		xfs_iunlock_map_shared(dp2, lock_mode);
+		IRELE (ip1);
+		return error;
+	} else {
+		ITRACE(ip2);
+	}
+
+	/*
+	 * i_tab contains a list of pointers to inodes.  We initialize
+	 * the table here & we'll sort it.  We will then use it to
+	 * order the acquisition of the inode locks.
+	 *
+	 * Note that the table may contain duplicates.  e.g., dp1 == dp2.
+	 */
+	i_tab[0] = dp1;
+	i_tab[1] = dp2;
+	i_tab[2] = ip1;
+	if (inum2 == 0) {
+		*num_inodes = 3;
+		i_tab[3] = NULL;
+	} else {
+		*num_inodes = 4;
+		i_tab[3] = ip2;
+	}
+
+	/*
+	 * Sort the elements via bubble sort.  (Remember, there are at
+	 * most 4 elements to sort, so this is adequate.)
+	 */
+	for (i=0; i < *num_inodes; i++) {
+		for (j=1; j < *num_inodes; j++) {
+			if (i_tab[j]->i_ino < i_tab[j-1]->i_ino) {
+				temp = i_tab[j];
+				i_tab[j] = i_tab[j-1];
+				i_tab[j-1] = temp;
+			}
+		}
+	}
+
+	/*
+	 * We have dp2 locked. If it isn't first, unlock it.
+	 * If it is first, tell xfs_lock_inodes so it can skip it
+	 * when locking. if dp1 == dp2, xfs_lock_inodes will skip both
+	 * since they are equal. xfs_lock_inodes needs all these inodes
+	 * so that it can unlock and retry if there might be a dead-lock
+	 * potential with the log.
+	 */
+
+	if (i_tab[0] == dp2 && lock_mode == XFS_ILOCK_SHARED) {
+#ifdef DEBUG
+		xfs_rename_skip++;
+#endif
+		xfs_lock_inodes(i_tab, *num_inodes, 1, XFS_ILOCK_SHARED);
+	} else {
+#ifdef DEBUG
+		xfs_rename_nskip++;
+#endif
+		xfs_iunlock_map_shared(dp2, lock_mode);
+		xfs_lock_inodes(i_tab, *num_inodes, 0, XFS_ILOCK_SHARED);
+	}
+
+	/*
+	 * Set the return value. Null out any unused entries in i_tab.
+	 */
+	*ipp1 = *ipp2 = NULL;
+	for (i=0; i < *num_inodes; i++) {
+		if (i_tab[i]->i_ino == inum1) {
+			*ipp1 = i_tab[i];
+		}
+		if (i_tab[i]->i_ino == inum2) {
+			*ipp2 = i_tab[i];
+		}
+	}
+	for (;i < 4; i++) {
+		i_tab[i] = NULL;
+	}
+	return 0;
+}
+
+
+int rename_which_error_return = 0;
+
+/*
+ * xfs_rename
+ */
+int
+xfs_rename(
+	bhv_desc_t	*src_dir_bdp,
+	vname_t		*src_vname,
+	vnode_t		*target_dir_vp,
+	vname_t		*target_vname,
+	cred_t		*credp)
+{
+	xfs_trans_t	*tp;
+	xfs_inode_t	*src_dp, *target_dp, *src_ip, *target_ip;
+	xfs_mount_t	*mp;
+	int		new_parent;		/* moving to a new dir */
+	int		src_is_directory;	/* src_name is a directory */
+	int		error;
+	xfs_bmap_free_t free_list;
+	xfs_fsblock_t   first_block;
+	int		cancel_flags;
+	int		committed;
+	xfs_inode_t	*inodes[4];
+	int		target_ip_dropped = 0;	/* dropped target_ip link? */
+	vnode_t		*src_dir_vp;
+	bhv_desc_t	*target_dir_bdp;
+	int		spaceres;
+	int		target_link_zero = 0;
+	int		num_inodes;
+	char		*src_name = VNAME(src_vname);
+	char		*target_name = VNAME(target_vname);
+	int		src_namelen = VNAMELEN(src_vname);
+	int		target_namelen = VNAMELEN(target_vname);
+
+	src_dir_vp = BHV_TO_VNODE(src_dir_bdp);
+	vn_trace_entry(src_dir_vp, "xfs_rename", (inst_t *)__return_address);
+	vn_trace_entry(target_dir_vp, "xfs_rename", (inst_t *)__return_address);
+
+	/*
+	 * Find the XFS behavior descriptor for the target directory
+	 * vnode since it was not handed to us.
+	 */
+	target_dir_bdp = vn_bhv_lookup_unlocked(VN_BHV_HEAD(target_dir_vp),
+						&xfs_vnodeops);
+	if (target_dir_bdp == NULL) {
+		return XFS_ERROR(EXDEV);
+	}
+
+	src_dp = XFS_BHVTOI(src_dir_bdp);
+	target_dp = XFS_BHVTOI(target_dir_bdp);
+	mp = src_dp->i_mount;
+
+	if (DM_EVENT_ENABLED(src_dir_vp->v_vfsp, src_dp, DM_EVENT_RENAME) ||
+	    DM_EVENT_ENABLED(target_dir_vp->v_vfsp,
+				target_dp, DM_EVENT_RENAME)) {
+		error = XFS_SEND_NAMESP(mp, DM_EVENT_RENAME,
+					src_dir_vp, DM_RIGHT_NULL,
+					target_dir_vp, DM_RIGHT_NULL,
+					src_name, target_name,
+					0, 0, 0);
+		if (error) {
+			return error;
+		}
+	}
+	/* Return through std_return after this point. */
+
+	/*
+	 * Lock all the participating inodes. Depending upon whether
+	 * the target_name exists in the target directory, and
+	 * whether the target directory is the same as the source
+	 * directory, we can lock from 2 to 4 inodes.
+	 * xfs_lock_for_rename() will return ENOENT if src_name
+	 * does not exist in the source directory.
+	 */
+	tp = NULL;
+	error = xfs_lock_for_rename(src_dp, target_dp, src_vname,
+			target_vname, &src_ip, &target_ip, inodes,
+			&num_inodes);
+
+	if (error) {
+		rename_which_error_return = __LINE__;
+		/*
+		 * We have nothing locked, no inode references, and
+		 * no transaction, so just get out.
+		 */
+		goto std_return;
+	}
+
+	ASSERT(src_ip != NULL);
+
+	if ((src_ip->i_d.di_mode & S_IFMT) == S_IFDIR) {
+		/*
+		 * Check for link count overflow on target_dp
+		 */
+		if (target_ip == NULL && (src_dp != target_dp) &&
+		    target_dp->i_d.di_nlink >= XFS_MAXLINK) {
+			rename_which_error_return = __LINE__;
+			error = XFS_ERROR(EMLINK);
+			xfs_rename_unlock4(inodes, XFS_ILOCK_SHARED);
+			goto rele_return;
+		}
+	}
+
+	new_parent = (src_dp != target_dp);
+	src_is_directory = ((src_ip->i_d.di_mode & S_IFMT) == S_IFDIR);
+
+	/*
+	 * Drop the locks on our inodes so that we can start the transaction.
+	 */
+	xfs_rename_unlock4(inodes, XFS_ILOCK_SHARED);
+
+	XFS_BMAP_INIT(&free_list, &first_block);
+	tp = xfs_trans_alloc(mp, XFS_TRANS_RENAME);
+	cancel_flags = XFS_TRANS_RELEASE_LOG_RES;
+	spaceres = XFS_RENAME_SPACE_RES(mp, target_namelen);
+	error = xfs_trans_reserve(tp, spaceres, XFS_RENAME_LOG_RES(mp), 0,
+			XFS_TRANS_PERM_LOG_RES, XFS_RENAME_LOG_COUNT);
+	if (error == ENOSPC) {
+		spaceres = 0;
+		error = xfs_trans_reserve(tp, 0, XFS_RENAME_LOG_RES(mp), 0,
+				XFS_TRANS_PERM_LOG_RES, XFS_RENAME_LOG_COUNT);
+	}
+	if (error) {
+		rename_which_error_return = __LINE__;
+		xfs_trans_cancel(tp, 0);
+		goto rele_return;
+	}
+
+	/*
+	 * Attach the dquots to the inodes
+	 */
+	if ((error = XFS_QM_DQVOPRENAME(mp, inodes))) {
+		xfs_trans_cancel(tp, cancel_flags);
+		rename_which_error_return = __LINE__;
+		goto rele_return;
+	}
+
+	/*
+	 * Reacquire the inode locks we dropped above.
+	 */
+	xfs_lock_inodes(inodes, num_inodes, 0, XFS_ILOCK_EXCL);
+
+	/*
+	 * Join all the inodes to the transaction. From this point on,
+	 * we can rely on either trans_commit or trans_cancel to unlock
+	 * them.  Note that we need to add a vnode reference to the
+	 * directories since trans_commit & trans_cancel will decrement
+	 * them when they unlock the inodes.  Also, we need to be careful
+	 * not to add an inode to the transaction more than once.
+	 */
+	VN_HOLD(src_dir_vp);
+	xfs_trans_ijoin(tp, src_dp, XFS_ILOCK_EXCL);
+	if (new_parent) {
+		VN_HOLD(target_dir_vp);
+		xfs_trans_ijoin(tp, target_dp, XFS_ILOCK_EXCL);
+	}
+	if ((src_ip != src_dp) && (src_ip != target_dp)) {
+		xfs_trans_ijoin(tp, src_ip, XFS_ILOCK_EXCL);
+	}
+	if ((target_ip != NULL) &&
+	    (target_ip != src_ip) &&
+	    (target_ip != src_dp) &&
+	    (target_ip != target_dp)) {
+		xfs_trans_ijoin(tp, target_ip, XFS_ILOCK_EXCL);
+	}
+
+	/*
+	 * Set up the target.
+	 */
+	if (target_ip == NULL) {
+		/*
+		 * If there's no space reservation, check the entry will
+		 * fit before actually inserting it.
+		 */
+		if (spaceres == 0 &&
+		    (error = XFS_DIR_CANENTER(mp, tp, target_dp, target_name,
+				target_namelen))) {
+			rename_which_error_return = __LINE__;
+			goto error_return;
+		}
+		/*
+		 * If target does not exist and the rename crosses
+		 * directories, adjust the target directory link count
+		 * to account for the ".." reference from the new entry.
+		 */
+		error = XFS_DIR_CREATENAME(mp, tp, target_dp, target_name,
+					   target_namelen, src_ip->i_ino,
+					   &first_block, &free_list, spaceres);
+		if (error == ENOSPC) {
+			rename_which_error_return = __LINE__;
+			goto error_return;
+		}
+		if (error) {
+			rename_which_error_return = __LINE__;
+			goto abort_return;
+		}
+		xfs_ichgtime(target_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
+
+		if (new_parent && src_is_directory) {
+			error = xfs_bumplink(tp, target_dp);
+			if (error) {
+				rename_which_error_return = __LINE__;
+				goto abort_return;
+			}
+		}
+	} else { /* target_ip != NULL */
+
+		/*
+		 * If target exists and it's a directory, check that both
+		 * target and source are directories and that target can be
+		 * destroyed, or that neither is a directory.
+		 */
+		if ((target_ip->i_d.di_mode & S_IFMT) == S_IFDIR) {
+			/*
+			 * Make sure target dir is empty.
+			 */
+			if (!(XFS_DIR_ISEMPTY(target_ip->i_mount, target_ip)) ||
+			    (target_ip->i_d.di_nlink > 2)) {
+				error = XFS_ERROR(EEXIST);
+				rename_which_error_return = __LINE__;
+				goto error_return;
+			}
+		}
+
+		/*
+		 * Link the source inode under the target name.
+		 * If the source inode is a directory and we are moving
+		 * it across directories, its ".." entry will be
+		 * inconsistent until we replace that down below.
+		 *
+		 * In case there is already an entry with the same
+		 * name at the destination directory, remove it first.
+		 */
+		error = XFS_DIR_REPLACE(mp, tp, target_dp, target_name,
+			target_namelen, src_ip->i_ino, &first_block,
+			&free_list, spaceres);
+		if (error) {
+			rename_which_error_return = __LINE__;
+			goto abort_return;
+		}
+		xfs_ichgtime(target_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
+
+		/*
+		 * Decrement the link count on the target since the target
+		 * dir no longer points to it.
+		 */
+		error = xfs_droplink(tp, target_ip);
+		if (error) {
+			rename_which_error_return = __LINE__;
+			goto abort_return;
+		}
+		target_ip_dropped = 1;
+
+		if (src_is_directory) {
+			/*
+			 * Drop the link from the old "." entry.
+			 */
+			error = xfs_droplink(tp, target_ip);
+			if (error) {
+				rename_which_error_return = __LINE__;
+				goto abort_return;
+			}
+		}
+
+		/* Do this test while we still hold the locks */
+		target_link_zero = (target_ip)->i_d.di_nlink==0;
+
+	} /* target_ip != NULL */
+
+	/*
+	 * Remove the source.
+	 */
+	if (new_parent && src_is_directory) {
+
+		/*
+		 * Rewrite the ".." entry to point to the new
+		 * directory.
+		 */
+		error = XFS_DIR_REPLACE(mp, tp, src_ip, "..", 2,
+					target_dp->i_ino, &first_block,
+					&free_list, spaceres);
+		ASSERT(error != EEXIST);
+		if (error) {
+			rename_which_error_return = __LINE__;
+			goto abort_return;
+		}
+		xfs_ichgtime(src_ip, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
+
+	} else {
+		/*
+		 * We always want to hit the ctime on the source inode.
+		 * We do it in the if clause above for the 'new_parent &&
+		 * src_is_directory' case, and here we get all the other
+		 * cases.  This isn't strictly required by the standards
+		 * since the source inode isn't really being changed,
+		 * but old unix file systems did it and some incremental
+		 * backup programs won't work without it.
+		 */
+		xfs_ichgtime(src_ip, XFS_ICHGTIME_CHG);
+	}
+
+	/*
+	 * Adjust the link count on src_dp.  This is necessary when
+	 * renaming a directory, either within one parent when
+	 * the target existed, or across two parent directories.
+	 */
+	if (src_is_directory && (new_parent || target_ip != NULL)) {
+
+		/*
+		 * Decrement link count on src_directory since the
+		 * entry that's moved no longer points to it.
+		 */
+		error = xfs_droplink(tp, src_dp);
+		if (error) {
+			rename_which_error_return = __LINE__;
+			goto abort_return;
+		}
+	}
+
+	error = XFS_DIR_REMOVENAME(mp, tp, src_dp, src_name, src_namelen,
+			src_ip->i_ino, &first_block, &free_list, spaceres);
+	if (error) {
+		rename_which_error_return = __LINE__;
+		goto abort_return;
+	}
+	xfs_ichgtime(src_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
+
+	/*
+	 * Update the generation counts on all the directory inodes
+	 * that we're modifying.
+	 */
+	src_dp->i_gen++;
+	xfs_trans_log_inode(tp, src_dp, XFS_ILOG_CORE);
+
+	if (new_parent) {
+		target_dp->i_gen++;
+		xfs_trans_log_inode(tp, target_dp, XFS_ILOG_CORE);
+	}
+
+	/*
+	 * If there was a target inode, take an extra reference on
+	 * it here so that it doesn't go to xfs_inactive() from
+	 * within the commit.
+	 */
+	if (target_ip != NULL) {
+		IHOLD(target_ip);
+	}
+
+	/*
+	 * If this is a synchronous mount, make sure that the
+	 * rename transaction goes to disk before returning to
+	 * the user.
+	 */
+	if (mp->m_flags & XFS_MOUNT_WSYNC) {
+		xfs_trans_set_sync(tp);
+	}
+
+	/*
+	 * Take refs. for vop_link_removed calls below.  No need to worry
+	 * about directory refs. because the caller holds them.
+	 *
+	 * Do holds before the xfs_bmap_finish since it might rele them down
+	 * to zero.
+	 */
+
+	if (target_ip_dropped)
+		IHOLD(target_ip);
+	IHOLD(src_ip);
+
+	error = xfs_bmap_finish(&tp, &free_list, first_block, &committed);
+	if (error) {
+		xfs_bmap_cancel(&free_list);
+		xfs_trans_cancel(tp, (XFS_TRANS_RELEASE_LOG_RES |
+				 XFS_TRANS_ABORT));
+		if (target_ip != NULL) {
+			IRELE(target_ip);
+		}
+		if (target_ip_dropped) {
+			IRELE(target_ip);
+		}
+		IRELE(src_ip);
+		goto std_return;
+	}
+
+	/*
+	 * trans_commit will unlock src_ip, target_ip & decrement
+	 * the vnode references.
+	 */
+	error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES, NULL);
+	if (target_ip != NULL) {
+		xfs_refcache_purge_ip(target_ip);
+		IRELE(target_ip);
+	}
+	/*
+	 * Let interposed file systems know about removed links.
+	 */
+	if (target_ip_dropped) {
+		VOP_LINK_REMOVED(XFS_ITOV(target_ip), target_dir_vp,
+					target_link_zero);
+		IRELE(target_ip);
+	}
+
+	FSC_NOTIFY_NAME_CHANGED(XFS_ITOV(src_ip));
+
+	IRELE(src_ip);
+
+	/* Fall through to std_return with error = 0 or errno from
+	 * xfs_trans_commit	 */
+std_return:
+	if (DM_EVENT_ENABLED(src_dir_vp->v_vfsp, src_dp, DM_EVENT_POSTRENAME) ||
+	    DM_EVENT_ENABLED(target_dir_vp->v_vfsp,
+				target_dp, DM_EVENT_POSTRENAME)) {
+		(void) XFS_SEND_NAMESP (mp, DM_EVENT_POSTRENAME,
+					src_dir_vp, DM_RIGHT_NULL,
+					target_dir_vp, DM_RIGHT_NULL,
+					src_name, target_name,
+					0, error, 0);
+	}
+	return error;
+
+ abort_return:
+	cancel_flags |= XFS_TRANS_ABORT;
+	/* FALLTHROUGH */
+ error_return:
+	xfs_bmap_cancel(&free_list);
+	xfs_trans_cancel(tp, cancel_flags);
+	goto std_return;
+
+ rele_return:
+	IRELE(src_ip);
+	if (target_ip != NULL) {
+		IRELE(target_ip);
+	}
+	goto std_return;
+}