From: Darrick J. Wong <djwong@xxxxxxxxxx>
Create a new libxfs function to rename two directory entries. The
upcoming metadata directory feature will need this to replace a metadata
inode directory entry.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
libxfs/xfs_dir2.c | 217 +++++++++++++++++++++++++++++++++++++++++++++++++++++
libxfs/xfs_dir2.h | 3 +
2 files changed, 220 insertions(+)
diff --git a/libxfs/xfs_dir2.c b/libxfs/xfs_dir2.c
index d14e81403ad..7a1d55dff69 100644
--- a/libxfs/xfs_dir2.c
+++ b/libxfs/xfs_dir2.c
@@ -23,6 +23,7 @@
#include "xfs_trans_space.h"
#include "xfs_parent.h"
#include "xfs_ag.h"
+#include "xfs_ialloc.h"
const struct xfs_name xfs_name_dotdot = {
.name = (const unsigned char *)"..",
@@ -1080,3 +1081,219 @@ xfs_dir_exchange_children(
return xfs_parent_replace(tp, du2->ppargs, dp2, name2, dp1, name1,
ip2);
}
+
+/*
+ * Given an entry (@src_name, @src_ip) in directory @src_dp, make the entry
+ * @target_name in directory @target_dp point to @src_ip and remove the
+ * original entry, cleaning up everything left behind.
+ *
+ * Cleanup involves dropping a link count on @target_ip, and either removing
+ * the (@src_name, @src_ip) entry from @src_dp or simply replacing the entry
+ * with (@src_name, @wip) if a whiteout inode @wip is supplied.
+ *
+ * All inodes must have the ILOCK held. We assume that if @src_ip is a
+ * directory then its '..' doesn't already point to @target_dp, and that @wip
+ * is a freshly allocated whiteout.
+ */
+int
+xfs_dir_rename_children(
+ struct xfs_trans *tp,
+ struct xfs_dir_update *du_src,
+ struct xfs_dir_update *du_tgt,
+ unsigned int spaceres,
+ struct xfs_dir_update *du_wip)
+{
+ struct xfs_mount *mp = tp->t_mountp;
+ struct xfs_inode *src_dp = du_src->dp;
+ const struct xfs_name *src_name = du_src->name;
+ struct xfs_inode *src_ip = du_src->ip;
+ struct xfs_inode *target_dp = du_tgt->dp;
+ const struct xfs_name *target_name = du_tgt->name;
+ struct xfs_inode *target_ip = du_tgt->ip;
+ bool new_parent = (src_dp != target_dp);
+ bool src_is_directory;
+ int error;
+
+ src_is_directory = S_ISDIR(VFS_I(src_ip)->i_mode);
+
+ /*
+ * Check for expected errors before we dirty the transaction
+ * so we can return an error without a transaction abort.
+ */
+ if (target_ip == NULL) {
+ /*
+ * If there's no space reservation, check the entry will
+ * fit before actually inserting it.
+ */
+ if (!spaceres) {
+ error = xfs_dir_canenter(tp, target_dp, target_name);
+ if (error)
+ return error;
+ }
+ } else {
+ /*
+ * If target exists and it's a directory, check that whether
+ * it can be destroyed.
+ */
+ if (S_ISDIR(VFS_I(target_ip)->i_mode) &&
+ (!xfs_dir_isempty(target_ip) ||
+ (VFS_I(target_ip)->i_nlink > 2)))
+ return -EEXIST;
+ }
+
+ /*
+ * Directory entry creation below may acquire the AGF. Remove
+ * the whiteout from the unlinked list first to preserve correct
+ * AGI/AGF locking order. This dirties the transaction so failures
+ * after this point will abort and log recovery will clean up the
+ * mess.
+ *
+ * For whiteouts, we need to bump the link count on the whiteout
+ * inode. After this point, we have a real link, clear the tmpfile
+ * state flag from the inode so it doesn't accidentally get misused
+ * in future.
+ */
+ if (du_wip->ip) {
+ struct xfs_perag *pag;
+
+ ASSERT(VFS_I(du_wip->ip)->i_nlink == 0);
+
+ pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, du_wip->ip->i_ino));
+ error = xfs_iunlink_remove(tp, pag, du_wip->ip);
+ xfs_perag_put(pag);
+ if (error)
+ return error;
+
+ xfs_bumplink(tp, du_wip->ip);
+ }
+
+ /*
+ * Set up the target.
+ */
+ if (target_ip == NULL) {
+ /*
+ * 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(tp, target_dp, target_name,
+ src_ip->i_ino, spaceres);
+ if (error)
+ return error;
+
+ xfs_trans_ichgtime(tp, target_dp,
+ XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
+
+ if (new_parent && src_is_directory) {
+ xfs_bumplink(tp, target_dp);
+ }
+ } else { /* target_ip != NULL */
+ /*
+ * 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(tp, target_dp, target_name,
+ src_ip->i_ino, spaceres);
+ if (error)
+ return error;
+
+ xfs_trans_ichgtime(tp, 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)
+ return error;
+
+ if (src_is_directory) {
+ /*
+ * Drop the link from the old "." entry.
+ */
+ error = xfs_droplink(tp, target_ip);
+ if (error)
+ return error;
+ }
+ } /* 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(tp, src_ip, &xfs_name_dotdot,
+ target_dp->i_ino, spaceres);
+ ASSERT(error != -EEXIST);
+ if (error)
+ return error;
+ }
+
+ /*
+ * We always want to hit the ctime on the source inode.
+ *
+ * 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_trans_ichgtime(tp, src_ip, XFS_ICHGTIME_CHG);
+ xfs_trans_log_inode(tp, src_ip, XFS_ILOG_CORE);
+
+ /*
+ * 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)
+ return error;
+ }
+
+ /*
+ * For whiteouts, we only need to update the source dirent with the
+ * inode number of the whiteout inode rather than removing it
+ * altogether.
+ */
+ if (du_wip->ip)
+ error = xfs_dir_replace(tp, src_dp, src_name, du_wip->ip->i_ino,
+ spaceres);
+ else
+ error = xfs_dir_removename(tp, src_dp, src_name, src_ip->i_ino,
+ spaceres);
+ if (error)
+ return error;
+
+ xfs_trans_ichgtime(tp, src_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
+ xfs_trans_log_inode(tp, src_dp, XFS_ILOG_CORE);
+ if (new_parent)
+ xfs_trans_log_inode(tp, target_dp, XFS_ILOG_CORE);
+
+ /* Schedule parent pointer updates. */
+ error = xfs_parent_add(tp, du_wip->ppargs, src_dp, src_name,
+ du_wip->ip);
+ if (error)
+ return error;
+
+ error = xfs_parent_replace(tp, du_src->ppargs, src_dp, src_name,
+ target_dp, target_name, src_ip);
+ if (error)
+ return error;
+
+ return xfs_parent_remove(tp, du_tgt->ppargs, target_dp, target_name,
+ target_ip);
+}
diff --git a/libxfs/xfs_dir2.h b/libxfs/xfs_dir2.h
index dbca60ec934..5e8b18f3f00 100644
--- a/libxfs/xfs_dir2.h
+++ b/libxfs/xfs_dir2.h
@@ -311,5 +311,8 @@ int xfs_dir_remove_child(struct xfs_trans *tp, unsigned int resblks,
int xfs_dir_exchange_children(struct xfs_trans *tp, struct xfs_dir_update *du1,
struct xfs_dir_update *du2, unsigned int spaceres);
+int xfs_dir_rename_children(struct xfs_trans *tp, struct xfs_dir_update *du_src,
+ struct xfs_dir_update *du_tgt, unsigned int spaceres,
+ struct xfs_dir_update *du_wip);
#endif /* __XFS_DIR2_H__ */
