[PATCH 20/22] xfs: create libxfs helper to rename two directory entries

Darrick J. Wong
2019-01-01T02:21:25Z

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 <darrick.wong@oracle.com>
---
fs/xfs/libxfs/xfs_dir2.c | 195 ++++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/libxfs/xfs_dir2.h | 5 +
fs/xfs/xfs_inode.c | 160 --------------------------------------
3 files changed, 202 insertions(+), 158 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_dir2.c b/fs/xfs/libxfs/xfs_dir2.c
index fbd5ce580b4a..77286d4f6e72 100644
--- a/fs/xfs/libxfs/xfs_dir2.c
+++ b/fs/xfs/libxfs/xfs_dir2.c
@@ -964,3 +964,198 @@ xfs_dir_exchange(

return 0;
}
+
+
+/*
+ * 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(
+ struct xfs_trans *tp,
+ struct xfs_inode *src_dp,
+ struct xfs_name *src_name,
+ struct xfs_inode *src_ip,
+ struct xfs_inode *target_dp,
+ struct xfs_name *target_name,
+ struct xfs_inode *target_ip,
+ unsigned int spaceres,
+ struct xfs_inode *wip)
+{
+ bool new_parent = (src_dp != target_dp);
+ bool src_is_directory;
+ int error;
+
+ src_is_directory = S_ISDIR(VFS_I(src_ip)->i_mode);
+
+ /*
+ * 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) {
+ error = xfs_dir_canenter(tp, target_dp, target_name);
+ if (error)
+ return error;
+ }
+ /*
+ * 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) {
+ error = xfs_bumplink(tp, target_dp);
+ if (error)
+ return error;
+ }
+ } 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 (S_ISDIR(VFS_I(target_ip)->i_mode)) {
+ /*
+ * Make sure target dir is empty.
+ */
+ if (!(xfs_dir_isempty(target_ip)) ||
+ (VFS_I(target_ip)->i_nlink > 2))
+ return -EEXIST;
+ }
+
+ /*
+ * 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 (wip) {
+ error = xfs_dir_replace(tp, src_dp, src_name, wip->i_ino,
+ spaceres);
+ } else
+ error = xfs_dir_removename(tp, src_dp, src_name, src_ip->i_ino,
+ spaceres);
+ if (error)
+ return error;
+
+ /*
+ * For whiteouts, we need to bump the link count on the whiteout inode.
+ * This means that failures all the way up to this point leave the inode
+ * on the unlinked list and so cleanup is a simple matter of dropping
+ * the remaining reference to it. If we fail here after bumping the link
+ * count, we're shutting down the filesystem so we'll never see the
+ * intermediate state on disk.
+ */
+ if (wip) {
+ ASSERT(VFS_I(wip)->i_nlink == 0);
+ error = xfs_bumplink(tp, wip);
+ if (error)
+ return error;
+ error = xfs_iunlink_remove(tp, wip);
+ if (error)
+ return error;
+ xfs_trans_log_inode(tp, wip, XFS_ILOG_CORE);
+ }
+
+ 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);
+
+ return 0;
+}
diff --git a/fs/xfs/libxfs/xfs_dir2.h b/fs/xfs/libxfs/xfs_dir2.h
index 09765f010f90..d89552b49791 100644
--- a/fs/xfs/libxfs/xfs_dir2.h
+++ b/fs/xfs/libxfs/xfs_dir2.h
@@ -340,5 +340,10 @@ int xfs_dir_exchange(struct xfs_trans *tp, struct xfs_inode *dp1,
struct xfs_name *name1, struct xfs_inode *ip1,
struct xfs_inode *dp2, struct xfs_name *name2,
struct xfs_inode *ip2, unsigned int spaceres);
+int xfs_dir_rename(struct xfs_trans *tp, struct xfs_inode *src_dp,
+ struct xfs_name *src_name, struct xfs_inode *src_ip,
+ struct xfs_inode *target_dp, struct xfs_name *target_name,
+ struct xfs_inode *target_ip, unsigned int spaceres,
+ struct xfs_inode *wip);

#endif /* __XFS_DIR2_H__ */
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 3bed0db609bd..52e29a27f514 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -2111,7 +2111,6 @@ xfs_rename(
struct xfs_inode *inodes[__XFS_SORT_INODES];
int num_inodes = __XFS_SORT_INODES;
bool new_parent = (src_dp != target_dp);
- bool src_is_directory = S_ISDIR(VFS_I(src_ip)->i_mode);
int spaceres;
int error;

@@ -2195,162 +2194,12 @@ xfs_rename(
target_dp, target_name, target_ip,
spaceres);

- /*
- * 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) {
- error = xfs_dir_canenter(tp, target_dp, target_name);
- if (error)
- goto out_trans_cancel;
- }
- /*
- * 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)
- goto out_trans_cancel;
-
- xfs_trans_ichgtime(tp, target_dp,
- XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
-
- if (new_parent && src_is_directory) {
- error = xfs_bumplink(tp, target_dp);
- if (error)
- goto out_trans_cancel;
- }
- } 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 (S_ISDIR(VFS_I(target_ip)->i_mode)) {
- /*
- * Make sure target dir is empty.
- */
- if (!(xfs_dir_isempty(target_ip)) ||
- (VFS_I(target_ip)->i_nlink > 2)) {
- error = -EEXIST;
- goto out_trans_cancel;
- }
- }
-
- /*
- * 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)
- goto out_trans_cancel;
-
- 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)
- goto out_trans_cancel;
-
- if (src_is_directory) {
- /*
- * Drop the link from the old "." entry.
- */
- error = xfs_droplink(tp, target_ip);
- if (error)
- goto out_trans_cancel;
- }
- } /* 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)
- goto out_trans_cancel;
- }
-
- /*
- * 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)
- goto out_trans_cancel;
- }
-
- /*
- * For whiteouts, we only need to update the source dirent with the
- * inode number of the whiteout inode rather than removing it
- * altogether.
- */
- if (wip) {
- error = xfs_dir_replace(tp, src_dp, src_name, wip->i_ino,
- spaceres);
- } else
- error = xfs_dir_removename(tp, src_dp, src_name, src_ip->i_ino,
- spaceres);
+ error = xfs_dir_rename(tp, src_dp, src_name, src_ip, target_dp,
+ target_name, target_ip, spaceres, wip);
if (error)
goto out_trans_cancel;

- /*
- * For whiteouts, we need to bump the link count on the whiteout inode.
- * This means that failures all the way up to this point leave the inode
- * on the unlinked list and so cleanup is a simple matter of dropping
- * the remaining reference to it. If we fail here after bumping the link
- * count, we're shutting down the filesystem so we'll never see the
- * intermediate state on disk.
- */
if (wip) {
- ASSERT(VFS_I(wip)->i_nlink == 0);
- error = xfs_bumplink(tp, wip);
- if (error)
- goto out_trans_cancel;
- error = xfs_iunlink_remove(tp, wip);
- if (error)
- goto out_trans_cancel;
- xfs_trans_log_inode(tp, wip, XFS_ILOG_CORE);
-
/*
* Now we have a real link, clear the "I'm a tmpfile" state
* flag from the inode so it doesn't accidentally get misused in
@@ -2359,11 +2208,6 @@ xfs_rename(
VFS_I(wip)->i_state &= ~I_LINKABLE;
}

- 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);
-
error = xfs_finish_rename(tp);
if (wip)
xfs_irele(wip);