[11/23] xfs: replace namebuf with parent pointer in directory repair

Commit Message

Darrick J. Wong March 18, 2024, 9:50 p.m. UTC

From: Darrick J. Wong <[e-mail]>

Replace the dirent name buffer at the end of struct xrep_dir with a
xfs_parent_name_irec object.  The namebuf and p_name usage do not
overlap, so we can save 256 bytes of memory by allowing them to overlap.
Doing so makes the code a bit more complex, so this is called out
separately.

Signed-off-by: Darrick J. Wong <[e-mail]>
---
 fs/xfs/scrub/dir_repair.c |   19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

Patch

diff --git a/fs/xfs/scrub/dir_repair.c b/fs/xfs/scrub/dir_repair.c
index 4cfda208e9e6b..e89703d1123cd 100644
--- a/fs/xfs/scrub/dir_repair.c
+++ b/fs/xfs/scrub/dir_repair.c
@@ -28,6 +28,7 @@ 
 #include "xfs_exchmaps.h"
 #include "xfs_exchrange.h"
 #include "xfs_ag.h"
+#include "xfs_parent.h"
 #include "scrub/xfs_scrub.h"
 #include "scrub/scrub.h"
 #include "scrub/common.h"
@@ -131,8 +132,14 @@  struct xrep_dir {
 	/* Should we move this directory to the orphanage? */
 	bool			needs_adoption;
 
-	/* Directory entry name, plus the trailing null. */
-	unsigned char		namebuf[MAXNAMELEN];
+	/*
+	 * Scratch buffer for reading parent pointers from child files.  The
+	 * p_name field is used to flush stashed dirents into the temporary
+	 * directory in between parent pointers.  At the very end of the
+	 * repair, it can also be used to compute the lost+found filename
+	 * if we need to reparent the directory.
+	 */
+	struct xfs_parent_name_irec pptr;
 };
 
 /* Tear down all the incore stuff we created. */
@@ -696,7 +703,7 @@  xrep_dir_replay_update(
 	struct xfs_name			name = {
 		.len			= dirent->namelen,
 		.type			= dirent->ftype,
-		.name			= rd->namebuf,
+		.name			= rd->pptr.p_name,
 	};
 	struct xfs_mount		*mp = rd->sc->mp;
 #ifdef DEBUG
@@ -773,10 +780,10 @@  xrep_dir_replay_updates(
 
 		/* The dirent name is stored in the in-core buffer. */
 		error = xfblob_load(rd->dir_names, dirent.name_cookie,
-				rd->namebuf, dirent.namelen);
+				rd->pptr.p_name, dirent.namelen);
 		if (error)
 			return error;
-		rd->namebuf[MAXNAMELEN - 1] = 0;
+		rd->pptr.p_name[MAXNAMELEN - 1] = 0;
 
 		error = xrep_dir_replay_update(rd, &dirent);
 		if (error)
@@ -1421,7 +1428,7 @@  xrep_dir_move_to_orphanage(
 	if (error)
 		return error;
 
-	error = xrep_adoption_compute_name(&rd->adoption, rd->namebuf);
+	error = xrep_adoption_compute_name(&rd->adoption, rd->pptr.p_name);
 	if (error)
 		return error;