Date: Mon,  6 May 2024 19:41:17 +0200
From: Jan Kara <jack@...e.cz>
To: <linux-ext4@...r.kernel.org>
Cc: Jan Kara <jack@...e.cz>
Subject: [PATCH 1/3] e2fsck: add more checks for ea inode consistency

Currently checking of EA inodes was rather weak. Add several more
consistency checks.

1) Check that EA inode is a regular file.
2) Check that EA_INODE feature is set if the filesystem has EA inodes.
3) Make sure that no EA inode is referenced from directory hierarchy.

Signed-off-by: Jan Kara <jack@...e.cz>
---
 e2fsck/e2fsck.h  |  6 ++++
 e2fsck/pass1.c   | 84 +++++++++++++++++++++++++++++++++++++++++-------
 e2fsck/pass2.c   | 15 +++++++++
 e2fsck/pass4.c   | 53 +++++++++++++++++++-----------
 e2fsck/problem.c | 18 +++++++++++
 e2fsck/problem.h | 12 +++++++
 6 files changed, 158 insertions(+), 30 deletions(-)

diff --git a/e2fsck/e2fsck.h b/e2fsck/e2fsck.h
index 55738fdc1d19..ae1273dc00af 100644
--- a/e2fsck/e2fsck.h
+++ b/e2fsck/e2fsck.h
@@ -533,6 +533,12 @@ extern struct dx_dir_info *e2fsck_dx_dir_info_iter(e2fsck_t ctx,
 typedef __u64 ea_key_t;
 typedef __u64 ea_value_t;
 
+/*
+ * Special refcount value we use for inodes which have EA_INODE flag set but we
+ * do not yet know about any references.
+ */
+#define EA_INODE_NO_REFS (~(ea_value_t)0)
+
 extern errcode_t ea_refcount_create(size_t size, ext2_refcount_t *ret);
 extern void ea_refcount_free(ext2_refcount_t refcount);
 extern errcode_t ea_refcount_fetch(ext2_refcount_t refcount, ea_key_t ea_key,
diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
index 8b6238e8434c..eb73922d3e2c 100644
--- a/e2fsck/pass1.c
+++ b/e2fsck/pass1.c
@@ -387,34 +387,71 @@ static problem_t check_large_ea_inode(e2fsck_t ctx,
 	return 0;
 }
 
+static int alloc_ea_inode_refs(e2fsck_t ctx, struct problem_context *pctx)
+{
+	pctx->errcode = ea_refcount_create(0, &ctx->ea_inode_refs);
+	if (pctx->errcode) {
+		pctx->num = 4;
+		fix_problem(ctx, PR_1_ALLOCATE_REFCOUNT, pctx);
+		ctx->flags |= E2F_FLAG_ABORT;
+		return 0;
+	}
+	return 1;
+}
+
 static void inc_ea_inode_refs(e2fsck_t ctx, struct problem_context *pctx,
 			      struct ext2_ext_attr_entry *first, void *end)
 {
 	struct ext2_ext_attr_entry *entry = first;
 	struct ext2_ext_attr_entry *np = EXT2_EXT_ATTR_NEXT(entry);
+	ea_value_t refs;
 
 	while ((void *) entry < end && (void *) np < end &&
 	       !EXT2_EXT_IS_LAST_ENTRY(entry)) {
 		if (!entry->e_value_inum)
 			goto next;
-		if (!ctx->ea_inode_refs) {
-			pctx->errcode = ea_refcount_create(0,
-							   &ctx->ea_inode_refs);
-			if (pctx->errcode) {
-				pctx->num = 4;
-				fix_problem(ctx, PR_1_ALLOCATE_REFCOUNT, pctx);
-				ctx->flags |= E2F_FLAG_ABORT;
-				return;
-			}
-		}
-		ea_refcount_increment(ctx->ea_inode_refs, entry->e_value_inum,
-				      0);
+		if (!ctx->ea_inode_refs && !alloc_ea_inode_refs(ctx, pctx))
+			return;
+		ea_refcount_fetch(ctx->ea_inode_refs, entry->e_value_inum,
+				  &refs);
+		if (refs == EA_INODE_NO_REFS)
+			refs = 1;
+		else
+			refs += 1;
+		ea_refcount_store(ctx->ea_inode_refs, entry->e_value_inum, refs);
 	next:
 		entry = np;
 		np = EXT2_EXT_ATTR_NEXT(entry);
 	}
 }
 
+/*
+ * Make sure inode is tracked as EA inode. We use special EA_INODE_NO_REFS
+ * value if we didn't find any xattrs referencing this inode yet.
+ */
+static int track_ea_inode(e2fsck_t ctx, struct problem_context *pctx,
+			  ext2_ino_t ino)
+{
+	ea_value_t refs;
+
+	if (!ctx->ea_inode_refs && !alloc_ea_inode_refs(ctx, pctx))
+		return 0;
+
+	ea_refcount_fetch(ctx->ea_inode_refs, ino, &refs);
+	if (refs > 0)
+		return 1;
+
+	pctx->errcode = ea_refcount_store(ctx->ea_inode_refs, ino,
+					  EA_INODE_NO_REFS);
+	if (pctx->errcode) {
+		pctx->num = 5;
+		fix_problem(ctx, PR_1_ALLOCATE_REFCOUNT, pctx);
+		ctx->flags |= E2F_FLAG_ABORT;
+		return 0;
+	}
+	return 1;
+}
+
 static void check_ea_in_inode(e2fsck_t ctx, struct problem_context *pctx,
 			      struct ea_quota *ea_ibody_quota)
 {
@@ -510,6 +547,12 @@ static void check_ea_in_inode(e2fsck_t ctx, struct problem_context *pctx,
 		} else {
 			blk64_t quota_blocks;
 
+			if (!ext2fs_has_feature_ea_inode(sb) &&
+			    fix_problem(ctx, PR_1_EA_INODE_FEATURE, pctx)) {
+				ext2fs_set_feature_ea_inode(sb);
+				ext2fs_mark_super_dirty(ctx->fs);
+			}
+
 			problem = check_large_ea_inode(ctx, entry, pctx,
 						       &quota_blocks);
 			if (problem != 0)
@@ -1502,6 +1545,17 @@ void e2fsck_pass1(e2fsck_t ctx)
 			e2fsck_write_inode(ctx, ino, inode, "pass1");
 		}
 
+		if (inode->i_flags & EXT4_EA_INODE_FL) {
+			if (!LINUX_S_ISREG(inode->i_mode) &&
+			    fix_problem(ctx, PR_1_EA_INODE_NONREG, &pctx)) {
+				inode->i_flags &= ~EXT4_EA_INODE_FL;
+				e2fsck_write_inode(ctx, ino, inode, "pass1");
+			}
+			if (inode->i_flags & EXT4_EA_INODE_FL)
+				if (!track_ea_inode(ctx, &pctx, ino))
+					continue;
+		}
+
 		/* Conflicting inlinedata/extents inode flags? */
 		if ((inode->i_flags & EXT4_INLINE_DATA_FL) &&
 		    (inode->i_flags & EXT4_EXTENTS_FL)) {
@@ -2622,6 +2676,12 @@ static int check_ext_attr(e2fsck_t ctx, struct problem_context *pctx,
 			problem_t problem;
 			blk64_t entry_quota_blocks;
 
+			if (!ext2fs_has_feature_ea_inode(fs->super) &&
+			    fix_problem(ctx, PR_1_EA_INODE_FEATURE, pctx)) {
+				ext2fs_set_feature_ea_inode(fs->super);
+				ext2fs_mark_super_dirty(fs);
+			}
+
 			problem = check_large_ea_inode(ctx, entry, pctx,
 						       &entry_quota_blocks);
 			if (problem && fix_problem(ctx, problem, pctx))
diff --git a/e2fsck/pass2.c b/e2fsck/pass2.c
index 08ab40fa8ba1..036c0022d38a 100644
--- a/e2fsck/pass2.c
+++ b/e2fsck/pass2.c
@@ -1501,6 +1501,21 @@ skip_checksum:
 			problem = PR_2_NULL_NAME;
 		}
 
+		/*
+		 * Check if inode was tracked as EA inode and has actual
+		 * references from xattrs. In that case dir entry is likely
+		 * bogus and we want to clear it. The case of EA inode without
+		 * references from xattrs will be handled in pass 4.
+		 */
+		if (!problem && ctx->ea_inode_refs) {
+			ea_value_t refs;
+
+			ea_refcount_fetch(ctx->ea_inode_refs, dirent->inode,
+					  &refs);
+			if (refs && refs != EA_INODE_NO_REFS)
+				problem = PR_2_EA_INODE_DIR_LINK;
+		}
+
 		if (problem) {
 			if (fix_problem(ctx, problem, &cd->pctx)) {
 				dirent->inode = 0;
diff --git a/e2fsck/pass4.c b/e2fsck/pass4.c
index d2dda02a94b8..cf0cf7c47582 100644
--- a/e2fsck/pass4.c
+++ b/e2fsck/pass4.c
@@ -96,9 +96,10 @@ static int disconnect_inode(e2fsck_t ctx, ext2_ino_t i, ext2_ino_t *last_ino,
  * an xattr inode at all. Return immediately if EA_INODE flag is not set.
  */
 static void check_ea_inode(e2fsck_t ctx, ext2_ino_t i, ext2_ino_t *last_ino,
-			   struct ext2_inode_large *inode, __u16 *link_counted)
+			   struct ext2_inode_large *inode, __u16 *link_counted,
+			   ea_value_t actual_refs)
 {
-	__u64 actual_refs = 0;
+	struct problem_context pctx;
 	__u64 ref_count;
 
 	if (*last_ino != i) {
@@ -107,13 +108,26 @@ static void check_ea_inode(e2fsck_t ctx, ext2_ino_t i, ext2_ino_t *last_ino,
 				       "pass4: check_ea_inode");
 		*last_ino = i;
 	}
-	if (!(inode->i_flags & EXT4_EA_INODE_FL))
-		return;
 
-	if (ctx->ea_inode_refs)
-		ea_refcount_fetch(ctx->ea_inode_refs, i, &actual_refs);
-	if (!actual_refs)
+	clear_problem_context(&pctx);
+	pctx.ino = i;
+	pctx.inode = EXT2_INODE(inode);
+
+	/* No references to the inode from xattrs? */
+	if (actual_refs == EA_INODE_NO_REFS) {
+		/*
+		 * No references from directory hierarchy either? Inode will
+		 * will get attached to lost+found so clear EA_INODE_FL.
+		 * Otherwise this is likely a spuriously set flag so clear it.
+		 */
+		if (*link_counted == 0 ||
+		    fix_problem(ctx, PR_4_EA_INODE_SPURIOUS_FLAG, &pctx)) {
+			/* Clear EA_INODE_FL (likely a normal file) */
+			inode->i_flags &= ~EXT4_EA_INODE_FL;
+			e2fsck_write_inode(ctx, i, EXT2_INODE(inode), "pass4");
+		}
 		return;
+	}
 
 	/*
 	 * There are some attribute references, link_counted is now considered
@@ -127,10 +141,6 @@ static void check_ea_inode(e2fsck_t ctx, ext2_ino_t i, ext2_ino_t *last_ino,
 	 * However, their i_ctime and i_atime should be the same.
 	 */
 	if (ref_count != actual_refs && inode->i_ctime != inode->i_atime) {
-		struct problem_context pctx;
-
-		clear_problem_context(&pctx);
-		pctx.ino = i;
 		pctx.num = ref_count;
 		pctx.num2 = actual_refs;
 		if (fix_problem(ctx, PR_4_EA_INODE_REF_COUNT, &pctx)) {
@@ -188,6 +198,7 @@ void e2fsck_pass4(e2fsck_t ctx)
 	/* Protect loop from wrap-around if s_inodes_count maxed */
 	for (i = 1; i <= fs->super->s_inodes_count && i > 0; i++) {
 		ext2_ino_t last_ino = 0;
+		ea_value_t ea_refs;
 		int isdir;
 
 		if (ctx->flags & E2F_FLAG_SIGNAL_MASK)
@@ -211,13 +222,19 @@ void e2fsck_pass4(e2fsck_t ctx)
 		ext2fs_icount_fetch(ctx->inode_link_info, i, &link_count);
 		ext2fs_icount_fetch(ctx->inode_count, i, &link_counted);
 
-		if (link_counted == 0) {
-			/*
-			 * link_counted is expected to be 0 for an ea_inode.
-			 * check_ea_inode() will update link_counted if
-			 * necessary.
-			 */
-			check_ea_inode(ctx, i, &last_ino, inode, &link_counted);
+		if (ctx->ea_inode_refs) {
+			ea_refcount_fetch(ctx->ea_inode_refs, i, &ea_refs);
+			if (ea_refs) {
+				/*
+				 * Final consolidation of EA inodes. We either
+				 * decide the inode is fine and set link_counted
+				 * to one, or we decide this is actually a
+				 * normal file and clear EA_INODE flag, or
+				 * decide the inode should just be deleted.
+				 */
+				check_ea_inode(ctx, i, &last_ino, inode,
+					       &link_counted, ea_refs);
+			}
 		}
 
 		if (link_counted == 0) {
diff --git a/e2fsck/problem.c b/e2fsck/problem.c
index 207ebbb34ec8..e433281fab4b 100644
--- a/e2fsck/problem.c
+++ b/e2fsck/problem.c
@@ -1309,6 +1309,16 @@ static struct e2fsck_problem problem_table[] = {
 	  N_("Orphan file @i %i is not in use, but contains data.  "),
 	  PROMPT_CLEAR, PR_PREEN_OK },
 
+	/* EA_INODE flag set on a non-regular file */
+	{ PR_1_EA_INODE_NONREG,
+	  N_("@i %i has the ea_inode flag set but is not a regular file.  "),
+	  PROMPT_CLEAR_FLAG, 0, 0, 0, 0 },
+
+	/* EA_INODE present but the file system is missing the ea_inode feature */
+	{ PR_1_EA_INODE_FEATURE,
+	  N_("@i %i references EA inode but @S is missing EA_INODE feature\n"),
+	  PROMPT_FIX, PR_PREEN_OK, 0, 0, 0 },
+
 	/* Pass 1b errors */
 
 	/* Pass 1B: Rescan for duplicate/bad blocks */
@@ -1860,6 +1870,10 @@ static struct e2fsck_problem problem_table[] = {
 	   N_("Duplicate filename @E found.  "),
 	   PROMPT_CLEAR, 0, 0, 0, 0 },
 
+	/* Directory filename is null */
+	{ PR_2_EA_INODE_DIR_LINK,
+	  N_("@E references EA @i %Di.\n"),
+	  PROMPT_CLEAR, 0, 0, 0, 0 },
 
 	/* Pass 3 errors */
 
@@ -2102,6 +2116,10 @@ static struct e2fsck_problem problem_table[] = {
 	  N_("@d @i %i ref count set to overflow but could be exact value %N.  "),
 	  PROMPT_FIX, PR_PREEN_OK, 0, 0, 0 },
 
+	{ PR_4_EA_INODE_SPURIOUS_FLAG,
+	  N_("Regular @f @i %i has EA_INODE flag set. "),
+	  PROMPT_CLEAR, PR_PREEN_OK, 0, 0, 0 },
+
 	/* Pass 5 errors */
 
 	/* Pass 5: Checking group summary information */
diff --git a/e2fsck/problem.h b/e2fsck/problem.h
index b47b0c630c67..ef15b8c84358 100644
--- a/e2fsck/problem.h
+++ b/e2fsck/problem.h
@@ -734,6 +734,12 @@ struct problem_context {
 /* Orphan file inode is not in use, but contains data */
 #define PR_1_ORPHAN_FILE_NOT_CLEAR		0x010090
 
+/* Inode has EA_INODE_FL set but is not a regular file */
+#define PR_1_EA_INODE_NONREG			0x010091
+
+/* Inode references EA inode but ea_inode feature is not enabled */
+#define PR_1_EA_INODE_FEATURE			0x010092
+
 /*
  * Pass 1b errors
  */
@@ -1061,6 +1067,9 @@ struct problem_context {
 /* Non-unique filename found, but can't rename */
 #define PR_2_NON_UNIQUE_FILE_NO_RENAME	0x020054
 
+/* EA inode referenced from directory */
+#define PR_2_EA_INODE_DIR_LINK 0x020055
+
 /*
  * Pass 3 errors
  */
@@ -1203,6 +1212,9 @@ struct problem_context {
 /* Directory ref count set to overflow but it doesn't have to be */
 #define PR_4_DIR_OVERFLOW_REF_COUNT	0x040007
 
+/* EA_INODE_FL set on normal file linked from directory hierarchy */
+#define PR_4_EA_INODE_SPURIOUS_FLAG	0x040008
+
 /*
  * Pass 5 errors
  */
-- 
2.35.3

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