Skip to contentSkip to conversation

e2fsprogs: allow more than 32000 subdirectories

PATCH In review Kalpak Shah 2 participants 2 messages Mar 21, 2007 – Mar 22, 2007 2 messages not in the archive

lore
Share & tools
lore

Kalpak Shah

author
#0 lore raw

PATCH 1/2 e2fsprogs: allow more than 32000 subdirectories

Hi,

This patch includes the changes required to e2fsck to understand the nlink count changes made in the kernel. In pass2, while counting the links for a directory, if the link count exceeds 65000, its permanently set to EXT2_NLINK_MAXED (EXT2_LINK_MAX + 100). In pass4, when the counted and actual nlink counts are compared, e2fsck does not flag an error if counted links = EXT2_NLINK_MAXED and existing link count is 1.

It also handles the case when a directory had more than 65000 subdirs and they were later deleted. The nlink count of such a directory remains 1. In pass4 if counted links are 2 and if existing nlink count = 1, e2fsck corrects the nlink count without displaying any errors.

Signed-off-by Andreas Dilger <[email protected]>
Signed-off-by Kalpak Shah <[email protected]>
e2fsck/pass4.c +29 -2
Index: e2fsprogs-1.40/e2fsck/pass4.c
===================================================================
@@ -145,7 +145,9 @@ void e2fsck_pass4(e2fsck_t ctx)
 			ext2fs_icount_fetch(ctx->inode_count, i,
 					    &link_counted);
 		}
-		if (link_counted != link_count) {
+		if (link_counted != link_count &&
+		    !(ext2fs_test_inode_bitmap(ctx->inode_dir_map, i) &&
+		    link_count == 1 && link_counted == EXT2_NLINK_MAXED)) {
 			e2fsck_read_inode(ctx, i, &inode, "pass4");
 			pctx.ino = i;
 			pctx.inode = &inode;

@@ -155,12 +157,37 @@ void e2fsck_pass4(e2fsck_t ctx)
 					    PR_4_INCONSISTENT_COUNT, &pctx);
 			}
 			pctx.num = link_counted;
-			if (fix_problem(ctx, PR_4_BAD_REF_COUNT, &pctx)) {
+			/* i_link_count was previously exceeded, but no longer
+			 * is, fix this but don't consider it an error */
+			if ((LINUX_S_ISDIR(inode.i_mode) && link_counted > 1 &&
+			     (inode.i_flags & EXT2_INDEX_FL) &&
+			     link_count == 1 && !(ctx->options & E2F_OPT_NO)) ||
+			     (fix_problem(ctx, PR_4_BAD_REF_COUNT, &pctx))) {
 				inode.i_links_count = link_counted;
 				e2fsck_write_inode(ctx, i, &inode, "pass4");
 			}
 		}
+		if (link_counted == EXT2_NLINK_MAXED)
+			ctx->fs_many_subdirs++;
 	}
+	if (ctx->fs_many_subdirs) {
+		if (!(fs->super->s_feature_ro_compat &
+		      EXT4_FEATURE_RO_COMPAT_DIR_NLINK) &&
+		    fix_problem(ctx, PR_4_FEATURE_DIR_NLINK, &pctx)) {
+			fs->super->s_feature_ro_compat |=
+				EXT4_FEATURE_RO_COMPAT_DIR_NLINK;
+			ext2fs_mark_super_dirty(fs);
+		}
+	} else if (!ctx->fs_many_subdirs &&
+	    (fs->super->s_feature_ro_compat &
+	      EXT4_FEATURE_RO_COMPAT_DIR_NLINK)) {
+		if (fs->flags & EXT2_FLAG_RW) {
+			fs->super->s_feature_ro_compat &=
+				~EXT4_FEATURE_RO_COMPAT_DIR_NLINK;
+			ext2fs_mark_super_dirty(fs);
+		}
+	}
+
 	ext2fs_free_icount(ctx->inode_link_info); ctx->inode_link_info = 0;
 	ext2fs_free_icount(ctx->inode_count); ctx->inode_count = 0;
 	ext2fs_free_inode_bitmap(ctx->inode_bb_map);
lib/ext2fs/ext2_fs.h +1 -0
Index: e2fsprogs-1.40/lib/ext2fs/ext2_fs.h
===================================================================
@@ -635,6 +635,7 @@ struct ext2_super_block {
 #define EXT2_FEATURE_INCOMPAT_SUPP	(EXT2_FEATURE_INCOMPAT_FILETYPE)
 #define EXT2_FEATURE_RO_COMPAT_SUPP	(EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
 					 EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
+					 EXT4_FEATURE_RO_COMPAT_DIR_NLINK| \
 					 EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
 
 /*
lib/ext2fs/ext2fs.h +9 -1
Index: e2fsprogs-1.40/lib/ext2fs/ext2fs.h
===================================================================
@@ -403,6 +403,9 @@ typedef struct ext2_struct_inode_scan *e
 
 typedef struct ext2_icount *ext2_icount_t;
 
+/* To handle the case when a directory has nlink = 1, but is empty. */
+#define EXT2_NLINK_MAXED	EXT2_LINK_MAX + 100
+
 /*
  * Flags for ext2fs_bmap
  */

@@ -460,7 +463,8 @@ typedef struct ext2_icount *ext2_icount_
 					 EXT3_FEATURE_INCOMPAT_RECOVER)
 #endif
 #define EXT2_LIB_FEATURE_RO_COMPAT_SUPP	(EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER|\
-					 EXT2_FEATURE_RO_COMPAT_LARGE_FILE)
+					 EXT2_FEATURE_RO_COMPAT_LARGE_FILE|\
+					 EXT4_FEATURE_RO_COMPAT_DIR_NLINK)
 
 /*
  * These features are only allowed if EXT2_FLAG_SOFTSUPP_FEATURES is passed

@@ -791,8 +795,12 @@ extern errcode_t ext2fs_create_icount(ex
 				      ext2_icount_t *ret);
 extern errcode_t ext2fs_icount_fetch(ext2_icount_t icount, ext2_ino_t ino,
 				     __u16 *ret);
+extern errcode_t ext2fs_icount_inc32(ext2_icount_t icount, ext2_ino_t ino,
+				     __u32 *ret, int is_dir);
 extern errcode_t ext2fs_icount_increment(ext2_icount_t icount, ext2_ino_t ino,
 					 __u16 *ret);
+extern errcode_t ext2fs_icount_dec32(ext2_icount_t icount, ext2_ino_t ino,
+				     __u32 *ret, int is_dir);
 extern errcode_t ext2fs_icount_decrement(ext2_icount_t icount, ext2_ino_t ino,
 					 __u16 *ret);
 extern errcode_t ext2fs_icount_store(ext2_icount_t icount, ext2_ino_t ino,
e2fsck/pass2.c +5 -4
Index: e2fsprogs-1.40/e2fsck/pass2.c
===================================================================
@@ -710,7 +710,7 @@ static int check_dir_block(ext2_filsys f
 	int			dot_state;
 	blk_t			block_nr = db->blk;
 	ext2_ino_t 		ino = db->ino;
-	__u16			links;
+	__u32			links;
 	struct check_dir_struct	*cd;
 	char 			*buf;
 	e2fsck_t		ctx;

@@ -1014,9 +1014,10 @@ static int check_dir_block(ext2_filsys f
 			dups_found++;
 		} else
 			dict_alloc_insert(&de_dict, dirent, dirent);
-		
-		ext2fs_icount_increment(ctx->inode_count, dirent->inode,
-					&links);
+
+		ext2fs_icount_inc32(ctx->inode_count, dirent->inode, &links,
+				    ext2fs_test_inode_bitmap(ctx->inode_dir_map,
+							     dirent->inode));
 		if (links > 1)
 			ctx->fs_links_count++;
 		ctx->fs_total_count++;
lib/ext2fs/icount.c +31 -3
Index: e2fsprogs-1.40/lib/ext2fs/icount.c
===================================================================
@@ -321,8 +321,8 @@ errcode_t ext2fs_icount_fetch(ext2_icoun
 	return 0;
 }
 
-errcode_t ext2fs_icount_increment(ext2_icount_t icount, ext2_ino_t ino,
-				  __u16 *ret)
+errcode_t ext2fs_icount_inc32(ext2_icount_t icount, ext2_ino_t ino,
+			      __u32 *ret, int is_dir)
 {
 	struct ext2_icount_el	*el;
 

@@ -381,14 +381,29 @@ errcode_t ext2fs_icount_increment(ext2_i
 	}
 	if (icount->multiple)
 		ext2fs_mark_inode_bitmap(icount->multiple, ino);
+	if (el->count >= EXT2_LINK_MAX && is_dir)
+		el->count = EXT2_NLINK_MAXED;
 	if (ret)
 		*ret = el->count;
 	return 0;
 }
 
-errcode_t ext2fs_icount_decrement(ext2_icount_t icount, ext2_ino_t ino,
+errcode_t ext2fs_icount_increment(ext2_icount_t icount, ext2_ino_t ino,
 				  __u16 *ret)
 {
+	__u32 links;
+	errcode_t err;
+
+	err = ext2fs_icount_inc32(icount, ino, &links, 0);
+	if (ret)
+		*ret = links;
+
+	return err;
+}
+
+errcode_t ext2fs_icount_dec32(ext2_icount_t icount, ext2_ino_t ino,
+			      __u32 *ret, int is_dir)
+{
 	struct ext2_icount_el	*el;
 
 	if (!ino || (ino > icount->num_inodes))

@@ -429,6 +444,19 @@ errcode_t ext2fs_icount_decrement(ext2_i
 	return 0;
 }
 
+errcode_t ext2fs_icount_decrement(ext2_icount_t icount, ext2_ino_t ino,
+				  __u16 *ret)
+{
+	__u32 links;
+	errcode_t err;
+
+	err = ext2fs_icount_dec32(icount, ino, &links, 0);
+	if (ret)
+		*ret = links;
+
+	return err;
+}
+
 errcode_t ext2fs_icount_store(ext2_icount_t icount, ext2_ino_t ino,
 			      __u16 count)
 {
e2fsck/e2fsck.c +1 -0
Index: e2fsprogs-1.40/e2fsck/e2fsck.c
===================================================================
@@ -150,6 +150,7 @@ errcode_t e2fsck_reset_context(e2fsck_t 
 	ctx->fs_tind_count = 0;
 	ctx->fs_fragmented = 0;
 	ctx->large_files = 0;
+	ctx->fs_many_subdirs = 0;
 
 	/* Reset the superblock to the user's requested value */
 	ctx->superblock = ctx->use_superblock;
e2fsck/e2fsck.h +1 -0
Index: e2fsprogs-1.40/e2fsck/e2fsck.h
===================================================================
@@ -327,6 +327,7 @@ struct e2fsck_struct {
 	__u32 large_files;
 	__u32 fs_ext_attr_inodes;
 	__u32 fs_ext_attr_blocks;
+	__u32 fs_many_subdirs;
 
 	time_t now;
e2fsck/problem.c +6 -0
Index: e2fsprogs-1.40/e2fsck/problem.c
===================================================================
@@ -1366,6 +1366,12 @@ static struct e2fsck_problem problem_tab
 	  "They @s the same!\n"),
 	  PROMPT_NONE, 0 },
 
+	/* DIR_NLINK flag not set but dirs with > 65000 subdirs found */
+	{ PR_4_FEATURE_DIR_NLINK,
+	  N_("@f contains directories with > 65000 subdirs, but lacks "
+	  "DIR_NLINK flag in @S.\n"),
+	  PROMPT_FIX, 0 },
+
 	/* Pass 5 errors */
 		  
 	/* Pass 5: Checking group summary information */
e2fsck/problem.h +4 -0
Index: e2fsprogs-1.40/e2fsck/problem.h
===================================================================
@@ -821,6 +821,10 @@ struct problem_context {
 /* Inconsistent inode count information cached */
 #define PR_4_INCONSISTENT_COUNT	0x040004
 
+/* Directory with > EXT2_LINK_MAX subdirs found but
+ * EXT4_FEATURE_RO_COMPAT_DIR_NLINK flag is reset */
+#define PR_4_FEATURE_DIR_NLINK	0x040005
+
 /*
  * Pass 5 errors
  */

Thanks,
Kalpak Shah.

A message that is not in the archive (sent off-list or not yet received): [email protected]

A message that is not in the archive (sent off-list or not yet received): 1174512908.3080.1.camel@garfield

#3 lore raw
Quoted 17 lines · Kalpak Shah

Index: e2fsprogs-1.40/lib/ext2fs/ext2_fs.h
===================================================================

lib/ext2fs/ext2_fs.h +1 -0
@@ -635,6 +635,7 @@ struct ext2_super_block {
 #define EXT2_FEATURE_INCOMPAT_SUPP	(EXT2_FEATURE_INCOMPAT_FILETYPE)
 #define EXT2_FEATURE_RO_COMPAT_SUPP	(EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
 					 EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
+					 EXT4_FEATURE_RO_COMPAT_DIR_NLINK| \
 					 EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
 
 /*

Index: e2fsprogs-1.40/lib/ext2fs/ext2fs.h
===================================================================

lib/ext2fs/ext2fs.h typedef struct ext2_icount *ext2_icount_ · line 467

Quoted 6 lines
lib/ext2fs/ext2fs.h +2 -1
@@ -460,7 +463,8 @@ typedef struct ext2_icount *ext2_icount_
 					 EXT3_FEATURE_INCOMPAT_RECOVER)
 #endif
 #define EXT2_LIB_FEATURE_RO_COMPAT_SUPP	(EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER|\
-					 EXT2_FEATURE_RO_COMPAT_LARGE_FILE)
+					 EXT2_FEATURE_RO_COMPAT_LARGE_FILE|\
+					 EXT4_FEATURE_RO_COMPAT_DIR_NLINK)

Ted, can you give a bit of clarification for these different masks. For EXT2_LIB_SOFTSUPP_RO_COMPAT, it says "These features are only allowed if EXT2_FLAG_SOFTSUPP_FEATURES is passed to ext2fs_openfs()". If the patch from Kalpak adds DIR_NLINK to EXT2_LIB_FEATURE_RO_COMPAT_SUPP, does that mean we should remove it from EXT2_FLAG_SOFTSUPP_FEATURES?

Also, I notice in ext2fs_open2() that there is a bit of code:

#ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT
	if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
		features &= !EXT2_LIB_SOFTSUPP_RO_COMPAT;

#endif

But what does "!EXT2_LIB_SOFTSUPP_RO_COMPAT" really mean? Should this be ~EXT2_LIB_SOFTSUPP_RO_COMPAT? Should it be instead:

features &= ~(EXT2_LIB_SOFTSUPP_RO_COMPAT|EXT2_LIB_FEATURE_RO_COMPAT_SUPP)

so that we don't mask out all of the features that are NOT in SOFTSUPP_RO_COMPAT? Otherwise we've just broken e2fsprogs feature compat support badly I think. A similar hunk exists for EXT2_LIB_SOFTSUPP_INCOMPAT.

Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.