If there are any directories with > 65000 subdirectories, enable the
DIR_NLINK feature in the superblock. If there are any directories
that formerly had > 65000 subdirs (i_links_count == 1) but no longer
do, don't consider this an error to alert the user about, but silently
fix the link count to the currently counted link count.
The DIR_NLINK feature is not disabled if set but no many-subdir directories
are found, so that the kernel is not required to enable it on-the-fly. The
admin should set it with tune2fs instead.
Index: e2fsprogs-1.40.5/e2fsck/pass4.c
===================================================================
--- e2fsprogs-1.40.5.orig/e2fsck/pass4.c
+++ e2fsprogs-1.40.5/e2fsck/pass4.c
@@ -101,6 +101,7 @@ void e2fsck_pass4(e2fsck_t ctx)
struct problem_context pctx;
__u16 link_count;
__u32 link_counted;
+ __u32 many_subdirs = 0;
char *buf = 0;
int group, maxgroup;
@@ -182,7 +183,20 @@ void e2fsck_pass4(e2fsck_t ctx)
e2fsck_write_inode(ctx, i, inode, "pass4");
}
}
+ if (link_count == 1 && link_counted > EXT2_LINK_MAX)
+ many_subdirs++;
}
+
+ if (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);
+ }
+ }
+
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);
Index: e2fsprogs-1.40.5/e2fsck/problem.c
===================================================================
--- e2fsprogs-1.40.5.orig/e2fsck/problem.c
+++ e2fsprogs-1.40.5/e2fsck/problem.c
@@ -1371,6 +1371,11 @@ 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 has @d with > 65000 subdirs, but no DIR_NLINK flag in @S.\n"),
+ PROMPT_FIX, 0 },
+
/* Pass 5 errors */
/* Pass 5: Checking group summary information */
Index: e2fsprogs-1.40.5/e2fsck/problem.h
===================================================================
--- e2fsprogs-1.40.5.orig/e2fsck/problem.h
+++ e2fsprogs-1.40.5/e2fsck/problem.h
@@ -824,6 +824,10 @@ 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 not set */
+#define PR_4_FEATURE_DIR_NLINK 0x040005
+
/*
* Pass 5 errors
*/
Index: e2fsprogs-1.40.5/misc/tune2fs.8.in
===================================================================
--- e2fsprogs-1.40.5.orig/misc/tune2fs.8.in
+++ e2fsprogs-1.40.5/misc/tune2fs.8.in
@@ -400,6 +400,10 @@ The following filesystem features can be
.B dir_index
Use hashed b-trees to speed up lookups in large directories.
.TP
+.B dir_nlink
+Allow directories to have more than 65000 subdirectories (read-only
+compatible).
+.TP
.B filetype
Store file type information in directory entries.
.TP
Index: e2fsprogs-1.40.5/misc/tune2fs.c
===================================================================
--- e2fsprogs-1.40.5.orig/misc/tune2fs.c
+++ e2fsprogs-1.40.5/misc/tune2fs.c
@@ -100,7 +100,8 @@ static __u32 ok_features[3] = {
EXT2_FEATURE_INCOMPAT_FILETYPE| /* Incompat */
EXT4_FEATURE_INCOMPAT_FLEX_BG,
EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER | /* R/O compat */
- EXT4_FEATURE_RO_COMPAT_GDT_CSUM
+ EXT4_FEATURE_RO_COMPAT_GDT_CSUM |
+ EXT4_FEATURE_RO_COMPAT_DIR_NLINK,
};
/*
@@ -286,6 +287,7 @@ static void update_feature_set(ext2_fils
int sparse, old_sparse, filetype, old_filetype;
int journal, old_journal, dxdir, old_dxdir;
int flex_bg, old_flex_bg;
+ int dir_nlink, old_dir_nlink;
struct ext2_super_block *sb= fs->super;
__u32 old_compat, old_incompat, old_ro_compat;
@@ -295,6 +297,8 @@ static void update_feature_set(ext2_fils
old_sparse = sb->s_feature_ro_compat &
EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER;
+ old_dir_nlink = sb->s_feature_ro_compat &
+ EXT4_FEATURE_RO_COMPAT_DIR_NLINK;
old_filetype = sb->s_feature_incompat &
EXT2_FEATURE_INCOMPAT_FILETYPE;
old_flex_bg = sb->s_feature_incompat &
@@ -311,6 +315,8 @@ static void update_feature_set(ext2_fils
}
sparse = sb->s_feature_ro_compat &
EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER;
+ dir_nlink = sb->s_feature_ro_compat &
+ EXT4_FEATURE_RO_COMPAT_DIR_NLINK;
filetype = sb->s_feature_incompat &
EXT2_FEATURE_INCOMPAT_FILETYPE;
flex_bg = sb->s_feature_incompat &
@@ -359,6 +365,14 @@ static void update_feature_set(ext2_fils
if (uuid_is_null((unsigned char *) sb->s_hash_seed))
uuid_generate((unsigned char *) sb->s_hash_seed);
}
+
+ if (old_dir_nlink && !dir_nlink) {
+ fputs(_("The dir_nlink flag was cleared. "
+ "Please run e2fsck before using the filesystem\n"
+ "to verify no many-linked directories exist or "
+ "data loss may result.\n"), stderr);
+ }
+
if (!flex_bg && old_flex_bg) {
if (ext2fs_check_desc(fs)) {
fputs(_("Clearing the flex_bg flag would "
Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.
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