From b9f9ed14bda93ecb407129b69e6476813c250046 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Wed, 15 Apr 2020 20:50:32 -0700
Subject: [PATCH] fts: remove NOSTAT_LEAF_OPTIMIZATION
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It caused ‘find’ and ‘du’ to dump core, and it was useful
only for obsolescent Linux filesystems anyway. Problem reported in:
https://lists.gnu.org/r/bug-gnulib/2020-04/msg00068.html
Quite possibly there is still a serious underlying fts bug with
tight-loop-check and mutating file systems, but if so this patch
should cause the bug to be triggered less often.
* lib/fts.c (enum leaf_optimization): Remove
NOSTAT_LEAF_OPTIMIZATION, as it’s problematic.
(S_MAGIC_REISERFS, S_MAGIC_XFS): Remove; no longer needed.
(leaf_optimization): Remove special cases for ReiserFS and XFS.
(fts_read): Remove NOSTAT_LEAF_OPTIMIZATION code.
* lib/fts_.h (struct _ftsent.fts_n_dirs_remaining):
Remove. All uses removed.
Upstream-commit: 47bf2cf3184027c1eb9c1dfeea5c5b8b2d69710d
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
lib/fts.c | 56 ++++++++-------------------------------------------
lib/fts_.h | 5 -----
2 files changed, 8 insertions(+), 53 deletions(-)
diff --git a/lib/fts.c b/lib/fts.c
index 1093ce5..dfe3fef 100644
--- a/lib/fts.c
+++ b/lib/fts.c
@@ -445,7 +445,6 @@ fts_open (char * const *argv,
if ((parent = fts_alloc(sp, "", 0)) == NULL)
goto mem2;
parent->fts_level = FTS_ROOTPARENTLEVEL;
- parent->fts_n_dirs_remaining = -1;
}
/* The classic fts implementation would call fts_stat with
@@ -634,9 +633,8 @@ fts_close (FTS *sp)
}
/* Minimum link count of a traditional Unix directory. When leaf
- optimization is OK and MIN_DIR_NLINK <= st_nlink, then st_nlink is
- an upper bound on the number of subdirectories (counting "." and
- ".."). */
+ optimization is OK and a directory's st_nlink == MIN_DIR_NLINK,
+ then the directory has no subdirectories. */
enum { MIN_DIR_NLINK = 2 };
/* Whether leaf optimization is OK for a directory. */
@@ -645,12 +643,8 @@ enum leaf_optimization
/* st_nlink is not reliable for this directory's subdirectories. */
NO_LEAF_OPTIMIZATION,
- /* Leaf optimization is OK, but is not useful for avoiding stat calls. */
- OK_LEAF_OPTIMIZATION,
-
- /* Leaf optimization is not only OK: it is useful for avoiding
- stat calls, because dirent.d_type does not work. */
- NOSTAT_LEAF_OPTIMIZATION
+ /* st_nlink == 2 means the directory lacks subdirectories. */
+ OK_LEAF_OPTIMIZATION
};
#if (defined __linux__ || defined __ANDROID__) \
@@ -663,9 +657,7 @@ enum leaf_optimization
# define S_MAGIC_CIFS 0xFF534D42
# define S_MAGIC_NFS 0x6969
# define S_MAGIC_PROC 0x9FA0
-# define S_MAGIC_REISERFS 0x52654973
# define S_MAGIC_TMPFS 0x1021994
-# define S_MAGIC_XFS 0x58465342
# ifdef HAVE___FSWORD_T
typedef __fsword_t fsword;
@@ -786,23 +778,15 @@ dirent_inode_sort_may_be_useful (FTSENT const *p, int dir_fd)
}
/* Given an FTS entry P for a directory with descriptor DIR_FD,
- return true if it is both useful and valid to apply leaf optimization.
- The optimization is useful only for file systems that lack usable
- dirent.d_type info. The optimization is valid if an st_nlink value
- of at least MIN_DIR_NLINK is an upper bound on the number of
- subdirectories of D, counting "." and ".." as subdirectories.
+ return whether it is valid to apply leaf optimization.
+ The optimization is valid if a directory's st_nlink value equal
+ to MIN_DIR_NLINK means the directory has no subdirectories.
DIR_FD is negative if unavailable. */
static enum leaf_optimization
leaf_optimization (FTSENT const *p, int dir_fd)
{
switch (filesystem_type (p, dir_fd))
{
- /* List here the file system types that may lack usable dirent.d_type
- info, yet for which the optimization does apply. */
- case S_MAGIC_REISERFS:
- case S_MAGIC_XFS: /* XFS lacked it until 2013-08-22 commit. */
- return NOSTAT_LEAF_OPTIMIZATION;
-
case 0:
/* Leaf optimization is unsafe if the file system type is unknown. */
FALLTHROUGH;
@@ -1027,26 +1011,7 @@ check_for_dir:
if (p->fts_info == FTS_NSOK)
{
if (p->fts_statp->st_size == FTS_STAT_REQUIRED)
- {
- FTSENT *parent = p->fts_parent;
- if (parent->fts_n_dirs_remaining == 0
- && ISSET(FTS_NOSTAT)
- && ISSET(FTS_PHYSICAL)
- && (leaf_optimization (parent, sp->fts_cwd_fd)
- == NOSTAT_LEAF_OPTIMIZATION))
- {
- /* nothing more needed */
- }
- else
- {
- p->fts_info = fts_stat(sp, p, false);
- if (S_ISDIR(p->fts_statp->st_mode)
- && p->fts_level != FTS_ROOTLEVEL
- && 0 < parent->fts_n_dirs_remaining
- && parent->fts_n_dirs_remaining != (nlink_t) -1)
- parent->fts_n_dirs_remaining--;
- }
- }
+ p->fts_info = fts_stat(sp, p, false);
else
fts_assert (p->fts_statp->st_size == FTS_NO_STAT_REQUIRED);
}
@@ -1830,11 +1795,6 @@ err: memset(sbp, 0, sizeof(struct stat));
}
if (S_ISDIR(sbp->st_mode)) {
- p->fts_n_dirs_remaining
- = ((sbp->st_nlink < MIN_DIR_NLINK
- || p->fts_level <= FTS_ROOTLEVEL)
- ? -1
- : sbp->st_nlink - (ISSET (FTS_SEEDOT) ? 0 : MIN_DIR_NLINK));
if (ISDOT(p->fts_name)) {
/* Command-line "." and ".." are real directories. */
return (p->fts_level == FTS_ROOTLEVEL ? FTS_D : FTS_DOT);
diff --git a/lib/fts_.h b/lib/fts_.h
index d40a116..2e76cc4 100644
--- a/lib/fts_.h
+++ b/lib/fts_.h
@@ -227,11 +227,6 @@ typedef struct _ftsent {
size_t fts_namelen; /* strlen(fts_name) */
- /* If not (nlink_t) -1, an upper bound on the number of
- remaining subdirectories of interest. If this becomes
- zero, some work can be avoided. */
- nlink_t fts_n_dirs_remaining;
-
# define FTS_D 1 /* preorder directory */
# define FTS_DC 2 /* directory that causes cycles */
# define FTS_DEFAULT 3 /* none of the above */
--
2.21.1