>From 6d6812a584ac16b21c1f06b89c28d74fe5931475 Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Wed, 15 Apr 2020 20:50:32 -0700 Subject: [PATCH] fts: remove NOSTAT_LEAF_OPTIMIZATION MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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. --- ChangeLog | 17 +++++++++++++++++ lib/fts.c | 56 ++++++++---------------------------------------------- lib/fts_.h | 5 ----- 3 files changed, 25 insertions(+), 53 deletions(-) diff --git a/ChangeLog b/ChangeLog index 36f4270c3..cea6074bc 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,20 @@ +2020-04-15 Paul Eggert + + fts: remove NOSTAT_LEAF_OPTIMIZATION + 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. + 2020-04-13 Bastien Roucariès explicit_bzero: Improve code style. diff --git a/lib/fts.c b/lib/fts.c index d3a0472a6..ade8c3349 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; @@ -782,23 +774,15 @@ 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; @@ -1023,26 +1007,7 @@ 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); } @@ -1826,11 +1791,6 @@ 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 6c7d0cef6..15c248cba 100644 --- a/lib/fts_.h +++ b/lib/fts_.h @@ -219,11 +219,6 @@ 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 */ -- 2.25.1