This patch adds to e2fsck the ability to pre-fetch metadata into the
page cache in the hopes of speeding up fsck runs. There are two new
functions -- the first allows a caller to readahead a list of blocks,
and the second is a helper function that uses that first mechanism to
load group data (bitmaps, inode tables).
These new e2fsck routines require the addition of a dblist API to
allow us to iterate a subset of a dblist. This will enable
incremental directory block readahead in e2fsck pass 2.
There's also a function to estimate the readahead given a FS.
v2: Add an API to create a dblist with a given number of list elements
pre-allocated. This enables us to save ~2ms per call to
e2fsck_readahead() (assuming a 2MB RA buffer) by not having to
repeatedly call ext2_resize_mem as we add blocks to the list.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
configure | 2
configure.in | 1
e2fsck/Makefile.in | 9 +-
e2fsck/e2fsck.h | 18 ++++
e2fsck/readahead.c | 252 +++++++++++++++++++++++++++++++++++++++++++++++++++
e2fsck/util.c | 51 ++++++++++
lib/config.h.in | 3 +
lib/ext2fs/dblist.c | 21 ++++
lib/ext2fs/ext2fs.h | 10 ++
9 files changed, 359 insertions(+), 8 deletions(-)
create mode 100644 e2fsck/readahead.c
diff --git a/configure b/configure
index 2bc1275..a65d3e6 100755
--- a/configure
+++ b/configure
@@ -12414,7 +12414,7 @@ fi
done
fi
-for ac_header in dirent.h errno.h execinfo.h getopt.h malloc.h mntent.h paths.h semaphore.h setjmp.h signal.h stdarg.h stdint.h stdlib.h termios.h termio.h unistd.h utime.h attr/xattr.h linux/falloc.h linux/fd.h linux/major.h linux/loop.h net/if_dl.h netinet/in.h sys/disklabel.h sys/disk.h sys/file.h sys/ioctl.h sys/mkdev.h sys/mman.h sys/mount.h sys/prctl.h sys/resource.h sys/select.h sys/socket.h sys/sockio.h sys/stat.h sys/syscall.h sys/sysmacros.h sys/time.h sys/types.h sys/un.h sys/wait.h
+for ac_header in dirent.h errno.h execinfo.h getopt.h malloc.h mntent.h paths.h semaphore.h setjmp.h signal.h stdarg.h stdint.h stdlib.h termios.h termio.h unistd.h utime.h attr/xattr.h linux/falloc.h linux/fd.h linux/major.h linux/loop.h net/if_dl.h netinet/in.h sys/disklabel.h sys/disk.h sys/file.h sys/ioctl.h sys/mkdev.h sys/mman.h sys/mount.h sys/prctl.h sys/resource.h sys/select.h sys/socket.h sys/sockio.h sys/stat.h sys/syscall.h sys/sysctl.h sys/sysmacros.h sys/time.h sys/types.h sys/un.h sys/wait.h
do :
as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"
diff --git a/configure.in b/configure.in
index e809324..d1be5b9 100644
--- a/configure.in
+++ b/configure.in
@@ -949,6 +949,7 @@ AC_CHECK_HEADERS(m4_flatten([
sys/sockio.h
sys/stat.h
sys/syscall.h
+ sys/sysctl.h
sys/sysmacros.h
sys/time.h
sys/types.h
diff --git a/e2fsck/Makefile.in b/e2fsck/Makefile.in
index d0e64eb..e40e51b 100644
--- a/e2fsck/Makefile.in
+++ b/e2fsck/Makefile.in
@@ -62,7 +62,7 @@ OBJS= dict.o unix.o e2fsck.o super.o pass1.o pass1b.o pass2.o \
pass3.o pass4.o pass5.o journal.o badblocks.o util.o dirinfo.o \
dx_dirinfo.o ehandler.o problem.o message.o quota.o recovery.o \
region.o revoke.o ea_refcount.o rehash.o profile.o prof_err.o \
- logfile.o sigcatcher.o $(MTRACE_OBJ) plausible.o
+ logfile.o sigcatcher.o $(MTRACE_OBJ) plausible.o readahead.o
PROFILED_OBJS= profiled/dict.o profiled/unix.o profiled/e2fsck.o \
profiled/super.o profiled/pass1.o profiled/pass1b.o \
@@ -73,7 +73,8 @@ PROFILED_OBJS= profiled/dict.o profiled/unix.o profiled/e2fsck.o \
profiled/recovery.o profiled/region.o profiled/revoke.o \
profiled/ea_refcount.o profiled/rehash.o profiled/profile.o \
profiled/prof_err.o profiled/logfile.o \
- profiled/sigcatcher.o profiled/plausible.o
+ profiled/sigcatcher.o profiled/plausible.o \
+ profiled/sigcatcher.o profiled/readahead.o
SRCS= $(srcdir)/e2fsck.c \
$(srcdir)/dict.c \
@@ -97,6 +98,7 @@ SRCS= $(srcdir)/e2fsck.c \
$(srcdir)/message.c \
$(srcdir)/ea_refcount.c \
$(srcdir)/rehash.c \
+ $(srcdir)/readahead.c \
$(srcdir)/region.c \
$(srcdir)/profile.c \
$(srcdir)/sigcatcher.c \
@@ -541,3 +543,6 @@ plausible.o: $(srcdir)/../misc/plausible.c $(top_builddir)/lib/config.h \
$(top_builddir)/lib/ext2fs/ext2_err.h \
$(top_srcdir)/lib/ext2fs/ext2_ext_attr.h $(top_srcdir)/lib/ext2fs/bitops.h \
$(srcdir)/../misc/nls-enable.h $(srcdir)/../misc/plausible.h
+readahead.o: $(srcdir)/readahead.c $(top_builddir)/lib/config.h \
+ $(top_srcdir)/lib/ext2fs/ext2fs.h $(top_srcdir)/lib/ext2fs/ext2_fs.h \
+ $(top_builddir)/lib/ext2fs/ext2_err.h $(srcdir)/e2fsck.h prof_err.h
diff --git a/e2fsck/e2fsck.h b/e2fsck/e2fsck.h
index 6ca3a6a..8837af9 100644
--- a/e2fsck/e2fsck.h
+++ b/e2fsck/e2fsck.h
@@ -490,6 +490,23 @@ extern ext2_ino_t e2fsck_get_lost_and_found(e2fsck_t ctx, int fix);
extern errcode_t e2fsck_adjust_inode_count(e2fsck_t ctx, ext2_ino_t ino,
int adj);
+/* readahead.c */
+#define E2FSCK_READA_SUPER (0x01)
+#define E2FSCK_READA_GDT (0x02)
+#define E2FSCK_READA_BBITMAP (0x04)
+#define E2FSCK_READA_IBITMAP (0x08)
+#define E2FSCK_READA_ITABLE (0x10)
+#define E2FSCK_READA_ALL_FLAGS (0x1F)
+errcode_t e2fsck_readahead(ext2_filsys fs, int flags, dgrp_t start,
+ dgrp_t ngroups);
+#define E2FSCK_RA_DBLIST_IGNORE_BLOCKCNT (0x01)
+#define E2FSCK_RA_DBLIST_ALL_FLAGS (0x01)
+errcode_t e2fsck_readahead_dblist(ext2_filsys fs, int flags,
+ ext2_dblist dblist,
+ unsigned long long start,
+ unsigned long long count);
+int e2fsck_can_readahead(ext2_filsys fs);
+unsigned long long e2fsck_guess_readahead(ext2_filsys fs);
/* region.c */
extern region_t region_create(region_addr_t min, region_addr_t max);
@@ -579,6 +596,7 @@ extern errcode_t e2fsck_allocate_subcluster_bitmap(ext2_filsys fs,
int default_type,
const char *profile_name,
ext2fs_block_bitmap *ret);
+unsigned long long get_memory_size(void);
/* unix.c */
extern void e2fsck_clear_progbar(e2fsck_t ctx);
diff --git a/e2fsck/readahead.c b/e2fsck/readahead.c
new file mode 100644
index 0000000..a35f9f8
--- /dev/null
+++ b/e2fsck/readahead.c
@@ -0,0 +1,252 @@
+/*
+ * readahead.c -- Prefetch filesystem metadata to speed up fsck.
+ *
+ * Copyright (C) 2014 Oracle.
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Library
+ * General Public License, version 2.
+ * %End-Header%
+ */
+
+#include "config.h"
+#include <string.h>
+
+#include "e2fsck.h"
+
+#undef DEBUG
+
+#ifdef DEBUG
+# define dbg_printf(f, a...) do {printf(f, ## a); fflush(stdout); } while (0)
+#else
+# define dbg_printf(f, a...)
+#endif
+
+struct read_dblist {
+ errcode_t err;
+ blk64_t run_start;
+ blk64_t run_len;
+ int flags;
+};
+
+static int readahead_dir_block(ext2_filsys fs, struct ext2_db_entry2 *db,
+ void *priv_data)
+{
+ struct read_dblist *pr = priv_data;
+ e2_blkcnt_t count = (pr->flags & E2FSCK_RA_DBLIST_IGNORE_BLOCKCNT ?
+ 1 : db->blockcnt);
+
+ if (!pr->run_len || db->blk != pr->run_start + pr->run_len) {
+ if (pr->run_len) {
+ pr->err = io_channel_cache_readahead(fs->io,
+ pr->run_start,
+ pr->run_len);
+ dbg_printf("readahead start=%llu len=%llu err=%d\n",
+ pr->run_start, pr->run_len,
+ (int)pr->err);
+ }
+ pr->run_start = db->blk;
+ pr->run_len = 0;
+ }
+ pr->run_len += count;
+
+ return pr->err ? DBLIST_ABORT : 0;
+}
+
+errcode_t e2fsck_readahead_dblist(ext2_filsys fs, int flags,
+ ext2_dblist dblist,
+ unsigned long long start,
+ unsigned long long count)
+{
+ errcode_t err;
+ struct read_dblist pr;
+
+ dbg_printf("%s: flags=0x%x\n", __func__, flags);
+ if (flags & ~E2FSCK_RA_DBLIST_ALL_FLAGS)
+ return EXT2_ET_INVALID_ARGUMENT;
+
+ memset(&pr, 0, sizeof(pr));
+ pr.flags = flags;
+ err = ext2fs_dblist_iterate3(dblist, readahead_dir_block, start,
+ count, &pr);
+ if (pr.err)
+ return pr.err;
+ if (err)
+ return err;
+
+ if (pr.run_len)
+ err = io_channel_cache_readahead(fs->io, pr.run_start,
+ pr.run_len);
+
+ return err;
+}
+
+static errcode_t e2fsck_readahead_bitmap(ext2_filsys fs,
+ ext2fs_block_bitmap ra_map)
+{
+ blk64_t start, end, out;
+ errcode_t err;
+
+ start = 1;
+ end = ext2fs_blocks_count(fs->super) - 1;
+
+ err = ext2fs_find_first_set_block_bitmap2(ra_map, start, end, &out);
+ while (err == 0) {
+ start = out;
+ err = ext2fs_find_first_zero_block_bitmap2(ra_map, start, end,
+ &out);
+ if (err == ENOENT) {
+ out = end;
+ err = 0;
+ } else if (err)
+ break;
+
+ err = io_channel_cache_readahead(fs->io, start, out - start);
+ if (err)
+ break;
+ start = out;
+ err = ext2fs_find_first_set_block_bitmap2(ra_map, start, end,
+ &out);
+ }
+
+ if (err == ENOENT)
+ err = 0;
+
+ return err;
+}
+
+/* Try not to spew bitmap range errors for readahead */
+static errcode_t mark_bmap_range(ext2_filsys fs, ext2fs_block_bitmap map,
+ blk64_t blk, unsigned int num)
+{
+ if (blk >= ext2fs_get_generic_bmap_start(map) &&
+ blk + num <= ext2fs_get_generic_bmap_end(map))
+ ext2fs_mark_block_bitmap_range2(map, blk, num);
+ else
+ return EXT2_ET_INVALID_ARGUMENT;
+ return 0;
+}
+
+static errcode_t mark_bmap(ext2_filsys fs, ext2fs_block_bitmap map, blk64_t blk)
+{
+ if (blk >= ext2fs_get_generic_bmap_start(map) &&
+ blk <= ext2fs_get_generic_bmap_end(map))
+ ext2fs_mark_block_bitmap2(map, blk);
+ else
+ return EXT2_ET_INVALID_ARGUMENT;
+ return 0;
+}
+
+errcode_t e2fsck_readahead(ext2_filsys fs, int flags, dgrp_t start,
+ dgrp_t ngroups)
+{
+ blk64_t super, old_gdt, new_gdt;
+ blk_t blocks;
+ dgrp_t i;
+ ext2fs_block_bitmap ra_map = NULL;
+ dgrp_t end = start + ngroups;
+ errcode_t err = 0;
+
+ dbg_printf("%s: flags=0x%x start=%d groups=%d\n", __func__, flags,
+ start, ngroups);
+ if (flags & ~E2FSCK_READA_ALL_FLAGS)
+ return EXT2_ET_INVALID_ARGUMENT;
+
+ if (end > fs->group_desc_count)
+ end = fs->group_desc_count;
+
+ if (flags == 0)
+ return 0;
+
+ err = ext2fs_allocate_block_bitmap(fs, "readahead bitmap",
+ &ra_map);
+ if (err)
+ return err;
+
+ for (i = start; i < end; i++) {
+ err = ext2fs_super_and_bgd_loc2(fs, i, &super, &old_gdt,
+ &new_gdt, &blocks);
+ if (err)
+ break;
+
+ if (flags & E2FSCK_READA_SUPER) {
+ err = mark_bmap(fs, ra_map, super);
+ if (err)
+ break;
+ }
+
+ if (flags & E2FSCK_READA_GDT) {
+ err = mark_bmap_range(fs, ra_map,
+ old_gdt ? old_gdt : new_gdt,
+ blocks);
+ if (err)
+ break;
+ }
+
+ if ((flags & E2FSCK_READA_BBITMAP) &&
+ !ext2fs_bg_flags_test(fs, i, EXT2_BG_BLOCK_UNINIT) &&
+ ext2fs_bg_free_blocks_count(fs, i) <
+ fs->super->s_blocks_per_group) {
+ super = ext2fs_block_bitmap_loc(fs, i);
+ err = mark_bmap(fs, ra_map, super);
+ if (err)
+ break;
+ }
+
+ if ((flags & E2FSCK_READA_IBITMAP) &&
+ !ext2fs_bg_flags_test(fs, i, EXT2_BG_INODE_UNINIT) &&
+ ext2fs_bg_free_inodes_count(fs, i) <
+ fs->super->s_inodes_per_group) {
+ super = ext2fs_inode_bitmap_loc(fs, i);
+ err = mark_bmap(fs, ra_map, super);
+ if (err)
+ break;
+ }
+
+ if ((flags & E2FSCK_READA_ITABLE) &&
+ ext2fs_bg_free_inodes_count(fs, i) <
+ fs->super->s_inodes_per_group) {
+ super = ext2fs_inode_table_loc(fs, i);
+ blocks = fs->inode_blocks_per_group -
+ (ext2fs_bg_itable_unused(fs, i) *
+ EXT2_INODE_SIZE(fs->super) / fs->blocksize);
+ err = mark_bmap_range(fs, ra_map, super, blocks);
+ if (err)
+ break;
+ }
+ }
+
+ if (!err)
+ err = e2fsck_readahead_bitmap(fs, ra_map);
+
+ ext2fs_free_block_bitmap(ra_map);
+ return err;
+}
+
+int e2fsck_can_readahead(ext2_filsys fs)
+{
+ errcode_t err;
+
+ err = io_channel_cache_readahead(fs->io, 0, 1);
+ dbg_printf("%s: supp=%d\n", __func__, err != EXT2_ET_OP_NOT_SUPPORTED);
+ return err != EXT2_ET_OP_NOT_SUPPORTED;
+}
+
+unsigned long long e2fsck_guess_readahead(ext2_filsys fs)
+{
+ unsigned long long guess;
+
+ /*
+ * The optimal readahead sizes were experimentally determined by
+ * djwong in August 2014. Setting the RA size to one block group's
+ * worth of inode table blocks seems to yield the largest reductions
+ * in e2fsck runtime.
+ */
+ guess = fs->blocksize * fs->inode_blocks_per_group;
+
+ /* Disable RA if it'd use more 1/100th of RAM. */
+ if (get_memory_size() > (guess * 100))
+ return guess / 1024;
+
+ return 0;
+}
diff --git a/e2fsck/util.c b/e2fsck/util.c
index 8237328..74f20062 100644
--- a/e2fsck/util.c
+++ b/e2fsck/util.c
@@ -37,6 +37,10 @@
#include <errno.h>
#endif
+#ifdef HAVE_SYS_SYSCTL_H
+#include <sys/sysctl.h>
+#endif
+
#include "e2fsck.h"
extern e2fsck_t e2fsck_global_ctx; /* Try your very best not to use this! */
@@ -848,3 +852,50 @@ errcode_t e2fsck_allocate_subcluster_bitmap(ext2_filsys fs, const char *descr,
fs->default_bitmap_type = save_type;
return retval;
}
+
+/* Return memory size in bytes */
+unsigned long long get_memory_size(void)
+{
+#if defined(_SC_PHYS_PAGES)
+# if defined(_SC_PAGESIZE)
+ return (unsigned long long)sysconf(_SC_PHYS_PAGES) *
+ (unsigned long long)sysconf(_SC_PAGESIZE);
+# elif defined(_SC_PAGE_SIZE)
+ return (unsigned long long)sysconf(_SC_PHYS_PAGES) *
+ (unsigned long long)sysconf(_SC_PAGE_SIZE);
+# endif
+#elif defined(CTL_HW)
+# if (defined(HW_MEMSIZE) || defined(HW_PHYSMEM64))
+# define CTL_HW_INT64
+# elif (defined(HW_PHYSMEM) || defined(HW_REALMEM))
+# define CTL_HW_UINT
+# endif
+ int mib[2];
+
+ mib[0] = CTL_HW;
+# if defined(HW_MEMSIZE)
+ mib[1] = HW_MEMSIZE;
+# elif defined(HW_PHYSMEM64)
+ mib[1] = HW_PHYSMEM64;
+# elif defined(HW_REALMEM)
+ mib[1] = HW_REALMEM;
+# elif defined(HW_PYSMEM)
+ mib[1] = HW_PHYSMEM;
+# endif
+# if defined(CTL_HW_INT64)
+ unsigned long long size = 0;
+# elif defined(CTL_HW_UINT)
+ unsigned int size = 0;
+# endif
+# if defined(CTL_HW_INT64) || defined(CTL_HW_UINT)
+ size_t len = sizeof(size);
+
+ if (sysctl(mib, 2, &size, &len, NULL, 0) == 0)
+ return (unsigned long long)size;
+# endif
+ return 0;
+#else
+# warning "Don't know how to detect memory on your platform?"
+ return 0;
+#endif
+}
diff --git a/lib/config.h.in b/lib/config.h.in
index e318969..92fca3e 100644
--- a/lib/config.h.in
+++ b/lib/config.h.in
@@ -509,6 +509,9 @@
/* Define to 1 if you have the <sys/syscall.h> header file. */
#undef HAVE_SYS_SYSCALL_H
+/* Define to 1 if you have the <sys/sysctl.h> header file. */
+#undef HAVE_SYS_SYSCTL_H
+
/* Define to 1 if you have the <sys/sysmacros.h> header file. */
#undef HAVE_SYS_SYSMACROS_H
diff --git a/lib/ext2fs/dblist.c b/lib/ext2fs/dblist.c
index 942c4f0..bbdb221 100644
--- a/lib/ext2fs/dblist.c
+++ b/lib/ext2fs/dblist.c
@@ -194,20 +194,25 @@ void ext2fs_dblist_sort2(ext2_dblist dblist,
/*
* This function iterates over the directory block list
*/
-errcode_t ext2fs_dblist_iterate2(ext2_dblist dblist,
+errcode_t ext2fs_dblist_iterate3(ext2_dblist dblist,
int (*func)(ext2_filsys fs,
struct ext2_db_entry2 *db_info,
void *priv_data),
+ unsigned long long start,
+ unsigned long long count,
void *priv_data)
{
- unsigned long long i;
+ unsigned long long i, end;
int ret;
EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
+ end = start + count;
if (!dblist->sorted)
ext2fs_dblist_sort2(dblist, 0);
- for (i=0; i < dblist->count; i++) {
+ if (end > dblist->count)
+ end = dblist->count;
+ for (i = start; i < end; i++) {
ret = (*func)(dblist->fs, &dblist->list[i], priv_data);
if (ret & DBLIST_ABORT)
return 0;
@@ -215,6 +220,16 @@ errcode_t ext2fs_dblist_iterate2(ext2_dblist dblist,
return 0;
}
+errcode_t ext2fs_dblist_iterate2(ext2_dblist dblist,
+ int (*func)(ext2_filsys fs,
+ struct ext2_db_entry2 *db_info,
+ void *priv_data),
+ void *priv_data)
+{
+ return ext2fs_dblist_iterate3(dblist, func, 0, dblist->count,
+ priv_data);
+}
+
static EXT2_QSORT_TYPE dir_block_cmp2(const void *a, const void *b)
{
const struct ext2_db_entry2 *db_a =
diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index fef6910..21fe45c 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -1055,11 +1055,17 @@ extern void ext2fs_dblist_sort2(ext2_dblist dblist,
extern errcode_t ext2fs_dblist_iterate(ext2_dblist dblist,
int (*func)(ext2_filsys fs, struct ext2_db_entry *db_info,
void *priv_data),
- void *priv_data);
+ void *priv_data);
extern errcode_t ext2fs_dblist_iterate2(ext2_dblist dblist,
int (*func)(ext2_filsys fs, struct ext2_db_entry2 *db_info,
void *priv_data),
- void *priv_data);
+ void *priv_data);
+extern errcode_t ext2fs_dblist_iterate3(ext2_dblist dblist,
+ int (*func)(ext2_filsys fs, struct ext2_db_entry2 *db_info,
+ void *priv_data),
+ unsigned long long start,
+ unsigned long long count,
+ void *priv_data);
extern errcode_t ext2fs_set_dir_block(ext2_dblist dblist, ext2_ino_t ino,
blk_t blk, int blockcnt);
extern errcode_t ext2fs_set_dir_block2(ext2_dblist dblist, ext2_ino_t ino,
--
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