This just gets us ready to support the SEEK_HOLE and SEEK_DATA flags. Turns out
using fiemap in things like cp cause more problems than it solves, so lets try
and give userspace an interface that doesn't suck. We need to match solaris
here, and the definitions are
*o* If /whence/ is SEEK_HOLE, the offset of the start of the
next hole greater than or equal to the supplied offset
is returned. The definition of a hole is provided near
the end of the DESCRIPTION.
*o* If /whence/ is SEEK_DATA, the file pointer is set to the
start of the next non-hole file region greater than or
equal to the supplied offset.
So in the generic case the entire file is data and there is a virtual hole at
the end. That means we will just return i_size for SEEK_HOLE and will return
the same offset for SEEK_DATA. This is how Solaris does it so we have to do it
the same way.
Thanks,
Signed-off-by: Josef Bacik <[email protected]>
---
fs/read_write.c | 44 +++++++++++++++++++++++++++++++++++++++++---
include/linux/fs.h | 4 +++-
2 files changed, 44 insertions(+), 4 deletions(-)
diff --git a/fs/read_write.c b/fs/read_write.c
index 5520f8a..5907b49 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -64,6 +64,23 @@ generic_file_llseek_unlocked(struct file *file, loff_t offset, int origin)
return file->f_pos;
offset += file->f_pos;
break;
+ case SEEK_DATA:
+ /*
+ * In the generic case the entire file is data, so as long as
+ * offset isn't at the end of the file then the offset is data.
+ */
+ if (offset >= inode->i_size)
+ return -ENXIO;
+ break;
+ case SEEK_HOLE:
+ /*
+ * There is a virtual hole at the end of the file, so as long as
+ * offset isn't i_size or larger, return i_size.
+ */
+ if (offset >= inode->i_size)
+ return -ENXIO;
+ offset = inode->i_size;
+ break;
}
if (offset < 0 && !unsigned_offsets(file))
@@ -128,12 +145,13 @@ EXPORT_SYMBOL(no_llseek);
loff_t default_llseek(struct file *file, loff_t offset, int origin)
{
+ struct inode *inode = file->f_path.dentry->d_inode;
loff_t retval;
- mutex_lock(&file->f_dentry->d_inode->i_mutex);
+ mutex_lock(&inode->i_mutex);
switch (origin) {
case SEEK_END:
- offset += i_size_read(file->f_path.dentry->d_inode);
+ offset += i_size_read(inode);
break;
case SEEK_CUR:
if (offset == 0) {
@@ -141,6 +159,26 @@ loff_t default_llseek(struct file *file, loff_t offset, int origin)
goto out;
}
offset += file->f_pos;
+ break;
+ case SEEK_DATA:
+ /*
+ * In the generic case the entire file is data, so as
+ * long as offset isn't at the end of the file then the
+ * offset is data.
+ */
+ if (offset >= inode->i_size)
+ return -ENXIO;
+ break;
+ case SEEK_HOLE:
+ /*
+ * There is a virtual hole at the end of the file, so
+ * as long as offset isn't i_size or larger, return
+ * i_size.
+ */
+ if (offset >= inode->i_size)
+ return -ENXIO;
+ offset = inode->i_size;
+ break;
}
retval = -EINVAL;
if (offset >= 0 || unsigned_offsets(file)) {
@@ -151,7 +189,7 @@ loff_t default_llseek(struct file *file, loff_t offset, int origin)
retval = offset;
}
out:
- mutex_unlock(&file->f_dentry->d_inode->i_mutex);
+ mutex_unlock(&inode->i_mutex);
return retval;
}
EXPORT_SYMBOL(default_llseek);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index b5b9792..c9156f3 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -32,7 +32,9 @@
#define SEEK_SET 0 /* seek relative to beginning of file */
#define SEEK_CUR 1 /* seek relative to current file position */
#define SEEK_END 2 /* seek relative to end of file */
-#define SEEK_MAX SEEK_END
+#define SEEK_DATA 3 /* seek to the next data */
+#define SEEK_HOLE 4 /* seek to the next hole */
+#define SEEK_MAX SEEK_HOLE
struct fstrim_range {
__u64 start;
--
1.7.5.2
In order to handle SEEK_HOLE/SEEK_DATA we need to implement our own llseek.
Basically for the normal SEEK_*'s we will just defer to the generic helper, and
for SEEK_HOLE/SEEK_DATA we will use our fiemap helper to figure out the nearest
hole or data. Currently this helper doesn't check for delalloc bytes for
prealloc space, so for now treat prealloc as data until that is fixed. Thanks,
Signed-off-by: Josef Bacik <[email protected]>
---
fs/btrfs/ctree.h | 3 +
fs/btrfs/file.c | 148 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 150 insertions(+), 1 deletions(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index f30ac05..32be5e0 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2505,6 +2505,9 @@ int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
struct list_head *list, int search_commit);
/* inode.c */
+struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
+ size_t pg_offset, u64 start, u64 len,
+ int create);
/* RHEL and EL kernels have a patch that renames PG_checked to FsMisc */
#if defined(ClearPageFsMisc) && !defined(ClearPageChecked)
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index fa4ef18..bd4d061 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1664,8 +1664,154 @@ out:
return ret;
}
+static int find_desired_extent(struct inode *inode, loff_t *offset, int origin)
+{
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ struct extent_map *em;
+ struct extent_state *cached_state = NULL;
+ u64 lockstart = *offset;
+ u64 lockend = i_size_read(inode);
+ u64 start = *offset;
+ u64 orig_start = *offset;
+ u64 len = i_size_read(inode);
+ u64 last_end = 0;
+ int ret = 0;
+
+ lockend = max_t(u64, root->sectorsize, lockend);
+ if (lockend <= lockstart)
+ lockend = lockstart + root->sectorsize;
+
+ len = lockend - lockstart + 1;
+
+ len = max_t(u64, len, root->sectorsize);
+ if (inode->i_size == 0)
+ return -ENXIO;
+
+ lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend, 0,
+ &cached_state, GFP_NOFS);
+
+ /*
+ * Delalloc is such a pain. If we have a hole and we have pending
+ * delalloc for a portion of the hole we will get back a hole that
+ * exists for the entire range since it hasn't been actually written
+ * yet. So to take care of this case we need to look for an extent just
+ * before the position we want in case there is outstanding delalloc
+ * going on here.
+ */
+ if (origin == SEEK_HOLE && start != 0) {
+ if (start <= root->sectorsize)
+ em = btrfs_get_extent_fiemap(inode, NULL, 0, 0,
+ root->sectorsize, 0);
+ else
+ em = btrfs_get_extent_fiemap(inode, NULL, 0,
+ start - root->sectorsize,
+ root->sectorsize, 0);
+ if (IS_ERR(em)) {
+ ret = -ENXIO;
+ goto out;
+ }
+ last_end = em->start + em->len;
+ if (em->block_start == EXTENT_MAP_DELALLOC)
+ last_end = min_t(u64, last_end, inode->i_size);
+ free_extent_map(em);
+ }
+
+ while (1) {
+ em = btrfs_get_extent_fiemap(inode, NULL, 0, start, len, 0);
+ if (IS_ERR(em)) {
+ ret = -ENXIO;
+ break;
+ }
+
+ if (em->block_start == EXTENT_MAP_HOLE) {
+ if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
+ if (last_end <= orig_start) {
+ free_extent_map(em);
+ ret = -ENXIO;
+ break;
+ }
+ }
+
+ if (origin == SEEK_HOLE) {
+ *offset = start;
+ free_extent_map(em);
+ break;
+ }
+ } else {
+ if (origin == SEEK_DATA) {
+ if (em->block_start == EXTENT_MAP_DELALLOC) {
+ if (start >= inode->i_size) {
+ free_extent_map(em);
+ ret = -ENXIO;
+ break;
+ }
+ }
+
+ *offset = start;
+ free_extent_map(em);
+ break;
+ }
+ }
+
+ start = em->start + em->len;
+ last_end = em->start + em->len;
+
+ if (em->block_start == EXTENT_MAP_DELALLOC)
+ last_end = min_t(u64, last_end, inode->i_size);
+
+ if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
+ free_extent_map(em);
+ ret = -ENXIO;
+ break;
+ }
+ free_extent_map(em);
+ cond_resched();
+ }
+ if (!ret)
+ *offset = min(*offset, inode->i_size);
+out:
+ unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
+ &cached_state, GFP_NOFS);
+ return ret;
+}
+
+static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int origin)
+{
+ struct inode *inode = file->f_mapping->host;
+ int ret;
+
+ mutex_lock(&inode->i_mutex);
+ switch (origin) {
+ case SEEK_END:
+ case SEEK_CUR:
+ offset = generic_file_llseek_unlocked(file, offset, origin);
+ goto out;
+ case SEEK_DATA:
+ case SEEK_HOLE:
+ ret = find_desired_extent(inode, &offset, origin);
+ if (ret) {
+ mutex_unlock(&inode->i_mutex);
+ return ret;
+ }
+ }
+
+ if (offset < 0 && !(file->f_mode & FMODE_UNSIGNED_OFFSET))
+ return -EINVAL;
+ if (offset > inode->i_sb->s_maxbytes)
+ return -EINVAL;
+
+ /* Special lock needed here? */
+ if (offset != file->f_pos) {
+ file->f_pos = offset;
+ file->f_version = 0;
+ }
+out:
+ mutex_unlock(&inode->i_mutex);
+ return offset;
+}
+
const struct file_operations btrfs_file_operations = {
- .llseek = generic_file_llseek,
+ .llseek = btrfs_file_llseek,
.read = do_sync_read,
.write = do_sync_write,
.aio_read = generic_file_aio_read,
--
1.7.5.2
Since Ext4 has its own lseek we need to make sure it handles
SEEK_HOLE/SEEK_DATA. For now just do the same thing that is done in the generic
case, somebody else can come along and make it do fancy things later. Thanks,
Signed-off-by: Josef Bacik <[email protected]>
---
fs/ext4/file.c | 21 +++++++++++++++++++++
1 files changed, 21 insertions(+), 0 deletions(-)
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 2c09723..ce766f9 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -236,6 +236,27 @@ loff_t ext4_llseek(struct file *file, loff_t offset, int origin)
}
offset += file->f_pos;
break;
+ case SEEK_DATA:
+ /*
+ * In the generic case the entire file is data, so as long as
+ * offset isn't at the end of the file then the offset is data.
+ */
+ if (offset >= inode->i_size) {
+ mutex_unlock(&inode->i_mutex);
+ return -ENXIO;
+ }
+ break;
+ case SEEK_HOLE:
+ /*
+ * There is a virtual hole at the end of the file, so as long as
+ * offset isn't i_size or larger, return i_size.
+ */
+ if (offset >= inode->i_size) {
+ mutex_unlock(&inode->i_mutex);
+ return -ENXIO;
+ }
+ offset = inode->i_size;
+ break;
}
if (offset < 0 || offset > maxbytes) {
--
1.7.5.2
This converts everybody to handle SEEK_HOLE/SEEK_DATA properly. In some cases
we just return -EINVAL, in others we do the normal generic thing, and in others
we're simply making sure that the properly due-dilligence is done. For example
in NFS/CIFS we need to make sure the file size is update properly for the
SEEK_HOLE and SEEK_DATA case, but since it calls the generic llseek stuff itself
that is all we have to do. Thanks,
Signed-off-by: Josef Bacik <[email protected]>
---
fs/block_dev.c | 11 ++++++++---
fs/ceph/dir.c | 8 +++++++-
fs/ceph/file.c | 20 ++++++++++++++++++--
fs/cifs/cifsfs.c | 7 +++++--
fs/fuse/file.c | 21 +++++++++++++++++++--
fs/hpfs/dir.c | 4 ++++
fs/nfs/file.c | 7 +++++--
7 files changed, 66 insertions(+), 12 deletions(-)
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 610e8e0..966617a 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -355,20 +355,25 @@ static loff_t block_llseek(struct file *file, loff_t offset, int origin)
mutex_lock(&bd_inode->i_mutex);
size = i_size_read(bd_inode);
+ retval = -EINVAL;
switch (origin) {
- case 2:
+ case SEEK_END:
offset += size;
break;
- case 1:
+ case SEEK_CUR:
offset += file->f_pos;
+ case SEEK_SET:
+ break;
+ default:
+ goto out;
}
- retval = -EINVAL;
if (offset >= 0 && offset <= size) {
if (offset != file->f_pos) {
file->f_pos = offset;
}
retval = offset;
}
+out:
mutex_unlock(&bd_inode->i_mutex);
return retval;
}
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index ef8f08c..79cd77c 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -446,14 +446,19 @@ static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int origin)
loff_t retval;
mutex_lock(&inode->i_mutex);
+ retval = -EINVAL;
switch (origin) {
case SEEK_END:
offset += inode->i_size + 2; /* FIXME */
break;
case SEEK_CUR:
offset += file->f_pos;
+ case SEEK_SET:
+ break;
+ default:
+ goto out;
}
- retval = -EINVAL;
+
if (offset >= 0 && offset <= inode->i_sb->s_maxbytes) {
if (offset != file->f_pos) {
file->f_pos = offset;
@@ -477,6 +482,7 @@ static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int origin)
if (offset > old_offset)
fi->dir_release_count--;
}
+out:
mutex_unlock(&inode->i_mutex);
return retval;
}
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 9542f07..774feb1 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -770,13 +770,16 @@ static loff_t ceph_llseek(struct file *file, loff_t offset, int origin)
mutex_lock(&inode->i_mutex);
__ceph_do_pending_vmtruncate(inode);
- switch (origin) {
- case SEEK_END:
+ if (origin != SEEK_CUR || origin != SEEK_SET) {
ret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE);
if (ret < 0) {
offset = ret;
goto out;
}
+ }
+
+ switch (origin) {
+ case SEEK_END:
offset += inode->i_size;
break;
case SEEK_CUR:
@@ -792,6 +795,19 @@ static loff_t ceph_llseek(struct file *file, loff_t offset, int origin)
}
offset += file->f_pos;
break;
+ case SEEK_DATA:
+ if (offset >= inode->i_size) {
+ ret = -ENXIO;
+ goto out;
+ }
+ break;
+ case SEEK_HOLE:
+ if (offset >= inode->i_size) {
+ ret = -ENXIO;
+ goto out;
+ }
+ offset = inode->i_size;
+ break;
}
if (offset < 0 || offset > inode->i_sb->s_maxbytes) {
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 35f9154..5feb6bb 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -746,8 +746,11 @@ static ssize_t cifs_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
static loff_t cifs_llseek(struct file *file, loff_t offset, int origin)
{
- /* origin == SEEK_END => we must revalidate the cached file length */
- if (origin == SEEK_END) {
+ /*
+ * origin == SEEK_END || SEEK_DATA || SEEK_HOLE => we must revalidate
+ * the cached file length
+ */
+ if (origin != SEEK_SET || origin != SEEK_CUR) {
int rc;
struct inode *inode = file->f_path.dentry->d_inode;
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 82a6646..73b89df 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1600,15 +1600,32 @@ static loff_t fuse_file_llseek(struct file *file, loff_t offset, int origin)
struct inode *inode = file->f_path.dentry->d_inode;
mutex_lock(&inode->i_mutex);
- switch (origin) {
- case SEEK_END:
+ if (origin != SEEK_CUR || origin != SEEK_SET) {
retval = fuse_update_attributes(inode, NULL, file, NULL);
if (retval)
goto exit;
+ }
+
+ switch (origin) {
+ case SEEK_END:
offset += i_size_read(inode);
break;
case SEEK_CUR:
offset += file->f_pos;
+ break;
+ case SEEK_DATA:
+ if (offset >= i_size_read(inode)) {
+ retval = -ENXIO;
+ goto exit;
+ }
+ break;
+ case SEEK_HOLE:
+ if (offset >= i_size_read(inode)) {
+ retval = -ENXIO;
+ goto exit;
+ }
+ offset = i_size_read(inode);
+ break;
}
retval = -EINVAL;
if (offset >= 0 && offset <= inode->i_sb->s_maxbytes) {
diff --git a/fs/hpfs/dir.c b/fs/hpfs/dir.c
index f46ae02..96a8ed9 100644
--- a/fs/hpfs/dir.c
+++ b/fs/hpfs/dir.c
@@ -29,6 +29,10 @@ static loff_t hpfs_dir_lseek(struct file *filp, loff_t off, int whence)
struct hpfs_inode_info *hpfs_inode = hpfs_i(i);
struct super_block *s = i->i_sb;
+ /* Somebody else will have to figure out what to do here */
+ if (whence == SEEK_DATA || whence == SEEK_HOLE)
+ return -EINVAL;
+
hpfs_lock(s);
/*printk("dir lseek\n");*/
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 2f093ed..2c1705b 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -187,8 +187,11 @@ static loff_t nfs_file_llseek(struct file *filp, loff_t offset, int origin)
filp->f_path.dentry->d_name.name,
offset, origin);
- /* origin == SEEK_END => we must revalidate the cached file length */
- if (origin == SEEK_END) {
+ /*
+ * origin == SEEK_END || SEEK_DATA || SEEK_HOLE => we must revalidate
+ * the cached file length
+ */
+ if (origin != SEEK_SET || origin != SEEK_CUR) {
struct inode *inode = filp->f_mapping->host;
int retval = nfs_revalidate_file_size(inode, filp);
--
1.7.5.2
This is a test to make sure seek_data/seek_hole is acting like it does on
Solaris. It will check to see if the fs supports finding a hole or not and will
adjust as necessary.
Signed-off-by: Josef Bacik <[email protected]>
---
255 | 71 ++++++++
255.out | 2 +
group | 1 +
src/Makefile | 2 +-
src/seek-tester.c | 475 +++++++++++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 550 insertions(+), 1 deletions(-)
create mode 100755 255
create mode 100644 255.out
create mode 100644 src/seek-tester.c
diff --git a/255 b/255
new file mode 100755
index 0000000..4bb4d0b
--- /dev/null
+++ b/255
@@ -0,0 +1,71 @@
+#! /bin/bash
+# FS QA Test No. 255
+#
+# Test SEEK_DATA and SEEK_HOLE
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2011 Red Hat. All Rights Reserved.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it would be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write the Free Software Foundation,
+# Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+#
+#-----------------------------------------------------------------------
+#
+# creator
[email protected]
+
+seq=`basename $0`
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1 # failure is the default!
+
+_cleanup()
+{
+ rm -f $tmp.*
+}
+
+trap "_cleanup ; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+# real QA test starts here
+_supported_fs generic
+_supported_os Linux
+
+testfile=$TEST_DIR/seek_test.$$
+logfile=$TEST_DIR/seek_test.$$.log
+
+[ -x $here/src/seek-tester ] || _notrun "seek-tester not built"
+
+_cleanup()
+{
+ rm -f $testfile
+ rm -f $logfile
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+echo "Silence is golden"
+$here/src/seek-tester -q $testfile 2>&1 | tee -a $logfile
+
+if grep -q "SEEK_HOLE is not supported" $logfile; then
+ _notrun "SEEK_HOLE/SEEK_DATA not supported by this kernel"
+fi
+
+rm -f $logfile
+rm -f $testfile
+
+status=0 ; exit
diff --git a/255.out b/255.out
new file mode 100644
index 0000000..7eefb82
--- /dev/null
+++ b/255.out
@@ -0,0 +1,2 @@
+QA output created by 255
+Silence is golden
diff --git a/group b/group
index 1f86075..c045e70 100644
--- a/group
+++ b/group
@@ -368,3 +368,4 @@ deprecated
252 auto quick prealloc
253 auto quick
254 auto quick
+255 auto quick
diff --git a/src/Makefile b/src/Makefile
index 91088bf..ccdaeec 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -17,7 +17,7 @@ LINUX_TARGETS = xfsctl bstat t_mtab getdevicesize preallo_rw_pattern_reader \
preallo_rw_pattern_writer ftrunc trunc fs_perms testx looptest \
locktest unwritten_mmap bulkstat_unlink_test t_stripealign \
bulkstat_unlink_test_modified t_dir_offset t_futimens t_immutable \
- stale_handle pwrite_mmap_blocked fstrim
+ stale_handle pwrite_mmap_blocked fstrim seek-tester
SUBDIRS =
diff --git a/src/seek-tester.c b/src/seek-tester.c
new file mode 100644
index 0000000..5141b45
--- /dev/null
+++ b/src/seek-tester.c
@@ -0,0 +1,475 @@
+/*
+ * Copyright (C) 2011 Oracle. All rights reserved.
+ * Copyright (C) 2011 Red Hat. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#define _XOPEN_SOURCE 500
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#ifndef SEEK_DATA
+#define SEEK_DATA 3
+#define SEEK_HOLE 4
+#endif
+
+#define FS_NO_HOLES (1 << 0)
+#define QUIET (1 << 1)
+
+static blksize_t alloc_size;
+static unsigned flags = 0;
+
+static int get_io_sizes(int fd)
+{
+ struct stat buf;
+ int ret;
+
+ ret = fstat(fd, &buf);
+ if (ret)
+ fprintf(stderr, " ERROR %d: Failed to find io blocksize\n",
+ errno);
+
+ /* st_blksize is typically also the allocation size */
+ alloc_size = buf.st_blksize;
+
+ if (!(flags & QUIET))
+ printf("Allocation size: %ld\n", alloc_size);
+
+ return ret;
+}
+
+#define do_free(x) do { if(x) free(x); } while(0);
+
+static void *do_malloc(size_t size)
+{
+ void *buf;
+
+ buf = malloc(size);
+ if (!buf)
+ fprintf(stderr, " ERROR: Unable to allocate %ld bytes\n",
+ (long)size);
+
+ return buf;
+}
+
+static int do_truncate(int fd, off_t length)
+{
+ int ret;
+
+ ret = ftruncate(fd, length);
+ if (ret)
+ fprintf(stderr, " ERROR %d: Failed to extend file "
+ "to %ld bytes\n", errno, (long)length);
+ return ret;
+}
+
+static ssize_t do_pwrite(int fd, const void *buf, size_t count, off_t offset)
+{
+ ssize_t ret, written = 0;
+
+ while (count > written) {
+ ret = pwrite(fd, buf + written, count - written, offset + written);
+ if (ret < 0) {
+ fprintf(stderr, " ERROR %d: Failed to write %ld "
+ "bytes\n", errno, (long)count);
+ return ret;
+ }
+ written += ret;
+ }
+
+ return 0;
+}
+
+static int do_lseek(int testnum, int subtest, int fd, int origin, off_t set,
+ off_t exp)
+{
+ off_t pos;
+ int ret = -1;
+
+ pos = lseek(fd, set, origin);
+
+ if (pos != exp) {
+ fprintf(stderr, " ERROR in Test %d.%d: POS expected %ld, "
+ "got %ld\n", testnum, subtest, (long)exp, (long)pos);
+ goto out;
+ }
+
+ if (pos == -1 && errno != ENXIO) {
+ fprintf(stderr, " ERROR in Test %d.%d: ERRNO expected %d, "
+ "got %d\n", testnum, subtest, ENXIO, errno);
+ goto out;
+ }
+
+ ret = 0;
+
+out:
+ return ret;
+}
+
+static int get_flags(int fd)
+{
+ const char *buf = "ABCDEF";
+ ssize_t written;
+ off_t pos;
+ int ret;
+
+ ret = do_truncate(fd, alloc_size * 2);
+ if (ret)
+ return ret;
+
+ written = do_pwrite(fd, buf, strlen(buf), 0);
+ if (written)
+ return -1;
+
+ pos = lseek(fd, 0, SEEK_HOLE);
+ if (pos == alloc_size * 2) {
+ if (!(flags & QUIET))
+ printf("File system does not recognize holes, the only "
+ "hole found will be at the end.\n");
+ flags |= FS_NO_HOLES;
+ } else if (pos == (off_t)-1) {
+ fprintf(stderr, "SEEK_HOLE is not supported\n");
+ return -1;
+ }
+
+ return 0;
+}
+
+/* test hole data hole data */
+static int test06(int fd, int testnum)
+{
+ int ret = 0;
+ char *buf = NULL;
+ int bufsz = alloc_size;
+ int filsz = bufsz * 4;
+ int off;
+
+ if (flags & FS_NO_HOLES)
+ return 1;
+
+ /* HOLE - DATA - HOLE - DATA */
+ /* Each unit is bufsz */
+
+ buf = do_malloc(bufsz);
+ if (!buf)
+ goto out;
+ memset(buf, 'a', bufsz);
+
+ ret = do_pwrite(fd, buf, bufsz, bufsz);
+ if (!ret)
+ do_pwrite(fd, buf, bufsz, bufsz * 3);
+ if (ret)
+ goto out;
+
+ /* offset at the beginning */
+ ret += do_lseek(testnum, 1, fd, SEEK_HOLE, 0, 0);
+ ret += do_lseek(testnum, 2, fd, SEEK_HOLE, 1, 1);
+ ret += do_lseek(testnum, 3, fd, SEEK_DATA, 0, bufsz);
+ ret += do_lseek(testnum, 4, fd, SEEK_DATA, 1, bufsz);
+
+ /* offset around first hole-data boundary */
+ off = bufsz;
+ ret += do_lseek(testnum, 5, fd, SEEK_HOLE, off - 1, off - 1);
+ ret += do_lseek(testnum, 6, fd, SEEK_DATA, off - 1, off);
+ ret += do_lseek(testnum, 7, fd, SEEK_HOLE, off, bufsz * 2);
+ ret += do_lseek(testnum, 8, fd, SEEK_DATA, off, off);
+ ret += do_lseek(testnum, 9, fd, SEEK_HOLE, off + 1, bufsz * 2);
+ ret += do_lseek(testnum, 10, fd, SEEK_DATA, off + 1, off + 1);
+
+ /* offset around data-hole boundary */
+ off = bufsz * 2;
+ ret += do_lseek(testnum, 11, fd, SEEK_HOLE, off - 1, off);
+ ret += do_lseek(testnum, 12, fd, SEEK_DATA, off - 1, off - 1);
+ ret += do_lseek(testnum, 13, fd, SEEK_HOLE, off, off);
+ ret += do_lseek(testnum, 14, fd, SEEK_DATA, off, bufsz * 3);
+ ret += do_lseek(testnum, 15, fd, SEEK_HOLE, off + 1, off + 1);
+ ret += do_lseek(testnum, 16, fd, SEEK_DATA, off + 1, bufsz * 3);
+
+ /* offset around second hole-data boundary */
+ off = bufsz * 3;
+ ret += do_lseek(testnum, 17, fd, SEEK_HOLE, off - 1, off - 1);
+ ret += do_lseek(testnum, 18, fd, SEEK_DATA, off - 1, off);
+ ret += do_lseek(testnum, 19, fd, SEEK_HOLE, off, filsz);
+ ret += do_lseek(testnum, 20, fd, SEEK_DATA, off, off);
+ ret += do_lseek(testnum, 21, fd, SEEK_HOLE, off + 1, filsz);
+ ret += do_lseek(testnum, 22, fd, SEEK_DATA, off + 1, off + 1);
+
+ /* offset around the end of file */
+ off = filsz;
+ ret += do_lseek(testnum, 23, fd, SEEK_HOLE, off - 1, filsz);
+ ret += do_lseek(testnum, 24, fd, SEEK_DATA, off - 1, filsz - 1);
+ ret += do_lseek(testnum, 25, fd, SEEK_HOLE, off, -1);
+ ret += do_lseek(testnum, 26, fd, SEEK_DATA, off, -1);
+ ret += do_lseek(testnum, 27, fd, SEEK_HOLE, off + 1, -1);
+ ret += do_lseek(testnum, 28, fd, SEEK_DATA, off + 1, -1);
+
+out:
+ do_free(buf);
+ return ret;
+}
+
+/* test file with data at the beginning and a hole at the end */
+static int test05(int fd, int testnum)
+{
+ int ret = -1;
+ char *buf = NULL;
+ int bufsz = alloc_size;
+ int filsz = bufsz * 4;
+
+ if (flags & FS_NO_HOLES)
+ return 1;
+
+ /* DATA - HOLE */
+ /* Each unit is bufsz */
+
+ buf = do_malloc(bufsz);
+ if (!buf)
+ goto out;
+ memset(buf, 'a', bufsz);
+
+ ret = do_truncate(fd, filsz);
+ if (!ret)
+ ret = do_pwrite(fd, buf, bufsz, 0);
+ if (ret)
+ goto out;
+
+ /* offset at the beginning */
+ ret += do_lseek(testnum, 1, fd, SEEK_HOLE, 0, bufsz);
+ ret += do_lseek(testnum, 2, fd, SEEK_HOLE, 1, bufsz);
+ ret += do_lseek(testnum, 3, fd, SEEK_DATA, 0, 0);
+ ret += do_lseek(testnum, 4, fd, SEEK_DATA, 1, 1);
+
+ /* offset around data-hole boundary */
+ ret += do_lseek(testnum, 5, fd, SEEK_HOLE, bufsz - 1, bufsz);
+ ret += do_lseek(testnum, 6, fd, SEEK_DATA, bufsz - 1, bufsz - 1);
+ ret += do_lseek(testnum, 7, fd, SEEK_HOLE, bufsz, bufsz);
+ ret += do_lseek(testnum, 8, fd, SEEK_DATA, bufsz, -1);
+ ret += do_lseek(testnum, 9, fd, SEEK_HOLE, bufsz + 1, bufsz + 1);
+ ret += do_lseek(testnum, 10, fd, SEEK_DATA, bufsz + 1, -1);
+
+ /* offset around eof */
+ ret += do_lseek(testnum, 11, fd, SEEK_HOLE, filsz - 1, filsz - 1);
+ ret += do_lseek(testnum, 12, fd, SEEK_DATA, filsz - 1, -1);
+ ret += do_lseek(testnum, 13, fd, SEEK_HOLE, filsz, -1);
+ ret += do_lseek(testnum, 14, fd, SEEK_DATA, filsz, -1);
+ ret += do_lseek(testnum, 15, fd, SEEK_HOLE, filsz + 1, -1);
+ ret += do_lseek(testnum, 16, fd, SEEK_DATA, filsz + 1, -1);
+
+out:
+ do_free(buf);
+ return ret;
+}
+
+/* test hole begin and data end */
+static int test04(int fd, int testnum)
+{
+ int ret;
+ char *buf = "ABCDEFGH";
+ int bufsz = sizeof(buf);
+ int holsz = alloc_size * 2;
+ int filsz = holsz + bufsz;
+
+ if (flags & FS_NO_HOLES)
+ return 1;
+
+ /* HOLE - DATA */
+
+ ret = do_pwrite(fd, buf, bufsz, holsz);
+ if (ret)
+ goto out;
+
+ /* offset at the beginning */
+ ret += do_lseek(testnum, 1, fd, SEEK_HOLE, 0, 0);
+ ret += do_lseek(testnum, 2, fd, SEEK_HOLE, 1, 1);
+ ret += do_lseek(testnum, 3, fd, SEEK_DATA, 0, holsz);
+ ret += do_lseek(testnum, 4, fd, SEEK_DATA, 1, holsz);
+
+ /* offset around hole-data boundary */
+ ret += do_lseek(testnum, 5, fd, SEEK_HOLE, holsz - 1, holsz - 1);
+ ret += do_lseek(testnum, 6, fd, SEEK_DATA, holsz - 1, holsz);
+ ret += do_lseek(testnum, 7, fd, SEEK_HOLE, holsz, filsz);
+ ret += do_lseek(testnum, 8, fd, SEEK_DATA, holsz, holsz);
+ ret += do_lseek(testnum, 9, fd, SEEK_HOLE, holsz + 1, filsz);
+ ret += do_lseek(testnum, 10, fd, SEEK_DATA, holsz + 1, holsz + 1);
+
+ /* offset around eof */
+ ret += do_lseek(testnum, 11, fd, SEEK_HOLE, filsz - 1, filsz);
+ ret += do_lseek(testnum, 12, fd, SEEK_DATA, filsz - 1, filsz - 1);
+ ret += do_lseek(testnum, 13, fd, SEEK_HOLE, filsz, -1);
+ ret += do_lseek(testnum, 14, fd, SEEK_DATA, filsz, -1);
+ ret += do_lseek(testnum, 15, fd, SEEK_HOLE, filsz + 1, -1);
+ ret += do_lseek(testnum, 16, fd, SEEK_DATA, filsz + 1, -1);
+out:
+ return ret;
+}
+
+/* test full file */
+static int test03(int fd, int testnum)
+{
+ char *buf = NULL;
+ int bufsz = alloc_size + 100;
+ int ret = -1;
+
+ buf = do_malloc(bufsz);
+ if (!buf)
+ goto out;
+ memset(buf, 'a', bufsz);
+
+ ret = do_pwrite(fd, buf, bufsz, 0);
+ if (ret)
+ goto out;
+
+ /* offset at the beginning */
+ ret += do_lseek(testnum, 1, fd, SEEK_HOLE, 0, bufsz);
+ ret += do_lseek(testnum, 2, fd, SEEK_HOLE, 1, bufsz);
+ ret += do_lseek(testnum, 3, fd, SEEK_DATA, 0, 0);
+ ret += do_lseek(testnum, 4, fd, SEEK_DATA, 1, 1);
+
+ /* offset around eof */
+ ret += do_lseek(testnum, 5, fd, SEEK_HOLE, bufsz - 1, bufsz);
+ ret += do_lseek(testnum, 6, fd, SEEK_DATA, bufsz - 1, bufsz - 1);
+ ret += do_lseek(testnum, 7, fd, SEEK_HOLE, bufsz, -1);
+ ret += do_lseek(testnum, 8, fd, SEEK_DATA, bufsz, -1);
+ ret += do_lseek(testnum, 9, fd, SEEK_HOLE, bufsz + 1, -1);
+ ret += do_lseek(testnum, 10, fd, SEEK_DATA, bufsz + 1, -1);
+
+out:
+ do_free(buf);
+ return ret;
+}
+
+/* test empty file */
+static int test02(int fd, int testnum)
+{
+ int ret = 0;
+
+ ret += do_lseek(testnum, 1, fd, SEEK_DATA, 0, -1);
+ ret += do_lseek(testnum, 2, fd, SEEK_HOLE, 0, -1);
+ ret += do_lseek(testnum, 3, fd, SEEK_HOLE, 1, -1);
+
+ return ret;
+}
+
+/* test feature support */
+static int test01(int fd, int testnum)
+{
+ int ret;
+ char buf[] = "ABCDEFGH";
+ int bufsz = sizeof(buf);
+
+ ret = do_pwrite(fd, buf, bufsz, 0);
+ if (ret)
+ goto out;
+
+ ret += do_lseek(testnum, 1, fd, SEEK_DATA, 0, 0);
+ ret += do_lseek(testnum, 2, fd, SEEK_HOLE, 0, bufsz);
+
+out:
+ return ret;
+}
+
+struct testrec {
+ int test_num;
+ int (*test_func)(int fd, int testnum);
+ char *test_desc;
+};
+
+struct testrec seek_tests[] = {
+ { 1, test01, "Test basic support" },
+ { 2, test02, "Test an empty file" },
+ { 3, test03, "Test a full file" },
+ { 4, test04, "Test file hole at beg, data at end" },
+ { 5, test05, "Test file data at beg, hole at end" },
+ { 6, test06, "Test file hole data hole data" },
+};
+
+static int run_test(int fd, struct testrec *tr)
+{
+ int ret;
+
+ ret = tr->test_func(fd, tr->test_num);
+ if (!(flags & QUIET))
+ printf("%02d. %-50s\t%s\n", tr->test_num, tr->test_desc,
+ ret < 0 ? "FAIL" : (ret == 0 ? "SUCC" : "NOT RUN"));
+ return ret;
+}
+
+void print_help()
+{
+ printf("seek-test [-h] [-q] filename\n");
+ printf("\t-h - this message\n");
+ printf("\t-q - quiet, no output\n");
+ printf("\tfilename - file to use for the test\n");
+}
+
+int main(int argc, char **argv)
+{
+ int ret = -1;
+ int i, fd = -1;
+ int c;
+ int numtests = sizeof(seek_tests) / sizeof(struct testrec);
+
+ while ((c = getopt(argc, argv, "qh")) != -1) {
+ switch (c) {
+ case 'q':
+ flags |= QUIET;
+ break;
+ case 'h':
+ print_help();
+ exit(0);
+ default:
+ print_help();
+ exit(1);
+ }
+ }
+
+ if (optind >= argc) {
+ print_help();
+ exit(1);
+ }
+
+ fd = open(argv[optind], O_RDWR|O_CREAT|O_TRUNC, 0644);
+ if (fd < 0) {
+ fprintf(stderr, "Failed to open testfile: %d\n", errno);
+ goto out;
+ }
+
+ ret = get_io_sizes(fd);
+ if (ret)
+ goto out;
+
+ ret = get_flags(fd);
+ if (ret)
+ goto out;
+
+ for (i = 0; i < numtests; ++i) {
+ ret = do_truncate(fd, 0);
+ if (ret)
+ goto out;
+ run_test(fd, &seek_tests[i]);
+ }
+
+out:
+ if (fd > -1)
+ close(fd);
+ return ret;
+}
--
1.7.5.2
On Tue, Jun 28, 2011 at 11:33:19AM -0400, Josef Bacik wrote:
> This is a test to make sure seek_data/seek_hole is acting like it does on
> Solaris. It will check to see if the fs supports finding a hole or not and will
> adjust as necessary.
So I just looked at this with an eye to validating an XFS
implementation, and I came up with this list of stuff that the test
does not cover that I'd need to test in some way:
- files with clean unwritten extents. Are they a hole or
data? What's SEEK_DATA supposed to return on layout like
hole-unwritten-data? i.e. needs to add fallocate to the
picture...
- files with dirty unwritten extents (i.e. dirty in memory,
not on disk). They are most definitely data, and most
filesystems will need a separate lookup path to detect
dirty unwritten ranges because the state is kept
separately (page cache vs extent cache). Plenty of scope
for filesystem specific bugs here so needs a roubust test.
- cold cache behaviour - all dirty data ranges the test
creates are hot in cache and not even forced to disk, so
it is not testing the no-page-cache-over-the-data-range
case. i.e. it tests delalloc state tracking but not
data-extent-already exists lookups during a seek.
- assumes that allocation size is the block size and that
holes follows block size alignment. We already know that
ext4 does not follow that rule when doing small sparse
writes close together in a file, and XFS is also known to
fill holes when doing sparse writes past EOF.
- only tests single block data extents ѕo doesn't cover
corner cases like skipping over multiple fragmented data
extents to the next hole.
Some more comments in line....
> +_cleanup()
> +{
> + rm -f $tmp.*
> +}
> +
> +trap "_cleanup ; exit \$status" 0 1 2 3 15
> +
> +# get standard environment, filters and checks
> +. ./common.rc
> +. ./common.filter
> +
> +# real QA test starts here
> +_supported_fs generic
> +_supported_os Linux
> +
> +testfile=$TEST_DIR/seek_test.$$
> +logfile=$TEST_DIR/seek_test.$$.log
The log file is usually named $seq.full, and doesn't get placed in
the filesystem being tested. It gets saved in the xfstests directory
along side $seq.out.bad for analysis whenteh test fails...
> +[ -x $here/src/seek-tester ] || _notrun "seek-tester not built"
> +
> +_cleanup()
> +{
> + rm -f $testfile
> + rm -f $logfile
> +}
> +trap "_cleanup; exit \$status" 0 1 2 3 15
> +
> +echo "Silence is golden"
> +$here/src/seek-tester -q $testfile 2>&1 | tee -a $logfile
Personally I'd prefer the test to be a bit noisy about what it is
running, especially when there are so many subtests the single
invocation is running. It makes no difference to the run time ofthe
test, or the output when something fails, but it at least allows you
to run the test manually and see what it is doing easily...
> +
> +if grep -q "SEEK_HOLE is not supported" $logfile; then
> + _notrun "SEEK_HOLE/SEEK_DATA not supported by this kernel"
> +fi
> +
> +rm -f $logfile
> +rm -f $testfile
> +
> +status=0 ; exit
> diff --git a/255.out b/255.out
> new file mode 100644
> index 0000000..7eefb82
> --- /dev/null
> +++ b/255.out
> @@ -0,0 +1,2 @@
> +QA output created by 255
> +Silence is golden
> diff --git a/group b/group
> index 1f86075..c045e70 100644
> --- a/group
> +++ b/group
> @@ -368,3 +368,4 @@ deprecated
> 252 auto quick prealloc
> 253 auto quick
> 254 auto quick
> +255 auto quick
I'd suggest that rw and prealloc (once unwritten extent
testing is added) groups should also be defined for this test.
Otherwise, the test code looks ok if a bit over-engineered....
> +struct testrec {
> + int test_num;
> + int (*test_func)(int fd, int testnum);
> + char *test_desc;
> +};
> +
> +struct testrec seek_tests[] = {
> + { 1, test01, "Test basic support" },
> + { 2, test02, "Test an empty file" },
> + { 3, test03, "Test a full file" },
> + { 4, test04, "Test file hole at beg, data at end" },
> + { 5, test05, "Test file data at beg, hole at end" },
> + { 6, test06, "Test file hole data hole data" },
So, to take from the hole punch test matrix, it covers a bunch more
file state transitions and cases that are just as relevant to
SEEK_HOLE/SEEK_DATA. Those cases are:
# 1. into a hole
# 2. into allocated space
# 3. into unwritten space
# 4. hole -> data
# 5. hole -> unwritten
# 6. data -> hole
# 7. data -> unwritten
# 8. unwritten -> hole
# 9. unwritten -> data
# 10. hole -> data -> hole
# 11. data -> hole -> data
# 12. unwritten -> data -> unwritten
# 13. data -> unwritten -> data
# 14. data -> hole @ EOF
# 15. data -> hole @ 0
# 16. data -> cache cold ->hole
# 17. data -> hole in single block file
I thikn we also need to cover most of these same cases, right? And
SEEK_HOLE/SEEK data also need to explicitly separate the unwritten
tests into "clean unwritten" and "dirty unwritten" and cover the
transitions between regions of those states as well, right?
Cheers,
Dave.
--
Dave Chinner
[email protected]
On Wed, Jun 29, 2011 at 04:53:07PM +1000, Dave Chinner wrote:
> On Tue, Jun 28, 2011 at 11:33:19AM -0400, Josef Bacik wrote:
> > This is a test to make sure seek_data/seek_hole is acting like it does on
> > Solaris. It will check to see if the fs supports finding a hole or not and will
> > adjust as necessary.
>
> So I just looked at this with an eye to validating an XFS
> implementation, and I came up with this list of stuff that the test
> does not cover that I'd need to test in some way:
>
> - files with clean unwritten extents. Are they a hole or
> data? What's SEEK_DATA supposed to return on layout like
> hole-unwritten-data? i.e. needs to add fallocate to the
> picture...
>
> - files with dirty unwritten extents (i.e. dirty in memory,
> not on disk). They are most definitely data, and most
> filesystems will need a separate lookup path to detect
> dirty unwritten ranges because the state is kept
> separately (page cache vs extent cache). Plenty of scope
> for filesystem specific bugs here so needs a roubust test.
The discussion leading up to the resurrection of SEEK_HOLE/SEEK_DATA
was pretty much about that point. The conclusion based on the Sun
documentation and common sense was that SEEK_DATA may only consider
unwritten extents as hole if the filesystem has a way to distinguish
plain unwritten extents and those that have been dirtied. Else it
should be considered data.
Testing for making sure dirty preallocated areas aren't wrongly
reported sounds relatively easy, the rest falls into implementation
details, which imho is fine. Not reporting preallocated extents
as holes just is a quality of implementation issue and not a bug.
On 29/06/11 08:40, Christoph Hellwig wrote:
> On Wed, Jun 29, 2011 at 04:53:07PM +1000, Dave Chinner wrote:
>> On Tue, Jun 28, 2011 at 11:33:19AM -0400, Josef Bacik wrote:
>>> This is a test to make sure seek_data/seek_hole is acting like it does on
>>> Solaris. It will check to see if the fs supports finding a hole or not and will
>>> adjust as necessary.
>>
>> So I just looked at this with an eye to validating an XFS
>> implementation, and I came up with this list of stuff that the test
>> does not cover that I'd need to test in some way:
>>
>> - files with clean unwritten extents. Are they a hole or
>> data? What's SEEK_DATA supposed to return on layout like
>> hole-unwritten-data? i.e. needs to add fallocate to the
>> picture...
>>
>> - files with dirty unwritten extents (i.e. dirty in memory,
>> not on disk). They are most definitely data, and most
>> filesystems will need a separate lookup path to detect
>> dirty unwritten ranges because the state is kept
>> separately (page cache vs extent cache). Plenty of scope
>> for filesystem specific bugs here so needs a roubust test.
>
> The discussion leading up to the resurrection of SEEK_HOLE/SEEK_DATA
> was pretty much about that point. The conclusion based on the Sun
> documentation and common sense was that SEEK_DATA may only consider
> unwritten extents as hole if the filesystem has a way to distinguish
> plain unwritten extents and those that have been dirtied. Else it
> should be considered data.
>
> Testing for making sure dirty preallocated areas aren't wrongly
> reported sounds relatively easy, the rest falls into implementation
> details, which imho is fine. Not reporting preallocated extents
> as holes just is a quality of implementation issue and not a bug.
There is the argument, that if this interface can distinguish
these dirty unwritten extents, then why can't the fiemap interface too?
The advantage of the fiemap interface is that it can distinguish
empty extents vs holes. Empty extents will become increasingly common
I think, given the fragmentation and space guarantee benefits they give.
It would be cool for cp for example to be able to efficiently copy
empty extents from source to dest.
cheers,
P?draig.
On 06/29/2011 02:53 AM, Dave Chinner wrote:
> On Tue, Jun 28, 2011 at 11:33:19AM -0400, Josef Bacik wrote:
>> This is a test to make sure seek_data/seek_hole is acting like it does on
>> Solaris. It will check to see if the fs supports finding a hole or not and will
>> adjust as necessary.
>
> So I just looked at this with an eye to validating an XFS
> implementation, and I came up with this list of stuff that the test
> does not cover that I'd need to test in some way:
>
> - files with clean unwritten extents. Are they a hole or
> data? What's SEEK_DATA supposed to return on layout like
> hole-unwritten-data? i.e. needs to add fallocate to the
> picture...
>
> - files with dirty unwritten extents (i.e. dirty in memory,
> not on disk). They are most definitely data, and most
> filesystems will need a separate lookup path to detect
> dirty unwritten ranges because the state is kept
> separately (page cache vs extent cache). Plenty of scope
> for filesystem specific bugs here so needs a roubust test.
>
> - cold cache behaviour - all dirty data ranges the test
> creates are hot in cache and not even forced to disk, so
> it is not testing the no-page-cache-over-the-data-range
> case. i.e. it tests delalloc state tracking but not
> data-extent-already exists lookups during a seek.
>
> - assumes that allocation size is the block size and that
> holes follows block size alignment. We already know that
> ext4 does not follow that rule when doing small sparse
> writes close together in a file, and XFS is also known to
> fill holes when doing sparse writes past EOF.
>
> - only tests single block data extents ѕo doesn't cover
> corner cases like skipping over multiple fragmented data
> extents to the next hole.
>
Yeah I intentionally left out preallocated stuff because these are going
to be implementation specific, so I was going to leave that for a later
exercise when people actually start doing proper implementations.
> Some more comments in line....
>
>> +_cleanup()
>> +{
>> + rm -f $tmp.*
>> +}
>> +
>> +trap "_cleanup ; exit \$status" 0 1 2 3 15
>> +
>> +# get standard environment, filters and checks
>> +. ./common.rc
>> +. ./common.filter
>> +
>> +# real QA test starts here
>> +_supported_fs generic
>> +_supported_os Linux
>> +
>> +testfile=$TEST_DIR/seek_test.$$
>> +logfile=$TEST_DIR/seek_test.$$.log
>
> The log file is usually named $seq.full, and doesn't get placed in
> the filesystem being tested. It gets saved in the xfstests directory
> along side $seq.out.bad for analysis whenteh test fails...
>
I only want it to see if SEEK_HOLE fails so I can say it didn't run. I
followed the same example as the fiemap test that Eric wrote.
>> +[ -x $here/src/seek-tester ] || _notrun "seek-tester not built"
>> +
>> +_cleanup()
>> +{
>> + rm -f $testfile
>> + rm -f $logfile
>> +}
>> +trap "_cleanup; exit \$status" 0 1 2 3 15
>> +
>> +echo "Silence is golden"
>> +$here/src/seek-tester -q $testfile 2>&1 | tee -a $logfile
>
> Personally I'd prefer the test to be a bit noisy about what it is
> running, especially when there are so many subtests the single
> invocation is running. It makes no difference to the run time ofthe
> test, or the output when something fails, but it at least allows you
> to run the test manually and see what it is doing easily...
>
Right, the problem with this test is it will run differently depending
on the implementation. I agree, I really like the noisy output tests,
but unfortunately if I run this test on ext4 where it currently treats
the entire file as data, and then run it on btrfs where it is smarter
and actually recognizes holes, we end up with two different outputs that
are both correct.
>> +
>> +if grep -q "SEEK_HOLE is not supported" $logfile; then
>> + _notrun "SEEK_HOLE/SEEK_DATA not supported by this kernel"
>> +fi
>> +
>> +rm -f $logfile
>> +rm -f $testfile
>> +
>> +status=0 ; exit
>> diff --git a/255.out b/255.out
>> new file mode 100644
>> index 0000000..7eefb82
>> --- /dev/null
>> +++ b/255.out
>> @@ -0,0 +1,2 @@
>> +QA output created by 255
>> +Silence is golden
>> diff --git a/group b/group
>> index 1f86075..c045e70 100644
>> --- a/group
>> +++ b/group
>> @@ -368,3 +368,4 @@ deprecated
>> 252 auto quick prealloc
>> 253 auto quick
>> 254 auto quick
>> +255 auto quick
>
> I'd suggest that rw and prealloc (once unwritten extent
> testing is added) groups should also be defined for this test.
>
> Otherwise, the test code looks ok if a bit over-engineered....
>
>> +struct testrec {
>> + int test_num;
>> + int (*test_func)(int fd, int testnum);
>> + char *test_desc;
>> +};
>> +
>> +struct testrec seek_tests[] = {
>> + { 1, test01, "Test basic support" },
>> + { 2, test02, "Test an empty file" },
>> + { 3, test03, "Test a full file" },
>> + { 4, test04, "Test file hole at beg, data at end" },
>> + { 5, test05, "Test file data at beg, hole at end" },
>> + { 6, test06, "Test file hole data hole data" },
>
> So, to take from the hole punch test matrix, it covers a bunch more
> file state transitions and cases that are just as relevant to
> SEEK_HOLE/SEEK_DATA. Those cases are:
>
> # 1. into a hole
> # 2. into allocated space
> # 3. into unwritten space
> # 4. hole -> data
> # 5. hole -> unwritten
> # 6. data -> hole
> # 7. data -> unwritten
> # 8. unwritten -> hole
> # 9. unwritten -> data
> # 10. hole -> data -> hole
> # 11. data -> hole -> data
> # 12. unwritten -> data -> unwritten
> # 13. data -> unwritten -> data
> # 14. data -> hole @ EOF
> # 15. data -> hole @ 0
> # 16. data -> cache cold ->hole
> # 17. data -> hole in single block file
>
> I thikn we also need to cover most of these same cases, right? And
> SEEK_HOLE/SEEK data also need to explicitly separate the unwritten
> tests into "clean unwritten" and "dirty unwritten" and cover the
> transitions between regions of those states as well, right?
>
Yeah you are right, but again doing preallocated stuff is tricky, but I
can expand it now if that's what we want. Thanks,
Josef
On 06/29/2011 12:40 AM, Christoph Hellwig wrote:
> On Wed, Jun 29, 2011 at 04:53:07PM +1000, Dave Chinner wrote:
>> On Tue, Jun 28, 2011 at 11:33:19AM -0400, Josef Bacik wrote:
>>> This is a test to make sure seek_data/seek_hole is acting like it does on
>>> Solaris. It will check to see if the fs supports finding a hole or not and will
>>> adjust as necessary.
>> So I just looked at this with an eye to validating an XFS
>> implementation, and I came up with this list of stuff that the test
>> does not cover that I'd need to test in some way:
>>
>> - files with clean unwritten extents. Are they a hole or
>> data? What's SEEK_DATA supposed to return on layout like
>> hole-unwritten-data? i.e. needs to add fallocate to the
>> picture...
>>
>> - files with dirty unwritten extents (i.e. dirty in memory,
>> not on disk). They are most definitely data, and most
>> filesystems will need a separate lookup path to detect
>> dirty unwritten ranges because the state is kept
>> separately (page cache vs extent cache). Plenty of scope
>> for filesystem specific bugs here so needs a roubust test.
> The discussion leading up to the resurrection of SEEK_HOLE/SEEK_DATA
> was pretty much about that point. The conclusion based on the Sun
> documentation and common sense was that SEEK_DATA may only consider
> unwritten extents as hole if the filesystem has a way to distinguish
> plain unwritten extents and those that have been dirtied. Else it
> should be considered data.
>
> Testing for making sure dirty preallocated areas aren't wrongly
> reported sounds relatively easy, the rest falls into implementation
> details, which imho is fine. Not reporting preallocated extents
> as holes just is a quality of implementation issue and not a bug.
I agree. And if I might add my 2 cents that it would be much easier
if we added another test that created files with all the worrisome boundary
conditions and used SEEK_DATA/HOLE to copy the files and compared
using md5sum. This would be far easier than one that expects a certain
pos for each operation.
On 06/29/2011 03:42 AM, P?draig Brady wrote:
> There is the argument, that if this interface can distinguish
> these dirty unwritten extents, then why can't the fiemap interface too?
> The advantage of the fiemap interface is that it can distinguish
> empty extents vs holes. Empty extents will become increasingly common
> I think, given the fragmentation and space guarantee benefits they give.
> It would be cool for cp for example to be able to efficiently copy
> empty extents from source to dest.
I'm not too sure about that. Atleast not enabled by default. Most users
use cp to backup data. Not empty space. In this case, this empty extent
may not even be de-dupable.
Frankly I'd be happier of cp started to exploited fallocate() to create larger
extents before copying data into them. Atleast for the large files.
On Wed, Jun 29, 2011 at 10:29:02AM -0700, Sunil Mushran wrote:
> I'm not too sure about that. Atleast not enabled by default. Most users
> use cp to backup data. Not empty space. In this case, this empty extent
> may not even be de-dupable.
>
> Frankly I'd be happier of cp started to exploited fallocate() to create larger
> extents before copying data into them. Atleast for the large files.
That's what delayed allocation is for.
On 06/29/2011 10:36 AM, Christoph Hellwig wrote:
> On Wed, Jun 29, 2011 at 10:29:02AM -0700, Sunil Mushran wrote:
>> I'm not too sure about that. Atleast not enabled by default. Most users
>> use cp to backup data. Not empty space. In this case, this empty extent
>> may not even be de-dupable.
>>
>> Frankly I'd be happier of cp started to exploited fallocate() to create larger
>> extents before copying data into them. Atleast for the large files.
> That's what delayed allocation is for.
A feature fewer file systems support than fallocate(). ;)
On 06/29/2011 01:10 PM, Sunil Mushran wrote:
> On 06/29/2011 12:40 AM, Christoph Hellwig wrote:
>> On Wed, Jun 29, 2011 at 04:53:07PM +1000, Dave Chinner wrote:
>>> On Tue, Jun 28, 2011 at 11:33:19AM -0400, Josef Bacik wrote:
>>>> This is a test to make sure seek_data/seek_hole is acting like it
>>>> does on
>>>> Solaris. It will check to see if the fs supports finding a hole or
>>>> not and will
>>>> adjust as necessary.
>>> So I just looked at this with an eye to validating an XFS
>>> implementation, and I came up with this list of stuff that the test
>>> does not cover that I'd need to test in some way:
>>>
>>> - files with clean unwritten extents. Are they a hole or
>>> data? What's SEEK_DATA supposed to return on layout like
>>> hole-unwritten-data? i.e. needs to add fallocate to the
>>> picture...
>>>
>>> - files with dirty unwritten extents (i.e. dirty in memory,
>>> not on disk). They are most definitely data, and most
>>> filesystems will need a separate lookup path to detect
>>> dirty unwritten ranges because the state is kept
>>> separately (page cache vs extent cache). Plenty of scope
>>> for filesystem specific bugs here so needs a roubust test.
>> The discussion leading up to the resurrection of SEEK_HOLE/SEEK_DATA
>> was pretty much about that point. The conclusion based on the Sun
>> documentation and common sense was that SEEK_DATA may only consider
>> unwritten extents as hole if the filesystem has a way to distinguish
>> plain unwritten extents and those that have been dirtied. Else it
>> should be considered data.
>>
>> Testing for making sure dirty preallocated areas aren't wrongly
>> reported sounds relatively easy, the rest falls into implementation
>> details, which imho is fine. Not reporting preallocated extents
>> as holes just is a quality of implementation issue and not a bug.
>
> I agree. And if I might add my 2 cents that it would be much easier
> if we added another test that created files with all the worrisome boundary
> conditions and used SEEK_DATA/HOLE to copy the files and compared
> using md5sum. This would be far easier than one that expects a certain
> pos for each operation.
That's a great point, I think I will rig something like that up. Thanks,
Josef
On 29/06/11 18:29, Sunil Mushran wrote:
> On 06/29/2011 03:42 AM, P?draig Brady wrote:
>> There is the argument, that if this interface can distinguish
>> these dirty unwritten extents, then why can't the fiemap interface too?
>> The advantage of the fiemap interface is that it can distinguish
>> empty extents vs holes. Empty extents will become increasingly common
>> I think, given the fragmentation and space guarantee benefits they give.
>> It would be cool for cp for example to be able to efficiently copy
>> empty extents from source to dest.
>
> I'm not too sure about that. Atleast not enabled by default. Most users
> use cp to backup data. Not empty space. In this case, this empty extent
> may not even be de-dupable.
That's a fair point. On the other hand if
you wanted to start working with the backup copy,
you might want it allocated to avoid fragmentation and ENOSPC issues.
What we were going with was empty -> hole with cp --sparse=always
and empty -> empty otherwise. If empty and hole can not be
distinguished though, then this process will be impacted.
>
> Frankly I'd be happier of cp started to exploited fallocate() to create
> larger
> extents before copying data into them. Atleast for the large files.
Yes we definitely will start doing that.
That will help fragmentation and give early ENOSPC.
We can't use fiemap for this at the moment
(on XSF or ext4 (without a sync))
but the seek_data interface should allow us
to do this to some extent (pardon the pun).
cheers,
P?draig.