| Age | Commit message (Collapse) | Author | Files | Lines |
|---|
|
[ Upstream commit be73f4448b607e6b7ce41cd8ef2214fdf6e7986f ]
The pointer to root is initialized in btrfs_init_delayed_node(), no need
to check for it again. Change the BUG_ON to assertion.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit 778e618b8bfedcc39354373c1b072c5fe044fa7b ]
There's a BUG_ON checking for a valid pointer of fs_info::delayed_root
but it is valid since init_mount_fs_info() and has the same lifetime as
fs_info.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
commit 71537e35c324ea6fbd68377a4f26bb93a831ae35 upstream.
When running delayed inode updates, we do not record the inode's root in
the transaction, but we do allocate PREALLOC and thus converted PERTRANS
space for it. To be sure we free that PERTRANS meta rsv, we must ensure
that we record the root in the transaction.
Fixes: 4f5427ccce5d ("btrfs: delayed-inode: Use new qgroup meta rsv for delayed inode and item")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 9b378f6ad48cfa195ed868db9123c09ee7ec5ea2 upstream.
The readdir implementation currently processes always up to the last index
it finds. This however can result in an infinite loop if the directory has
a large number of entries such that they won't all fit in the given buffer
passed to the readdir callback, that is, dir_emit() returns a non-zero
value. Because in that case readdir() will be called again and if in the
meanwhile new directory entries were added and we still can't put all the
remaining entries in the buffer, we keep repeating this over and over.
The following C program and test script reproduce the problem:
$ cat /mnt/readdir_prog.c
#include <sys/types.h>
#include <dirent.h>
#include <stdio.h>
int main(int argc, char *argv[])
{
DIR *dir = opendir(".");
struct dirent *dd;
while ((dd = readdir(dir))) {
printf("%s\n", dd->d_name);
rename(dd->d_name, "TEMPFILE");
rename("TEMPFILE", dd->d_name);
}
closedir(dir);
}
$ gcc -o /mnt/readdir_prog /mnt/readdir_prog.c
$ cat test.sh
#!/bin/bash
DEV=/dev/sdi
MNT=/mnt/sdi
mkfs.btrfs -f $DEV &> /dev/null
#mkfs.xfs -f $DEV &> /dev/null
#mkfs.ext4 -F $DEV &> /dev/null
mount $DEV $MNT
mkdir $MNT/testdir
for ((i = 1; i <= 2000; i++)); do
echo -n > $MNT/testdir/file_$i
done
cd $MNT/testdir
/mnt/readdir_prog
cd /mnt
umount $MNT
This behaviour is surprising to applications and it's unlike ext4, xfs,
tmpfs, vfat and other filesystems, which always finish. In this case where
new entries were added due to renames, some file names may be reported
more than once, but this varies according to each filesystem - for example
ext4 never reported the same file more than once while xfs reports the
first 13 file names twice.
So change our readdir implementation to track the last index number when
opendir() is called and then make readdir() never process beyond that
index number. This gives the same behaviour as ext4.
Reported-by: Rob Landley <rob@landley.net>
Link: https://lore.kernel.org/linux-btrfs/2c8c55ec-04c6-e0dc-9c5c-8c7924778c35@landley.net/
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217681
CC: stable@vger.kernel.org # 5.15
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
[ Upstream commit a57c2d4e46f519b24558ae0752c17eec416ac72a ]
When removing a delayed item, or releasing which will remove it as well,
we will modify one of the delayed node's rbtrees and item counter if the
delayed item is in one of the rbtrees. This require having the delayed
node's mutex locked, otherwise we will race with other tasks modifying
the rbtrees and the counter.
This is motivated by a previous version of another patch actually calling
btrfs_release_delayed_item() after unlocking the delayed node's mutex and
against a delayed item that is in a rbtree.
So assert at __btrfs_remove_delayed_item() that the delayed node's mutex
is locked.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit 2c58c3931ede7cd08cbecf1f1a4acaf0a04a41a9 ]
Instead of calling BUG() when we fail to insert a delayed dir index item
into the delayed node's tree, we can just release all the resources we
have allocated/acquired before and return the error to the caller. This is
fine because all existing call chains undo anything they have done before
calling btrfs_insert_delayed_dir_index() or BUG_ON (when creating pending
snapshots in the transaction commit path).
So remove the BUG() call and do proper error handling.
This relates to a syzbot report linked below, but does not fix it because
it only prevents hitting a BUG(), it does not fix the issue where somehow
we attempt to use twice the same index number for different index items.
Link: https://lore.kernel.org/linux-btrfs/00000000000036e1290603e097e0@google.com/
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit 91bfe3104b8db0310f76f2dcb6aacef24c889366 ]
If we fail to add a delayed dir index item because there's already another
item with the same index number, we print an error message (and then BUG).
However that message isn't very helpful to debug anything because we don't
know what's the index number and what are the values of index counters in
the inode and its delayed inode (index_cnt fields of struct btrfs_inode
and struct btrfs_delayed_node).
So update the error message to include the index number and counters.
We actually had a recent case where this issue was hit by a syzbot report
(see the link below).
Link: https://lore.kernel.org/linux-btrfs/00000000000036e1290603e097e0@google.com/
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 2c58c3931ede ("btrfs: remove BUG() after failure to insert delayed dir index item")
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
delayed items
commit e110f8911ddb93e6f55da14ccbbe705397b30d0b upstream.
When running delayed items we are holding a delayed node's mutex and then
we will attempt to modify a subvolume btree to insert/update/delete the
delayed items. However if have an error during the insertions for example,
btrfs_insert_delayed_items() may return with a path that has locked extent
buffers (a leaf at the very least), and then we attempt to release the
delayed node at __btrfs_run_delayed_items(), which requires taking the
delayed node's mutex, causing an ABBA type of deadlock. This was reported
by syzbot and the lockdep splat is the following:
WARNING: possible circular locking dependency detected
6.5.0-rc7-syzkaller-00024-g93f5de5f648d #0 Not tainted
------------------------------------------------------
syz-executor.2/13257 is trying to acquire lock:
ffff88801835c0c0 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node+0x9a/0xaa0 fs/btrfs/delayed-inode.c:256
but task is already holding lock:
ffff88802a5ab8e8 (btrfs-tree-00){++++}-{3:3}, at: __btrfs_tree_lock+0x3c/0x2a0 fs/btrfs/locking.c:198
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (btrfs-tree-00){++++}-{3:3}:
__lock_release kernel/locking/lockdep.c:5475 [inline]
lock_release+0x36f/0x9d0 kernel/locking/lockdep.c:5781
up_write+0x79/0x580 kernel/locking/rwsem.c:1625
btrfs_tree_unlock_rw fs/btrfs/locking.h:189 [inline]
btrfs_unlock_up_safe+0x179/0x3b0 fs/btrfs/locking.c:239
search_leaf fs/btrfs/ctree.c:1986 [inline]
btrfs_search_slot+0x2511/0x2f80 fs/btrfs/ctree.c:2230
btrfs_insert_empty_items+0x9c/0x180 fs/btrfs/ctree.c:4376
btrfs_insert_delayed_item fs/btrfs/delayed-inode.c:746 [inline]
btrfs_insert_delayed_items fs/btrfs/delayed-inode.c:824 [inline]
__btrfs_commit_inode_delayed_items+0xd24/0x2410 fs/btrfs/delayed-inode.c:1111
__btrfs_run_delayed_items+0x1db/0x430 fs/btrfs/delayed-inode.c:1153
flush_space+0x269/0xe70 fs/btrfs/space-info.c:723
btrfs_async_reclaim_metadata_space+0x106/0x350 fs/btrfs/space-info.c:1078
process_one_work+0x92c/0x12c0 kernel/workqueue.c:2600
worker_thread+0xa63/0x1210 kernel/workqueue.c:2751
kthread+0x2b8/0x350 kernel/kthread.c:389
ret_from_fork+0x2e/0x60 arch/x86/kernel/process.c:145
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
-> #0 (&delayed_node->mutex){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3142 [inline]
check_prevs_add kernel/locking/lockdep.c:3261 [inline]
validate_chain kernel/locking/lockdep.c:3876 [inline]
__lock_acquire+0x39ff/0x7f70 kernel/locking/lockdep.c:5144
lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5761
__mutex_lock_common+0x1d8/0x2530 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x1b/0x20 kernel/locking/mutex.c:799
__btrfs_release_delayed_node+0x9a/0xaa0 fs/btrfs/delayed-inode.c:256
btrfs_release_delayed_node fs/btrfs/delayed-inode.c:281 [inline]
__btrfs_run_delayed_items+0x2b5/0x430 fs/btrfs/delayed-inode.c:1156
btrfs_commit_transaction+0x859/0x2ff0 fs/btrfs/transaction.c:2276
btrfs_sync_file+0xf56/0x1330 fs/btrfs/file.c:1988
vfs_fsync_range fs/sync.c:188 [inline]
vfs_fsync fs/sync.c:202 [inline]
do_fsync fs/sync.c:212 [inline]
__do_sys_fsync fs/sync.c:220 [inline]
__se_sys_fsync fs/sync.c:218 [inline]
__x64_sys_fsync+0x196/0x1e0 fs/sync.c:218
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(btrfs-tree-00);
lock(&delayed_node->mutex);
lock(btrfs-tree-00);
lock(&delayed_node->mutex);
*** DEADLOCK ***
3 locks held by syz-executor.2/13257:
#0: ffff88802c1ee370 (btrfs_trans_num_writers){++++}-{0:0}, at: spin_unlock include/linux/spinlock.h:391 [inline]
#0: ffff88802c1ee370 (btrfs_trans_num_writers){++++}-{0:0}, at: join_transaction+0xb87/0xe00 fs/btrfs/transaction.c:287
#1: ffff88802c1ee398 (btrfs_trans_num_extwriters){++++}-{0:0}, at: join_transaction+0xbb2/0xe00 fs/btrfs/transaction.c:288
#2: ffff88802a5ab8e8 (btrfs-tree-00){++++}-{3:3}, at: __btrfs_tree_lock+0x3c/0x2a0 fs/btrfs/locking.c:198
stack backtrace:
CPU: 0 PID: 13257 Comm: syz-executor.2 Not tainted 6.5.0-rc7-syzkaller-00024-g93f5de5f648d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
check_noncircular+0x375/0x4a0 kernel/locking/lockdep.c:2195
check_prev_add kernel/locking/lockdep.c:3142 [inline]
check_prevs_add kernel/locking/lockdep.c:3261 [inline]
validate_chain kernel/locking/lockdep.c:3876 [inline]
__lock_acquire+0x39ff/0x7f70 kernel/locking/lockdep.c:5144
lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5761
__mutex_lock_common+0x1d8/0x2530 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x1b/0x20 kernel/locking/mutex.c:799
__btrfs_release_delayed_node+0x9a/0xaa0 fs/btrfs/delayed-inode.c:256
btrfs_release_delayed_node fs/btrfs/delayed-inode.c:281 [inline]
__btrfs_run_delayed_items+0x2b5/0x430 fs/btrfs/delayed-inode.c:1156
btrfs_commit_transaction+0x859/0x2ff0 fs/btrfs/transaction.c:2276
btrfs_sync_file+0xf56/0x1330 fs/btrfs/file.c:1988
vfs_fsync_range fs/sync.c:188 [inline]
vfs_fsync fs/sync.c:202 [inline]
do_fsync fs/sync.c:212 [inline]
__do_sys_fsync fs/sync.c:220 [inline]
__se_sys_fsync fs/sync.c:218 [inline]
__x64_sys_fsync+0x196/0x1e0 fs/sync.c:218
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f3ad047cae9
Code: 28 00 00 00 75 (...)
RSP: 002b:00007f3ad12510c8 EFLAGS: 00000246 ORIG_RAX: 000000000000004a
RAX: ffffffffffffffda RBX: 00007f3ad059bf80 RCX: 00007f3ad047cae9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007f3ad04c847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f3ad059bf80 R15: 00007ffe56af92f8
</TASK>
------------[ cut here ]------------
Fix this by releasing the path before releasing the delayed node in the
error path at __btrfs_run_delayed_items().
Reported-by: syzbot+a379155f07c134ea9879@syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/000000000000abba27060403b5bd@google.com/
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
When logging a directory we start by flushing all its delayed items.
That results in adding dir index items to the subvolume btree, for new
dentries, and removing dir index items from the subvolume btree for any
dentries that were deleted.
This makes it straightforward to log a directory simply by iterating over
all the modified subvolume btree leaves, especially when we used to log
both dir index keys and dir item keys (before commit 339d035424849c
("btrfs: only copy dir index keys when logging a directory") and when we
used to copy old dir index entries for leaves modified in the current
transaction (before commit 732d591a5d6c12 ("btrfs: stop copying old dir
items when logging a directory")).
From an efficiency point of view this has a couple of drawbacks:
1) Adds extra latency, due to copying delayed items to the subvolume btree
and deleting dir index items from the btree.
Further if there are other tasks accessing the btree, which is common
(syscalls like creat, mkdir, rename, link, unlink, truncate, reflinks,
etc, finishing an ordered extent, etc), lock contention can cause
further delays, both to the task logging a directory and to the other
tasks accessing the btree;
2) More time spent overall flushing delayed items, if after logging the
directory further changes are done to the directory in the same
transaction.
For example, if we add 10 dentries to a directory, fsync it, add more
10 dentries, fsync it again, then add more 10 dentries and fsync it
again, then we end up inserting 3 batches of 10 items to the subvolume
btree. With the changes from this patch, we flush all the delayed items
to the btree only once - a single batch of 30 items, and outside the
logging code (transaction commit or when delayed items are flushed
asynchronously).
This change simply skips the flushing of delayed items every time we log a
directory. Instead we copy the delayed insertion items directly to the log
tree and delete delayed deletion items directly from the log tree.
Therefore avoiding changing first the subvolume btree and then scanning it
for new items to copy from it to the log tree and detecting deletions
by observing gaps in consecutive dir index keys in subvolume btree leaves.
Running the following tests on a non-debug kernel (Debian's default kernel
config), on a box with a NVMe device, a 12 cores Intel CPU and 64G of ram,
produced the results below.
The results compare a branch without this patch and all the other patches
it depends on versus the same branch with the patchset applied.
The patchset is comprised of the following patches:
btrfs: don't drop dir index range items when logging a directory
btrfs: remove the root argument from log_new_dir_dentries()
btrfs: update stale comment for log_new_dir_dentries()
btrfs: free list element sooner at log_new_dir_dentries()
btrfs: avoid memory allocation at log_new_dir_dentries() for common case
btrfs: remove root argument from btrfs_delayed_item_reserve_metadata()
btrfs: store index number instead of key in struct btrfs_delayed_item
btrfs: remove unused logic when looking up delayed items
btrfs: shrink the size of struct btrfs_delayed_item
btrfs: search for last logged dir index if it's not cached in the inode
btrfs: move need_log_inode() to above log_conflicting_inodes()
btrfs: move log_new_dir_dentries() above btrfs_log_inode()
btrfs: log conflicting inodes without holding log mutex of the initial inode
btrfs: skip logging parent dir when conflicting inode is not a dir
btrfs: use delayed items when logging a directory
Custom test script for testing time spent at btrfs_log_inode():
#!/bin/bash
DEV=/dev/nvme0n1
MNT=/mnt/nvme0n1
# Total number of files to create in the test directory.
NUM_FILES=10000
# Fsync after creating or renaming N files.
FSYNC_AFTER=100
umount $DEV &> /dev/null
mkfs.btrfs -f $DEV
mount -o ssd $DEV $MNT
TEST_DIR=$MNT/testdir
mkdir $TEST_DIR
echo "Creating files..."
for ((i = 1; i <= $NUM_FILES; i++)); do
echo -n > $TEST_DIR/file_$i
if (( ($i % $FSYNC_AFTER) == 0 )); then
xfs_io -c "fsync" $TEST_DIR
fi
done
sync
echo "Renaming files..."
for ((i = 1; i <= $NUM_FILES; i++)); do
mv $TEST_DIR/file_$i $TEST_DIR/file_$i.renamed
if (( ($i % $FSYNC_AFTER) == 0 )); then
xfs_io -c "fsync" $TEST_DIR
fi
done
umount $MNT
And using the following bpftrace script to capture the total time that is
spent at btrfs_log_inode():
#!/usr/bin/bpftrace
k:btrfs_log_inode
{
@start_log_inode[tid] = nsecs;
}
kr:btrfs_log_inode
/@start_log_inode[tid]/
{
$dur = (nsecs - @start_log_inode[tid]) / 1000;
@btrfs_log_inode_total_time = sum($dur);
delete(@start_log_inode[tid]);
}
END
{
clear(@start_log_inode);
}
Result before applying patchset:
@btrfs_log_inode_total_time: 622642
Result after applying patchset:
@btrfs_log_inode_total_time: 354134 (-43.1% time spent)
The following dbench script was also used for testing:
#!/bin/bash
NUM_JOBS=$(nproc --all)
DEV=/dev/nvme0n1
MNT=/mnt/nvme0n1
MOUNT_OPTIONS="-o ssd"
MKFS_OPTIONS="-O no-holes -R free-space-tree"
echo "performance" | \
tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
umount $DEV &> /dev/null
mkfs.btrfs -f $MKFS_OPTIONS $DEV
mount $MOUNT_OPTIONS $DEV $MNT
dbench -D $MNT --skip-cleanup -t 120 -S $NUM_JOBS
umount $MNT
Before patchset:
Operation Count AvgLat MaxLat
----------------------------------------
NTCreateX 3322265 0.034 21.032
Close 2440562 0.002 0.994
Rename 140664 1.150 269.633
Unlink 670796 1.093 269.678
Deltree 96 5.481 15.510
Mkdir 48 0.004 0.052
Qpathinfo 3010924 0.014 8.127
Qfileinfo 528055 0.001 0.518
Qfsinfo 552113 0.003 0.372
Sfileinfo 270575 0.005 0.688
Find 1164176 0.052 13.931
WriteX 1658537 0.019 5.918
ReadX 5207412 0.003 1.034
LockX 10818 0.003 0.079
UnlockX 10818 0.002 0.313
Flush 232811 1.027 269.735
Throughput 869.867 MB/sec (sync dirs) 12 clients 12 procs max_latency=269.741 ms
After patchset:
Operation Count AvgLat MaxLat
----------------------------------------
NTCreateX 4152738 0.029 20.863
Close 3050770 0.002 1.119
Rename 175829 0.871 211.741
Unlink 838447 0.845 211.724
Deltree 120 4.798 14.162
Mkdir 60 0.003 0.005
Qpathinfo 3763807 0.011 4.673
Qfileinfo 660111 0.001 0.400
Qfsinfo 690141 0.003 0.429
Sfileinfo 338260 0.005 0.725
Find 1455273 0.046 6.787
WriteX 2073307 0.017 5.690
ReadX 6509193 0.003 1.171
LockX 13522 0.003 0.077
UnlockX 13522 0.002 0.125
Flush 291044 0.811 211.631
Throughput 1089.27 MB/sec (sync dirs) 12 clients 12 procs max_latency=211.750 ms
(+25.2% throughput, -21.5% max latency)
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Currently struct btrfs_delayed_item has a base size of 96 bytes, but its
size can be decreased by doing the following 2 tweaks:
1) Change data_len from u32 to u16. Our maximum possible leaf size is 64K,
so the data_len can never be larger than that, and in fact it is always
much smaller than that. The max length for a dentry's name is ensured
at the VFS level (PATH_MAX, 4096 bytes) and in struct btrfs_inode_ref
and btrfs_dir_item we use a u16 to store the name's length;
2) Change 'ins_or_del' to a 1 bit enum, which is all we need since it
can only have 2 values. After this there's also no longer the need to
BUG_ON() before using 'ins_or_del' in several places. Also rename the
field from 'ins_or_del' to 'type', which is more clear.
These two tweaks decrease the size of struct btrfs_delayed_item from 96
bytes down to 88 bytes. A previous patch already reduced the size of this
structure by 16 bytes, but an upcoming change will increase its size by
16 bytes (adding a struct list_head element).
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
All callers pass NULL to the 'prev' and 'next' arguments of the function
__btrfs_lookup_delayed_item(), so remove these arguments. Also, remove
the unnecessary wrapper __btrfs_lookup_delayed_insertion_item(), making
btrfs_delete_delayed_insertion_item() directly call
__btrfs_lookup_delayed_item().
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
All delayed items are for dir index keys, so there's really no point of
having an embedded struct btrfs_key in struct btrfs_delayed_item, which
makes the structure use more space than necessary (and adds a hole of 7
bytes).
So replace the key field with an index number (u64), which reduces the
size of struct btrfs_delayed_item from 112 bytes down to 96 bytes.
Some upcoming work will increase the structure size by 16 bytes, so this
change compensates for that future size increase.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
The root argument of btrfs_delayed_item_reserve_metadata() is used only
to get the fs_info object, but we already have a transaction handle, which
we can use to get the fs_info. So remove the root argument.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
With Filipe's recent rework of the delayed inode code one aspect which
isn't batched is the release of the reserved metadata of delayed inode's
delete items. With this patch on top of Filipe's rework and running the
same test as provided in the description of a patch titled
"btrfs: improve batch deletion of delayed dir index items" I observe
the following change of the number of calls to btrfs_block_rsv_release:
Before this change:
- block_rsv_release: 1004
- btrfs_delete_delayed_items_total_time: 14602
- delete_batches: 505
After:
- block_rsv_release: 510
- btrfs_delete_delayed_items_total_time: 13643
- delete_batches: 507
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
While running generic/475 in a loop I got the following error
BTRFS critical (device dm-11): corrupt leaf: root=5 block=31096832 slot=69, bad key order, prev (263 96 531) current (263 96 524)
<snip>
item 65 key (263 96 517) itemoff 14132 itemsize 33
item 66 key (263 96 523) itemoff 14099 itemsize 33
item 67 key (263 96 525) itemoff 14066 itemsize 33
item 68 key (263 96 531) itemoff 14033 itemsize 33
item 69 key (263 96 524) itemoff 14000 itemsize 33
As you can see here we have 3 dir index keys with the dir index value of
523, 524, and 525 inserted between 517 and 524. This occurs because our
dir index insertion code will bulk insert all dir index items on the
node regardless of their actual key value.
This makes sense on a normally running system, because if there's a gap
in between the items there was a deletion before the item was inserted,
so there's not going to be an overlap of the dir index items that need
to be inserted and what exists on disk.
However during log replay this isn't necessarily true, we could have any
number of dir indexes in the tree already.
Fix this by seeing if we're replaying the log, and if we are simply skip
batching if there's a gap in the key space.
This file system was left broken from the fstest, I tested this patch
against the broken fs to make sure it replayed the log properly, and
then btrfs checked the file system after the log replay to verify
everything was ok.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Whenever we want to create a new dir index item (when creating an inode,
create a hard link, rename a file) we reserve 1 unit of metadata space
for it in a transaction (that's 256K for a node/leaf size of 16K), and
then create a delayed insertion item for it to be added later to the
subvolume's tree. That unit of metadata is kept until the delayed item
is inserted into the subvolume tree, which may take a while to happen
(in the worst case, it's done only when the transaction commits). If we
have multiple dir index items to insert for the same directory, say N
index items, and they all fit in a single leaf of metadata, then we are
holding N units of reserved metadata space when all we need is 1 unit.
This change addresses that, whenever a new delayed dir index item is
added, we release the unit of metadata the caller has reserved when it
started the transaction if adding that new dir index item does not
result in touching one more metadata leaf, otherwise the reservation
is kept by transferring it from the transaction block reserve to the
delayed items block reserve, just like before. Given that with a leaf
size of 16K we can have a few hundred dir index items in a single leaf
(the exact value depends on file name lengths), this reduces pressure on
metadata reservation by releasing unnecessary space much sooner.
The following fs_mark test showed some improvement when creating many
files in parallel on machine running a non debug kernel (debian's default
kernel config) with 12 cores:
$ cat test.sh
#!/bin/bash
DEV=/dev/nvme0n1
MNT=/mnt/nvme0n1
MOUNT_OPTIONS="-o ssd"
FILES=100000
THREADS=$(nproc --all)
echo "performance" | \
tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
mkfs.btrfs -f $DEV
mount $MOUNT_OPTIONS $DEV $MNT
OPTS="-S 0 -L 10 -n $FILES -s 0 -t $THREADS -k"
for ((i = 1; i <= $THREADS; i++)); do
OPTS="$OPTS -d $MNT/d$i"
done
fs_mark $OPTS
umount $MNT
Before:
FSUse% Count Size Files/sec App Overhead
2 1200000 0 225991.3 5465891
4 2400000 0 345728.1 5512106
4 3600000 0 346959.5 5557653
8 4800000 0 329643.0 5587548
8 6000000 0 312657.4 5606717
8 7200000 0 281707.5 5727985
12 8400000 0 88309.8 5020422
12 9600000 0 85835.9 5207496
16 10800000 0 81039.2 5404964
16 12000000 0 58548.6 5842468
After:
FSUse% Count Size Files/sec App Overhead
2 1200000 0 230604.5 5778375
4 2400000 0 348908.3 5508072
4 3600000 0 357028.7 5484337
6 4800000 0 342898.3 5565703
6 6000000 0 314670.8 5751555
8 7200000 0 282548.2 5778177
12 8400000 0 90844.9 5306819
12 9600000 0 86963.1 5304689
16 10800000 0 89113.2 5455248
16 12000000 0 86693.5 5518933
The "after" results are after applying this patch and all the other
patches in the same patchset, which is comprised of the following
changes:
btrfs: balance btree dirty pages and delayed items after a rename
btrfs: free the path earlier when creating a new inode
btrfs: balance btree dirty pages and delayed items after clone and dedupe
btrfs: add assertions when deleting batches of delayed items
btrfs: deal with deletion errors when deleting delayed items
btrfs: refactor the delayed item deletion entry point
btrfs: improve batch deletion of delayed dir index items
btrfs: assert that delayed item is a dir index item when adding it
btrfs: improve batch insertion of delayed dir index items
btrfs: do not BUG_ON() on failure to reserve metadata for delayed item
btrfs: set delayed item type when initializing it
btrfs: reduce amount of reserved metadata for delayed item insertion
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Currently we set the type of a delayed item only after successfully
inserting it into its respective rbtree. This is fine, as the type
is not used anywhere before that point, but for the next patch in the
series, there will be the need to check the type of a delayed item
before inserting it into a rbtree.
So set the type of a delayed item immediately after allocating it.
This also makes the trivial wrappers for adding insertion and deletion
useless, so it removes them as well.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
At btrfs_insert_delayed_dir_index(), we don't expect the metadata
reservation for the delayed dir index item insertion to fail, because the
caller is supposed to have reserved 1 unit of metadata space for that.
All callers are able to deal with an error in case that happens, so there
is no need for something so drastic as a BUG_ON() in case of failure.
Instead just emit a warning, so that's easily noticed during development
(fstests in particular), and return the error to the caller.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Currently we group delayed dir index items for insertion as a single batch
(a single btree operation) as long as their keys are sequential in the key
space.
For example we have delayed index items for the following index keys:
10, 11, 12, 15, 16, 20, 21
We end up building three batches:
1) First one for index keys 10, 11 and 12;
2) Second one for index keys 15 and 16;
3) Third one for index keys 20 and 21.
However, since the dir index numbers come from a monotonically increasing
counter and are never reused, we could group all these items into a single
batch. The existence of holes in the sequence happens only when we had
delayed dir index items for insertion that got deleted before they were
flushed to the subvolume's tree.
The delayed items are stored in a rbtree based on their key order, so
we can just group items into a batch as long as they all fit in a leaf,
and ignore if there's a gap (key offset, index number) between two
consecutive items. This is more efficient and reduces the amount of
time spent when running delayed items if there are gaps between dir
index items.
For example running the following test script:
$ cat test.sh
#!/bin/bash
DEV=/dev/sdj
MNT=/mnt/sdj
mkfs.btrfs -f $DEV
mount $DEV $MNT
NUM_FILES=100
mkdir $MNT/testdir
for ((i = 1; i <= $NUM_FILES; i++)); do
echo -n > $MNT/testdir/file_$i
done
# Now delete every other file, to create gaps in the dir index keys.
for ((i = 1; i <= $NUM_FILES; i += 2)); do
rm -f $MNT/testdir/file_$i
done
start=$(date +%s%N)
sync
end=$(date +%s%N)
dur=$(( (end - start) / 1000000 ))
echo -e "\nsync took $dur milliseconds"
umount $MNT
While having the following bpftrace script running in another shell:
$ cat bpf-delayed-items-inserts.sh
#!/usr/bin/bpftrace
/* Must add 'noinline' to btrfs_insert_delayed_items(). */
k:btrfs_insert_delayed_items
{
@start_insert_delayed_items[tid] = nsecs;
}
k:btrfs_insert_empty_items
/@start_insert_delayed_items[tid]/
{
@insert_batches = count();
}
kr:btrfs_insert_delayed_items
/@start_insert_delayed_items[tid]/
{
$dur = (nsecs - @start_insert_delayed_items[tid]) / 1000;
@btrfs_insert_delayed_items_total_time = sum($dur);
delete(@start_insert_delayed_items[tid]);
}
Before this change:
@btrfs_insert_delayed_items_total_time: 576
@insert_batches: 51
After this change:
@btrfs_insert_delayed_items_total_time: 174
@insert_batches: 2
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
All delayed items are for dir index items, we don't support any other item
types at the moment. So simplify __btrfs_add_delayed_item() and add an
assertion for checking the item's key type. This also allows the next
change to be simpler and avoid to check key types. In case we add support
for different item types in the future, then we'll hit the assertion
during development and be able to adjust any code that is assuming delayed
items are always associated to dir index items.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Currently we group delayed dir index items for deletion in a single batch
(single btree operation) as long as they all exist in the same leaf and as
long as their keys are sequential in the key space. For example if we have
a leaf that has dir index items with offsets:
2, 3, 4, 6, 7, 10
And we have delayed dir index items for deleting all these indexes, and
no delayed items for any other index keys in between, then we end up
deleting in 3 batches:
1) First batch for indexes 2, 3 and 4;
2) Second batch for indexes 6 and 7;
3) Third batch for index 10.
This is a waste because we can delete all the index keys in a single
batch. What matters is that each consecutive delayed index key matches
each consecutive dir index key in a leaf.
So update the logic at btrfs_batch_delete_items() to check only for a
key match between delayed dir index items and dir index items in a leaf.
Also avoid the useless first iteration on comparing the key of the
first slot to delete with the key of the first delayed item, as it's
silly since they always match, as the delayed item's key was used for
the btree search that gave us the path we have.
This is more efficient and reduces runtime of running delayed items, as
well as lock contention on the subvolume's tree.
For example, the following test script:
$ cat test.sh
#!/bin/bash
DEV=/dev/sdj
MNT=/mnt/sdj
mkfs.btrfs -f $DEV
mount $DEV $MNT
NUM_FILES=1000
mkdir $MNT/testdir
for ((i = 1; i <= $NUM_FILES; i++)); do
echo -n > $MNT/testdir/file_$i
done
# Now delete every other file, to create gaps in the dir index keys.
for ((i = 1; i <= $NUM_FILES; i += 2)); do
rm -f $MNT/testdir/file_$i
done
# Sync to force any delayed items to be flushed to the tree.
sync
start=$(date +%s%N)
rm -fr $MNT/testdir
end=$(date +%s%N)
dur=$(( (end - start) / 1000000 ))
echo -e "\nrm -fr took $dur milliseconds"
umount $MNT
Running that test script while having the following bpftrace script
running in another shell:
$ cat bpf-measure.sh
#!/usr/bin/bpftrace
/* Add 'noinline' to btrfs_delete_delayed_items()'s definition. */
k:btrfs_delete_delayed_items
{
@start_delete_delayed_items[tid] = nsecs;
}
k:btrfs_del_items
/@start_delete_delayed_items[tid]/
{
@delete_batches = count();
}
kr:btrfs_delete_delayed_items
/@start_delete_delayed_items[tid]/
{
$dur = (nsecs - @start_delete_delayed_items[tid]) / 1000;
@btrfs_delete_delayed_items_total_time = sum($dur);
delete(@start_delete_delayed_items[tid]);
}
Before this change:
@btrfs_delete_delayed_items_total_time: 9563
@delete_batches: 1001
After this change:
@btrfs_delete_delayed_items_total_time: 7328
@delete_batches: 509
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
The delayed item deletion entry point, btrfs_delete_delayed_items(), is a
bit convoluted for a few reasons:
1) It's really a loop disguised with labels and goto statements;
2) There's a 'delete_fail' label which isn't only for error cases, we can
jump to that label even if no error happened, if we simply don't have
more delayed items to delete;
3) Unnecessarily keeps track of the current and previous items for no
good reason, as after getting the next item and releasing the current
one, it just jumps to the 'again' label just to look again for the
first delayed item;
4) When a delayed item is not in the tree (because it was already deleted
before), it releases the item while holding a path locked, which is
not necessary and adds more contention to the tree, specially taking
into account that the path came from a deletion search, meaning we have
write locks for nodes at levels 2, 1 and 0. And releasing the item is
not computationally trivial (rb tree deletion, a kfree() and some
trivial things).
So refactor it to use a while loop and add some comments to make it more
obvious why we can have delayed items without a matching item in the tree
as well as why not keep the delayed node locked all the time when running
all its deletion items. This is also a preparation for some upcoming work
involving delayed items.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Currently, btrfs_delete_delayed_items() ignores any errors returned from
btrfs_batch_delete_items(). This looks fishy but it's not a problem at
the moment because:
1) Two of the errors returned from btrfs_batch_delete_items() are for
impossible cases, cases where a delayed item does not match any item
in the leaf the path points to - btrfs_delete_delayed_items() always
calls btrfs_batch_delete_items() with a path that points to a leaf
that contains an item matching a delayed item;
2) btrfs_batch_delete_items() may return an error from btrfs_del_items(),
in which case it does not release the delayed items of the batch.
At the moment this is harmless because btrfs_del_items() actually is
always able to delete items, even if it returns an error - when it
returns an error it's because it ended up with a leaf mostly empty
(less than 1/3 full) and failed to migrate items from that leaf into
its neighbour leaves - this is not critical, as all the items were
deleted, we just left the tree a bit unbalanced, but it's still a
valid tree and causes no harm, and future operations on the tree will
eventually balance it.
So even if we get an error from btrfs_del_items(), the delayed items
will not be released but the next time we run delayed items we will
find out, at btrfs_delete_delayed_items(), that they are not present
in the tree anymore and then release them.
This is all a bit subtle, and it's certainly prone to be a disaster in
case btrfs_del_items() changes one day and may return errors before being
able to delete all the requested items, in which case we could leave the
filesystem in an inconsistent state as we would commit a transaction
despite a failure from deleting items from the tree.
So make btrfs_delete_delayed_items() check for any errors from the call
to btrfs_batch_delete_items().
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
There are a few impossible cases that btrfs_batch_delete_items() tries to
deal with:
1) Getting a path pointing to a NULL leaf;
2) The leaf slot is pointing beyond the last item in the leaf;
3) We can't find a single item to delete.
The first case is impossible because the given path was returned by a
successful call to btrfs_search_slot(). Replace the BUG_ON() with an
ASSERT for this.
The second case is impossible because we are always called when a delayed
item matches an item in the given leaf. So add an ASSERT() for that and
if that condition is not satisfied, trigger a warning and return an error.
The third case is impossible exactly because of the same reason as the
second case. The given delayed item matches one item in the leaf, so we
know that our batch always has at least one item. Add an ASSERT to check
that, trigger a warning if that expectation fails and return an error.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
This reverts commit 253bf57555e451dec5a7f09dc95d380ce8b10e5b.
Revert the xarray conversion, there's a problem with potential
sleep-inside-spinlock [1] when calling xa_insert that triggers GFP_NOFS
allocation. The radix tree used the preloading mechanism to avoid
sleeping but this is not available in xarray.
Conversion from spin lock to mutex is possible but at time of rc6 is
riskier than a clean revert.
[1] https://lore.kernel.org/linux-btrfs/cover.1657097693.git.fdmanana@suse.com/
Reported-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
… in the btrfs_root struct and adjust all usages of this object to use
the XArray API, because it is notionally easier to use and understand,
as it provides array semantics, and also takes care of locking for us,
further simplifying the code.
Also use the opportunity to do some light refactoring.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Gabriel Niebler <gniebler@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
We have a few helpers in inode-item.c, and I'm going to make a few
changes to how we do truncate in the future, so break out these
definitions into their own header file to trim down ctree.h some and
make it easier to do the work on truncate in the future.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
We used to need the root for btrfs_reserve_metadata_bytes to check the
orphan cleanup state, but we no longer need that, we simply need the
fs_info. Change btrfs_reserve_metadata_bytes() to use the fs_info, and
change both btrfs_block_rsv_refill() and btrfs_block_rsv_add() to do the
same as they simply call btrfs_reserve_metadata_bytes() and then
manipulate the block_rsv that is being used.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
When inserting a batch of items into a btree, we end up looping over the
data sizes array 3 times:
1) Once in the caller of btrfs_insert_empty_items(), when it populates the
array with the data sizes for each item;
2) Once at btrfs_insert_empty_items() to sum the elements of the data
sizes array and compute the total data size;
3) And then once again at setup_items_for_insert(), where we do exactly
the same as what we do at btrfs_insert_empty_items(), to compute the
total data size.
That is not bad for small arrays, but when the arrays have hundreds of
elements, the time spent on looping is not negligible. For example when
doing batch inserts of delayed items for dir index items or when logging
a directory, it's common to have 200 to 260 dir index items in a single
batch when using a leaf size of 16K and using file names between 8 and 12
characters. For a 64K leaf size, multiply that by 4. Taking into account
that during directory logging or when flushing delayed dir index items we
can have many of those large batches, the time spent on the looping adds
up quickly.
It's also more important to avoid it at setup_items_for_insert(), since
we are holding a write lock on a leaf and, in some cases, on upper nodes
of the btree, which causes us to block other tasks that |
