======================================================
WARNING: possible circular locking dependency detected
4.18.0-rc4-xfstests-00025-g5de5edbaf1d4 #411 Not tainted
------------------------------------------------------
aio-dio-invalid/30928 is trying to acquire lock:
0000000092621cfd (&mm->mmap_sem){++++}, at: get_user_pages_unlocked+0x5a/0x1e0
but task is already holding lock:
00000000cefe6b35 (&ei->dio_sem){++++}, at: btrfs_direct_IO+0x3be/0x400
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #5 (&ei->dio_sem){++++}:
lock_acquire+0xbd/0x220
down_write+0x51/0xb0
btrfs_log_changed_extents+0x80/0xa40
btrfs_log_inode+0xbaf/0x1000
btrfs_log_inode_parent+0x26f/0xa80
btrfs_log_dentry_safe+0x50/0x70
btrfs_sync_file+0x357/0x540
do_fsync+0x38/0x60
__ia32_sys_fdatasync+0x12/0x20
do_fast_syscall_32+0x9a/0x2f0
entry_SYSENTER_compat+0x84/0x96
-> #4 (&ei->log_mutex){+.+.}:
lock_acquire+0xbd/0x220
__mutex_lock+0x86/0xa10
btrfs_record_unlink_dir+0x2a/0xa0
btrfs_unlink+0x5a/0xc0
vfs_unlink+0xb1/0x1a0
do_unlinkat+0x264/0x2b0
do_fast_syscall_32+0x9a/0x2f0
entry_SYSENTER_compat+0x84/0x96
-> #3 (sb_internal#2){.+.+}:
lock_acquire+0xbd/0x220
__sb_start_write+0x14d/0x230
start_transaction+0x3e6/0x590
btrfs_evict_inode+0x475/0x640
evict+0xbf/0x1b0
btrfs_run_delayed_iputs+0x6c/0x90
cleaner_kthread+0x124/0x1a0
kthread+0x106/0x140
ret_from_fork+0x3a/0x50
-> #2 (&fs_info->cleaner_delayed_iput_mutex){+.+.}:
lock_acquire+0xbd/0x220
__mutex_lock+0x86/0xa10
btrfs_alloc_data_chunk_ondemand+0x197/0x530
btrfs_check_data_free_space+0x4c/0x90
btrfs_delalloc_reserve_space+0x20/0x60
btrfs_page_mkwrite+0x87/0x520
do_page_mkwrite+0x31/0xa0
__handle_mm_fault+0x799/0xb00
handle_mm_fault+0x7c/0xe0
__do_page_fault+0x1d3/0x4a0
async_page_fault+0x1e/0x30
-> #1 (sb_pagefaults){.+.+}:
lock_acquire+0xbd/0x220
__sb_start_write+0x14d/0x230
btrfs_page_mkwrite+0x6a/0x520
do_page_mkwrite+0x31/0xa0
__handle_mm_fault+0x799/0xb00
handle_mm_fault+0x7c/0xe0
__do_page_fault+0x1d3/0x4a0
async_page_fault+0x1e/0x30
-> #0 (&mm->mmap_sem){++++}:
__lock_acquire+0x42e/0x7a0
lock_acquire+0xbd/0x220
down_read+0x48/0xb0
get_user_pages_unlocked+0x5a/0x1e0
get_user_pages_fast+0xa4/0x150
iov_iter_get_pages+0xc3/0x340
do_direct_IO+0xf93/0x1d70
__blockdev_direct_IO+0x32d/0x1c20
btrfs_direct_IO+0x227/0x400
generic_file_direct_write+0xcf/0x180
btrfs_file_write_iter+0x308/0x58c
aio_write+0xf8/0x1d0
io_submit_one+0x3a9/0x620
__ia32_compat_sys_io_submit+0xb2/0x270
do_int80_syscall_32+0x5b/0x1a0
entry_INT80_compat+0x88/0xa0
other info that might help us debug this:
Chain exists of:
&mm->mmap_sem --> &ei->log_mutex --> &ei->dio_sem
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&ei->dio_sem);
lock(&ei->log_mutex);
lock(&ei->dio_sem);
lock(&mm->mmap_sem);
*** DEADLOCK ***
1 lock held by aio-dio-invalid/30928:
#0: 00000000cefe6b35 (&ei->dio_sem){++++}, at: btrfs_direct_IO+0x3be/0x400
stack backtrace:
CPU: 0 PID: 30928 Comm: aio-dio-invalid Not tainted 4.18.0-rc4-xfstests-00025-g5de5edbaf1d4 #411
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014
Call Trace:
dump_stack+0x7c/0xbb
print_circular_bug.isra.37+0x297/0x2a4
check_prev_add.constprop.45+0x781/0x7a0
? __lock_acquire+0x42e/0x7a0
validate_chain.isra.41+0x7f0/0xb00
__lock_acquire+0x42e/0x7a0
lock_acquire+0xbd/0x220
? get_user_pages_unlocked+0x5a/0x1e0
down_read+0x48/0xb0
? get_user_pages_unlocked+0x5a/0x1e0
get_user_pages_unlocked+0x5a/0x1e0
get_user_pages_fast+0xa4/0x150
iov_iter_get_pages+0xc3/0x340
do_direct_IO+0xf93/0x1d70
? __alloc_workqueue_key+0x358/0x490
? __blockdev_direct_IO+0x14b/0x1c20
__blockdev_direct_IO+0x32d/0x1c20
? btrfs_run_delalloc_work+0x40/0x40
? can_nocow_extent+0x490/0x490
? kvm_clock_read+0x1f/0x30
? can_nocow_extent+0x490/0x490
? btrfs_run_delalloc_work+0x40/0x40
btrfs_direct_IO+0x227/0x400
? btrfs_run_delalloc_work+0x40/0x40
generic_file_direct_write+0xcf/0x180
btrfs_file_write_iter+0x308/0x58c
aio_write+0xf8/0x1d0
? kvm_clock_read+0x1f/0x30
? __might_fault+0x3e/0x90
io_submit_one+0x3a9/0x620
? io_submit_one+0xe5/0x620
__ia32_compat_sys_io_submit+0xb2/0x270
do_int80_syscall_32+0x5b/0x1a0
entry_INT80_compat+0x88/0xa0
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
---
fs/btrfs/file.c | 12 ++++++++++++
fs/btrfs/tree-log.c | 2 --
2 files changed, 12 insertions(+), 2 deletions(-)
@@ -2079,6 +2079,14 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
goto out;
inode_lock(inode);
+
+ /*
+ * We take the dio_sem here because the tree log stuff can race with
+ * lockless dio writes and get an extent map logged for an extent we
+ * never waited on. We need it this high up for lockdep reasons.
+ */
+ down_write(&BTRFS_I(inode)->dio_sem);
+
atomic_inc(&root->log_batch);
/*
@@ -2087,6 +2095,7 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
*/
ret = btrfs_wait_ordered_range(inode, start, len);
if (ret) {
+ up_write(&BTRFS_I(inode)->dio_sem);
inode_unlock(inode);
goto out;
}
@@ -2110,6 +2119,7 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
* checked called fsync.
*/
ret = filemap_check_wb_err(inode->i_mapping, file->f_wb_err);
+ up_write(&BTRFS_I(inode)->dio_sem);
inode_unlock(inode);
goto out;
}
@@ -2128,6 +2138,7 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
trans = btrfs_start_transaction(root, 0);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
+ up_write(&BTRFS_I(inode)->dio_sem);
inode_unlock(inode);
goto out;
}
@@ -2149,6 +2160,7 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
* file again, but that will end up using the synchronization
* inside btrfs_sync_log to keep things safe.
*/
+ up_write(&BTRFS_I(inode)->dio_sem);
inode_unlock(inode);
/*
@@ -4374,7 +4374,6 @@ static int btrfs_log_changed_extents(struct btrfs_trans_handle *trans,
INIT_LIST_HEAD(&extents);
- down_write(&inode->dio_sem);
write_lock(&tree->lock);
test_gen = root->fs_info->last_trans_committed;
logged_start = start;
@@ -4440,7 +4439,6 @@ static int btrfs_log_changed_extents(struct btrfs_trans_handle *trans,
}
WARN_ON(!list_empty(&extents));
write_unlock(&tree->lock);
- up_write(&inode->dio_sem);
btrfs_release_path(path);
if (!ret)