| Message ID | 20181129093132.25147-1-lufq.fnst@cn.fujitsu.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | btrfs: skip file_extent generation check for free_space_inode in run_delalloc_nocow | expand |
On Thu, Nov 29, 2018 at 9:32 AM Lu Fengqi <lufq.fnst@cn.fujitsu.com> wrote: > > The btrfs/001 with inode_cache mount option will encounter the following > warning: "The test case btrfs/001 ..." > > WARNING: CPU: 1 PID: 23700 at fs/btrfs/inode.c:956 cow_file_range.isra.19+0x32b/0x430 [btrfs] > CPU: 1 PID: 23700 Comm: btrfs Kdump: loaded Tainted: G W O 4.20.0-rc4-custom+ #30 > Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 > RIP: 0010:cow_file_range.isra.19+0x32b/0x430 [btrfs] > Call Trace: > ? free_extent_buffer+0x46/0x90 [btrfs] > run_delalloc_nocow+0x455/0x900 [btrfs] > btrfs_run_delalloc_range+0x1a7/0x360 [btrfs] > writepage_delalloc+0xf9/0x150 [btrfs] > __extent_writepage+0x125/0x3e0 [btrfs] > extent_write_cache_pages+0x1b6/0x3e0 [btrfs] > ? __wake_up_common_lock+0x63/0xc0 > extent_writepages+0x50/0x80 [btrfs] > do_writepages+0x41/0xd0 > ? __filemap_fdatawrite_range+0x9e/0xf0 > __filemap_fdatawrite_range+0xbe/0xf0 > btrfs_fdatawrite_range+0x1b/0x50 [btrfs] > __btrfs_write_out_cache+0x42c/0x480 [btrfs] > btrfs_write_out_ino_cache+0x84/0xd0 [btrfs] > btrfs_save_ino_cache+0x551/0x660 [btrfs] > commit_fs_roots+0xc5/0x190 [btrfs] > btrfs_commit_transaction+0x2bf/0x8d0 [btrfs] > btrfs_mksubvol+0x48d/0x4d0 [btrfs] > btrfs_ioctl_snap_create_transid+0x170/0x180 [btrfs] > btrfs_ioctl_snap_create_v2+0x124/0x180 [btrfs] > btrfs_ioctl+0x123f/0x3030 [btrfs] > > The file extent generation of the free space inode is equal to the last > snapshot of the file root, so the inode will be passed to cow_file_rage. > But the inode was created and its extents were preallocated in > btrfs_save_ino_cache, there are no cow copies on disk. > > The preallocated extents don't present on disk, and the The preallocated extent is not yet in the extent tree, and the ... (singular, it's only used for each space cache) > btrfs_cross_ref_exist will ignore the -ENOENT returned by > check_committed_ref, so we can directly write the inode to the disk. > > Fixes: 78d4295b1eee ("btrfs: lift some btrfs_cross_ref_exist checks in nocow path") > Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com> The code changes look good to me. Reviewed-by: Filipe Manana <fdmanana@suse.com> Thanks. > --- > fs/btrfs/inode.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c > index d54bdef16d8d..9c5e9629eb6c 100644 > --- a/fs/btrfs/inode.c > +++ b/fs/btrfs/inode.c > @@ -1369,7 +1369,8 @@ static noinline int run_delalloc_nocow(struct inode *inode, > * Do the same check as in btrfs_cross_ref_exist but > * without the unnecessary search. > */ > - if (btrfs_file_extent_generation(leaf, fi) <= > + if (!nolock && > + btrfs_file_extent_generation(leaf, fi) <= > btrfs_root_last_snapshot(&root->root_item)) > goto out_check; > if (extent_type == BTRFS_FILE_EXTENT_REG && !force) > -- > 2.19.2 > > >
On Thu, Nov 29, 2018 at 05:31:32PM +0800, Lu Fengqi wrote: > The btrfs/001 with inode_cache mount option will encounter the following > warning: > > WARNING: CPU: 1 PID: 23700 at fs/btrfs/inode.c:956 cow_file_range.isra.19+0x32b/0x430 [btrfs] > CPU: 1 PID: 23700 Comm: btrfs Kdump: loaded Tainted: G W O 4.20.0-rc4-custom+ #30 > Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 > RIP: 0010:cow_file_range.isra.19+0x32b/0x430 [btrfs] > Call Trace: > ? free_extent_buffer+0x46/0x90 [btrfs] > run_delalloc_nocow+0x455/0x900 [btrfs] > btrfs_run_delalloc_range+0x1a7/0x360 [btrfs] > writepage_delalloc+0xf9/0x150 [btrfs] > __extent_writepage+0x125/0x3e0 [btrfs] > extent_write_cache_pages+0x1b6/0x3e0 [btrfs] > ? __wake_up_common_lock+0x63/0xc0 > extent_writepages+0x50/0x80 [btrfs] > do_writepages+0x41/0xd0 > ? __filemap_fdatawrite_range+0x9e/0xf0 > __filemap_fdatawrite_range+0xbe/0xf0 > btrfs_fdatawrite_range+0x1b/0x50 [btrfs] > __btrfs_write_out_cache+0x42c/0x480 [btrfs] > btrfs_write_out_ino_cache+0x84/0xd0 [btrfs] > btrfs_save_ino_cache+0x551/0x660 [btrfs] > commit_fs_roots+0xc5/0x190 [btrfs] > btrfs_commit_transaction+0x2bf/0x8d0 [btrfs] > btrfs_mksubvol+0x48d/0x4d0 [btrfs] > btrfs_ioctl_snap_create_transid+0x170/0x180 [btrfs] > btrfs_ioctl_snap_create_v2+0x124/0x180 [btrfs] > btrfs_ioctl+0x123f/0x3030 [btrfs] > > The file extent generation of the free space inode is equal to the last > snapshot of the file root, so the inode will be passed to cow_file_rage. > But the inode was created and its extents were preallocated in > btrfs_save_ino_cache, there are no cow copies on disk. > > The preallocated extents don't present on disk, and the > btrfs_cross_ref_exist will ignore the -ENOENT returned by > check_committed_ref, so we can directly write the inode to the disk. > > Fixes: 78d4295b1eee ("btrfs: lift some btrfs_cross_ref_exist checks in nocow path") > Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com> With updated changelog and reviewed-by added to misc-next, thanks.
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index d54bdef16d8d..9c5e9629eb6c 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -1369,7 +1369,8 @@ static noinline int run_delalloc_nocow(struct inode *inode, * Do the same check as in btrfs_cross_ref_exist but * without the unnecessary search. */ - if (btrfs_file_extent_generation(leaf, fi) <= + if (!nolock && + btrfs_file_extent_generation(leaf, fi) <= btrfs_root_last_snapshot(&root->root_item)) goto out_check; if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
The btrfs/001 with inode_cache mount option will encounter the following warning: WARNING: CPU: 1 PID: 23700 at fs/btrfs/inode.c:956 cow_file_range.isra.19+0x32b/0x430 [btrfs] CPU: 1 PID: 23700 Comm: btrfs Kdump: loaded Tainted: G W O 4.20.0-rc4-custom+ #30 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:cow_file_range.isra.19+0x32b/0x430 [btrfs] Call Trace: ? free_extent_buffer+0x46/0x90 [btrfs] run_delalloc_nocow+0x455/0x900 [btrfs] btrfs_run_delalloc_range+0x1a7/0x360 [btrfs] writepage_delalloc+0xf9/0x150 [btrfs] __extent_writepage+0x125/0x3e0 [btrfs] extent_write_cache_pages+0x1b6/0x3e0 [btrfs] ? __wake_up_common_lock+0x63/0xc0 extent_writepages+0x50/0x80 [btrfs] do_writepages+0x41/0xd0 ? __filemap_fdatawrite_range+0x9e/0xf0 __filemap_fdatawrite_range+0xbe/0xf0 btrfs_fdatawrite_range+0x1b/0x50 [btrfs] __btrfs_write_out_cache+0x42c/0x480 [btrfs] btrfs_write_out_ino_cache+0x84/0xd0 [btrfs] btrfs_save_ino_cache+0x551/0x660 [btrfs] commit_fs_roots+0xc5/0x190 [btrfs] btrfs_commit_transaction+0x2bf/0x8d0 [btrfs] btrfs_mksubvol+0x48d/0x4d0 [btrfs] btrfs_ioctl_snap_create_transid+0x170/0x180 [btrfs] btrfs_ioctl_snap_create_v2+0x124/0x180 [btrfs] btrfs_ioctl+0x123f/0x3030 [btrfs] The file extent generation of the free space inode is equal to the last snapshot of the file root, so the inode will be passed to cow_file_rage. But the inode was created and its extents were preallocated in btrfs_save_ino_cache, there are no cow copies on disk. The preallocated extents don't present on disk, and the btrfs_cross_ref_exist will ignore the -ENOENT returned by check_committed_ref, so we can directly write the inode to the disk. Fixes: 78d4295b1eee ("btrfs: lift some btrfs_cross_ref_exist checks in nocow path") Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com> --- fs/btrfs/inode.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)