linux/fs
Qu Wenruo 112974d406 btrfs: volumes: Remove ENOSPC-prone btrfs_can_relocate()
[BUG]
Test case btrfs/156 fails since commit 302167c50b ("btrfs: don't end
the transaction for delayed refs in throttle") with ENOSPC.

[CAUSE]
The ENOSPC is reported from btrfs_can_relocate().

This function will check:
- If this block group is empty, we can relocate
- If we can enough free space, we can relocate

Above checks are valid but the following check is vague due to its
implementation:
- If and only if we can allocated a new block group to contain all the
  used space, we can relocate

This design itself is OK, but the way to determine if we can allocate a
new block group is problematic.

btrfs_can_relocate() uses find_free_dev_extent() to find free space on a
device.
However find_free_dev_extent() only searches commit root and excludes
dev extents allocated in current trans, this makes it unable to use dev
extent just freed in current transaction.

So for the following example, btrfs_can_relocate() will report ENOSPC:
The example block group layout:
1M      129M        257M       385M      513M       550M
|///////|///////////|//////////|         |          |
// = Used bg, consider all bg is 100% used for easy calculation.
And all block groups are SINGLE, on-disk bytenr is the same as the
logical bytenr.

1) Bg in [129M, 257M) get relocated to [385M, 513M), transid=100
1M      129M        257M       385M      513M       550M
|///////|           |//////////|/////////|
In transid 100, bg in [129M, 257M) get relocated to [385M, 513M)

However transid 100 is not committed yet, so in dev commit tree, we
still have the old dev extents layout:
1M      129M        257M       385M      513M       550M
|///////|///////////|//////////|         |          |

2) Try to relocate bg [257M, 385M)
We goes into btrfs_can_relocate(), no free space in current bgs, so we
check if we can find large enough free dev extents.

The first slot is [385M, 513M), but that is already used by new bg at
[385M, 513M), so we continue search.

The remaining slot is [512M, 550M), smaller than the bg's length 128M.
So btrfs_can_relocate report ENOSPC.

However this is over killed, in fact if we just skip btrfs_can_relocate()
check, and go into regular relocation routine, at extent reservation time,
if we can't find free extent, then we fallback to commit transaction,
which will free up the dev extents and allow new block group to be created.

[FIX]
The fix here is to remove btrfs_can_relocate() completely.

If we hit the false ENOSPC case just like btrfs/156, extent allocator
will push harder by committing transaction and we will have space for
new block group, avoiding the false ENOSPC.

If we really ran out of space, we will hit ENOSPC at
relocate_block_group(), and btrfs will just reports the ENOSPC error as
usual.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09 14:59:01 +02:00
..
9p 9p: pass the correct prototype to read_cache_page 2019-07-12 11:05:43 -07:00
adfs Merge branch 'work.adfs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 11:33:22 -07:00
affs treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
afs afs: use correct afs_call_type in yfs_fs_store_opaque_acl2 2019-08-22 13:33:27 +01:00
autofs treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 83 2019-05-24 17:37:52 +02:00
befs treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
bfs treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
btrfs btrfs: volumes: Remove ENOSPC-prone btrfs_can_relocate() 2019-09-09 14:59:01 +02:00
cachefiles treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
ceph ceph: don't try fill file_lock on unsuccessful GETFILELOCK reply 2019-08-22 10:47:41 +02:00
cifs cifs: update internal module number 2019-08-27 17:29:56 -05:00
coda coda: add hinting support for partial file caching 2019-07-16 19:23:23 -07:00
configfs configfs: provide exclusion between IO and removals 2019-09-04 22:33:51 +02:00
cramfs treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
crypto Revert "Merge tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs" 2019-07-10 18:43:43 -07:00
debugfs Driver Core and debugfs changes for 5.3-rc1 2019-07-12 12:24:03 -07:00
devpts devpts: call fsnotify_unlink() hook 2019-06-20 14:46:34 +02:00
dlm dlm for 5.3 2019-07-12 17:37:53 -07:00
ecryptfs - Fix error handling when ecryptfs_read_lower() encounters an error 2019-07-14 19:29:04 -07:00
efivarfs Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
efs treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
exportfs treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
ext2 New for 5.3: 2019-07-12 16:54:37 -07:00
ext4 - virtio_pmem: The new virtio_pmem facility introduces a paravirtualized 2019-07-18 10:52:08 -07:00
f2fs f2fs-for-5.4-rc3 2019-07-30 13:15:39 -07:00
fat treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 282 2019-06-05 17:36:37 +02:00
freevxfs treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
fscache Revert "Merge tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs" 2019-07-10 18:43:43 -07:00
fuse Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
gfs2 gfs2: gfs2_walk_metadata fix 2019-08-09 16:56:12 +01:00
hfs treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
hfsplus fs/hfsplus/xattr.c: replace strncpy with memcpy 2019-07-16 19:23:23 -07:00
hostfs This pull request contains the following changes for UML: 2019-05-12 17:52:13 -04:00
hpfs treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
hugetlbfs Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
iomap iomap: fix Invalid License ID 2019-07-25 11:05:11 +02:00
isofs treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 142 2019-05-30 11:25:17 -07:00
jbd2 jbd2: drop declaration of journal_sync_buffer() 2019-06-20 17:32:21 -04:00
jffs2 jffs2: pass the correct prototype to read_cache_page 2019-07-12 11:05:43 -07:00
jfs vfs: create a generic checking and prep function for FS_IOC_SETFLAGS 2019-07-01 08:25:34 -07:00
kernfs treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428 2019-06-05 17:37:16 +02:00
lockd lockd: Make two symbols static 2019-07-03 17:52:09 -04:00
minix treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
nfs NFS: Fix inode fileid checks in attribute revalidation code 2019-09-02 13:10:19 -04:00
nfs_common treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
nfsd nfsd4: Fix kernel crash when reading proc file reply_cache_stats 2019-08-16 13:36:55 -04:00
nilfs2 vfs: create a generic checking and prep function for FS_IOC_SETFLAGS 2019-07-01 08:25:34 -07:00
nls treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
notify proc/sysctl: add shared variables for range check 2019-07-18 17:08:07 -07:00
ntfs treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 97 2019-05-24 17:37:53 +02:00
ocfs2 ocfs2: remove set but not used variable 'last_hash' 2019-08-03 07:02:00 -07:00
omfs treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 209 2019-05-30 11:29:53 -07:00
openpromfs Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
orangefs orangefs: This simple pull request is just a fix for an 2019-07-16 15:15:29 -07:00
overlayfs SPDX update for 5.2-rc6 2019-06-21 09:58:42 -07:00
proc Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
pstore pstore: Fix double-free in pstore_mkfile() failure path 2019-07-08 21:04:42 -07:00
qnx4 treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
qnx6 treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
quota \n 2019-07-10 20:27:07 -07:00
ramfs Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
reiserfs fs/reiserfs/journal.c: change return type of dirty_one_transaction 2019-07-16 19:23:24 -07:00
romfs treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
squashfs treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 499 2019-06-19 17:09:53 +02:00
sysfs Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
sysv treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
tracefs \n 2019-07-10 20:09:17 -07:00
ubifs ubifs: Limit the number of pages in shrink_liability 2019-08-22 17:25:33 +02:00
udf \n 2019-07-10 20:27:07 -07:00
ufs fs/ufs/super.c: remove set but not used variable 'usb3' 2019-07-16 19:23:23 -07:00
unicode Many bug fixes and cleanups, and an optimization for case-insensitive 2019-07-10 21:06:01 -07:00
xfs xfs: fix missing ILOCK unlock when xfs_setattr_nonsize fails due to EDQUOT 2019-08-22 20:55:54 -07:00
aio.c Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
anon_inodes.c Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
attr.c
bad_inode.c
binfmt_aout.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
binfmt_elf_fdpic.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
binfmt_elf.c fs/binfmt_elf.c: delete stale comment 2019-07-16 19:23:22 -07:00
binfmt_em86.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
binfmt_flat.c fs/binfmt_flat.c: remove set but not used variable 'inode' 2019-07-16 19:23:22 -07:00
binfmt_misc.c Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
binfmt_script.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
block_dev.c block: remove REQ_NOWAIT_INLINE 2019-08-15 11:09:16 -06:00
buffer.c for-linus-20190715 2019-07-15 21:20:52 -07:00
char_dev.c chardev: set variable ret to -EBUSY before checking minor range overlap 2019-05-24 20:50:36 +02:00
compat_binfmt_elf.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 193 2019-05-30 11:29:21 -07:00
compat_ioctl.c compat_ioctl: pppoe: fix PPPOEIOCSFWD handling 2019-07-30 14:42:13 -07:00
compat.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
coredump.c coredump: split pipe command whitespace before expanding template 2019-08-03 07:02:01 -07:00
d_path.c unexport simple_dname() 2019-05-21 08:23:41 +01:00
dax.c dax: dax_layout_busy_page() should not unmap cow pages 2019-08-05 14:59:05 -07:00
dcache.c Merge branch 'work.dcache2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-20 09:15:51 -07:00
dcookies.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
direct-io.c direct-io: use bio_release_pages in dio_bio_complete 2019-06-29 09:47:31 -06:00
drop_caches.c
eventfd.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
eventpoll.c proc/sysctl: add shared variables for range check 2019-07-18 17:08:07 -07:00
exec.c sched/fair: Don't free p->numa_faults with concurrent readers 2019-07-25 15:37:04 +02:00
fcntl.c fs: mark expected switch fall-throughs 2019-04-08 18:21:02 -05:00
fhandle.c
file_table.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
file.c io_uring-2019-03-06 2019-03-08 14:48:40 -08:00
filesystems.c vfs: Implement a filesystem superblock creation/configuration context 2019-02-28 03:29:26 -05:00
fs_context.c move mount_capable() calls to vfs_get_tree() 2019-05-25 18:00:01 -04:00
fs_parser.c Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
fs_pin.c switch the remnants of releasing the mountpoint away from fs_pin 2019-07-16 22:52:37 -04:00
fs_struct.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
fs_types.c
fs-writeback.c blkcg, writeback: Add wbc->no_cgroup_owner 2019-07-10 09:00:57 -06:00
fsopen.c Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
inode.c New for 5.3: 2019-07-12 16:54:37 -07:00
internal.h Merge branch 'work.dcache2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-20 09:15:51 -07:00
io_uring.c io_uring: add need_resched() check in inner poll loop 2019-08-22 15:32:28 -06:00
ioctl.c
Kconfig fs: VALIDATE_FS_PARSER should default to n 2019-07-05 11:22:11 -04:00
Kconfig.binfmt binfmt_flat: make support for old format binaries optional 2019-06-24 09:16:47 +10:00
libfs.c Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
locks.c Highlights: 2019-07-10 21:22:43 -07:00
Makefile iomap: move the main iteration code into a separate file 2019-07-17 07:20:43 -07:00
mbcache.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
mount.h switch the remnants of releasing the mountpoint away from fs_pin 2019-07-16 22:52:37 -04:00
mpage.c blkcg, writeback: Rename wbc_account_io() to wbc_account_cgroup_owner() 2019-07-10 09:00:57 -06:00
namei.c fsnotify: add empty fsnotify_{unlink,rmdir}() hooks 2019-06-20 14:44:55 +02:00
namespace.c fix the struct mount leak in umount_tree() 2019-07-26 07:59:06 -04:00
no-block.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
nsfs.c vfs: Convert nsfs to use the new mount API 2019-05-25 18:00:06 -04:00
open.c access: avoid the RCU grace period for the temporary subjective credentials 2019-07-24 10:12:09 -07:00
pipe.c vfs: Convert pipe to use the new mount API 2019-05-25 18:00:07 -04:00
pnode.c fs/namespace: fix unprivileged mount propagation 2019-06-17 17:36:09 -04:00
pnode.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 209 2019-05-30 11:29:53 -07:00
posix_acl.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
proc_namespace.c
read_write.c vfs: fix page locking deadlocks when deduping files 2019-08-16 18:43:24 -07:00
readdir.c
select.c fs/select.c: use struct_size() in kmalloc() 2019-07-16 19:23:25 -07:00
seq_file.c seq_file: fix problem when seeking mid-record 2019-08-13 16:06:52 -07:00
signalfd.c fs: mark expected switch fall-throughs 2019-04-08 18:21:02 -05:00
splice.c uio: make import_iovec()/compat_import_iovec() return bytes on success 2019-05-31 15:30:03 -06:00
stack.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
stat.c
statfs.c
super.c Unbreak mount_capable() 2019-07-31 12:22:32 -04:00
sync.c fs/sync.c: sync_file_range(2) may use WB_SYNC_ALL writeback 2019-05-14 09:47:50 -07:00
timerfd.c
userfaultfd.c userfaultfd_release: always remove uffd flags and clear vm_userfaultfd_ctx 2019-08-24 19:48:42 -07:00
utimes.c
xattr.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00