linux-hardened/fs/btrfs
Josef Bacik 556755a8a9 btrfs: fix improper setting of scanned for range cyclic write cache pages
We noticed that we were having regular CG OOM kills in cases where there
was still enough dirty pages to avoid OOM'ing.  It turned out there's
this corner case in btrfs's handling of range_cyclic where files that
were being redirtied were not getting fully written out because of how
we do range_cyclic writeback.

We unconditionally were setting scanned = 1; the first time we found any
pages in the inode.  This isn't actually what we want, we want it to be
set if we've scanned the entire file.  For range_cyclic we could be
starting in the middle or towards the end of the file, so we could write
one page and then not write any of the other dirty pages in the file
because we set scanned = 1.

Fix this by not setting scanned = 1 if we find pages.  The rules for
setting scanned should be

1) !range_cyclic.  In this case we have a specified range to write out.
2) range_cyclic && index == 0.  In this case we've started at the
   beginning and there is no need to loop around a second time.
3) range_cyclic && we started at index > 0 and we've reached the end of
   the file without satisfying our nr_to_write.

This patch fixes both of our writepages implementations to make sure
these rules hold true.  This fixed our over zealous CG OOMs in
production.

Fixes: d1310b2e0c ("Btrfs: Split the extent_map code into two parts")
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add comment ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:41:02 +01:00
..
tests btrfs: drop create parameter to btrfs_get_extent() 2020-01-20 16:40:55 +01:00
acl.c
async-thread.c btrfs: add __pure attribute to functions 2019-11-18 12:46:52 +01:00
async-thread.h btrfs: add __pure attribute to functions 2019-11-18 12:46:52 +01:00
backref.c Btrfs: fix deadlock between fiemap and transaction commits 2019-07-30 18:25:12 +02:00
backref.h btrfs: fiemap: preallocate ulists for btrfs_check_shared 2019-07-01 13:34:53 +02:00
block-group.c btrfs: remove unnecessary wrapper get_alloc_profile 2020-01-20 16:41:01 +01:00
block-group.h btrfs: only keep track of data extents for async discard 2020-01-20 16:41:00 +01:00
block-rsv.c btrfs: use btrfs_try_granting_tickets in update_global_rsv 2019-09-09 14:59:19 +02:00
block-rsv.h btrfs: migrate the global_block_rsv helpers to block-rsv.c 2019-07-02 12:30:55 +02:00
btrfs_inode.h Btrfs: remove unnecessary delalloc mutex for inodes 2019-11-18 17:51:46 +01:00
check-integrity.c btrfs: remove superfluous BUG_ON() in integrity checks 2020-01-20 16:40:52 +01:00
check-integrity.h
compression.c btrfs: get rid of at_offset parameter to btrfs_lookup_bio_sums() 2020-01-20 16:40:54 +01:00
compression.h btrfs: compression: remove ops pointer from workspace_manager 2019-11-18 12:46:59 +01:00
ctree.c Btrfs: fix removal logic of the tree mod log that leads to use-after-free issues 2019-12-13 14:09:25 +01:00
ctree.h btrfs: keep track of discard reuse stats 2020-01-20 16:41:00 +01:00
delalloc-space.c Btrfs: remove unnecessary delalloc mutex for inodes 2019-11-18 17:51:46 +01:00
delalloc-space.h btrfs: migrate the delalloc space stuff to it's own home 2019-07-04 17:26:17 +02:00
delayed-inode.c btrfs: use refcount_inc_not_zero in kill_all_nodes 2019-11-18 12:46:51 +01:00
delayed-inode.h
delayed-ref.c btrfs: rename btrfs_space_info_add_old_bytes 2019-09-09 14:59:18 +02:00
delayed-ref.h btrfs: migrate the delayed refs rsv code 2019-07-04 17:26:17 +02:00
dev-replace.c btrfs: add __pure attribute to functions 2019-11-18 12:46:52 +01:00
dev-replace.h btrfs: add __pure attribute to functions 2019-11-18 12:46:52 +01:00
dir-item.c
discard.c btrfs: add correction to handle -1 edge case in async discard 2020-01-20 16:41:01 +01:00
discard.h btrfs: have multiple discard lists 2020-01-20 16:41:00 +01:00
disk-io.c btrfs: add the beginning of async discard, discard workqueue 2020-01-20 16:40:57 +01:00
disk-io.h btrfs: drop create parameter to btrfs_get_extent() 2020-01-20 16:40:55 +01:00
export.c btrfs: drop unused parameter is_new from btrfs_iget 2019-11-18 12:46:52 +01:00
export.h
extent-io-tree.h btrfs: move the failrec tree stuff into extent-io-tree.h 2019-11-18 12:46:47 +01:00
extent-tree.c btrfs: calculate discard delay based on number of extents 2020-01-20 16:40:59 +01:00
extent_io.c btrfs: fix improper setting of scanned for range cyclic write cache pages 2020-01-20 16:41:02 +01:00
extent_io.h btrfs: drop create parameter to btrfs_get_extent() 2020-01-20 16:40:55 +01:00
extent_map.c btrfs: remove extent_map::bdev 2019-11-18 23:43:44 +01:00
extent_map.h btrfs: remove extent_map::bdev 2019-11-18 23:43:44 +01:00
file-item.c btrfs: safely advance counter when looking up bio csums 2020-01-20 16:41:01 +01:00
file.c btrfs: drop create parameter to btrfs_get_extent() 2020-01-20 16:40:55 +01:00
free-space-cache.c btrfs: ensure removal of discardable_* in free_bitmap() 2020-01-20 16:41:01 +01:00
free-space-cache.h btrfs: have multiple discard lists 2020-01-20 16:41:00 +01:00
free-space-tree.c btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
free-space-tree.h btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
inode-item.c btrfs: Make btrfs_find_name_in_ext_backref return struct btrfs_inode_extref 2019-09-09 14:59:16 +02:00
inode-map.c btrfs: keep track of which extents have been discarded 2020-01-20 16:40:57 +01:00
inode-map.h
inode.c btrfs: rename DISCARD mount option to to DISCARD_SYNC 2020-01-20 16:40:57 +01:00
ioctl.c btrfs: drop create parameter to btrfs_get_extent() 2020-01-20 16:40:55 +01:00
Kconfig btrfs: add Kconfig dependency for BLAKE2B 2019-12-09 17:56:06 +01:00
locking.c btrfs: document extent buffer locking 2019-11-18 17:51:50 +01:00
locking.h btrfs: move btrfs_unlock_up_safe to other locking functions 2019-11-18 12:46:49 +01:00
lzo.c btrfs: compression: inline free_workspace 2019-11-18 12:46:59 +01:00
Makefile btrfs: add the beginning of async discard, discard workqueue 2020-01-20 16:40:57 +01:00
misc.h btrfs: add 64bit safe helper for power of two checks 2019-11-18 12:46:50 +01:00
ordered-data.c btrfs: make btrfs_ordered_extent naming consistent with btrfs_file_extent_item 2020-01-20 16:40:54 +01:00
ordered-data.h btrfs: make btrfs_ordered_extent naming consistent with btrfs_file_extent_item 2020-01-20 16:40:54 +01:00
orphan.c
print-tree.c btrfs: Remove unneeded semicolon 2020-01-20 16:40:55 +01:00
print-tree.h
props.c btrfs: props: remove unnecessary hash_init() 2019-11-18 12:46:55 +01:00
props.h
qgroup.c btrfs: qgroup: return ENOTCONN instead of EINVAL when quotas are not enabled 2020-01-20 16:40:50 +01:00
qgroup.h btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
raid56.c btrfs: remove pointless local variable in lock_stripe_add() 2019-11-18 12:47:00 +01:00
raid56.h btrfs: constify map parameter for nr_parity_stripes and nr_data_stripes 2019-07-01 13:34:58 +02:00
rcu-string.h
reada.c btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
ref-verify.c btrfs: fix uninitialized ret in ref-verify 2019-10-03 15:00:56 +02:00
ref-verify.h
relocation.c btrfs: make btrfs_ordered_extent naming consistent with btrfs_file_extent_item 2020-01-20 16:40:54 +01:00
root-tree.c btrfs: do not delete mismatched root refs 2020-01-08 14:44:24 +01:00
scrub.c btrfs: handle empty block_group removal for async discard 2020-01-20 16:40:57 +01:00
send.c btrfs: send: remove WARN_ON for readonly mount 2019-12-13 14:10:46 +01:00
send.h
space-info.c btrfs: don't pass system_chunk into can_overcommit 2020-01-20 16:40:52 +01:00
space-info.h Btrfs: remove wait queue from space_info structure 2019-11-18 17:51:46 +01:00
struct-funcs.c btrfs: tie extent buffer and it's token together 2019-09-09 14:59:16 +02:00
super.c btrfs: add the beginning of async discard, discard workqueue 2020-01-20 16:40:57 +01:00
sysfs.c btrfs: keep track of discard reuse stats 2020-01-20 16:41:00 +01:00
sysfs.h btrfs: sysfs, merge btrfs_sysfs_add devices_kobj and fsid 2020-01-20 16:40:50 +01:00
transaction.c btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
transaction.h btrfs: Rename btrfs_join_transaction_nolock 2019-11-18 12:46:54 +01:00
tree-checker.c btrfs: tree-checker: Verify location key for DIR_ITEM/DIR_INDEX 2020-01-20 16:40:56 +01:00
tree-checker.h
tree-defrag.c
tree-log.c btrfs: Remove redundant WARN_ON in walk_down_log_tree 2020-01-20 16:40:51 +01:00
tree-log.h
ulist.c
ulist.h
uuid-tree.c btrfs: handle ENOENT in btrfs_uuid_tree_iterate 2019-12-13 14:10:45 +01:00
volumes.c btrfs: add the beginning of async discard, discard workqueue 2020-01-20 16:40:57 +01:00
volumes.h btrfs: remove unused member btrfs_device::work 2020-01-20 16:41:01 +01:00
xattr.c Btrfs: fix failure to persist compression property xattr deletion on fsync 2019-06-17 16:37:17 +02:00
xattr.h
zlib.c btrfs: compression: inline free_workspace 2019-11-18 12:46:59 +01:00
zstd.c btrfs: compression: inline free_workspace 2019-11-18 12:46:59 +01:00