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author | Jeff Mahoney <jeffm@suse.com> | 2018-03-20 15:25:26 -0400 |
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committer | David Sterba <dsterba@suse.com> | 2018-03-31 01:41:12 +0200 |
commit | 75cb379d2635215ad2c67750693f7dc45ad19a5f (patch) | |
tree | 0e3a1380015be15bbed794330fae015c3ca6a537 /fs/btrfs/math.h | |
parent | dc2d3005d27da41247d6c42077e335a777afc79c (diff) | |
download | linux-75cb379d2635215ad2c67750693f7dc45ad19a5f.tar.gz |
btrfs: defer adding raid type kobject until after chunk relocation
Any time the first block group of a new type is created, we add a new kobject to sysfs to hold the attributes for that type. Kobject-internal allocations always use GFP_KERNEL, making them prone to fs-reclaim races. While it appears as if this can occur any time a block group is created, the only times the first block group of a new type can be created in memory is at mount and when we create the first new block group during raid conversion. This patch adds a new list to track pending kobject additions and then handles them after we do chunk relocation. Between relocating the target chunk (or forcing allocation of a new chunk in the case of data) and removing the old chunk, we're in a safe place for fs-reclaim to occur. We're holding the volume mutex, which is already held across page faults, and the delete_unused_bgs_mutex, which will only stall the cleaner thread. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/math.h')
0 files changed, 0 insertions, 0 deletions