diff options
Diffstat (limited to 'fs/btrfs/extent-tree.c')
| -rw-r--r-- | fs/btrfs/extent-tree.c | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 5e81e36..b4e3ab1 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -9656,12 +9656,14 @@ int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range) } /* - * btrfs_{start,end}_write() is similar to mnt_{want, drop}_write(), - * they are used to prevent the some tasks writing data into the page cache - * by nocow before the subvolume is snapshoted, but flush the data into - * the disk after the snapshot creation. + * btrfs_{start,end}_write_no_snapshoting() are similar to + * mnt_{want,drop}_write(), they are used to prevent some tasks from writing + * data into the page cache through nocow before the subvolume is snapshoted, + * but flush the data into disk after the snapshot creation, or to prevent + * operations while snapshoting is ongoing and that cause the snapshot to be + * inconsistent (writes followed by expanding truncates for example). */ -void btrfs_end_nocow_write(struct btrfs_root *root) +void btrfs_end_write_no_snapshoting(struct btrfs_root *root) { percpu_counter_dec(&root->subv_writers->counter); /* @@ -9673,7 +9675,7 @@ void btrfs_end_nocow_write(struct btrfs_root *root) wake_up(&root->subv_writers->wait); } -int btrfs_start_nocow_write(struct btrfs_root *root) +int btrfs_start_write_no_snapshoting(struct btrfs_root *root) { if (atomic_read(&root->will_be_snapshoted)) return 0; @@ -9684,7 +9686,7 @@ int btrfs_start_nocow_write(struct btrfs_root *root) */ smp_mb(); if (atomic_read(&root->will_be_snapshoted)) { - btrfs_end_nocow_write(root); + btrfs_end_write_no_snapshoting(root); return 0; } return 1; |
