btrfs: call btrfs_check_rw_degradable only if there is a missing device
In open_ctree() in btrfs_check_rw_degradable() [1], we check each block group individually if at least the minimum number of devices is available for that profile. If all the devices are available, then we don't have to check degradable. [1] open_ctree() :: 3559 if (!sb_rdonly(sb) && !btrfs_check_rw_degradable(fs_info, NULL)) { Also before calling btrfs_check_rw_degradable() in open_ctee() at the line number shown below [2] we call btrfs_read_chunk_tree() and down to add_missing_dev() to record number of missing devices. [2] open_ctree() :: 3454 ret = btrfs_read_chunk_tree(fs_info); btrfs_read_chunk_tree() read_one_chunk() / read_one_dev() add_missing_dev() So, check if there is any missing device before btrfs_check_rw_degradable() in open_ctree(). Also, with this the mount command could save ~16ms.[3] in the most common case, that is no device is missing. [3] 1) * 16934.96 us | btrfs_check_rw_degradable [btrfs](); CC: stable@vger.kernel.org # 4.19+ Reviewed-by:Josef Bacik <josef@toxicpanda.com> Signed-off-by:
Anand Jain <anand.jain@oracle.com> Reviewed-by:
David Sterba <dsterba@suse.com> Signed-off-by:
David Sterba <dsterba@suse.com>
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e77fbf99
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