From: Anand Jain anand.jain@oracle.com
stable inclusion from stable-5.10.80 commit b4a4c9dc4407ae77ebf4ad8bdf9ecf57e29658b4 bugzilla: 185821 https://gitee.com/openeuler/kernel/issues/I4L7CG
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 5c78a5e7aa835c4f08a7c90fe02d19f95a776f29 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Chen Jun chenjun102@huawei.com Reviewed-by: Weilong Chen chenweilong@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com
Signed-off-by: Chen Jun chenjun102@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- fs/btrfs/disk-io.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index ef7df2141f34..9051bb47cbdd 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -3223,7 +3223,8 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device goto fail_sysfs; }
- if (!sb_rdonly(sb) && !btrfs_check_rw_degradable(fs_info, NULL)) { + if (!sb_rdonly(sb) && fs_info->fs_devices->missing_devices && + !btrfs_check_rw_degradable(fs_info, NULL)) { btrfs_warn(fs_info, "writable mount is not allowed due to too many missing devices"); goto fail_sysfs;