Commit 6528b99d authored by Anand Jain's avatar Anand Jain Committed by David Sterba
Browse files

btrfs: factor btrfs_check_rw_degradable() to check given device 



Update btrfs_check_rw_degradable() to check against the given device if
its lost.

We can use this function to know if the volume is going to be in
degraded mode OR failed state, when the given device fails.  Which is
needed when we are handling the device failed state.

A preparatory patch does not affect the flow as such.

Signed-off-by: default avatarAnand Jain <anand.jain@oracle.com>
Reviewed-by: default avatarQu Wenruo <wqu@suse.com>
[ enhance comment ]
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent e43bbe5e

fs/btrfs/disk-io.c

+2 −2
Original line number Diff line number Diff line
@@ -2866,7 +2866,7 @@ retry_root_backup: 
		goto fail_sysfs;

	}



	if (!sb_rdonly(sb) && !btrfs_check_rw_degradable(fs_info)) {

	if (!sb_rdonly(sb) && !btrfs_check_rw_degradable(fs_info, NULL)) {

		btrfs_warn(fs_info,

		"writeable mount is not allowed due to too many missing devices");

		goto fail_sysfs;
@@ -3369,7 +3369,7 @@ static blk_status_t wait_dev_flush(struct btrfs_device *device) 


static int check_barrier_error(struct btrfs_fs_info *fs_info)

{

	if (!btrfs_check_rw_degradable(fs_info))

	if (!btrfs_check_rw_degradable(fs_info, NULL))

		return -EIO;

	return 0;

}

fs/btrfs/super.c

+1 −1
Original line number Diff line number Diff line
@@ -1844,7 +1844,7 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data) 
			goto restore;

		}



		if (!btrfs_check_rw_degradable(fs_info)) {

		if (!btrfs_check_rw_degradable(fs_info, NULL)) {

			btrfs_warn(fs_info,

				"too many missing devices, writeable remount is not allowed");

			ret = -EACCES;

fs/btrfs/volumes.c

+8 −2
Original line number Diff line number Diff line
@@ -6851,10 +6851,13 @@ out_short_read: 
/*

 * Check if all chunks in the fs are OK for read-write degraded mount

 *

 * If the @failing_dev is specified, it's accounted as missing.

 *

 * Return true if all chunks meet the minimal RW mount requirements.

 * Return false if any chunk doesn't meet the minimal RW mount requirements.

 */

bool btrfs_check_rw_degradable(struct btrfs_fs_info *fs_info)

bool btrfs_check_rw_degradable(struct btrfs_fs_info *fs_info,

					struct btrfs_device *failing_dev)

{

	struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;

	struct extent_map *em;
@@ -6886,8 +6889,11 @@ bool btrfs_check_rw_degradable(struct btrfs_fs_info *fs_info) 
			    test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state) ||

			    dev->last_flush_error)

				missing++;

			else if (failing_dev && failing_dev == dev)

				missing++;

		}

		if (missing > max_tolerated) {

			if (!failing_dev)

				btrfs_warn(fs_info,

	"chunk %llu missing %d devices, max tolerance is %d for writeable mount",

				   em->start, missing, max_tolerated);

fs/btrfs/volumes.h

+2 −2
Original line number Diff line number Diff line
@@ -554,7 +554,7 @@ void btrfs_update_commit_device_bytes_used(struct btrfs_fs_info *fs_info, 
struct list_head *btrfs_get_fs_uuids(void);

void btrfs_set_fs_info_ptr(struct btrfs_fs_info *fs_info);

void btrfs_reset_fs_info_ptr(struct btrfs_fs_info *fs_info);



bool btrfs_check_rw_degradable(struct btrfs_fs_info *fs_info);

bool btrfs_check_rw_degradable(struct btrfs_fs_info *fs_info,

					struct btrfs_device *failing_dev);



#endif

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