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2ba48b2004
[BUG] Even with commit81d5d61454
("btrfs: enhance unsupported compat RO flags handling"), btrfs can still mount a fs with unsupported compat_ro flags read-only, then remount it RW: # btrfs ins dump-super /dev/loop0 | grep compat_ro_flags -A 3 compat_ro_flags 0x403 ( FREE_SPACE_TREE | FREE_SPACE_TREE_VALID | unknown flag: 0x400 ) # mount /dev/loop0 /mnt/btrfs mount: /mnt/btrfs: wrong fs type, bad option, bad superblock on /dev/loop0, missing codepage or helper program, or other error. dmesg(1) may have more information after failed mount system call. ^^^ RW mount failed as expected ^^^ # dmesg -t | tail -n5 loop0: detected capacity change from 0 to 1048576 BTRFS: device fsid cb5b82f5-0fdd-4d81-9b4b-78533c324afa devid 1 transid 7 /dev/loop0 scanned by mount (1146) BTRFS info (device loop0): using crc32c (crc32c-intel) checksum algorithm BTRFS info (device loop0): using free space tree BTRFS error (device loop0): cannot mount read-write because of unknown compat_ro features (0x403) BTRFS error (device loop0): open_ctree failed # mount /dev/loop0 -o ro /mnt/btrfs # mount -o remount,rw /mnt/btrfs ^^^ RW remount succeeded unexpectedly ^^^ [CAUSE] Currently we use btrfs_check_features() to check compat_ro flags against our current mount flags. That function get reused between open_ctree() and btrfs_remount(). But for btrfs_remount(), the super block we passed in still has the old mount flags, thus btrfs_check_features() still believes we're mounting read-only. [FIX] Replace the existing @sb argument with @is_rw_mount. As originally we only use @sb to determine if the mount is RW. Now it's callers' responsibility to determine if the mount is RW, and since there are only two callers, the check is pretty simple: - caller in open_ctree() Just pass !sb_rdonly(). - caller in btrfs_remount() Pass !(*flags & SB_RDONLY), as our check should be against the new flags. Now we can correctly reject the RW remount: # mount /dev/loop0 -o ro /mnt/btrfs # mount -o remount,rw /mnt/btrfs mount: /mnt/btrfs: mount point not mounted or bad option. dmesg(1) may have more information after failed mount system call. # dmesg -t | tail -n 1 BTRFS error (device loop0: state M): cannot mount read-write because of unknown compat_ro features (0x403) Reported-by: Chung-Chiang Cheng <shepjeng@gmail.com> Fixes:81d5d61454
("btrfs: enhance unsupported compat RO flags handling") CC: stable@vger.kernel.org # 5.15+ Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
143 lines
5.5 KiB
C
143 lines
5.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2007 Oracle. All rights reserved.
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*/
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#ifndef BTRFS_DISK_IO_H
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#define BTRFS_DISK_IO_H
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#define BTRFS_SUPER_MIRROR_MAX 3
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#define BTRFS_SUPER_MIRROR_SHIFT 12
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/*
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* Fixed blocksize for all devices, applies to specific ways of reading
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* metadata like superblock. Must meet the set_blocksize requirements.
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*
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* Do not change.
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*/
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#define BTRFS_BDEV_BLOCKSIZE (4096)
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static inline u64 btrfs_sb_offset(int mirror)
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{
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u64 start = SZ_16K;
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if (mirror)
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return start << (BTRFS_SUPER_MIRROR_SHIFT * mirror);
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return BTRFS_SUPER_INFO_OFFSET;
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}
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struct btrfs_device;
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struct btrfs_fs_devices;
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struct btrfs_tree_parent_check;
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void btrfs_check_leaked_roots(struct btrfs_fs_info *fs_info);
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void btrfs_init_fs_info(struct btrfs_fs_info *fs_info);
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int btrfs_verify_level_key(struct extent_buffer *eb, int level,
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struct btrfs_key *first_key, u64 parent_transid);
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struct extent_buffer *read_tree_block(struct btrfs_fs_info *fs_info, u64 bytenr,
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struct btrfs_tree_parent_check *check);
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struct extent_buffer *btrfs_find_create_tree_block(
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struct btrfs_fs_info *fs_info,
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u64 bytenr, u64 owner_root,
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int level);
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void btrfs_clean_tree_block(struct extent_buffer *buf);
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void btrfs_clear_oneshot_options(struct btrfs_fs_info *fs_info);
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int btrfs_start_pre_rw_mount(struct btrfs_fs_info *fs_info);
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int btrfs_check_super_csum(struct btrfs_fs_info *fs_info,
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const struct btrfs_super_block *disk_sb);
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int __cold open_ctree(struct super_block *sb,
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struct btrfs_fs_devices *fs_devices,
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char *options);
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void __cold close_ctree(struct btrfs_fs_info *fs_info);
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int btrfs_validate_super(struct btrfs_fs_info *fs_info,
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struct btrfs_super_block *sb, int mirror_num);
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int btrfs_check_features(struct btrfs_fs_info *fs_info, bool is_rw_mount);
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int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors);
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struct btrfs_super_block *btrfs_read_dev_super(struct block_device *bdev);
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struct btrfs_super_block *btrfs_read_dev_one_super(struct block_device *bdev,
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int copy_num, bool drop_cache);
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int btrfs_commit_super(struct btrfs_fs_info *fs_info);
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struct btrfs_root *btrfs_read_tree_root(struct btrfs_root *tree_root,
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struct btrfs_key *key);
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int btrfs_insert_fs_root(struct btrfs_fs_info *fs_info,
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struct btrfs_root *root);
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void btrfs_free_fs_roots(struct btrfs_fs_info *fs_info);
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struct btrfs_root *btrfs_get_fs_root(struct btrfs_fs_info *fs_info,
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u64 objectid, bool check_ref);
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struct btrfs_root *btrfs_get_new_fs_root(struct btrfs_fs_info *fs_info,
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u64 objectid, dev_t anon_dev);
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struct btrfs_root *btrfs_get_fs_root_commit_root(struct btrfs_fs_info *fs_info,
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struct btrfs_path *path,
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u64 objectid);
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int btrfs_global_root_insert(struct btrfs_root *root);
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void btrfs_global_root_delete(struct btrfs_root *root);
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struct btrfs_root *btrfs_global_root(struct btrfs_fs_info *fs_info,
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struct btrfs_key *key);
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struct btrfs_root *btrfs_csum_root(struct btrfs_fs_info *fs_info, u64 bytenr);
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struct btrfs_root *btrfs_extent_root(struct btrfs_fs_info *fs_info, u64 bytenr);
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struct btrfs_root *btrfs_block_group_root(struct btrfs_fs_info *fs_info);
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void btrfs_free_fs_info(struct btrfs_fs_info *fs_info);
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int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info);
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void btrfs_btree_balance_dirty(struct btrfs_fs_info *fs_info);
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void btrfs_btree_balance_dirty_nodelay(struct btrfs_fs_info *fs_info);
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void btrfs_drop_and_free_fs_root(struct btrfs_fs_info *fs_info,
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struct btrfs_root *root);
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int btrfs_validate_metadata_buffer(struct btrfs_bio *bbio,
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struct page *page, u64 start, u64 end,
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int mirror);
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void btrfs_submit_metadata_bio(struct btrfs_inode *inode, struct bio *bio, int mirror_num);
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#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
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struct btrfs_root *btrfs_alloc_dummy_root(struct btrfs_fs_info *fs_info);
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#endif
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/*
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* This function is used to grab the root, and avoid it is freed when we
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* access it. But it doesn't ensure that the tree is not dropped.
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*
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* If you want to ensure the whole tree is safe, you should use
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* fs_info->subvol_srcu
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*/
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static inline struct btrfs_root *btrfs_grab_root(struct btrfs_root *root)
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{
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if (!root)
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return NULL;
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if (refcount_inc_not_zero(&root->refs))
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return root;
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return NULL;
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}
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void btrfs_put_root(struct btrfs_root *root);
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void btrfs_mark_buffer_dirty(struct extent_buffer *buf);
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int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid,
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int atomic);
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int btrfs_read_extent_buffer(struct extent_buffer *buf,
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struct btrfs_tree_parent_check *check);
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enum btrfs_wq_submit_cmd {
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WQ_SUBMIT_METADATA,
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WQ_SUBMIT_DATA,
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WQ_SUBMIT_DATA_DIO,
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};
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bool btrfs_wq_submit_bio(struct btrfs_inode *inode, struct bio *bio, int mirror_num,
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u64 dio_file_offset, enum btrfs_wq_submit_cmd cmd);
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blk_status_t btree_submit_bio_start(struct bio *bio);
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int btrfs_alloc_log_tree_node(struct btrfs_trans_handle *trans,
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struct btrfs_root *root);
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int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
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struct btrfs_fs_info *fs_info);
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int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
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struct btrfs_root *root);
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void btrfs_cleanup_dirty_bgs(struct btrfs_transaction *trans,
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struct btrfs_fs_info *fs_info);
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void btrfs_cleanup_one_transaction(struct btrfs_transaction *trans,
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struct btrfs_fs_info *fs_info);
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struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
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u64 objectid);
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int btrfs_get_num_tolerated_disk_barrier_failures(u64 flags);
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int btrfs_get_free_objectid(struct btrfs_root *root, u64 *objectid);
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int btrfs_init_root_free_objectid(struct btrfs_root *root);
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#endif
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