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There's an inherent race in taking a snapshot while an unlinked file is open, and then reattaching it in the child snapshot. In the interior snapshot node the file will appear unlinked, as though it should be deleted - it's not referenced by anything in that snapshot - but we can't delete it, because the file data is referenced by the child snapshot. This was being handled incorrectly with propagate_key_to_snapshot_leaves() - but that doesn't resolve the fundamental inconsistency of "this file looks like it should be deleted according to normal rules, but - ". To fix this, we need to fix the rule for when an inode is deleted. The previous rule, ignoring snapshots (there was no well-defined rule for with snapshots) was: Unlinked, non open files are deleted, either at recovery time or during online fsck The new rule is: Unlinked, non open files, that do not exist in child snapshots, are deleted. To make this work transactionally, we add a new inode flag, BCH_INODE_has_child_snapshot; it overrides BCH_INODE_unlinked when considering whether to delete an inode, or put it on the deleted list. For transactional consistency, clearing it handled by the inode trigger: when deleting an inode we check if there are parent inodes which can now have the BCH_INODE_has_child_snapshot flag cleared. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
168 lines
3.8 KiB
C
168 lines
3.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _BCACHEFS_INODE_FORMAT_H
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#define _BCACHEFS_INODE_FORMAT_H
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#define BLOCKDEV_INODE_MAX 4096
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#define BCACHEFS_ROOT_INO 4096
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struct bch_inode {
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struct bch_val v;
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__le64 bi_hash_seed;
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__le32 bi_flags;
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__le16 bi_mode;
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__u8 fields[];
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} __packed __aligned(8);
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struct bch_inode_v2 {
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struct bch_val v;
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__le64 bi_journal_seq;
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__le64 bi_hash_seed;
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__le64 bi_flags;
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__le16 bi_mode;
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__u8 fields[];
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} __packed __aligned(8);
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struct bch_inode_v3 {
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struct bch_val v;
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__le64 bi_journal_seq;
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__le64 bi_hash_seed;
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__le64 bi_flags;
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__le64 bi_sectors;
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__le64 bi_size;
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__le64 bi_version;
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__u8 fields[];
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} __packed __aligned(8);
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#define INODEv3_FIELDS_START_INITIAL 6
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#define INODEv3_FIELDS_START_CUR (offsetof(struct bch_inode_v3, fields) / sizeof(__u64))
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struct bch_inode_generation {
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struct bch_val v;
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__le32 bi_generation;
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__le32 pad;
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} __packed __aligned(8);
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/*
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* bi_subvol and bi_parent_subvol are only set for subvolume roots:
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*/
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#define BCH_INODE_FIELDS_v2() \
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x(bi_atime, 96) \
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x(bi_ctime, 96) \
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x(bi_mtime, 96) \
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x(bi_otime, 96) \
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x(bi_size, 64) \
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x(bi_sectors, 64) \
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x(bi_uid, 32) \
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x(bi_gid, 32) \
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x(bi_nlink, 32) \
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x(bi_generation, 32) \
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x(bi_dev, 32) \
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x(bi_data_checksum, 8) \
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x(bi_compression, 8) \
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x(bi_project, 32) \
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x(bi_background_compression, 8) \
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x(bi_data_replicas, 8) \
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x(bi_promote_target, 16) \
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x(bi_foreground_target, 16) \
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x(bi_background_target, 16) \
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x(bi_erasure_code, 16) \
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x(bi_fields_set, 16) \
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x(bi_dir, 64) \
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x(bi_dir_offset, 64) \
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x(bi_subvol, 32) \
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x(bi_parent_subvol, 32)
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#define BCH_INODE_FIELDS_v3() \
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x(bi_atime, 96) \
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x(bi_ctime, 96) \
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x(bi_mtime, 96) \
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x(bi_otime, 96) \
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x(bi_uid, 32) \
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x(bi_gid, 32) \
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x(bi_nlink, 32) \
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x(bi_generation, 32) \
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x(bi_dev, 32) \
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x(bi_data_checksum, 8) \
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x(bi_compression, 8) \
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x(bi_project, 32) \
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x(bi_background_compression, 8) \
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x(bi_data_replicas, 8) \
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x(bi_promote_target, 16) \
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x(bi_foreground_target, 16) \
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x(bi_background_target, 16) \
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x(bi_erasure_code, 16) \
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x(bi_fields_set, 16) \
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x(bi_dir, 64) \
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x(bi_dir_offset, 64) \
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x(bi_subvol, 32) \
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x(bi_parent_subvol, 32) \
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x(bi_nocow, 8)
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/* subset of BCH_INODE_FIELDS */
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#define BCH_INODE_OPTS() \
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x(data_checksum, 8) \
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x(compression, 8) \
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x(project, 32) \
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x(background_compression, 8) \
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x(data_replicas, 8) \
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x(promote_target, 16) \
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x(foreground_target, 16) \
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x(background_target, 16) \
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x(erasure_code, 16) \
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x(nocow, 8)
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enum inode_opt_id {
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#define x(name, ...) \
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Inode_opt_##name,
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BCH_INODE_OPTS()
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#undef x
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Inode_opt_nr,
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};
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#define BCH_INODE_FLAGS() \
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x(sync, 0) \
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x(immutable, 1) \
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x(append, 2) \
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x(nodump, 3) \
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x(noatime, 4) \
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x(i_size_dirty, 5) \
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x(i_sectors_dirty, 6) \
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x(unlinked, 7) \
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x(backptr_untrusted, 8) \
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x(has_child_snapshot, 9)
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/* bits 20+ reserved for packed fields below: */
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enum bch_inode_flags {
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#define x(t, n) BCH_INODE_##t = 1U << n,
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BCH_INODE_FLAGS()
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#undef x
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};
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enum __bch_inode_flags {
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#define x(t, n) __BCH_INODE_##t = n,
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BCH_INODE_FLAGS()
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#undef x
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};
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LE32_BITMASK(INODE_STR_HASH, struct bch_inode, bi_flags, 20, 24);
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LE32_BITMASK(INODE_NR_FIELDS, struct bch_inode, bi_flags, 24, 31);
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LE32_BITMASK(INODE_NEW_VARINT, struct bch_inode, bi_flags, 31, 32);
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LE64_BITMASK(INODEv2_STR_HASH, struct bch_inode_v2, bi_flags, 20, 24);
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LE64_BITMASK(INODEv2_NR_FIELDS, struct bch_inode_v2, bi_flags, 24, 31);
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LE64_BITMASK(INODEv3_STR_HASH, struct bch_inode_v3, bi_flags, 20, 24);
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LE64_BITMASK(INODEv3_NR_FIELDS, struct bch_inode_v3, bi_flags, 24, 31);
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LE64_BITMASK(INODEv3_FIELDS_START,
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struct bch_inode_v3, bi_flags, 31, 36);
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LE64_BITMASK(INODEv3_MODE, struct bch_inode_v3, bi_flags, 36, 52);
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#endif /* _BCACHEFS_INODE_FORMAT_H */
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