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710fb4e0ab
Previously, io path option changes on a file would be picked up automatically and applied to existing data - but not for reflinked data, as we had no way of doing this safely. A user may have had permission to copy (and reflink) a given file, but not write to it, and if so they shouldn't be allowed to change e.g. nr_replicas or other options. This uses the incompat feature mechanism in the previous patch to add a new incompatible flag to bch_reflink_p, indicating whether a given reflink pointer may propagate io path option changes back to the indirect extent. In this initial patch we're only setting it for the source extents. We'd like to set it for the destination in a reflink copy, when the user has write access to the source, but that requires mnt_idmap which is not curretly plumbed up to remap_file_range. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
39 lines
1.1 KiB
C
39 lines
1.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _BCACHEFS_REFLINK_FORMAT_H
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#define _BCACHEFS_REFLINK_FORMAT_H
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struct bch_reflink_p {
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struct bch_val v;
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__le64 idx_flags;
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/*
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* A reflink pointer might point to an indirect extent which is then
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* later split (by copygc or rebalance). If we only pointed to part of
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* the original indirect extent, and then one of the fragments is
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* outside the range we point to, we'd leak a refcount: so when creating
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* reflink pointers, we need to store pad values to remember the full
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* range we were taking a reference on.
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*/
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__le32 front_pad;
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__le32 back_pad;
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} __packed __aligned(8);
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LE64_BITMASK(REFLINK_P_IDX, struct bch_reflink_p, idx_flags, 0, 56);
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LE64_BITMASK(REFLINK_P_ERROR, struct bch_reflink_p, idx_flags, 56, 57);
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LE64_BITMASK(REFLINK_P_MAY_UPDATE_OPTIONS,
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struct bch_reflink_p, idx_flags, 57, 58);
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struct bch_reflink_v {
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struct bch_val v;
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__le64 refcount;
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union bch_extent_entry start[0];
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__u64 _data[];
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} __packed __aligned(8);
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struct bch_indirect_inline_data {
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struct bch_val v;
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__le64 refcount;
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u8 data[];
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};
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#endif /* _BCACHEFS_REFLINK_FORMAT_H */
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