ext4: correct the judgment of BUG in ext4_mb_normalize_request
ext4_mb_normalize_request() can move logical start of allocated blocks to reduce fragmentation and better utilize preallocation. However logical block requested as a start of allocation (ac->ac_o_ex.fe_logical) should always be covered by allocated blocks so we should check that by modifying and to or in the assertion. Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Ritesh Harjani <ritesh.list@gmail.com> Link: https://lore.kernel.org/r/20220528110017.354175-3-libaokun1@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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@ -4185,7 +4185,22 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac,
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}
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rcu_read_unlock();
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if (start + size <= ac->ac_o_ex.fe_logical &&
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/*
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* In this function "start" and "size" are normalized for better
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* alignment and length such that we could preallocate more blocks.
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* This normalization is done such that original request of
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* ac->ac_o_ex.fe_logical & fe_len should always lie within "start" and
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* "size" boundaries.
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* (Note fe_len can be relaxed since FS block allocation API does not
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* provide gurantee on number of contiguous blocks allocation since that
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* depends upon free space left, etc).
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* In case of inode pa, later we use the allocated blocks
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* [pa_start + fe_logical - pa_lstart, fe_len/size] from the preallocated
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* range of goal/best blocks [start, size] to put it at the
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* ac_o_ex.fe_logical extent of this inode.
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* (See ext4_mb_use_inode_pa() for more details)
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*/
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if (start + size <= ac->ac_o_ex.fe_logical ||
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start > ac->ac_o_ex.fe_logical) {
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ext4_msg(ac->ac_sb, KERN_ERR,
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"start %lu, size %lu, fe_logical %lu",
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