bio中储存私有数据

最新推荐文章于 2021-11-13 14:49:49 发布

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最新推荐文章于 2021-11-13 14:49:49 发布 · 1.2k 阅读

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#LINUX #内核

文章探讨了Linux内核中bio结构体的bi_private成员并不适合用于存储私有数据的原因，同时提到了内核如何频繁利用这一成员。尽管在查找解决方案时遇到困难，但作者聚焦于bio.bi_rw的使用。

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bio.bi_private是不能储存私有数据的，内核中会频繁使用这个成员。

找了好久也就只找到bio.bi_rw：

/*
 * bio bi_rw flags
 *
 * bit 0 -- data direction
 *	If not set, bio is a read from device. If set, it's a write to device.
 * bit 1 -- fail fast device errors
 * bit 2 -- fail fast transport errors
 * bit 3 -- fail fast driver errors
 * bit 4 -- rw-ahead when set
 * bit 5 -- barrier
 *	Insert a serialization point in the IO queue, forcing previously
 *	submitted IO to be completed before this one is issued.
 * bit 6 -- synchronous I/O hint.
 * bit 7 -- Unplug the device immediately after submitting this bio.
 * bit 8 -- metadata request
 *	Used for tracing to differentiate metadata and data IO. May also
 *	get some preferential treatment in the IO scheduler
 * bit 9 -- discard sectors
 *	Informs the lower level device that this range of sectors is no longer
 *	used by the file system and may thus be freed by the device. Used
 *	for flash based storage.
 *	Don't want dri