mirror of
https://github.com/seaweedfs/seaweedfs.git
synced 2026-09-17 03:50:51 +02:00
Chris Lu
b5a952bcb1
* fix(mount): don't strand a directory cached-but-empty when an off-loop wipe races a rebuild Idle eviction, kernel Forget, and the copy-range fallback cleared a directory's cached entries directly, off the metaCache apply loop, after resetting the cached flag in inodeToPath as a separate step. A concurrent rebuild could publish a fresh listing (markCachedFn) in between, so the late DeleteFolderChildren left the directory flagged cached over an empty store. lookupEntry then returns an authoritative ENOENT and ReadDir returns nothing, so every file in the directory disappears from the mount although it is still present on the filer. Route those wipes through a new apply-loop step that resets the flag and wipes the store together, serialized with a build's markCachedFn, and skips a directory while it is building. * fix(mount): route the meta-event retry cleanup through the apply-loop purge The subscription-retry callback wiped the mount root's cached children directly off the apply loop and reset the cache flags as a separate step — the same pattern that can leave a concurrently-rebuilding root cached-but-empty. Invalidate all flags (safe on its own, it never deletes entries) then purge the root's children through the apply loop.
75 lines
2.7 KiB
Go
75 lines
2.7 KiB
Go
package mount
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import (
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"github.com/seaweedfs/seaweedfs/weed/util"
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)
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// Forget is called when the kernel discards entries from its
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// dentry cache. This happens on unmount, and when the kernel
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// is short on memory. Since it is not guaranteed to occur at
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// any moment, and since there is no return value, Forget
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// should not do I/O, as there is no channel to report back
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// I/O errors.
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// from https://github.com/libfuse/libfuse/blob/master/include/fuse_lowlevel.h
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/**
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* Forget about an inode
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*
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* This function is called when the kernel removes an inode
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* from its internal caches.
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*
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* The inode's lookup count increases by one for every call to
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* fuse_reply_entry and fuse_reply_create. The nlookup parameter
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* indicates by how much the lookup count should be decreased.
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*
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* Inodes with a non-zero lookup count may receive request from
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* the kernel even after calls to unlink, rmdir or (when
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* overwriting an existing file) rename. Filesystems must handle
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* such requests properly and it is recommended to defer removal
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* of the inode until the lookup count reaches zero. Calls to
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* unlink, rmdir or rename will be followed closely by forget
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* unless the file or directory is open, in which case the
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* kernel issues forget only after the release or releasedir
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* calls.
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*
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* Note that if a file system will be exported over NFS the
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* inodes lifetime must extend even beyond forget. See the
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* generation field in struct fuse_entry_param above.
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*
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* On unmount the lookup count for all inodes implicitly drops
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* to zero. It is not guaranteed that the file system will
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* receive corresponding forget messages for the affected
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* inodes.
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*
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* Valid replies:
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* fuse_reply_none
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*
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* @param req request handle
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* @param ino the inode number
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* @param nlookup the number of lookups to forget
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*/
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/*
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https://libfuse.github.io/doxygen/include_2fuse__lowlevel_8h.html
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int fuse_reply_entry ( fuse_req_t req,
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const struct fuse_entry_param * e
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)
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Reply with a directory entry
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Possible requests: lookup, mknod, mkdir, symlink, link
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Side effects: increments the lookup count on success
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*/
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func (wfs *WFS) Forget(nodeid, nlookup uint64) {
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// Forget only decrements the kernel's inode lookup count. File handle
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// lifecycle is driven independently by FUSE Open/Release — touching the
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// fhMap here would couple two unrelated refcounts and could tear down a
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// still-live handle if Forget ever raced ahead of Release.
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wfs.inodeToPath.Forget(nodeid, nlookup, func(dir util.FullPath) {
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// Runs after Forget releases its lock; a concurrent lookup+rebuild can
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// re-cache the directory in that window, so purge through the apply loop
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// rather than wiping the store directly.
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wfs.purgeDirectoryCache(dir)
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})
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}
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