swh:1:snp:173f8deb0c56c557784b4fd217e7608ac6197844
Revision 0d74471924f2a01dcd32d154510c0500780b531a authored by Linus Torvalds on 17 May 2019, 00:18:41 UTC, committed by Linus Torvalds on 17 May 2019, 00:18:41 UTC
Pull AFS callback promise fixes from David Howells: "This series fixes a bunch of problems in callback promise handling, where a callback promise indicates a promise on the part of the server to notify the client in the event of some sort of change to a file or volume. In the event of a break, the client has to go and refetch the client status from the server and discard any cached permission information as the ACL might have changed. The problem in the current code is that changes made by other clients aren't always noticed, primarily because the file status information and the callback information aren't updated in the same critical section, even if these are carried in the same reply from an RPC operation, and so the AFS_VNODE_CB_PROMISED flag is unreliable. Arranging for them to be done in the same critical section during reply decoding is tricky because of the FS.InlineBulkStatus op - which has all the statuses in the reply arriving and then all the callbacks, so they have to be buffered. It simplifies things a lot to move the critical section out of the decode phase and do it after the RPC function returns. Also new inodes (either newly fetched or newly created) aren't properly managed against a callback break happening before we get the local inode up and running. Fix this by: - There's now a combined file status and callback record (struct afs_status_cb) to carry both plus some flags. - Each operation wrapper function allocates sufficient afs_status_cb records for all the vnodes it is interested in and passes them into RPC operations to be filled in from the reply. - The FileStatus and CallBack record decoders no longer apply the new/revised status and callback information to the inode/vnode at the point of decoding and instead store the information into the record from (2). - afs_vnode_commit_status() then revises the file status, detects deletion and notes callback information inside of a single critical section. It also checks the callback break counters and cancels the callback promise if they changed during the operation. [*] Note that "callback break counters" are counters of server events that cancel one or more callback promises that the client thinks it has. The client counts the events and compares the counters before and after an operation to see if the callback promise it thinks it just got evaporated before it got recorded under lock. - Volume and server callback break counters are passed into afs_iget() allowing callback breaks concurrent with inode set up to be detected and the callback promise thence to be cancelled. - AFS validation checks are now done under RCU conditions using a read lock on cb_lock. This requires vnode->cb_interest to be made RCU safe. - If the checks in (6) fail, the callback breaker is then called under write lock on the cb_lock - but only if the callback break counter didn't change from the value read before the checks were made. - Results from FS.InlineBulkStatus that correspond to inodes we currently have in memory are now used to update those inodes' status and callback information rather than being discarded. This requires those inodes to be looked up before the RPC op is made and all their callback break values saved. To aid in this, the following changes have also been made: - Don't pass the vnode into the reply delivery functions or the decoders. The vnode shouldn't be altered anywhere in those paths. The only exception, for the moment, is for the call done hook for file lock ops that wants access to both the vnode and the call - this can be fixed at a later time. - Get rid of the call->reply[] void* array and replace it with named and typed members. This avoids confusion since different ops were mapping different reply[] members to different things. - Fix an order-1 kmalloc allocation in afs_do_lookup() and replace it with kvcalloc(). - Always get the reply time. Since callback, lock and fileserver record expiry times are calculated for several RPCs, make this mandatory. - Call afs_pages_written_back() from the operation wrapper rather than from the delivery function. - Don't store the version and type from a callback promise in a reply as the information in them is of very limited use" * tag 'afs-fixes-b-20190516' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: afs: Fix application of the results of a inline bulk status fetch afs: Pass pre-fetch server and volume break counts into afs_iget5_set() afs: Fix unlink to handle YFS.RemoveFile2 better afs: Clear AFS_VNODE_CB_PROMISED if we detect callback expiry afs: Make vnode->cb_interest RCU safe afs: Split afs_validate() so first part can be used under LOOKUP_RCU afs: Don't save callback version and type fields afs: Fix application of status and callback to be under same lock afs: Always get the reply time afs: Fix order-1 allocation in afs_do_lookup() afs: Get rid of afs_call::reply[] afs: Don't pass the vnode pointer through into the inline bulk status op
Tip revision: a9c9a6f741cdaa2fa9ba24a790db8d07295761e3 authored by Linus Torvalds on 02 September 2021, 22:09:46 UTC
Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Tip revision: a9c9a6f
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Makefile | -rw-r--r-- | 59.0 KB |
README | -rw-r--r-- | 727 bytes |
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