- 07 Jan, 2022 18 commits
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David Howells authored
Provide a pair of functions to count the number of users of a cookie (open files, writeback, invalidation, resizing, reads, writes), to obtain and pin resources for the cookie and to prevent culling for the whilst there are users. The first function marks a cookie as being in use: void fscache_use_cookie(struct fscache_cookie *cookie, bool will_modify); The caller should indicate the cookie to use and whether or not the caller is in a context that may modify the cookie (e.g. a file open O_RDWR). If the cookie is not already resourced, fscache will ask the cache backend in the background to do whatever it needs to look up, create or otherwise obtain the resources necessary to access data. This is pinned to the cookie and may not be culled, though it may be withdrawn if the cache as a whole is withdrawn. The second function removes the in-use mark from a cookie and, optionally, updates the coherency data: void fscache_unuse_cookie(struct fscache_cookie *cookie, const void *aux_data, const loff_t *object_size); If non-NULL, the aux_data buffer and/or the object_size will be saved into the cookie and will be set on the backing store when the object is committed. If this removes the last usage on a cookie, the cookie is placed onto an LRU list from which it will be removed and closed after a couple of seconds if it doesn't get reused. This prevents resource overload in the cache - in particular it prevents it from holding too many files open. Changes ======= ver #2: - Fix fscache_unuse_cookie() to use atomic_dec_and_lock() to avoid a potential race if the cookie gets reused before it completes the unusement. - Added missing transition to LRU_DISCARDING state. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819600612.215744.13678350304176542741.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906907567.143852.16979631199380722019.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967106467.1823006.6790864931048582667.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021511674.640689.10084988363699111860.stgit@warthog.procyon.org.uk/ # v4
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David Howells authored
Implement a very simple cookie state machine to handle lookup, invalidation, withdrawal, relinquishment and, to be added later, commit on LRU discard. Three cache methods are provided: ->lookup_cookie() to look up and, if necessary, create a data storage object; ->withdraw_cookie() to free the resources associated with that object and potentially delete it; and ->prepare_to_write(), to do prepare for changes to the cached data to be modified locally. Changes ======= ver #3: - Fix a race between LRU discard and relinquishment whereby the former would override the latter and thus the latter would never happen[1]. ver #2: - Don't hold n_accesses elevated whilst cache is bound to a cookie, but rather add a flag that prevents the state machine from being queued when n_accesses reaches 0. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/599331.1639410068@warthog.procyon.org.uk/ [1] Link: https://lore.kernel.org/r/163819599657.215744.15799615296912341745.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906903925.143852.1805855338154353867.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967105456.1823006.14730395299835841776.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021510706.640689.7961423370243272583.stgit@warthog.procyon.org.uk/ # v4
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David Howells authored
Add a function to the backend API to note an I/O error in a cache. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819598741.215744.891281275151382095.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906901316.143852.15225412215771586528.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967100721.1823006.16435671567428949398.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021508840.640689.11902836226570620424.stgit@warthog.procyon.org.uk/ # v4
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David Howells authored
Add cache methods to lookup, create and remove a volume. Looking up or creating the volume requires the cache pinning for access; freeing the volume requires the volume pinning for access. The ->acquire_volume() method is used to ask the cache backend to lookup and, if necessary, create a volume; the ->free_volume() method is used to free the resources for a volume. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819597821.215744.5225318658134989949.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906898645.143852.8537799955945956818.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967099771.1823006.1455197910571061835.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021507345.640689.4073511598838843040.stgit@warthog.procyon.org.uk/ # v4
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David Howells authored
Implement functions to allow the cache backend to add or remove a cache: (1) Declare a cache to be live: int fscache_add_cache(struct fscache_cache *cache, const struct fscache_cache_ops *ops, void *cache_priv); Take a previously acquired cache cookie, set the operations table and private data and mark the cache open for access. (2) Withdraw a cache from service: void fscache_withdraw_cache(struct fscache_cache *cache); This marks the cache as withdrawn and thus prevents further cache-level and volume-level accesses. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819596022.215744.8799712491432238827.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906896599.143852.17049208999019262884.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967097870.1823006.3470041000971522030.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021505541.640689.1819714759326331054.stgit@warthog.procyon.org.uk/ # v4
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David Howells authored
Add a number of helper functions to manage access to a cookie, pinning the cache object in place for the duration to prevent cache withdrawal from removing it: (1) void fscache_init_access_gate(struct fscache_cookie *cookie); This function initialises the access count when a cache binds to a cookie. An extra ref is taken on the access count to prevent wakeups while the cache is active. We're only interested in the wakeup when a cookie is being withdrawn and we're waiting for it to quiesce - at which point the counter will be decremented before the wait. The FSCACHE_COOKIE_NACC_ELEVATED flag is set on the cookie to keep track of the extra ref in order to handle a race between relinquishment and withdrawal both trying to drop the extra ref. (2) bool fscache_begin_cookie_access(struct fscache_cookie *cookie, enum fscache_access_trace why); This function attempts to begin access upon a cookie, pinning it in place if it's cached. If successful, it returns true and leaves a the access count incremented. (3) void fscache_end_cookie_access(struct fscache_cookie *cookie, enum fscache_access_trace why); This function drops the access count obtained by (2), permitting object withdrawal to take place when it reaches zero. A tracepoint is provided to track changes to the access counter on a cookie. Changes ======= ver #2: - Don't hold n_accesses elevated whilst cache is bound to a cookie, but rather add a flag that prevents the state machine from being queued when n_accesses reaches 0. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819595085.215744.1706073049250505427.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906895313.143852.10141619544149102193.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967095980.1823006.1133648159424418877.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021503063.640689.8870918985269528670.stgit@warthog.procyon.org.uk/ # v4
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David Howells authored
Add a pair of helper functions to manage access to a volume, pinning the volume in place for the duration to prevent cache withdrawal from removing it: bool fscache_begin_volume_access(struct fscache_volume *volume, enum fscache_access_trace why); void fscache_end_volume_access(struct fscache_volume *volume, enum fscache_access_trace why); The way the access gate on the volume works/will work is: (1) If the cache tests as not live (state is not FSCACHE_CACHE_IS_ACTIVE), then we return false to indicate access was not permitted. (2) If the cache tests as live, then we increment the volume's n_accesses count and then recheck the cache liveness, ending the access if it ceased to be live. (3) When we end the access, we decrement the volume's n_accesses and wake up the any waiters if it reaches 0. (4) Whilst the cache is caching, the volume's n_accesses is kept artificially incremented to prevent wakeups from happening. (5) When the cache is taken offline, the state is changed to prevent new accesses, the volume's n_accesses is decremented and we wait for it to become 0. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819594158.215744.8285859817391683254.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906894315.143852.5454793807544710479.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967095028.1823006.9173132503876627466.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021501546.640689.9631510472149608443.stgit@warthog.procyon.org.uk/ # v4
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David Howells authored
Add a pair of functions to pin/unpin a cache that we're wanting to do a high-level access to (such as creating or removing a volume): bool fscache_begin_cache_access(struct fscache_cache *cache, enum fscache_access_trace why); void fscache_end_cache_access(struct fscache_cache *cache, enum fscache_access_trace why); The way the access gate works/will work is: (1) If the cache tests as not live (state is not FSCACHE_CACHE_IS_ACTIVE), then we return false to indicate access was not permitted. (2) If the cache tests as live, then we increment the n_accesses count and then recheck the liveness, ending the access if it ceased to be live. (3) When we end the access, we decrement n_accesses and wake up the any waiters if it reaches 0. (4) Whilst the cache is caching, n_accesses is kept artificially incremented to prevent wakeups from happening. (5) When the cache is taken offline, the state is changed to prevent new accesses, n_accesses is decremented and we wait for n_accesses to become 0. Note that some of this is implemented in a later patch. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819593239.215744.7537428720603638088.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906893368.143852.14164004598465617981.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967093977.1823006.6967886507023056409.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021499995.640689.18286203753480287850.stgit@warthog.procyon.org.uk/ # v4
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David Howells authored
Add functions to the fscache API to allow data file cookies to be acquired and relinquished by the network filesystem. It is intended that the filesystem will create such cookies per-inode under a volume. To request a cookie, the filesystem should call: struct fscache_cookie * fscache_acquire_cookie(struct fscache_volume *volume, u8 advice, const void *index_key, size_t index_key_len, const void *aux_data, size_t aux_data_len, loff_t object_size) The filesystem must first have created a volume cookie, which is passed in here. If it passes in NULL then the function will just return a NULL cookie. A binary key should be passed in index_key and is of size index_key_len. This is saved in the cookie and is used to locate the associated data in the cache. A coherency data buffer of size aux_data_len will be allocated and initialised from the buffer pointed to by aux_data. This is used to validate cache objects when they're opened and is stored on disk with them when they're committed. The data is stored in the cookie and will be updateable by various functions in later patches. The object_size must also be given. This is also used to perform a coherency check and to size the backing storage appropriately. This function disallows a cookie from being acquired twice in parallel, though it will cause the second user to wait if the first is busy relinquishing its cookie. When a network filesystem has finished with a cookie, it should call: void fscache_relinquish_cookie(struct fscache_volume *volume, bool retire) If retire is true, any backing data will be discarded immediately. Changes ======= ver #3: - fscache_hash()'s size parameter is now in bytes. Use __le32 as the unit to round up to. - When comparing cookies, simply see if the attributes are the same rather than subtracting them to produce a strcmp-style return[1]. - Add a check to see if the cookie is still hashed at the point of freeing. ver #2: - Don't hold n_accesses elevated whilst cache is bound to a cookie, but rather add a flag that prevents the state machine from being queued when n_accesses reaches 0. - Remove the unused cookie pointer field from the fscache_acquire tracepoint. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/CAHk-=whtkzB446+hX0zdLsdcUJsJ=8_-0S1mE_R+YurThfUbLA@mail.gmail.com/ [1] Link: https://lore.kernel.org/r/163819590658.215744.14934902514281054323.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906891983.143852.6219772337558577395.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967088507.1823006.12659006350221417165.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021498432.640689.12743483856927722772.stgit@warthog.procyon.org.uk/ # v4
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David Howells authored
Add functions to the fscache API to allow volumes to be acquired and relinquished by the network filesystem. A volume is an index of data storage cache objects. A volume is represented by a volume cookie in the API. A filesystem would typically create a volume for a superblock and then create per-inode cookies within it. To request a volume, the filesystem calls: struct fscache_volume * fscache_acquire_volume(const char *volume_key, const char *cache_name, const void *coherency_data, size_t coherency_len) The volume_key is a printable string used to match the volume in the cache. It should not contain any '/' characters. For AFS, for example, this would be "afs,<cellname>,<volume_id>", e.g. "afs,example.com,523001". The cache_name can be NULL, but if not it should be a string indicating the name of the cache to use if there's more than one available. The coherency data, if given, is an arbitrarily-sized blob that's attached to the volume and is compared when the volume is looked up. If it doesn't match, the old volume is judged to be out of date and it and everything within it is discarded. Acquiring a volume twice concurrently is disallowed, though the function will wait if an old volume cookie is being relinquishing. When a network filesystem has finished with a volume, it should return the volume cookie by calling: void fscache_relinquish_volume(struct fscache_volume *volume, const void *coherency_data, bool invalidate) If invalidate is true, the entire volume will be discarded; if false, the volume will be synced and the coherency data will be updated. Changes ======= ver #4: - Removed an extraneous param from kdoc on fscache_relinquish_volume()[3]. ver #3: - fscache_hash()'s size parameter is now in bytes. Use __le32 as the unit to round up to. - When comparing cookies, simply see if the attributes are the same rather than subtracting them to produce a strcmp-style return[2]. - Make the coherency data an arbitrary blob rather than a u64, but don't store it for the moment. ver #2: - Fix error check[1]. - Make a fscache_acquire_volume() return errors, including EBUSY if a conflicting volume cookie already exists. No error is printed now - that's left to the netfs. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/20211203095608.GC2480@kili/ [1] Link: https://lore.kernel.org/r/CAHk-=whtkzB446+hX0zdLsdcUJsJ=8_-0S1mE_R+YurThfUbLA@mail.gmail.com/ [2] Link: https://lore.kernel.org/r/20211220224646.30e8205c@canb.auug.org.au/ [3] Link: https://lore.kernel.org/r/163819588944.215744.1629085755564865996.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906890630.143852.13972180614535611154.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967086836.1823006.8191672796841981763.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021495816.640689.4403156093668590217.stgit@warthog.procyon.org.uk/ # v4
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David Howells authored
Implement a register of caches and provide functions to manage it. Two functions are provided for the cache backend to use: (1) Acquire a cache cookie: struct fscache_cache *fscache_acquire_cache(const char *name) This gets the cache cookie for a cache of the specified name and moves it to the preparation state. If a nameless cache cookie exists, that will be given this name and used. (2) Relinquish a cache cookie: void fscache_relinquish_cache(struct fscache_cache *cache); This relinquishes a cache cookie, cleans it and makes it available if it's still referenced by a network filesystem. Note that network filesystems don't deal with cache cookies directly, but rather go straight to the volume registration. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819587157.215744.13523139317322503286.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906889665.143852.10378009165231294456.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967085081.1823006.2218944206363626210.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021494847.640689.10109692261640524343.stgit@warthog.procyon.org.uk/ # v4
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David Howells authored
Implement a function to generate hashes. It needs to be stable over time and endianness-independent as the hashes will appear on disk in future patches. It can assume that its input is a multiple of four bytes in size and alignment. This is borrowed from the VFS and simplified. le32_to_cpu() is added to make it endianness-independent. Changes ======= ver #3: - Read the data being hashed in an endianness-independent way[1]. - Change the size parameter to be in bytes rather than words. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/CAHk-=whtkzB446+hX0zdLsdcUJsJ=8_-0S1mE_R+YurThfUbLA@mail.gmail.com [1] Link: https://lore.kernel.org/r/163819586113.215744.1699465806130102367.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906888735.143852.10944614318596881429.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967082342.1823006.8915671045444488742.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021493624.640689.9990442668811178628.stgit@warthog.procyon.org.uk/ # v4
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David Howells authored
Introduce basic skeleton of the new, rewritten fscache driver. Changes ======= ver #3: - Use remove_proc_subtree(), not remove_proc_entry() to remove a populated dir. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819584034.215744.4290533472390439030.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906887770.143852.3577888294989185666.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967080039.1823006.5702921801104057922.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021491014.640689.4292699878317589512.stgit@warthog.procyon.org.uk/ # v4
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David Howells authored
Pass a flag to ->prepare_write() to indicate if there's definitely no space allocated in the cache yet (for instance if we've already checked as we were asked to do a read). Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819583123.215744.12783808230464471417.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906886835.143852.6689886781122679769.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967079100.1823006.12889542712309574359.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021489334.640689.3131206613015409076.stgit@warthog.procyon.org.uk/ # v4
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David Howells authored
Display the netfs inode number in the netfs_read tracepoint so that this can be used to correlate with the cachefiles_prep_read tracepoint. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819581097.215744.17476611915583897051.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906885903.143852.12229407815154182247.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967078164.1823006.15286989199782861123.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021487412.640689.7544388469390936443.stgit@warthog.procyon.org.uk/ # v4
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David Howells authored
Remove the code that comprises the fscache driver as it's going to be substantially rewritten, with the majority of the code being erased in the rewrite. A small piece of linux/fscache.h is left as that is #included by a bunch of network filesystems. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819578724.215744.18210619052245724238.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906884814.143852.6727245089843862889.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967077097.1823006.1377665951499979089.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021485548.640689.13876080567388696162.stgit@warthog.procyon.org.uk/ # v4
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David Howells authored
Delete the code from the cachefiles driver to make it easier to rewrite and resubmit in a logical manner. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819577641.215744.12718114397770666596.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906883770.143852.4149714614981373410.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967076066.1823006.7175712134577687753.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021483619.640689.7586546280515844702.stgit@warthog.procyon.org.uk/ # v4
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David Howells authored
Disable fscache and cachefiles in Kconfig whilst it is rewritten. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819576672.215744.12444272479560406780.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906882835.143852.11073015983885872901.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967075113.1823006.277316290062782998.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021481179.640689.2004199594774033658.stgit@warthog.procyon.org.uk/ # v4
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- 07 Dec, 2021 2 commits
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Jeffle Xu authored
The order of these two parameters is just reversed. gcc didn't warn on that, probably because 'void *' can be converted from or to other pointer types without warning. Cc: stable@vger.kernel.org Fixes: 3d3c9504 ("netfs: Provide readahead and readpage netfs helpers") Fixes: e1b1240c ("netfs: Add write_begin helper") Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> Link: https://lore.kernel.org/r/20211207031449.100510-1-jefflexu@linux.alibaba.com/ # v1
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David Howells authored
Taking sb_writers whilst holding mmap_lock isn't allowed and will result in a lockdep warning like that below. The problem comes from cachefiles needing to take the sb_writers lock in order to do a write to the cache, but being asked to do this by netfslib called from readpage, readahead or write_begin[1]. Fix this by always offloading the write to the cache off to a worker thread. The main thread doesn't need to wait for it, so deadlock can be avoided. This can be tested by running the quick xfstests on something like afs or ceph with lockdep enabled. WARNING: possible circular locking dependency detected 5.15.0-rc1-build2+ #292 Not tainted ------------------------------------------------------ holetest/65517 is trying to acquire lock: ffff88810c81d730 (mapping.invalidate_lock#3){.+.+}-{3:3}, at: filemap_fault+0x276/0x7a5 but task is already holding lock: ffff8881595b53e8 (&mm->mmap_lock#2){++++}-{3:3}, at: do_user_addr_fault+0x28d/0x59c which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&mm->mmap_lock#2){++++}-{3:3}: validate_chain+0x3c4/0x4a8 __lock_acquire+0x89d/0x949 lock_acquire+0x2dc/0x34b __might_fault+0x87/0xb1 strncpy_from_user+0x25/0x18c removexattr+0x7c/0xe5 __do_sys_fremovexattr+0x73/0x96 do_syscall_64+0x67/0x7a entry_SYSCALL_64_after_hwframe+0x44/0xae -> #1 (sb_writers#10){.+.+}-{0:0}: validate_chain+0x3c4/0x4a8 __lock_acquire+0x89d/0x949 lock_acquire+0x2dc/0x34b cachefiles_write+0x2b3/0x4bb netfs_rreq_do_write_to_cache+0x3b5/0x432 netfs_readpage+0x2de/0x39d filemap_read_page+0x51/0x94 filemap_get_pages+0x26f/0x413 filemap_read+0x182/0x427 new_sync_read+0xf0/0x161 vfs_read+0x118/0x16e ksys_read+0xb8/0x12e do_syscall_64+0x67/0x7a entry_SYSCALL_64_after_hwframe+0x44/0xae -> #0 (mapping.invalidate_lock#3){.+.+}-{3:3}: check_noncircular+0xe4/0x129 check_prev_add+0x16b/0x3a4 validate_chain+0x3c4/0x4a8 __lock_acquire+0x89d/0x949 lock_acquire+0x2dc/0x34b down_read+0x40/0x4a filemap_fault+0x276/0x7a5 __do_fault+0x96/0xbf do_fault+0x262/0x35a __handle_mm_fault+0x171/0x1b5 handle_mm_fault+0x12a/0x233 do_user_addr_fault+0x3d2/0x59c exc_page_fault+0x85/0xa5 asm_exc_page_fault+0x1e/0x30 other info that might help us debug this: Chain exists of: mapping.invalidate_lock#3 --> sb_writers#10 --> &mm->mmap_lock#2 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&mm->mmap_lock#2); lock(sb_writers#10); lock(&mm->mmap_lock#2); lock(mapping.invalidate_lock#3); *** DEADLOCK *** 1 lock held by holetest/65517: #0: ffff8881595b53e8 (&mm->mmap_lock#2){++++}-{3:3}, at: do_user_addr_fault+0x28d/0x59c stack backtrace: CPU: 0 PID: 65517 Comm: holetest Not tainted 5.15.0-rc1-build2+ #292 Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014 Call Trace: dump_stack_lvl+0x45/0x59 check_noncircular+0xe4/0x129 ? print_circular_bug+0x207/0x207 ? validate_chain+0x461/0x4a8 ? add_chain_block+0x88/0xd9 ? hlist_add_head_rcu+0x49/0x53 check_prev_add+0x16b/0x3a4 validate_chain+0x3c4/0x4a8 ? check_prev_add+0x3a4/0x3a4 ? mark_lock+0xa5/0x1c6 __lock_acquire+0x89d/0x949 lock_acquire+0x2dc/0x34b ? filemap_fault+0x276/0x7a5 ? rcu_read_unlock+0x59/0x59 ? add_to_page_cache_lru+0x13c/0x13c ? lock_is_held_type+0x7b/0xd3 down_read+0x40/0x4a ? filemap_fault+0x276/0x7a5 filemap_fault+0x276/0x7a5 ? pagecache_get_page+0x2dd/0x2dd ? __lock_acquire+0x8bc/0x949 ? pte_offset_kernel.isra.0+0x6d/0xc3 __do_fault+0x96/0xbf ? do_fault+0x124/0x35a do_fault+0x262/0x35a ? handle_pte_fault+0x1c1/0x20d __handle_mm_fault+0x171/0x1b5 ? handle_pte_fault+0x20d/0x20d ? __lock_release+0x151/0x254 ? mark_held_locks+0x1f/0x78 ? rcu_read_unlock+0x3a/0x59 handle_mm_fault+0x12a/0x233 do_user_addr_fault+0x3d2/0x59c ? pgtable_bad+0x70/0x70 ? rcu_read_lock_bh_held+0xab/0xab exc_page_fault+0x85/0xa5 ? asm_exc_page_fault+0x8/0x30 asm_exc_page_fault+0x1e/0x30 RIP: 0033:0x40192f Code: ff 48 89 c3 48 8b 05 50 28 00 00 48 85 ed 7e 23 31 d2 4b 8d 0c 2f eb 0a 0f 1f 00 48 8b 05 39 28 00 00 48 0f af c2 48 83 c2 01 <48> 89 1c 01 48 39 d5 7f e8 8b 0d f2 27 00 00 31 c0 85 c9 74 0e 8b RSP: 002b:00007f9931867eb0 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 00007f9931868700 RCX: 00007f993206ac00 RDX: 0000000000000001 RSI: 0000000000000000 RDI: 00007ffc13e06ee0 RBP: 0000000000000100 R08: 0000000000000000 R09: 00007f9931868700 R10: 00007f99318689d0 R11: 0000000000000202 R12: 00007ffc13e06ee0 R13: 0000000000000c00 R14: 00007ffc13e06e00 R15: 00007f993206a000 Fixes: 726218fd ("netfs: Define an interface to talk to a cache") Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Jeff Layton <jlayton@kernel.org> cc: Jan Kara <jack@suse.cz> cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/20210922110420.GA21576@quack2.suse.cz/ [1] Link: https://lore.kernel.org/r/163887597541.1596626.2668163316598972956.stgit@warthog.procyon.org.uk/ # v1
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- 05 Dec, 2021 12 commits
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Linus Torvalds authored
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git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linuxLinus Torvalds authored
Pull parisc fixes from Helge Deller: "Some bug and warning fixes: - Fix "make install" to use debians "installkernel" script which is now in /usr/sbin - Fix the bindeb-pkg make target by giving the correct KBUILD_IMAGE file name - Fix compiler warnings by annotating parisc agp init functions with __init - Fix timekeeping on SMP machines with dual-core CPUs - Enable some more config options in the 64-bit defconfig" * tag 'for-5.16/parisc-6' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux: parisc: Mark cr16 CPU clocksource unstable on all SMP machines parisc: Fix "make install" on newer debian releases parisc/agp: Annotate parisc agp init functions with __init parisc: Enable sata sil, audit and usb support on 64-bit defconfig parisc: Fix KBUILD_IMAGE for self-extracting kernel
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usbLinus Torvalds authored
Pull USB fixes from Greg KH: "Here are some small USB fixes for a few reported issues. Included in here are: - xhci fix for a _much_ reported regression. I don't think there's a community distro that has not reported this problem yet :( - new USB quirk addition - cdns3 minor fixes - typec regression fix. All of these have been in linux-next with no reported problems, and the xhci fix has been reported by many to resolve their reported problem" * tag 'usb-5.16-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: usb: cdnsp: Fix a NULL pointer dereference in cdnsp_endpoint_init() usb: cdns3: gadget: fix new urb never complete if ep cancel previous requests usb: typec: tcpm: Wait in SNK_DEBOUNCED until disconnect USB: NO_LPM quirk Lenovo Powered USB-C Travel Hub xhci: Fix commad ring abort, write all 64 bits to CRCR register.
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/ttyLinus Torvalds authored
Pull tty/serial fixes from Greg KH: "Here are some small TTY and Serial driver fixes for 5.16-rc4 to resolve a number of reported problems. They include: - liteuart serial driver fixes - 8250_pci serial driver fixes for pericom devices - 8250 RTS line control fix while in RS-485 mode - tegra serial driver fix - msm_serial driver fix - pl011 serial driver new id - fsl_lpuart revert of broken change - 8250_bcm7271 serial driver fix - MAINTAINERS file update for rpmsg tty driver that came in 5.16-rc1 - vgacon fix for reported problem All of these, except for the 8250_bcm7271 fix have been in linux-next with no reported problem. The 8250_bcm7271 fix was added to the tree on Friday so no chance to be linux-next yet. But it should be fine as the affected developers submitted it" * tag 'tty-5.16-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: serial: 8250_bcm7271: UART errors after resuming from S2 serial: 8250_pci: rewrite pericom_do_set_divisor() serial: 8250_pci: Fix ACCES entries in pci_serial_quirks array serial: 8250: Fix RTS modem control while in rs485 mode Revert "tty: serial: fsl_lpuart: drop earlycon entry for i.MX8QXP" serial: tegra: Change lower tolerance baud rate limit for tegra20 and tegra30 serial: liteuart: relax compile-test dependencies serial: liteuart: fix minor-number leak on probe errors serial: liteuart: fix use-after-free and memleak on unbind serial: liteuart: Fix NULL pointer dereference in ->remove() vgacon: Propagate console boot parameters before calling `vc_resize' tty: serial: msm_serial: Deactivate RX DMA for polling support serial: pl011: Add ACPI SBSA UART match id serial: core: fix transmit-buffer reset and memleak MAINTAINERS: Add rpmsg tty driver maintainer
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull timer fix from Borislav Petkov: - Prevent a tick storm when a dedicated timekeeper CPU in nohz_full mode runs for prolonged periods with interrupts disabled and ends up programming the next tick in the past, leading to that storm * tag 'timers_urgent_for_v5.16_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: timers/nohz: Last resort update jiffies on nohz_full IRQ entry
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull scheduler fixes from Borislav Petkov: - Properly init uclamp_flags of a runqueue, on first enqueuing - Fix preempt= callback return values - Correct utime/stime resource usage reporting on nohz_full to return the proper times instead of shorter ones * tag 'sched_urgent_for_v5.16_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/uclamp: Fix rq->uclamp_max not set on first enqueue preempt/dynamic: Fix setup_preempt_mode() return value sched/cputime: Fix getrusage(RUSAGE_THREAD) with nohz_full
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull x86 fixes from Borislav Petkov: - Fix a couple of SWAPGS fencing issues in the x86 entry code - Use the proper operand types in __{get,put}_user() to prevent truncation in SEV-ES string io - Make sure the kernel mappings are present in trampoline_pgd in order to prevent any potential accesses to unmapped memory after switching to it - Fix a trivial list corruption in objtool's pv_ops validation - Disable the clocksource watchdog for TSC on platforms which claim that the TSC is constant, doesn't stop in sleep states, CPU has TSC adjust and the number of sockets of the platform are max 2, to prevent erroneous markings of the TSC as unstable. - Make sure TSC adjust is always checked not only when going idle - Prevent a stack leak by initializing struct _fpx_sw_bytes properly in the FPU code - Fix INTEL_FAM6_RAPTORLAKE define naming to adhere to the convention * tag 'x86_urgent_for_v5.16_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/xen: Add xenpv_restore_regs_and_return_to_usermode() x86/entry: Use the correct fence macro after swapgs in kernel CR3 x86/entry: Add a fence for kernel entry SWAPGS in paranoid_entry() x86/sev: Fix SEV-ES INS/OUTS instructions for word, dword, and qword x86/64/mm: Map all kernel memory into trampoline_pgd objtool: Fix pv_ops noinstr validation x86/tsc: Disable clocksource watchdog for TSC on qualified platorms x86/tsc: Add a timer to make sure TSC_adjust is always checked x86/fpu/signal: Initialize sw_bytes in save_xstate_epilog() x86/cpu: Drop spurious underscore from RAPTOR_LAKE #define
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git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds authored
Pull more kvm fixes from Paolo Bonzini: - Static analysis fix - New SEV-ES protocol for communicating invalid VMGEXIT requests - Ensure APICv is considered inactive if there is no APIC - Fix reserved bits for AMD PerfEvtSeln register * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: KVM: SVM: Do not terminate SEV-ES guests on GHCB validation failure KVM: SEV: Fall back to vmalloc for SEV-ES scratch area if necessary KVM: SEV: Return appropriate error codes if SEV-ES scratch setup fails KVM: x86/mmu: Retry page fault if root is invalidated by memslot update KVM: VMX: Set failure code in prepare_vmcs02() KVM: ensure APICv is considered inactive if there is no APIC KVM: x86/pmu: Fix reserved bits for AMD PerfEvtSeln register
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Tom Lendacky authored
Currently, an SEV-ES guest is terminated if the validation of the VMGEXIT exit code or exit parameters fails. The VMGEXIT instruction can be issued from userspace, even though userspace (likely) can't update the GHCB. To prevent userspace from being able to kill the guest, return an error through the GHCB when validation fails rather than terminating the guest. For cases where the GHCB can't be updated (e.g. the GHCB can't be mapped, etc.), just return back to the guest. The new error codes are documented in the lasest update to the GHCB specification. Fixes: 291bd20d ("KVM: SVM: Add initial support for a VMGEXIT VMEXIT") Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Message-Id: <b57280b5562893e2616257ac9c2d4525a9aeeb42.1638471124.git.thomas.lendacky@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Use kvzalloc() to allocate KVM's buffer for SEV-ES's GHCB scratch area so that KVM falls back to __vmalloc() if physically contiguous memory isn't available. The buffer is purely a KVM software construct, i.e. there's no need for it to be physically contiguous. Cc: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211109222350.2266045-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Return appropriate error codes if setting up the GHCB scratch area for an SEV-ES guest fails. In particular, returning -EINVAL instead of -ENOMEM when allocating the kernel buffer could be confusing as userspace would likely suspect a guest issue. Fixes: 8f423a80 ("KVM: SVM: Support MMIO for an SEV-ES guest") Cc: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211109222350.2266045-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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git://git.kernel.org/pub/scm/fs/xfs/xfs-linuxLinus Torvalds authored
Pull xfs fix from Darrick Wong: "Remove an unnecessary (and backwards) rename flags check that duplicates a VFS level check" * tag 'xfs-5.16-fixes-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: xfs: remove incorrect ASSERT in xfs_rename
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- 04 Dec, 2021 8 commits
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git://git.samba.org/sfrench/cifs-2.6Linus Torvalds authored
Pull cifs fixes from Steve French: "Three SMB3 multichannel/fscache fixes and a DFS fix. In testing multichannel reconnect scenarios recently various problems with the cifs.ko implementation of fscache were found (e.g. incorrect initialization of fscache cookies in some cases)" * tag '5.16-rc3-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6: cifs: avoid use of dstaddr as key for fscache client cookie cifs: add server conn_id to fscache client cookie cifs: wait for tcon resource_id before getting fscache super cifs: fix missed refcounting of ipc tcon
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Helge Deller authored
In commit c8c37359 ("parisc: Enhance detection of synchronous cr16 clocksources") I assumed that CPUs on the same physical core are syncronous. While booting up the kernel on two different C8000 machines, one with a dual-core PA8800 and one with a dual-core PA8900 CPU, this turned out to be wrong. The symptom was that I saw a jump in the internal clocks printed to the syslog and strange overall behaviour. On machines which have 4 cores (2 dual-cores) the problem isn't visible, because the current logic already marked the cr16 clocksource unstable in this case. This patch now marks the cr16 interval timers unstable if we have more than one CPU in the system, and it fixes this issue. Fixes: c8c37359 ("parisc: Enhance detection of synchronous cr16 clocksources") Signed-off-by: Helge Deller <deller@gmx.de> Cc: <stable@vger.kernel.org> # v5.15+
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Helge Deller authored
On newer debian releases the debian-provided "installkernel" script is installed in /usr/sbin. Fix the kernel install.sh script to look for the script in this directory as well. Signed-off-by: Helge Deller <deller@gmx.de> Cc: <stable@vger.kernel.org> # v3.13+
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git://git.kernel.dk/linux-blockLinus Torvalds authored
Pull block fix from Jens Axboe: "A single fix for repeated printk spam from loop" * tag 'block-5.16-2021-12-03' of git://git.kernel.dk/linux-block: loop: Use pr_warn_once() for loop_control_remove() warning
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git://git.kernel.dk/linux-blockLinus Torvalds authored
Pull io_uring fix from Jens Axboe: "Just a single fix preventing repeated retries of task_work based io-wq thread creation, fixing a regression from when io-wq was made more (a bit too much) resilient against signals" * tag 'io_uring-5.16-2021-12-03' of git://git.kernel.dk/linux-block: io-wq: don't retry task_work creation failure on fatal conditions
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git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsiLinus Torvalds authored
Pull SCSI fixes from James Bottomley: "Two patches, both in drivers. One is a fix to FC recovery (lpfc) and the other is an enhancement to support the Intel Alder Motherboard with the UFS driver which comes under the -rc exception process for hardware enabling" * tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: scsi: ufs: ufs-pci: Add support for Intel ADL scsi: lpfc: Fix non-recovery of remote ports following an unsolicited LOGO
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git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2Linus Torvalds authored
Pull gfs2 fixes from Andreas Gruenbacher: - Since commit 486408d6 ("gfs2: Cancel remote delete work asynchronously"), inode create and lookup-by-number can overlap more easily and we can end up with temporary duplicate inodes. Fix the code to prevent that. - Fix a BUG demoting weak glock holders from a remote node. * tag 'gfs2-v5.16-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2: gfs2: gfs2_create_inode rework gfs2: gfs2_inode_lookup rework gfs2: gfs2_inode_lookup cleanup gfs2: Fix remote demote of weak glock holders
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Qais Yousef authored
Commit d81ae8aa ("sched/uclamp: Fix initialization of struct uclamp_rq") introduced a bug where uclamp_max of the rq is not reset to match the woken up task's uclamp_max when the rq is idle. The code was relying on rq->uclamp_max initialized to zero, so on first enqueue static inline void uclamp_rq_inc_id(struct rq *rq, struct task_struct *p, enum uclamp_id clamp_id) { ... if (uc_se->value > READ_ONCE(uc_rq->value)) WRITE_ONCE(uc_rq->value, uc_se->value); } was actually resetting it. But since commit d81ae8aa changed the default to 1024, this no longer works. And since rq->uclamp_flags is also initialized to 0, neither above code path nor uclamp_idle_reset() update the rq->uclamp_max on first wake up from idle. This is only visible from first wake up(s) until the first dequeue to idle after enabling the static key. And it only matters if the uclamp_max of this task is < 1024 since only then its uclamp_max will be effectively ignored. Fix it by properly initializing rq->uclamp_flags = UCLAMP_FLAG_IDLE to ensure uclamp_idle_reset() is called which then will update the rq uclamp_max value as expected. Fixes: d81ae8aa ("sched/uclamp: Fix initialization of struct uclamp_rq") Signed-off-by: Qais Yousef <qais.yousef@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Valentin Schneider <Valentin.Schneider@arm.com> Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Link: https://lkml.kernel.org/r/20211202112033.1705279-1-qais.yousef@arm.com
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