kernel.git/fs/gfs2/glops.c, branch linux-6.5.y

gfs2: Fix another freeze/thaw hang

2023-10-06T11:15:45Z

[ Upstream commit 52954b750958dcab9e44935f0c32643279091c85 ] On a thawed filesystem, the freeze glock is held in shared mode. In order to initiate a cluster-wide freeze, the node initiating the freeze drops the freeze glock and grabs it in exclusive mode. The other nodes recognize this as contention on the freeze glock; function freeze_go_callback is invoked. This indicates to them that they must freeze the filesystem locally, drop the freeze glock, and then re-acquire it in shared mode before being able to unfreeze the filesystem locally. While a node is trying to re-acquire the freeze glock in shared mode, additional contention can occur. In that case, the node must behave in the same way as above. Unfortunately, freeze_go_callback() contains a check that causes it to bail out when the freeze glock isn't held in shared mode. Fix that to allow the glock to be unlocked or held in shared mode. In addition, update a reference to trylock_super() which has been renamed to super_trylock_shared() in the meantime. Fixes: b77b4a4815a9 ("gfs2: Rework freeze / thaw logic") Signed-off-by: Andreas Gruenbacher Signed-off-by: Sasha Levin

gfs: Get rid of unnucessary locking in inode_go_dump

2023-07-03T20:30:47Z

Commit 27a2660f1ef9 ("gfs2: Dump nrpages for inodes and their glocks") added some locking around reading inode->i_data.nrpages. That locking doesn't do anything really, so get rid of it. With that, the glock argument to ->go_dump() can be made const again as well. Signed-off-by: Andreas Gruenbacher

gfs2: Rework freeze / thaw logic

2023-07-03T20:25:02Z

So far, at mount time, gfs2 would take the freeze glock in shared mode and then immediately drop it again, turning it into a cached glock that can be reclaimed at any time. To freeze the filesystem cluster-wide, the node initiating the freeze would take the freeze glock in exclusive mode, which would cause the freeze glock's freeze_go_sync() callback to run on each node. There, gfs2 would freeze the filesystem and schedule gfs2_freeze_func() to run. gfs2_freeze_func() would re-acquire the freeze glock in shared mode, thaw the filesystem, and drop the freeze glock again. The initiating node would keep the freeze glock held in exclusive mode. To thaw the filesystem, the initiating node would drop the freeze glock again, which would allow gfs2_freeze_func() to resume on all nodes, leaving the filesystem in the thawed state. It turns out that in freeze_go_sync(), we cannot reliably and safely freeze the filesystem. This is primarily because the final unmount of a filesystem takes a write lock on the s_umount rw semaphore before calling into gfs2_put_super(), and freeze_go_sync() needs to call freeze_super() which also takes a write lock on the same semaphore, causing a deadlock. We could work around this by trying to take an active reference on the super block first, which would prevent unmount from running at the same time. But that can fail, and freeze_go_sync() isn't actually allowed to fail. To get around this, this patch changes the freeze glock locking scheme as follows: At mount time, each node takes the freeze glock in shared mode. To freeze a filesystem, the initiating node first freezes the filesystem locally and then drops and re-acquires the freeze glock in exclusive mode. All other nodes notice that there is contention on the freeze glock in their go_callback callbacks, and they schedule gfs2_freeze_func() to run. There, they freeze the filesystem locally and drop and re-acquire the freeze glock before re-thawing the filesystem. This is happening outside of the glock state engine, so there, we are allowed to fail. From a cluster point of view, taking and immediately dropping a glock is indistinguishable from taking the glock and only dropping it upon contention, so this new scheme is compatible with the old one. Thanks to Li Dong for reporting a locking bug in gfs2_freeze_func() in a previous version of this commit. Signed-off-by: Andreas Gruenbacher

gfs2: gfs2_ail_empty_gl no log flush on error

2023-04-25T09:07:16Z

Before this patch, function gfs2_ail_empty_gl called gfs2_log_flush even in cases where it encountered an error. It should probably skip the log flush and leave the file system in an inconsistent state, letting a subsequent withdraw force the journal to be replayed to reestablish metadata consistency. Signed-off-by: Bob Peterson Signed-off-by: Andreas Gruenbacher

gfs2: Issue message when revokes cannot be written

2023-04-25T09:06:30Z

Before this patch, function gfs2_ail_empty_gl would silently return an error to the caller. This would get silently set into sd_log_error which would cause a withdraw, but there was no indication why the file system was withdrawn. This patch adds a fs_err to log the appropriate error message. Signed-off-by: Bob Peterson Signed-off-by: Andreas Gruenbacher

gfs2: return errors from gfs2_ail_empty_gl

2023-04-25T09:00:21Z

Before this patch, function gfs2_ail_empty_gl did not return errors it encountered from __gfs2_trans_begin. Those errors usually came from the fact that the file system was made read-only, often due to unmount (but theoretically could be due to -o remount,ro), which prevented the transaction from starting. The inability to start a transaction prevented its revokes from being properly written to the journal for glocks during unmount (and transition to ro). That meant glocks could be unlocked without the metadata properly revoked in the journal. So other nodes could grab the glock thinking that their lvb values were correct, but in fact corresponded to the glock without its revokes properly synced. That presented as lvb mismatch errors. This patch allows gfs2_ail_empty_gl to return the error properly to the caller. Signed-off-by: Bob Peterson Signed-off-by: Andreas Gruenbacher

gfs2: Move variable assignment behind a null pointer check in inode_go_dump

2023-04-18T12:58:32Z

Since commit 27a2660f1ef9 ("gfs2: Dump nrpages for inodes and their glocks"), inode_go_dump() computes the address of inode within ip before checking if ip is NULL. This isn't a bug by itself, but it can give rise to bugs later. Avoid that by checking if ip is NULL first. Signed-off-by: Markus Elfring Signed-off-by: Andreas Gruenbacher

gfs2: Fix inode height consistency check

2023-03-27T22:57:47Z

The maximum allowed height of an inode's metadata tree depends on the filesystem block size; it is lower for bigger-block filesystems. When reading in an inode, make sure that the height doesn't exceed the maximum allowed height. Arrays like sd_heightsize are sized to be big enough for any filesystem block size; they will often be slightly bigger than what's needed for a specific filesystem. Reported-by: syzbot+45d4691b1ed3c48eba05@syzkaller.appspotmail.com Signed-off-by: Andreas Gruenbacher

Merge tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-02-24T01:09:35Z

Pull MM updates from Andrew Morton: - Daniel Verkamp has contributed a memfd series ("mm/memfd: add F_SEAL_EXEC") which permits the setting of the memfd execute bit at memfd creation time, with the option of sealing the state of the X bit. - Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset() thread-safe for pmd unshare") which addresses a rare race condition related to PMD unsharing. - Several folioification patch serieses from Matthew Wilcox, Vishal Moola, Sidhartha Kumar and Lorenzo Stoakes - Johannes Weiner has a series ("mm: push down lock_page_memcg()") which does perform some memcg maintenance and cleanup work. - SeongJae Park has added DAMOS filtering to DAMON, with the series "mm/damon/core: implement damos filter". These filters provide users with finer-grained control over DAMOS's actions. SeongJae has also done some DAMON cleanup work. - Kairui Song adds a series ("Clean up and fixes for swap"). - Vernon Yang contributed the series "Clean up and refinement for maple tree". - Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It adds to MGLRU an LRU of memcgs, to improve the scalability of global reclaim. - David Hildenbrand has added some userfaultfd cleanup work in the series "mm: uffd-wp + change_protection() cleanups". - Christoph Hellwig has removed the generic_writepages() library function in the series "remove generic_writepages". - Baolin Wang has performed some maintenance on the compaction code in his series "Some small improvements for compaction". - Sidhartha Kumar is doing some maintenance work on struct page in his series "Get rid of tail page fields". - David Hildenbrand contributed some cleanup, bugfixing and generalization of pte management and of pte debugging in his series "mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with swap PTEs". - Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation flag in the series "Discard __GFP_ATOMIC". - Sergey Senozhatsky has improved zsmalloc's memory utilization with his series "zsmalloc: make zspage chain size configurable". - Joey Gouly has added prctl() support for prohibiting the creation of writeable+executable mappings. The previous BPF-based approach had shortcomings. See "mm: In-kernel support for memory-deny-write-execute (MDWE)". - Waiman Long did some kmemleak cleanup and bugfixing in the series "mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF". - T.J. Alumbaugh has contributed some MGLRU cleanup work in his series "mm: multi-gen LRU: improve". - Jiaqi Yan has provided some enhancements to our memory error statistics reporting, mainly by presenting the statistics on a per-node basis. See the series "Introduce per NUMA node memory error statistics". - Mel Gorman has a second and hopefully final shot at fixing a CPU-hog regression in compaction via his series "Fix excessive CPU usage during compaction". - Christoph Hellwig does some vmalloc maintenance work in the series "cleanup vfree and vunmap". - Christoph Hellwig has removed block_device_operations.rw_page() in ths series "remove ->rw_page". - We get some maple_tree improvements and cleanups in Liam Howlett's series "VMA tree type safety and remove __vma_adjust()". - Suren Baghdasaryan has done some work on the maintainability of our vm_flags handling in the series "introduce vm_flags modifier functions". - Some pagemap cleanup and generalization work in Mike Rapoport's series "mm, arch: add generic implementation of pfn_valid() for FLATMEM" and "fixups for generic implementation of pfn_valid()" - Baoquan He has done some work to make /proc/vmallocinfo and /proc/kcore better represent the real state of things in his series "mm/vmalloc.c: allow vread() to read out vm_map_ram areas". - Jason Gunthorpe rationalized the GUP system's interface to the rest of the kernel in the series "Simplify the external interface for GUP". - SeongJae Park wishes to migrate people from DAMON's debugfs interface over to its sysfs interface. To support this, we'll temporarily be printing warnings when people use the debugfs interface. See the series "mm/damon: deprecate DAMON debugfs interface". - Andrey Konovalov provided the accurately named "lib/stackdepot: fixes and clean-ups" series. - Huang Ying has provided a dramatic reduction in migration's TLB flush IPI rates with the series "migrate_pages(): batch TLB flushing". - Arnd Bergmann has some objtool fixups in "objtool warning fixes". * tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (505 commits) include/linux/migrate.h: remove unneeded externs mm/memory_hotplug: cleanup return value handing in do_migrate_range() mm/uffd: fix comment in handling pte markers mm: change to return bool for isolate_movable_page() mm: hugetlb: change to return bool for isolate_hugetlb() mm: change to return bool for isolate_lru_page() mm: change to return bool for folio_isolate_lru() objtool: add UACCESS exceptions for __tsan_volatile_read/write kmsan: disable ftrace in kmsan core code kasan: mark addr_has_metadata __always_inline mm: memcontrol: rename memcg_kmem_enabled() sh: initialize max_mapnr m68k/nommu: add missing definition of ARCH_PFN_OFFSET mm: percpu: fix incorrect size in pcpu_obj_full_size() maple_tree: reduce stack usage with gcc-9 and earlier mm: page_alloc: call panic() when memoryless node allocation fails mm: multi-gen LRU: avoid futile retries migrate_pages: move THP/hugetlb migration support check to simplify code migrate_pages: batch flushing TLB migrate_pages: share more code between _unmap and _move ...

gfs2: Cease delete work during unmount

2023-01-31T21:40:24Z

Add a check to delete_work_func() so that it quits when it finds that the filesystem is deactivating. This speeds up the delete workqueue draining in gfs2_kill_sb(). In addition, make sure that iopen_go_callback() won't queue any new delete work while the filesystem is deactivating. Signed-off-by: Bob Peterson Signed-off-by: Andreas Gruenbacher