Merge tag 'netfs-fixes-20211207' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull netfslib fixes from David Howells: - Fix a lockdep warning and potential deadlock. This is takes the simple approach of offloading the write-to-cache done from within a network filesystem read to a worker thread to avoid taking the sb_writer lock from the cache backing filesystem whilst holding the mmap lock on an inode from the network filesystem. Jan Kara posits a scenario whereby this can cause deadlock[1], though it's quite complex and I think requires someone in userspace to actually do I/O on the cache files. Matthew Wilcox isn't so certain, though[2]. An alternative way to fix this, suggested by Darrick Wong, might be to allow cachefiles to prevent userspace from performing I/O upon the file - something like an exclusive open - but that's beyond the scope of a fix here if we do want to make such a facility in the future. - In some of the error handling paths where netfs_ops->cleanup() is called, the arguments are transposed[3]. gcc doesn't complain because one of the parameters is void* and one of the values is void*. Link: https://lore.kernel.org/r/20210922110420.GA21576@quack2.suse.cz/ [1] Link: https://lore.kernel.org/r/Ya9eDiFCE2fO7K/S@casper.infradead.org/ [2] Link: https://lore.kernel.org/r/20211207031449.100510-1-jefflexu@linux.alibaba.com/ [3] * tag 'netfs-fixes-20211207' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: netfs: fix parameter of cleanup() netfs: Fix lockdep warning from taking sb_writers whilst holding mmap_lock
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