| Message ID | 2420479.1638912905@warthog.procyon.org.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [GIT,PULL] netfs: Potential deadlock and error handling fixes | expand |
The pull request you sent on Tue, 07 Dec 2021 21:35:05 +0000:
> git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git tags/netfs-fixes-20211207
has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/2990c89d1df457bd623371324998ee849806ddd3
Thank you!
Hi Linus, Could you pull these fixes for the netfs lib? There are two: (1) 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. (2) 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*. David 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] --- The following changes since commit 0fcfb00b28c0b7884635dacf38e46d60bf3d4eb1: Linux 5.16-rc4 (2021-12-05 14:08:22 -0800) are available in the Git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git tags/netfs-fixes-20211207 for you to fetch changes up to 3cfef1b612e15a0c2f5b1c9d3f3f31ad72d56fcd: netfs: fix parameter of cleanup() (2021-12-07 15:47:09 +0000) ---------------------------------------------------------------- netfslib fixes ---------------------------------------------------------------- David Howells (1): netfs: Fix lockdep warning from taking sb_writers whilst holding mmap_lock Jeffle Xu (1): netfs: fix parameter of cleanup() fs/netfs/read_helper.c | 21 ++++++++------------- 1 file changed, 8 insertions(+), 13 deletions(-)