Pull 9p update from Dominique Martinet: - fix long-standing limitation on open-unlink-fop pattern - add refcount to p9_fid (fixes the above and will allow for more cleanups and simplifications in the future) * tag '9p-for-5.11-rc1' of git://github.com/martinetd/linux: 9p: Remove unnecessary IS_ERR() check 9p: Uninitialized variable in v9fs_writeback_fid() 9p: Fix writeback fid incorrectly being attached to dentry 9p: apply review requests for fid refcounting 9p: add refcount to p9_fid struct fs/9p: search open fids first fs/9p: track open fids fs/9p: fix create-unlink-getattr idiom
Fix style issues in parent commit ("apply review requests for fid
refcounting"), no functional change.
Link: http://lkml.kernel.org/r/1605802012-31133-2-git-send-email-asmadeus@codewreck.org
Fixes: 6636b6dcc3db ("9p: add refcount to p9_fid struct")
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Fix race issue in fid contention.
Eric's and Greg's patch offer a mechanism to fix open-unlink-f*syscall
bug in 9p. But there is race issue in fid parallel accesses.
As Greg's patch stores all of fids from opened files into according inode,
so all the lookup fid ops can retrieve fid from inode preferentially. But
there is no mechanism to handle the fid contention issue. For example,
there are two threads get the same fid in the same time and one of them
clunk the fid before the other thread ready to discard the fid. In this
scenario, it will lead to some fatal problems, even kernel core dump.
I introduce a mechanism to fix this race issue. A counter field introduced
into p9_fid struct to store the reference counter to the fid. When a fid
is allocated from the inode or dentry, the counter will increase, and
will decrease at the end of its occupation. It is guaranteed that the
fid won't be clunked before the reference counter go down to 0, then
we can avoid the clunked fid to be used.
tests:
race issue test from the old test case:
for file in {01..50}; do touch f.${file}; done
seq 1 1000 | xargs -n 1 -P 50 -I{} cat f.* > /dev/null
open-unlink-f*syscall test:
I have tested for f*syscall include: ftruncate fstat fchown fchmod faccessat.
Link: http://lkml.kernel.org/r/20200923141146.90046-5-jianyong.wu@arm.com
Fixes: 478ba09edc1f ("fs/9p: search open fids first")
Signed-off-by: Jianyong Wu <jianyong.wu@arm.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Fixes several outstanding bug reports of not being able to getattr from an open file after an unlink. This patch cleans up transient fids on an unlink and will search open fids on a client if it detects a dentry that appears to have been unlinked. This search is necessary because fstat does not pass fd information through the VFS API to the filesystem, only the dentry which for 9p has an imperfect match to fids. Inherent in this patch is also a fix for the qid handling on create/open which apparently wasn't being set correctly and was necessary for the search to succeed. A possible optimization over this fix is to include accounting of open fids with the inode in the private data (in a similar fashion to the way we track transient fids with dentries). This would allow a much quicker search for a matching open fid. (changed v9fs_fid_find_global to v9fs_fid_find_inode in comment) Link: http://lkml.kernel.org/r/20200923141146.90046-2-jianyong.wu@arm.com Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com> Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com> Signed-off-by: Jianyong Wu <jianyong.wu@arm.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
net/9p/client.c:420: warning: Function parameter or member 'c' not described in 'p9_client_cb' net/9p/client.c:420: warning: Function parameter or member 'req' not described in 'p9_client_cb' net/9p/client.c:420: warning: Function parameter or member 'status' not described in 'p9_client_cb' net/9p/client.c:568: warning: Function parameter or member 'uidata' not described in 'p9_check_zc_errors' net/9p/trans_common.c:23: warning: Function parameter or member 'nr_pages' not described in 'p9_release_pages' net/9p/trans_common.c:23: warning: Function parameter or member 'pages' not described in 'p9_release_pages' net/9p/trans_fd.c:132: warning: Function parameter or member 'rreq' not described in 'p9_conn' net/9p/trans_fd.c:132: warning: Function parameter or member 'wreq' not described in 'p9_conn' net/9p/trans_fd.c:56: warning: Function parameter or member 'privport' not described in 'p9_fd_opts' net/9p/trans_rdma.c:113: warning: Function parameter or member 'cqe' not described in 'p9_rdma_context' net/9p/trans_rdma.c:129: warning: Function parameter or member 'privport' not described in 'p9_rdma_opts' net/9p/trans_virtio.c:215: warning: Function parameter or member 'limit' not described in 'pack_sg_list_p' net/9p/trans_virtio.c:83: warning: Function parameter or member 'chan_list' not described in 'virtio_chan' net/9p/trans_virtio.c:83: warning: Function parameter or member 'p9_max_pages' not described in 'virtio_chan' net/9p/trans_virtio.c:83: warning: Function parameter or member 'ring_bufs_avail' not described in 'virtio_chan' net/9p/trans_virtio.c:83: warning: Function parameter or member 'tag' not described in 'virtio_chan' net/9p/trans_virtio.c:83: warning: Function parameter or member 'vc_wq' not described in 'virtio_chan' Signed-off-by: Andrew Lunn <andrew@lunn.ch> Acked-by: Dominique Martinet <asmadeus@codewreck.org> Link: https://lore.kernel.org/r/20201031182655.1082065-1-andrew@lunn.ch Signed-off-by: Jakub Kicinski <kuba@kernel.org>
In p9_fd_create_unix, checking is performed to see if the addr (passed as an argument) is NULL or not. However, no check is performed to see if addr is a valid address, i.e., it doesn't entirely consist of only 0's. The initialization of sun_server.sun_path to be equal to this faulty addr value leads to an uninitialized variable, as detected by KMSAN. Checking for this (faulty addr) and returning a negative error number appropriately, resolves this issue. Link: http://lkml.kernel.org/r/20201012042404.2508-1-anant.thazhemadam@gmail.com Reported-by: syzbot+75d51fe5bf4ebe988518@syzkaller.appspotmail.com Tested-by: syzbot+75d51fe5bf4ebe988518@syzkaller.appspotmail.com Signed-off-by: Anant Thazhemadam <anant.thazhemadam@gmail.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Fix follow warnings: [net/9p/trans_xen.c:454]: (warning) %u in format string (no. 1) requires 'unsigned int' but the argument type is 'int'. [net/9p/trans_xen.c:460]: (warning) %u in format string (no. 1) requires 'unsigned int' but the argument type is 'int'. Link: http://lkml.kernel.org/r/20201009080552.89918-1-yebin10@huawei.com Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Ye Bin <yebin10@huawei.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Pull 9p updates from Dominique Martinet: - some code cleanup - a couple of static analysis fixes - setattr: try to pick a fid associated with the file rather than the dentry, which might sometimes matter * tag '9p-for-5.9-rc1' of git://github.com/martinetd/linux: 9p: Remove unneeded cast from memory allocation 9p: remove unused code in 9p net/9p: Fix sparse endian warning in trans_fd.c 9p: Fix memory leak in v9fs_mount 9p: retrieve fid from file when file instance exist.
Resolved kernel/bpf/btf.c using instructions from merge commit 69138b34a7248d2396ab85c8652e20c0c39beaba Signed-off-by: David S. Miller <davem@davemloft.net>