Detect and mitigate inode collsions that now occur since we fixed 9p generating duplicate inode structures. Underlying cause of these appears to be a race condition between reuse of inode numbers in underlying file system and cleanup of inode numbers in the client. Enabling caching makes this much more likely to happen as it increases cleanup latency due to writebacks. Reported-by: Kent Overstreet <kent.overstreet@linux.dev> Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
Signed-off-by: Joakim Sindholt <opensource@zhasha.com> Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
This reverts commit be57855f505003c5cafff40338d5d0f23b00ba4d. It caused a regression involving duplicate inode numbers in some tester trees. The bad behavior seems to be dependent on inode reuse policy in underlying file system, so it did not trigger in my test setup. Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
In 9p2000 legacy mode, stat2inode initializes nlink to 1, which is redundant with what alloc_inode should have already set. 9p2000.u overrides this with extensions if present in the stat structure, and 9p2000.L incorporates nlink into its stat structure. At the very least this probably messes with directory nlink accounting in legacy mode. Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
9p is a remote network protocol, and it doesn't support asynchronous notifications from the server. Ensure that we don't hand out any leases since we can't guarantee they'll be broken when a file's contents change. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
I'm not sure why this check was ever here. After updating to 6.6 I suddenly found caching had been turned on by default and neither cache=none nor the new directio would turn it off. After walking through the new code very manually I realized that it's because the caching has to be, in effect, turned off explicitly by setting P9L_DIRECT and whenever a file has a flag, in my case QTAPPEND, it doesn't get set. Setting aside QTDIR which seems to ignore the new fid->mode entirely, the rest of these either should be subject to the same cache rules as every other QTFILE or perhaps very explicitly not cached in the case of QTAUTH. Signed-off-by: Joakim Sindholt <opensource@zhasha.com> Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
This one hits both 9P2000 and .u as it appears v9fs has never translated the O_TRUNC flag. Signed-off-by: Joakim Sindholt <opensource@zhasha.com> Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
Garbage in plain 9P2000's perm bits is allowed through, which causes it to be able to set (among others) the suid bit. This was presumably not the intent since the unix extended bits are handled explicitly and conditionally on .u. Signed-off-by: Joakim Sindholt <opensource@zhasha.com> Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
If an iget fails due to not being able to retrieve information from the server then the inode structure is only partially initialized. When the inode gets evicted, references to uninitialized structures (like fscache cookies) were being made. This patch checks for a bad_inode before doing anything other than clearing the inode from the cache. Since the inode is bad, it shouldn't have any state associated with it that needs to be written back (and there really isn't a way to complete those anyways). Reported-by: syzbot+eb83fe1cce5833cd66a0@syzkaller.appspotmail.com Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
Pointer v9ses is being assigned the value from the return of inlined function v9fs_inode2v9ses (which just returns inode->i_sb->s_fs_info). The pointer is not used after the assignment, so the variable is redundant and can be removed. Cleans up clang scan warnings such as: fs/9p/vfs_inode_dotl.c:300:28: warning: variable 'v9ses' set but not used [-Wunused-but-set-variable] Signed-off-by: Colin Ian King <colin.i.king@gmail.com> Reviewed-by: Dominique Martinet <asmadeus@codewreck.org> Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>