kernel/git/stable/linux.git/fs/afs/dir.c, branch linux-5.3.y

afs: Fix race in commit bulk status fetch

2019-12-13T07:48:47+00:00

[ Upstream commit a28f239e296767ebf4ec4ae8a9ecb57d0d444b3f ] When a lookup is done, the afs filesystem will perform a bulk status-fetch operation on the requested vnode (file) plus the next 49 other vnodes from the directory list (in AFS, directory contents are downloaded as blobs and parsed locally). When the results are received, it will speculatively populate the inode cache from the extra data. However, if the lookup races with another lookup on the same directory, but for a different file - one that's in the 49 extra fetches, then if the bulk status-fetch operation finishes first, it will try and update the inode from the other lookup. If this other inode is still in the throes of being created, however, this will cause an assertion failure in afs_apply_status(): BUG_ON(test_bit(AFS_VNODE_UNSET, &vnode->flags)); on or about fs/afs/inode.c:175 because it expects data to be there already that it can compare to. Fix this by skipping the update if the inode is being created as the creator will presumably set up the inode with the same information. Fixes: 39db9815da48 ("afs: Fix application of the results of a inline bulk status fetch") Signed-off-by: David Howells Reviewed-by: Marc Dionne Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

afs: Fix possible oops in afs_lookup trace event

2019-08-22T12:33:26+00:00

The afs_lookup trace event can cause the following: [ 216.576777] BUG: kernel NULL pointer dereference, address: 000000000000023b [ 216.576803] #PF: supervisor read access in kernel mode [ 216.576813] #PF: error_code(0x0000) - not-present page ... [ 216.576913] RIP: 0010:trace_event_raw_event_afs_lookup+0x9e/0x1c0 [kafs] If the inode from afs_do_lookup() is an error other than ENOENT, or if it is ENOENT and afs_try_auto_mntpt() returns an error, the trace event will try to dereference the error pointer as a valid pointer. Use IS_ERR_OR_NULL to only pass a valid pointer for the trace, or NULL. Ideally the trace would include the error value, but for now just avoid the oops. Fixes: 80548b03991f ("afs: Add more tracepoints") Signed-off-by: Marc Dionne Signed-off-by: David Howells

afs: Fix missing dentry data version updating

2019-07-30T13:38:52+00:00

In the in-kernel afs filesystem, the d_fsdata dentry field is used to hold the data version of the parent directory when it was created or when d_revalidate() last caused it to be updated. This is compared to the ->invalid_before field in the directory inode, rather than the actual data version number, thereby allowing changes due to local edits to be ignored. Only if the server data version gets bumped unexpectedly (eg. by a competing client), do we need to revalidate stuff. However, the d_fsdata field should also be updated if an rpc op is performed that modifies that particular dentry. Such ops return the revised data version of the directory(ies) involved, so we should use that. This is particularly problematic for rename, since a dentry from one directory may be moved directly into another directory (ie. mv a/x b/x). It would then be sporting the wrong data version - and if this is in the future, for the destination directory, revalidations would be missed, leading to foreign renames and hard-link deletion being missed. Fix this by the following means: (1) Return the data version number from operations that read the directory contents - if they issue the read. This starts in afs_dir_iterate() and is used, ignored or passed back by its callers. (2) In afs_lookup*(), set the dentry version to the version returned by (1) before d_splice_alias() is called and the dentry published. (3) In afs_d_revalidate(), set the dentry version to that returned from (1) if an rpc call was issued. This means that if a parallel procedure, such as mkdir(), modifies the directory, we won't accidentally use the data version from that. (4) In afs_{mkdir,create,link,symlink}(), set the new dentry's version to the directory data version before d_instantiate() is called. (5) In afs_{rmdir,unlink}, update the target dentry's version to the directory data version as soon as we've updated the directory inode. (6) In afs_rename(), we need to unhash the old dentry before we start so that we don't get afs_d_revalidate() reverting the version change in cross-directory renames. We then need to set both the old and the new dentry versions the data version of the new directory before we call d_move() as d_move() will rehash them. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: David Howells

afs: Only update d_fsdata if different in afs_d_revalidate()

2019-07-30T13:38:51+00:00

In the in-kernel afs filesystem, d_fsdata is set with the data version of the parent directory. afs_d_revalidate() will update this to the current directory version, but it shouldn't do this if it the value it read from d_fsdata is the same as no lock is held and cmpxchg() is not used. Fix the code to only change the value if it is different from the current directory version. Fixes: 260a980317da ("[AFS]: Add "directory write" support.") Signed-off-by: David Howells

afs: Fix off-by-one in afs_rename() expected data version calculation

2019-07-30T13:38:51+00:00

When afs_rename() calculates the expected data version of the target directory in a cross-directory rename, it doesn't increment it as it should, so it always thinks that the target inode is unexpectedly modified on the server. Fixes: a58823ac4589 ("afs: Fix application of status and callback to be under same lock") Signed-off-by: David Howells

Merge tag 'afs-next-20190628' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

2019-07-11T03:55:33+00:00

Pull afs updates from David Howells: "A set of minor changes for AFS: - Remove an unnecessary check in afs_unlink() - Add a tracepoint for tracking callback management - Add a tracepoint for afs_server object usage - Use struct_size() - Add mappings for AFS UAE abort codes to Linux error codes, using symbolic names rather than hex numbers in the .c file" * tag 'afs-next-20190628' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: afs: Add support for the UAE error table fs/afs: use struct_size() in kzalloc() afs: Trace afs_server usage afs: Add some callback management tracepoints afs: afs_unlink() doesn't need to check dentry->d_inode

fs/afs: use struct_size() in kzalloc()

2019-06-20T17:12:17+00:00

As Gustavo said in other patches doing the same replace, we can now use the new struct_size() helper to avoid leaving these open-coded and prone to type mistake. Signed-off-by: Zhengyuan Liu Signed-off-by: David Howells

afs: Add some callback management tracepoints

2019-06-20T17:12:16+00:00

Add a couple of tracepoints to track callback management: (1) afs_cb_miss - Logs when we were unable to apply a callback, either due to the inode being discarded or due to a competing thread applying a callback first. (2) afs_cb_break - Logs when we attempted to clear the noted callback promise, either due to the server explicitly breaking the callback, the callback promise lapsing or a local event obsoleting it. Signed-off-by: David Howells

afs: afs_unlink() doesn't need to check dentry->d_inode

2019-06-20T17:12:16+00:00

Don't check that dentry->d_inode is valid in afs_unlink(). We should be able to take that as given. This caused Smatch to issue the following warning: fs/afs/dir.c:1392 afs_unlink() error: we previously assumed 'vnode' could be null (see line 1375) Reported-by: kbuild test robot Reported-by: Dan Carpenter Signed-off-by: David Howells

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

2019-05-30T18:26:32+00:00

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman