kernel.git/fs/afs/dir.c, branch linux-5.4.y

afs: Revert "afs: Hide silly-rename files from userspace"

2024-03-26T22:22:24Z

[ Upstream commit 0aec3847d044273733285dcff90afda89ad461d2 ] This reverts commit 57e9d49c54528c49b8bffe6d99d782ea051ea534. This undoes the hiding of .__afsXXXX silly-rename files. The problem with hiding them is that rm can't then manually delete them. This also reverts commit 5f7a07646655fb4108da527565dcdc80124b14c4 ("afs: Fix endless loop in directory parsing") as that's a bugfix for the above. Fixes: 57e9d49c5452 ("afs: Hide silly-rename files from userspace") Reported-by: Markus Suvanto Link: https://lists.infradead.org/pipermail/linux-afs/2024-February/008102.html Signed-off-by: David Howells Link: https://lore.kernel.org/r/3085695.1710328121@warthog.procyon.org.uk Reviewed-by: Jeffrey E Altman cc: Marc Dionne cc: linux-afs@lists.infradead.org Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin

afs: Fix endless loop in directory parsing

2024-03-06T14:36:09Z

[ Upstream commit 5f7a07646655fb4108da527565dcdc80124b14c4 ] If a directory has a block with only ".__afsXXXX" files in it (from uncompleted silly-rename), these .__afsXXXX files are skipped but without advancing the file position in the dir_context. This leads to afs_dir_iterate() repeating the block again and again. Fix this by making the code that skips the .__afsXXXX file also manually advance the file position. The symptoms are a soft lookup: watchdog: BUG: soft lockup - CPU#3 stuck for 52s! [check:5737] ... RIP: 0010:afs_dir_iterate_block+0x39/0x1fd ... ? watchdog_timer_fn+0x1a6/0x213 ... ? asm_sysvec_apic_timer_interrupt+0x16/0x20 ? afs_dir_iterate_block+0x39/0x1fd afs_dir_iterate+0x10a/0x148 afs_readdir+0x30/0x4a iterate_dir+0x93/0xd3 __do_sys_getdents64+0x6b/0xd4 This is almost certainly the actual fix for: https://bugzilla.kernel.org/show_bug.cgi?id=218496 Fixes: 57e9d49c5452 ("afs: Hide silly-rename files from userspace") Signed-off-by: David Howells Link: https://lore.kernel.org/r/786185.1708694102@warthog.procyon.org.uk Reviewed-by: Marc Dionne cc: Marc Dionne cc: Markus Suvanto cc: linux-afs@lists.infradead.org Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin

afs: Hide silly-rename files from userspace

2024-02-23T07:24:50Z

[ Upstream commit 57e9d49c54528c49b8bffe6d99d782ea051ea534 ] There appears to be a race between silly-rename files being created/removed and various userspace tools iterating over the contents of a directory, leading to such errors as: find: './kernel/.tmp_cpio_dir/include/dt-bindings/reset/.__afs2080': No such file or directory tar: ./include/linux/greybus/.__afs3C95: File removed before we read it when building a kernel. Fix afs_readdir() so that it doesn't return .__afsXXXX silly-rename files to userspace. This doesn't stop them being looked up directly by name as we need to be able to look them up from within the kernel as part of the silly-rename algorithm. Fixes: 79ddbfa500b3 ("afs: Implement sillyrename for unlink and rename") Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org Signed-off-by: Sasha Levin

treewide: Remove uninitialized_var() usage

2023-06-09T08:29:01Z

commit 3f649ab728cda8038259d8f14492fe400fbab911 upstream. Using uninitialized_var() is dangerous as it papers over real bugs[1] (or can in the future), and suppresses unrelated compiler warnings (e.g. "unused variable"). If the compiler thinks it is uninitialized, either simply initialize the variable or make compiler changes. In preparation for removing[2] the[3] macro[4], remove all remaining needless uses with the following script: git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \ xargs perl -pi -e \ 's/\buninitialized_var$([^$]+)\)/\1/g; s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;' drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid pathological white-space. No outstanding warnings were found building allmodconfig with GCC 9.3.0 for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64, alpha, and m68k. [1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/ [2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/ [3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/ [4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ Reviewed-by: Leon Romanovsky # drivers/infiniband and mlx4/mlx5 Acked-by: Jason Gunthorpe # IB Acked-by: Kalle Valo # wireless drivers Reviewed-by: Chao Yu # erofs Signed-off-by: Kees Cook Signed-off-by: Greg Kroah-Hartman

afs: Fix infinite loop found by xfstest generic/676

2022-06-14T16:11:55Z

[ Upstream commit 17eabd42560f4636648ad65ba5b20228071e2363 ] In AFS, a directory is handled as a file that the client downloads and parses locally for the purposes of performing lookup and getdents operations. The in-kernel afs filesystem has a number of functions that do this. A directory file is arranged as a series of 2K blocks divided into 32-byte slots, where a directory entry occupies one or more slots, plus each block starts with one or more metadata blocks. When parsing a block, if the last slots are occupied by a dirent that occupies more than a single slot and the file position points at a slot that's not the initial one, the logic in afs_dir_iterate_block() that skips over it won't advance the file pointer to the end of it. This will cause an infinite loop in getdents() as it will keep retrying that block and failing to advance beyond the final entry. Fix this by advancing the file pointer if the next entry will be beyond it when we skip a block. This was found by the generic/676 xfstest but can also be triggered with something like: ~/xfstests-dev/src/t_readdir_3 /xfstest.test/z 4000 1 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: David Howells Reviewed-by: Marc Dionne Tested-by: Marc Dionne cc: linux-afs@lists.infradead.org Link: http://lore.kernel.org/r/165391973497.110268.2939296942213894166.stgit@warthog.procyon.org.uk/ Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

afs: Fix incorrect triggering of sillyrename on 3rd-party invalidation

2021-09-30T08:09:22Z

[ Upstream commit 63d49d843ef5fffeea069e0ffdfbd2bf40ba01c6 ] The AFS filesystem is currently triggering the silly-rename cleanup from afs_d_revalidate() when it sees that a dentry has been changed by a third party[1]. It should not be doing this as the cleanup includes deleting the silly-rename target file on iput. Fix this by removing the places in the d_revalidate handling that validate anything other than the directory and the dirent. It probably should not be looking to validate the target inode of the dentry also. This includes removing the point in afs_d_revalidate() where the inode that a dentry used to point to was marked as being deleted (AFS_VNODE_DELETED). We don't know it got deleted. It could have been renamed or it could have hard links remaining. This was reproduced by cloning a git repo onto an afs volume on one machine, switching to another machine and doing "git status", then switching back to the first and doing "git status". The second status would show weird output due to ".git/index" getting deleted by the above mentioned mechanism. A simpler way to do it is to do: machine 1: touch a machine 2: touch b; mv -f b a machine 1: stat a on an afs volume. The bug shows up as the stat failing with ENOENT and the file server log showing that machine 1 deleted "a". Fixes: 79ddbfa500b3 ("afs: Implement sillyrename for unlink and rename") Reported-by: Markus Suvanto Signed-off-by: David Howells Tested-by: Markus Suvanto cc: linux-afs@lists.infradead.org Link: https://bugzilla.kernel.org/show_bug.cgi?id=214217#c4 [1] Link: https://lore.kernel.org/r/163111668100.283156.3851669884664475428.stgit@warthog.procyon.org.uk/ Signed-off-by: Sasha Levin

afs: Stop listxattr() from listing "afs.*" attributes

2021-03-24T10:26:37Z

commit a7889c6320b9200e3fe415238f546db677310fa9 upstream. afs_listxattr() lists all the available special afs xattrs (i.e. those in the "afs.*" space), no matter what type of server we're dealing with. But OpenAFS servers, for example, cannot deal with some of the extra-capable attributes that AuriStor (YFS) servers provide. Unfortunately, the presence of the afs.yfs.* attributes causes errors[1] for anything that tries to read them if the server is of the wrong type. Fix the problem by removing afs_listxattr() so that none of the special xattrs are listed (AFS doesn't support xattrs). It does mean, however, that getfattr won't list them, though they can still be accessed with getxattr() and setxattr(). This can be tested with something like: getfattr -d -m ".*" /afs/example.com/path/to/file With this change, none of the afs.* attributes should be visible. Changes: ver #2: - Hide all of the afs.* xattrs, not just the ACL ones. Fixes: ae46578b963f ("afs: Get YFS ACLs and information through xattrs") Reported-by: Gaja Sophie Peters Signed-off-by: David Howells Tested-by: Gaja Sophie Peters Reviewed-by: Jeffrey Altman Reviewed-by: Marc Dionne cc: linux-afs@lists.infradead.org Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003502.html [1] Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003567.html # v1 Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003573.html # v2 Signed-off-by: Greg Kroah-Hartman

afs: Always include dir in bulk status fetch from afs_do_lookup()

2020-06-24T15:50:46Z

[ Upstream commit 13fcc6356a94558a0a4857dc00cd26b3834a1b3e ] When a lookup is done in an AFS directory, the filesystem will speculate and fetch up to 49 other statuses for files in the same directory and fetch those as well, turning them into inodes or updating inodes that already exist. However, occasionally, a callback break might go missing due to NAT timing out, but the afs filesystem doesn't then realise that the directory is not up to date. Alleviate this by using one of the status slots to check the directory in which the lookup is being done. Reported-by: Dave Botsch Suggested-by: Jeffrey Altman Signed-off-by: David Howells Signed-off-by: Sasha Levin

afs: Fix race between post-modification dir edit and readdir/d_revalidate

2020-04-23T08:36:25Z

commit 2105c2820d366b76f38e6ad61c75771881ecc532 upstream. AFS directories are retained locally as a structured file, with lookup being effected by a local search of the file contents. When a modification (such as mkdir) happens, the dir file content is modified locally rather than redownloading the directory. The directory contents are accessed in a number of ways, with a number of different locks schemes: (1) Download of contents - dvnode->validate_lock/write in afs_read_dir(). (2) Lookup and readdir - dvnode->validate_lock/read in afs_dir_iterate(), downgrading from (1) if necessary. (3) d_revalidate of child dentry - dvnode->validate_lock/read in afs_do_lookup_one() downgrading from (1) if necessary. (4) Edit of dir after modification - page locks on individual dir pages. Unfortunately, because (4) uses different locking scheme to (1) - (3), nothing protects against the page being scanned whilst the edit is underway. Even download is not safe as it doesn't lock the pages - relying instead on the validate_lock to serialise as a whole (the theory being that directory contents are treated as a block and always downloaded as a block). Fix this by write-locking dvnode->validate_lock around the edits. Care must be taken in the rename case as there may be two different dirs - but they need not be locked at the same time. In any case, once the lock is taken, the directory version must be rechecked, and the edit skipped if a later version has been downloaded by revalidation (there can't have been any local changes because the VFS holds the inode lock, but there can have been remote changes). Fixes: 63a4681ff39c ("afs: Locally edit directory data for mkdir/create/unlink/...") Signed-off-by: David Howells Signed-off-by: Greg Kroah-Hartman

afs: Fix afs_d_validate() to set the right directory version

2020-04-23T08:36:25Z

commit 40fc81027f892284ce31f8b6de1e497f5b47e71f upstream. If a dentry's version is somewhere between invalid_before and the current directory version, we should be setting it forward to the current version, not backwards to the invalid_before version. Note that we're only doing this at all because dentry::d_fsdata isn't large enough on a 32-bit system. Fix this by using a separate variable for invalid_before so that we don't accidentally clobber the current dir version. Fixes: a4ff7401fbfa ("afs: Keep track of invalid-before version for dentry coherency") Signed-off-by: David Howells Signed-off-by: Greg Kroah-Hartman