kernel/git/stable/linux.git/fs/overlayfs/dir.c, branch linux-5.11.y

ovl: fix dentry leak in ovl_get_redirect

2021-01-28T09:22:48+00:00

We need to lock d_parent->d_lock before dget_dlock, or this may have d_lockref updated parallelly like calltrace below which will cause dentry->d_lockref leak and risk a crash. CPU 0 CPU 1 ovl_set_redirect lookup_fast ovl_get_redirect __d_lookup dget_dlock //no lock protection here spin_lock(&dentry->d_lock) dentry->d_lockref.count++ dentry->d_lockref.count++ [ 49.799059] PGD 800000061fed7067 P4D 800000061fed7067 PUD 61fec5067 PMD 0 [ 49.799689] Oops: 0002 [#1] SMP PTI [ 49.800019] CPU: 2 PID: 2332 Comm: node Not tainted 4.19.24-7.20.al7.x86_64 #1 [ 49.800678] Hardware name: Alibaba Cloud Alibaba Cloud ECS, BIOS 8a46cfe 04/01/2014 [ 49.801380] RIP: 0010:_raw_spin_lock+0xc/0x20 [ 49.803470] RSP: 0018:ffffac6fc5417e98 EFLAGS: 00010246 [ 49.803949] RAX: 0000000000000000 RBX: ffff93b8da3446c0 RCX: 0000000a00000000 [ 49.804600] RDX: 0000000000000001 RSI: 000000000000000a RDI: 0000000000000088 [ 49.805252] RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff993cf040 [ 49.805898] R10: ffff93b92292e580 R11: ffffd27f188a4b80 R12: 0000000000000000 [ 49.806548] R13: 00000000ffffff9c R14: 00000000fffffffe R15: ffff93b8da3446c0 [ 49.807200] FS: 00007ffbedffb700(0000) GS:ffff93b927880000(0000) knlGS:0000000000000000 [ 49.807935] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 49.808461] CR2: 0000000000000088 CR3: 00000005e3f74006 CR4: 00000000003606a0 [ 49.809113] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 49.809758] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 49.810410] Call Trace: [ 49.810653] d_delete+0x2c/0xb0 [ 49.810951] vfs_rmdir+0xfd/0x120 [ 49.811264] do_rmdir+0x14f/0x1a0 [ 49.811573] do_syscall_64+0x5b/0x190 [ 49.811917] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 49.812385] RIP: 0033:0x7ffbf505ffd7 [ 49.814404] RSP: 002b:00007ffbedffada8 EFLAGS: 00000297 ORIG_RAX: 0000000000000054 [ 49.815098] RAX: ffffffffffffffda RBX: 00007ffbedffb640 RCX: 00007ffbf505ffd7 [ 49.815744] RDX: 0000000004449700 RSI: 0000000000000000 RDI: 0000000006c8cd50 [ 49.816394] RBP: 00007ffbedffaea0 R08: 0000000000000000 R09: 0000000000017d0b [ 49.817038] R10: 0000000000000000 R11: 0000000000000297 R12: 0000000000000012 [ 49.817687] R13: 00000000072823d8 R14: 00007ffbedffb700 R15: 00000000072823d8 [ 49.818338] Modules linked in: pvpanic cirrusfb button qemu_fw_cfg atkbd libps2 i8042 [ 49.819052] CR2: 0000000000000088 [ 49.819368] ---[ end trace 4e652b8aa299aa2d ]--- [ 49.819796] RIP: 0010:_raw_spin_lock+0xc/0x20 [ 49.821880] RSP: 0018:ffffac6fc5417e98 EFLAGS: 00010246 [ 49.822363] RAX: 0000000000000000 RBX: ffff93b8da3446c0 RCX: 0000000a00000000 [ 49.823008] RDX: 0000000000000001 RSI: 000000000000000a RDI: 0000000000000088 [ 49.823658] RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff993cf040 [ 49.825404] R10: ffff93b92292e580 R11: ffffd27f188a4b80 R12: 0000000000000000 [ 49.827147] R13: 00000000ffffff9c R14: 00000000fffffffe R15: ffff93b8da3446c0 [ 49.828890] FS: 00007ffbedffb700(0000) GS:ffff93b927880000(0000) knlGS:0000000000000000 [ 49.830725] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 49.832359] CR2: 0000000000000088 CR3: 00000005e3f74006 CR4: 00000000003606a0 [ 49.834085] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 49.835792] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Cc: Fixes: a6c606551141 ("ovl: redirect on rename-dir") Signed-off-by: Liangyan Reviewed-by: Joseph Qi Suggested-by: Al Viro Signed-off-by: Miklos Szeredi

ovl: pass ovl_fs down to functions accessing private xattrs

2020-09-02T08:58:49+00:00

This paves the way for optionally using the "user.overlay." xattr namespace. Signed-off-by: Miklos Szeredi

ovl: initialize OVL_UPPERDATA in ovl_lookup()

2020-06-02T20:20:25+00:00

Currently ovl_get_inode() initializes OVL_UPPERDATA flag and for that it has to call ovl_check_metacopy_xattr() and check if metacopy xattr is present or not. yangerkun reported sometimes underlying filesystem might return -EIO and in that case error handling path does not cleanup properly leading to various warnings. Run generic/461 with ext4 upper/lower layer sometimes may trigger the bug as below(linux 4.19): [ 551.001349] overlayfs: failed to get metacopy (-5) [ 551.003464] overlayfs: failed to get inode (-5) [ 551.004243] overlayfs: cleanup of 'd44/fd51' failed (-5) [ 551.004941] overlayfs: failed to get origin (-5) [ 551.005199] ------------[ cut here ]------------ [ 551.006697] WARNING: CPU: 3 PID: 24674 at fs/inode.c:1528 iput+0x33b/0x400 ... [ 551.027219] Call Trace: [ 551.027623] ovl_create_object+0x13f/0x170 [ 551.028268] ovl_create+0x27/0x30 [ 551.028799] path_openat+0x1a35/0x1ea0 [ 551.029377] do_filp_open+0xad/0x160 [ 551.029944] ? vfs_writev+0xe9/0x170 [ 551.030499] ? page_counter_try_charge+0x77/0x120 [ 551.031245] ? __alloc_fd+0x160/0x2a0 [ 551.031832] ? do_sys_open+0x189/0x340 [ 551.032417] ? get_unused_fd_flags+0x34/0x40 [ 551.033081] do_sys_open+0x189/0x340 [ 551.033632] __x64_sys_creat+0x24/0x30 [ 551.034219] do_syscall_64+0xd5/0x430 [ 551.034800] entry_SYSCALL_64_after_hwframe+0x44/0xa9 One solution is to improve error handling and call iget_failed() if error is encountered. Amir thinks that this path is little intricate and there is not real need to check and initialize OVL_UPPERDATA in ovl_get_inode(). Instead caller of ovl_get_inode() can initialize this state. And this will avoid double checking of metacopy xattr lookup in ovl_lookup() and ovl_get_inode(). OVL_UPPERDATA is inode flag. So I was little concerned that initializing it outside ovl_get_inode() might have some races. But this is one way transition. That is once a file has been fully copied up, it can't go back to metacopy file again. And that seems to help avoid races. So as of now I can't see any races w.r.t OVL_UPPERDATA being set wrongly. So move settingof OVL_UPPERDATA inside the callers of ovl_get_inode(). ovl_obtain_alias() already does it. So only two callers now left are ovl_lookup() and ovl_instantiate(). Reported-by: yangerkun Suggested-by: Amir Goldstein Signed-off-by: Vivek Goyal Reviewed-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: whiteout inode sharing

2020-05-13T09:11:24+00:00

Share inode with different whiteout files for saving inode and speeding up delete operation. If EMLINK is encountered when linking a shared whiteout, create a new one. In case of any other error, disable sharing for this super block. Note: ofs->whiteout is protected by inode lock on workdir. Signed-off-by: Chengguang Xu Reviewed-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: fix WARN_ON nlink drop to zero

2020-03-27T15:51:02+00:00

Changes to underlying layers should not cause WARN_ON(), but this repro does: mkdir w l u mnt sudo mount -t overlay -o workdir=w,lowerdir=l,upperdir=u overlay mnt touch mnt/h ln u/h u/k rm -rf mnt/k rm -rf mnt/h dmesg ------------[ cut here ]------------ WARNING: CPU: 1 PID: 116244 at fs/inode.c:302 drop_nlink+0x28/0x40 After upper hardlinks were added while overlay is mounted, unlinking all overlay hardlinks drops overlay nlink to zero before all upper inodes are unlinked. After unlink/rename prevent i_nlink from going to zero if there are still hashed aliases (i.e. cached hard links to the victim) remaining. Reported-by: Phasip Signed-off-by: Miklos Szeredi

ovl: check if upper fs supports RENAME_WHITEOUT

2020-03-17T14:04:22+00:00

As with other required upper fs features, we only warn if support is missing to avoid breaking existing sub-optimal setups. Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: decide if revalidate needed on a per-dentry basis

2020-03-17T14:04:22+00:00

Allow completely skipping ->revalidate() on a per-dentry basis, in case the underlying layers used for a dentry do not themselves have ->revalidate(). E.g. negative overlay dentry has no underlying layers, hence revalidate is unnecessary. Or if lower layer is remote but overlay dentry is pure-upper, then can skip revalidate. The following places need to update whether the dentry needs revalidate or not: - fill-super (root dentry) - lookup - create - fh_to_dentry Signed-off-by: Miklos Szeredi

ovl: use pr_fmt auto generate prefix

2020-01-22T19:11:41+00:00

Use pr_fmt auto generate "overlayfs: " prefix. Signed-off-by: lijiazi Signed-off-by: Miklos Szeredi

ovl: relax WARN_ON() on rename to self

2019-12-10T15:00:55+00:00

In ovl_rename(), if new upper is hardlinked to old upper underneath overlayfs before upper dirs are locked, user will get an ESTALE error and a WARN_ON will be printed. Changes to underlying layers while overlayfs is mounted may result in unexpected behavior, but it shouldn't crash the kernel and it shouldn't trigger WARN_ON() either, so relax this WARN_ON(). Reported-by: syzbot+bb1836a212e69f8e201a@syzkaller.appspotmail.com Fixes: 804032fabb3b ("ovl: don't check rename to self") Cc: # v4.9+ Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

Merge tag 'spdx-5.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx

2019-06-21T16:58:42+00:00

Pull still more SPDX updates from Greg KH: "Another round of SPDX updates for 5.2-rc6 Here is what I am guessing is going to be the last "big" SPDX update for 5.2. It contains all of the remaining GPLv2 and GPLv2+ updates that were "easy" to determine by pattern matching. The ones after this are going to be a bit more difficult and the people on the spdx list will be discussing them on a case-by-case basis now. Another 5000+ files are fixed up, so our overall totals are: Files checked: 64545 Files with SPDX: 45529 Compared to the 5.1 kernel which was: Files checked: 63848 Files with SPDX: 22576 This is a huge improvement. Also, we deleted another 20000 lines of boilerplate license crud, always nice to see in a diffstat" * tag 'spdx-5.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx: (65 commits) treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 507 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 506 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 505 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 504 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 503 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 502 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 501 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 499 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 498 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 497 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 496 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 495 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 491 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 490 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 489 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 488 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 487 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 486 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 485 ...