From mboxrd@z Thu Jan 1 00:00:00 1970 From: Amir Goldstein Subject: Re: [RFC PATCH 16/35] ovl: readd lsattr/chattr support Date: Tue, 17 Apr 2018 22:51:03 +0300 Message-ID: References: <20180412150826.20988-1-mszeredi@redhat.com> <20180412150826.20988-17-mszeredi@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: In-Reply-To: <20180412150826.20988-17-mszeredi@redhat.com> Sender: linux-kernel-owner@vger.kernel.org To: Miklos Szeredi Cc: overlayfs , linux-fsdevel , linux-kernel List-Id: linux-unionfs@vger.kernel.org On Thu, Apr 12, 2018 at 6:08 PM, Miklos Szeredi wrote: > Implement FS_IOC_GETFLAGS and FS_IOC_SETFLAGS. > > Needs vfs_ioctl() exported to modules. > > Signed-off-by: Miklos Szeredi > --- > fs/internal.h | 1 - > fs/ioctl.c | 1 + > fs/overlayfs/file.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/fs.h | 2 ++ > 4 files changed, 62 insertions(+), 1 deletion(-) > > diff --git a/fs/internal.h b/fs/internal.h > index 3319bf39e339..d5108d9c6a2f 100644 > --- a/fs/internal.h > +++ b/fs/internal.h > @@ -176,7 +176,6 @@ extern const struct dentry_operations ns_dentry_operations; > */ > extern int do_vfs_ioctl(struct file *file, unsigned int fd, unsigned int cmd, > unsigned long arg); > -extern long vfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg); > > /* > * iomap support: > diff --git a/fs/ioctl.c b/fs/ioctl.c > index 5ace7efb0d04..696f4c46a868 100644 > --- a/fs/ioctl.c > +++ b/fs/ioctl.c > @@ -49,6 +49,7 @@ long vfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) > out: > return error; > } > +EXPORT_SYMBOL(vfs_ioctl); > > static int ioctl_fibmap(struct file *filp, int __user *p) > { > diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c > index 05e3e2f80b89..cc004ff1b05b 100644 > --- a/fs/overlayfs/file.c > +++ b/fs/overlayfs/file.c > @@ -8,6 +8,7 @@ > > #include > #include > +#include > #include > #include > #include "overlayfs.h" > @@ -291,6 +292,63 @@ long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len) > return ret; > } > > +static long ovl_real_ioctl(struct file *file, unsigned int cmd, > + unsigned long arg) > +{ > + struct fd real; > + const struct cred *old_cred; > + long ret; > + > + ret = ovl_real_file(file, &real); > + if (ret) > + return ret; > + > + old_cred = ovl_override_creds(file_inode(file)->i_sb); > + ret = vfs_ioctl(real.file, cmd, arg); > + revert_creds(old_cred); > + > + fdput(real); > + > + return ret; > +} > + > +long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg) > +{ > + long ret; > + struct inode *inode = file_inode(file); > + > + switch (cmd) { > + case FS_IOC_GETFLAGS: > + ret = ovl_real_ioctl(file, cmd, arg); > + break; > + > + case FS_IOC_SETFLAGS: > + if (!inode_owner_or_capable(inode)) > + return -EACCES; > + > + ret = mnt_want_write_file(file); > + if (ret) > + return ret; > + > + ret = ovl_copy_up(file_dentry(file)); > + if (!ret) { > + ret = ovl_real_ioctl(file, cmd, arg); > + I got this lockdep splat with overlayfs-rorw and overlay/040, but I don't see the problem in the patch: overlay/040 [19:29:01][ 7.414427] [ 7.415349] ============================================ [ 7.417863] WARNING: possible recursive locking detected [ 7.419652] 4.16.0-rc7-xfstests-00054-g1b18a246f764-dirty #3233 Not tainted [ 7.421517] -------------------------------------------- [ 7.422736] chattr/2376 is trying to acquire lock: [ 7.423843] (sb_writers#10){.+.+}, at: [<000000003170ac81>] mnt_want_write_file+0x21/0x4a [ 7.425683] [ 7.425683] but task is already holding lock: [ 7.427397] (sb_writers#10){.+.+}, at: [<000000003170ac81>] mnt_want_write_file+0x21/0x4a [ 7.430180] [ 7.430180] other info that might help us debug this: [ 7.432511] Possible unsafe locking scenario: [ 7.432511] [ 7.433860] CPU0 [ 7.434424] ---- [ 7.434987] lock(sb_writers#10); [ 7.435768] lock(sb_writers#10); [ 7.436692] [ 7.436692] *** DEADLOCK *** [ 7.436692] [ 7.438460] May be due to missing lock nesting notation [ 7.438460] [ 7.440477] 1 lock held by chattr/2376: [ 7.441876] #0: (sb_writers#10){.+.+}, at: [<000000003170ac81>] mnt_want_write_file+0x21/0x4a [ 7.444537] [ 7.444537] stack backtrace: [ 7.445881] CPU: 1 PID: 2376 Comm: chattr Not tainted 4.16.0-rc7-xfstests-00054-g1b18a246f764-dirty #3233 [ 7.449594] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 [ 7.453121] Call Trace: [ 7.453945] dump_stack+0x7c/0xb2 [ 7.454957] validate_chain.isra.24+0x6da/0x8af [ 7.456341] __lock_acquire+0x5e6/0x67b [ 7.457643] ? __lock_acquire+0x5e6/0x67b [ 7.458879] lock_acquire+0x139/0x1dd [ 7.459988] ? mnt_want_write_file+0x21/0x4a [ 7.461317] __sb_start_write+0x91/0x163 [ 7.462500] ? mnt_want_write_file+0x21/0x4a [ 7.463822] mnt_want_write_file+0x21/0x4a [ 7.465091] xfs_ioc_setxflags+0x70/0xe5 [ 7.466266] xfs_file_ioctl+0x4a7/0xa90 [ 7.467452] ? __lock_acquire+0x5e6/0x67b [ 7.468681] ? terminate_walk+0x20/0xd9 [ 7.469835] ? __lock_is_held+0x40/0x71 [ 7.471012] vfs_ioctl+0x1e/0x2b [ 7.472008] ovl_real_ioctl+0x45/0x71 [ 7.473122] ovl_ioctl+0x9a/0xf2 [ 7.474114] vfs_ioctl+0x1e/0x2b [ 7.475149] do_vfs_ioctl+0x579/0x5f1 [ 7.476341] ? entry_SYSCALL_64_after_hwframe+0x52/0xb7 [ 7.477765] SyS_ioctl+0x52/0x74 [ 7.479041] do_syscall_64+0x76/0x182 [ 7.480419] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 7.482536] RIP: 0033:0x7fde8d270dd7 [ 7.483919] RSP: 002b:00007ffde2ae7e98 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 7.486862] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fde8d270dd7 [ 7.489554] RDX: 00007ffde2ae7eac RSI: 0000000040086602 RDI: 0000000000000003 [ 7.492227] RBP: 0000000000000010 R08: 0000000000000000 R09: 0000000000000001 [ 7.494922] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 7.497642] R13: 00007ffde2ae81a0 R14: 00007ffde2ae8188 R15: 0000000000000000 [ 7.540886] XFS (vdf): Mounting V5 Filesystem [ 7.563795] XFS (vdf): Ending clean mount Thanks, Amir.