On Wed, Aug 01, 2018 at 04:25:41PM +0100, David Howells wrote: > Implement a filesystem context concept to be used during superblock > creation for mount and superblock reconfiguration for remount. > > The mounting procedure then becomes: > > (1) Allocate new fs_context context. > > (2) Configure the context. > > (3) Create superblock. > > (4) Query the superblock. > > (5) Create a mount for the superblock. > > (6) Destroy the context. > > Rather than calling fs_type->mount(), an fs_context struct is created and > fs_type->init_fs_context() is called to set it up. Pointers exist for the > filesystem and LSM to hang their private data off. > > A set of operations has to be set by ->init_fs_context() to provide > freeing, duplication, option parsing, binary data parsing, validation, > mounting and superblock filling. > > Legacy filesystems are supported by the provision of a set of legacy > fs_context operations that build up a list of mount options and then invoke > fs_type->mount() from within the fs_context ->get_tree() operation. This > allows all filesystems to be accessed using fs_context. > > It should be noted that, whilst this patch adds a lot of lines of code, > there is quite a bit of duplication with existing code that can be > eliminated should all filesystems be converted over. > > Signed-off-by: David Howells <dhowells@xxxxxxxxxx> I don't find a more recent version of this patch in patchwork on kernel.org, so I am replying to this one. My apologies if there are more recent versions. This patch is causing widespread crashes in next-20180910 and next-20180911. Example and bisect log (for x86_64) attached. Guenter --- Rebooting. [ 4.894299] random: dd: uninitialized urandom read (512 bytes read) [ 5.055206] BUG: unable to handle kernel NULL pointer dereference at 0000000000000030 [ 5.055518] PGD 800000000c025067 P4D 800000000c025067 PUD c7a3067 PMD 0 [ 5.055941] Oops: 0000 [#1] SMP PTI [ 5.056191] CPU: 0 PID: 1208 Comm: umount Not tainted 4.19.0-rc3-next-20180911 #1 [ 5.056367] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.11.2-0-gf9626ccb91-prebuilt.qemu-project.org 04/01/2014 [ 5.057003] RIP: 0010:reconfigure_super+0x47/0x210 [ 5.057214] Code: d4 01 00 00 44 8b a3 30 02 00 00 45 85 e4 0f 85 9d 01 00 00 a8 01 48 89 fd 75 4f 48 89 df 45 31 ed e8 ad 4f 01 00 48 8b 45 00 <48> 8b 40 30 48 85 c0 0f 84 d3 00 00 00 48 89 ef ff d0 85 c0 0f 84 [ 5.057573] RSP: 0018:ffffa8560011bdd0 EFLAGS: 00000246 [ 5.057709] RAX: 0000000000000000 RBX: ffffa2cd4c72c000 RCX: ffffa2cd4c72c0b8 [ 5.057850] RDX: ffffa2cd4c72c048 RSI: 0000000000000000 RDI: ffffffff98b49e28 [ 5.057991] RBP: ffffa8560011be00 R08: 000000000000019b R09: 0000000000000000 [ 5.058132] R10: ffffa856000bfd08 R11: 0000000000000001 R12: 0000000000000000 [ 5.058274] R13: 0000000000000001 R14: ffffa2cd4f38f920 R15: 0000000000000000 [ 5.058451] FS: 00007fa2f1a15500(0000) GS:ffffa2cd4f600000(0000) knlGS:0000000000000000 [ 5.059178] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 5.059302] CR2: 0000000000000030 CR3: 000000000c7b4000 CR4: 00000000003406f0 [ 5.059496] Call Trace: [ 5.060118] do_umount_root+0x7b/0xb0 [ 5.060244] ksys_umount+0x250/0x3e0 [ 5.060345] ? vfs_write+0x13f/0x190 [ 5.060439] __x64_sys_umount+0xd/0x10 [ 5.060537] do_syscall_64+0x39/0xe0 [ 5.060635] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 5.060874] RIP: 0033:0x7fa2f1534b47 [ 5.060970] Code: 73 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 11 73 2b 00 f7 d8 64 89 01 48 [ 5.061311] RSP: 002b:00007ffeb7926e68 EFLAGS: 00000206 ORIG_RAX: 00000000000000a6 [ 5.061478] RAX: ffffffffffffffda RBX: 0000000000d078e0 RCX: 00007fa2f1534b47 [ 5.061612] RDX: 00007ffeb7927050 RSI: 0000000000000000 RDI: 0000000000d078e0 [ 5.061744] RBP: 0000000000d07b40 R08: 0000000000d07920 R09: 00007fa2f15726c0 [ 5.061875] R10: 000000000000089e R11: 0000000000000206 R12: 0000000000d078a0 [ 5.062006] R13: 0000000000d07ba0 R14: 0000000000000000 R15: 00007ffeb7927050 [ 5.062188] Modules linked in: [ 5.062375] CR2: 0000000000000030 [ 5.062675] ---[ end trace c42a74534e5e2f3f ]--- [ 5.062816] RIP: 0010:reconfigure_super+0x47/0x210 [ 5.062924] Code: d4 01 00 00 44 8b a3 30 02 00 00 45 85 e4 0f 85 9d 01 00 00 a8 01 48 89 fd 75 4f 48 89 df 45 31 ed e8 ad 4f 01 00 48 8b 45 00 <48> 8b 40 30 48 85 c0 0f 84 d3 00 00 00 48 89 ef ff d0 85 c0 0f 84 [ 5.063263] RSP: 0018:ffffa8560011bdd0 EFLAGS: 00000246 [ 5.063372] RAX: 0000000000000000 RBX: ffffa2cd4c72c000 RCX: ffffa2cd4c72c0b8 [ 5.063526] RDX: ffffa2cd4c72c048 RSI: 0000000000000000 RDI: ffffffff98b49e28 [ 5.063665] RBP: ffffa8560011be00 R08: 000000000000019b R09: 0000000000000000 [ 5.063797] R10: ffffa856000bfd08 R11: 0000000000000001 R12: 0000000000000000 [ 5.063928] R13: 0000000000000001 R14: ffffa2cd4f38f920 R15: 0000000000000000 [ 5.064060] FS: 00007fa2f1a15500(0000) GS:ffffa2cd4f600000(0000) knlGS:0000000000000000 [ 5.064224] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 5.064337] CR2: 0000000000000030 CR3: 000000000c7b4000 CR4: 00000000003406f0 --- # bad: [09c0888767529cdb382f34452819e42d1a66a114] Add linux-next specific files for 20180911 # good: [11da3a7f84f19c26da6f86af878298694ede0804] Linux 4.19-rc3 git bisect start 'HEAD' 'v4.19-rc3' # bad: [a2ebc71cf97bed9b453318418e4a281434565e8b] Merge remote-tracking branch 'nfc-next/master' git bisect bad a2ebc71cf97bed9b453318418e4a281434565e8b # good: [6fde463b32bf4105c28c0a297a5b66aca5d6ecd4] Merge remote-tracking branch 's390/features' git bisect good 6fde463b32bf4105c28c0a297a5b66aca5d6ecd4 # bad: [136fd6d530a3ae0dd003984f683345cfe88c01f3] Merge remote-tracking branch 'v4l-dvb/master' git bisect bad 136fd6d530a3ae0dd003984f683345cfe88c01f3 # good: [c7ae95368af43c08f5f615b00f2f7bf2e9c45788] Merge remote-tracking branch 'v9fs/9p-next' git bisect good c7ae95368af43c08f5f615b00f2f7bf2e9c45788 # good: [4c640c41381e47b328c6507bcf534812761256cd] Merge branch 'for-4.19/fixes' into for-next git bisect good 4c640c41381e47b328c6507bcf534812761256cd # bad: [5bc91f70c5ecc2bc5967b98ce7fa4e55ad230d99] Merge remote-tracking branch 'hid/for-next' git bisect bad 5bc91f70c5ecc2bc5967b98ce7fa4e55ad230d99 # bad: [88abb54c46648cf25930133fbdeb145bf8537673] vfs: syscall: Add fsconfig() for configuring and managing a context git bisect bad 88abb54c46648cf25930133fbdeb145bf8537673 # good: [b2bbd433151748c5268769f560c926343dece319] vfs: Separate changing mount flags full remount git bisect good b2bbd433151748c5268769f560c926343dece319 # bad: [b348b6230aac28ffe555000831966d45529ab3b0] kernfs, sysfs, cgroup, intel_rdt: Support fs_context git bisect bad b348b6230aac28ffe555000831966d45529ab3b0 # bad: [bf090f3c0282903ad55bca27a482180c70627bd5] procfs: Move proc_fill_super() to fs/proc/root.c git bisect bad bf090f3c0282903ad55bca27a482180c70627bd5 # bad: [d3f3eaba540acf5b521865dec5634e3a1e138f1d] vfs: Remove unused code after filesystem context changes git bisect bad d3f3eaba540acf5b521865dec5634e3a1e138f1d # bad: [5d5eb529715b5a7a4caf10825e2a330608dcd1ef] vfs: Implement a filesystem superblock creation/configuration context git bisect bad 5d5eb529715b5a7a4caf10825e2a330608dcd1ef # first bad commit: [5d5eb529715b5a7a4caf10825e2a330608dcd1ef] vfs: Implement a filesystem superblock creation/configuration context
