[PATCH v3 0/2] quota: Add mountpath based quota support

[PATCH v3 0/2] quota: Add mountpath based quota support

[Sascha Hauer]

Current quotactl syscall uses a path to a block device to specify the
filesystem to work on which makes it unsuitable for filesystems that
do not have a block device. This series adds a new syscall quotactl_path()
which replaces the path to the block device with a mountpath, but otherwise
behaves like original quotactl.

This is done to add quota support to UBIFS. UBIFS quota support has been
posted several times with different approaches to put the mountpath into
the existing quotactl() syscall until it has been suggested to make it a
new syscall instead, so here it is.

I'm not posting the full UBIFS quota series here as it remains unchanged
and I'd like to get feedback to the new syscall first. For those interested
the most recent series can be found here: https://lwn.net/Articles/810463/

Changes since v2:
- Rebase on v5.12-rc1
- replace mountpath.dentry->d_inode->i_sb with mountpath.mnt->mnt_sb
- fix wrong macro usage in arch/x86/entry/syscalls/syscall_32.tbl
- +Cc linux-api@vger.kernel.org

Changes since (implicit) v1:
- Ignore second path argument to Q_QUOTAON. With this quotactl_path() can
  only do the Q_QUOTAON operation on filesystems which use hidden inodes
  for quota metadata storage
- Drop unnecessary quotactl_cmd_onoff() check

Sascha Hauer (2):
  quota: Add mountpath based quota support
  quota: wire up quotactl_path

 arch/alpha/kernel/syscalls/syscall.tbl      |  1 +
 arch/arm/tools/syscall.tbl                  |  1 +
 arch/arm64/include/asm/unistd.h             |  2 +-
 arch/arm64/include/asm/unistd32.h           |  2 +
 arch/ia64/kernel/syscalls/syscall.tbl       |  1 +
 arch/m68k/kernel/syscalls/syscall.tbl       |  1 +
 arch/microblaze/kernel/syscalls/syscall.tbl |  1 +
 arch/mips/kernel/syscalls/syscall_n32.tbl   |  1 +
 arch/mips/kernel/syscalls/syscall_n64.tbl   |  1 +
 arch/mips/kernel/syscalls/syscall_o32.tbl   |  1 +
 arch/parisc/kernel/syscalls/syscall.tbl     |  1 +
 arch/powerpc/kernel/syscalls/syscall.tbl    |  1 +
 arch/s390/kernel/syscalls/syscall.tbl       |  1 +
 arch/sh/kernel/syscalls/syscall.tbl         |  1 +
 arch/sparc/kernel/syscalls/syscall.tbl      |  1 +
 arch/x86/entry/syscalls/syscall_32.tbl      |  1 +
 arch/x86/entry/syscalls/syscall_64.tbl      |  1 +
 arch/xtensa/kernel/syscalls/syscall.tbl     |  1 +
 fs/quota/quota.c                            | 49 +++++++++++++++++++--
 include/linux/syscalls.h                    |  2 +
 include/uapi/asm-generic/unistd.h           |  4 +-
 kernel/sys_ni.c                             |  1 +
 22 files changed, 71 insertions(+), 5 deletions(-)

-- 
2.29.2

[PATCH 1/2] quota: Add mountpath based quota support

[Sascha Hauer]

Add syscall quotactl_path, a variant of quotactl which allows to specify
the mountpath instead of a path of to a block device.

The quotactl syscall expects a path to the mounted block device to
specify the filesystem to work on. This limits usage to filesystems
which actually have a block device. quotactl_path replaces the path
to the block device with a path where the filesystem is mounted at.

The global Q_SYNC command to sync all filesystems is not supported for
this new syscall, otherwise quotactl_path behaves like quotactl.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 fs/quota/quota.c | 49 +++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 46 insertions(+), 3 deletions(-)

diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index 6d16b2be5ac4..f7b4b66491fc 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -17,6 +17,7 @@
 #include <linux/capability.h>
 #include <linux/quotaops.h>
 #include <linux/types.h>
+#include <linux/mount.h>
 #include <linux/writeback.h>
 #include <linux/nospec.h>
 #include "compat.h"
@@ -827,8 +828,6 @@ static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
 	}
 }
 
-#ifdef CONFIG_BLOCK
-
 /* Return 1 if 'cmd' will block on frozen filesystem */
 static int quotactl_cmd_write(int cmd)
 {
@@ -850,7 +849,6 @@ static int quotactl_cmd_write(int cmd)
 	}
 	return 1;
 }
-#endif /* CONFIG_BLOCK */
 
 /* Return true if quotactl command is manipulating quota on/off state */
 static bool quotactl_cmd_onoff(int cmd)
@@ -968,3 +966,48 @@ SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
 		path_put(pathp);
 	return ret;
 }
+
+SYSCALL_DEFINE4(quotactl_path, unsigned int, cmd, const char __user *,
+		mountpoint, qid_t, id, void __user *, addr)
+{
+	struct super_block *sb;
+	struct path mountpath;
+	unsigned int cmds = cmd >> SUBCMDSHIFT;
+	unsigned int type = cmd & SUBCMDMASK;
+	int ret;
+
+	if (type >= MAXQUOTAS)
+		return -EINVAL;
+
+	ret = user_path_at(AT_FDCWD, mountpoint,
+			     LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT, &mountpath);
+	if (ret)
+		return ret;
+
+	sb = mountpath.mnt->mnt_sb;
+
+	if (quotactl_cmd_write(cmds)) {
+		ret = mnt_want_write(mountpath.mnt);
+		if (ret)
+			goto out;
+	}
+
+	if (quotactl_cmd_onoff(cmds))
+		down_write(&sb->s_umount);
+	else
+		down_read(&sb->s_umount);
+
+	ret = do_quotactl(sb, type, cmds, id, addr, ERR_PTR(-EINVAL));
+
+	if (quotactl_cmd_onoff(cmds))
+		up_write(&sb->s_umount);
+	else
+		up_read(&sb->s_umount);
+
+	if (quotactl_cmd_write(cmds))
+		mnt_drop_write(mountpath.mnt);
+out:
+	path_put(&mountpath);
+
+	return ret;
+}
-- 
2.29.2

[PATCH 2/2] quota: wire up quotactl_path

[Sascha Hauer]

Wire up the quotactl_path syscall added in the previous patch.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 arch/alpha/kernel/syscalls/syscall.tbl      | 1 +
 arch/arm/tools/syscall.tbl                  | 1 +
 arch/arm64/include/asm/unistd.h             | 2 +-
 arch/arm64/include/asm/unistd32.h           | 2 ++
 arch/ia64/kernel/syscalls/syscall.tbl       | 1 +
 arch/m68k/kernel/syscalls/syscall.tbl       | 1 +
 arch/microblaze/kernel/syscalls/syscall.tbl | 1 +
 arch/mips/kernel/syscalls/syscall_n32.tbl   | 1 +
 arch/mips/kernel/syscalls/syscall_n64.tbl   | 1 +
 arch/mips/kernel/syscalls/syscall_o32.tbl   | 1 +
 arch/parisc/kernel/syscalls/syscall.tbl     | 1 +
 arch/powerpc/kernel/syscalls/syscall.tbl    | 1 +
 arch/s390/kernel/syscalls/syscall.tbl       | 1 +
 arch/sh/kernel/syscalls/syscall.tbl         | 1 +
 arch/sparc/kernel/syscalls/syscall.tbl      | 1 +
 arch/x86/entry/syscalls/syscall_32.tbl      | 1 +
 arch/x86/entry/syscalls/syscall_64.tbl      | 1 +
 arch/xtensa/kernel/syscalls/syscall.tbl     | 1 +
 include/linux/syscalls.h                    | 2 ++
 include/uapi/asm-generic/unistd.h           | 4 +++-
 kernel/sys_ni.c                             | 1 +
 21 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
index 02f0244e005c..c5f7e595adab 100644
--- a/arch/alpha/kernel/syscalls/syscall.tbl
+++ b/arch/alpha/kernel/syscalls/syscall.tbl
@@ -482,3 +482,4 @@
 550	common	process_madvise			sys_process_madvise
 551	common	epoll_pwait2			sys_epoll_pwait2
 552	common	mount_setattr			sys_mount_setattr
+553	common	quotactl_path			sys_quotactl_path
diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
index dcc1191291a2..90cbe207cf3e 100644
--- a/arch/arm/tools/syscall.tbl
+++ b/arch/arm/tools/syscall.tbl
@@ -456,3 +456,4 @@
 440	common	process_madvise			sys_process_madvise
 441	common	epoll_pwait2			sys_epoll_pwait2
 442	common	mount_setattr			sys_mount_setattr
+443	common	quotactl_path			sys_quotactl_path
diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h
index 949788f5ba40..d1f7d35f986e 100644
--- a/arch/arm64/include/asm/unistd.h
+++ b/arch/arm64/include/asm/unistd.h
@@ -38,7 +38,7 @@
 #define __ARM_NR_compat_set_tls		(__ARM_NR_COMPAT_BASE + 5)
 #define __ARM_NR_COMPAT_END		(__ARM_NR_COMPAT_BASE + 0x800)
 
-#define __NR_compat_syscalls		443
+#define __NR_compat_syscalls		444
 #endif
 
 #define __ARCH_WANT_SYS_CLONE
diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
index 3d874f624056..8361c5138e5f 100644
--- a/arch/arm64/include/asm/unistd32.h
+++ b/arch/arm64/include/asm/unistd32.h
@@ -893,6 +893,8 @@ __SYSCALL(__NR_process_madvise, sys_process_madvise)
 __SYSCALL(__NR_epoll_pwait2, compat_sys_epoll_pwait2)
 #define __NR_mount_setattr 442
 __SYSCALL(__NR_mount_setattr, sys_mount_setattr)
+#define __NR_quotactl_path 443
+__SYSCALL(__NR_quotactl_path, sys_quotactl_path)
 
 /*
  * Please add new compat syscalls above this comment and update
diff --git a/arch/ia64/kernel/syscalls/syscall.tbl b/arch/ia64/kernel/syscalls/syscall.tbl
index d89231166e19..c072cd459bb5 100644
--- a/arch/ia64/kernel/syscalls/syscall.tbl
+++ b/arch/ia64/kernel/syscalls/syscall.tbl
@@ -363,3 +363,4 @@
 440	common	process_madvise			sys_process_madvise
 441	common	epoll_pwait2			sys_epoll_pwait2
 442	common	mount_setattr			sys_mount_setattr
+443	common	quotactl_path			sys_quotactl_path
diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl
index 72bde6707dd3..5e9f81073ff4 100644
--- a/arch/m68k/kernel/syscalls/syscall.tbl
+++ b/arch/m68k/kernel/syscalls/syscall.tbl
@@ -442,3 +442,4 @@
 440	common	process_madvise			sys_process_madvise
 441	common	epoll_pwait2			sys_epoll_pwait2
 442	common	mount_setattr			sys_mount_setattr
+443	common	quotactl_path			sys_quotactl_path
diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl
index d603a5ec9338..8e74d690c64d 100644
--- a/arch/microblaze/kernel/syscalls/syscall.tbl
+++ b/arch/microblaze/kernel/syscalls/syscall.tbl
@@ -448,3 +448,4 @@
 440	common	process_madvise			sys_process_madvise
 441	common	epoll_pwait2			sys_epoll_pwait2
 442	common	mount_setattr			sys_mount_setattr
+443	common	quotactl_path			sys_quotactl_path
diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
index 8fd8c1790941..6f397e56926f 100644
--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -381,3 +381,4 @@
 440	n32	process_madvise			sys_process_madvise
 441	n32	epoll_pwait2			compat_sys_epoll_pwait2
 442	n32	mount_setattr			sys_mount_setattr
+443	n32	quotactl_path			sys_quotactl_path
diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
index 169f21438065..ab85a357c4fa 100644
--- a/arch/mips/kernel/syscalls/syscall_n64.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
@@ -357,3 +357,4 @@
 440	n64	process_madvise			sys_process_madvise
 441	n64	epoll_pwait2			sys_epoll_pwait2
 442	n64	mount_setattr			sys_mount_setattr
+443	n64	quotactl_path			sys_quotactl_path
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
index 090d29ca80ff..9c4cd2b40b38 100644
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -430,3 +430,4 @@
 440	o32	process_madvise			sys_process_madvise
 441	o32	epoll_pwait2			sys_epoll_pwait2		compat_sys_epoll_pwait2
 442	o32	mount_setattr			sys_mount_setattr
+443	o32	quotactl_path			sys_quotactl_path
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
index 271a92519683..80fba3f7d47b 100644
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -440,3 +440,4 @@
 440	common	process_madvise			sys_process_madvise
 441	common	epoll_pwait2			sys_epoll_pwait2		compat_sys_epoll_pwait2
 442	common	mount_setattr			sys_mount_setattr
+443	common	quotactl_path			sys_quotactl_path
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
index 0b2480cf3e47..f66f9c9b9d6c 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -522,3 +522,4 @@
 440	common	process_madvise			sys_process_madvise
 441	common	epoll_pwait2			sys_epoll_pwait2		compat_sys_epoll_pwait2
 442	common	mount_setattr			sys_mount_setattr
+443	common	quotactl_path			sys_quotactl_path
diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
index 3abef2144dac..4aeaa89fa774 100644
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -445,3 +445,4 @@
 440  common	process_madvise		sys_process_madvise		sys_process_madvise
 441  common	epoll_pwait2		sys_epoll_pwait2		compat_sys_epoll_pwait2
 442  common	mount_setattr		sys_mount_setattr		sys_mount_setattr
+443  common	quotactl_path		sys_quotactl_path
diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl
index d08eebad6b7f..f68517aaa4f1 100644
--- a/arch/sh/kernel/syscalls/syscall.tbl
+++ b/arch/sh/kernel/syscalls/syscall.tbl
@@ -445,3 +445,4 @@
 440	common	process_madvise			sys_process_madvise
 441	common	epoll_pwait2			sys_epoll_pwait2
 442	common	mount_setattr			sys_mount_setattr
+443	common	quotactl_path			sys_quotactl_path
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
index 84403a99039c..3ee82321504d 100644
--- a/arch/sparc/kernel/syscalls/syscall.tbl
+++ b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -488,3 +488,4 @@
 440	common	process_madvise			sys_process_madvise
 441	common	epoll_pwait2			sys_epoll_pwait2		compat_sys_epoll_pwait2
 442	common	mount_setattr			sys_mount_setattr
+443	common	quotactl_path			sys_quotactl_path
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index a1c9f496fca6..f52a443eede0 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -447,3 +447,4 @@
 440	i386	process_madvise		sys_process_madvise
 441	i386	epoll_pwait2		sys_epoll_pwait2		compat_sys_epoll_pwait2
 442	i386	mount_setattr		sys_mount_setattr
+443	i386	quotactl_path		sys_quotactl_path
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 7bf01cbe582f..7eb007b8cab5 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -364,6 +364,7 @@
 440	common	process_madvise		sys_process_madvise
 441	common	epoll_pwait2		sys_epoll_pwait2
 442	common	mount_setattr		sys_mount_setattr
+443	common	quotactl_path		sys_quotactl_path
 
 #
 # Due to a historical design error, certain syscalls are numbered differently
diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl
index 365a9b849224..c71cc45633de 100644
--- a/arch/xtensa/kernel/syscalls/syscall.tbl
+++ b/arch/xtensa/kernel/syscalls/syscall.tbl
@@ -413,3 +413,4 @@
 440	common	process_madvise			sys_process_madvise
 441	common	epoll_pwait2			sys_epoll_pwait2
 442	common	mount_setattr			sys_mount_setattr
+443	common	quotactl_path			sys_quotactl_path
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 2839dc9a7c01..a672bbe28577 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -483,6 +483,8 @@ asmlinkage long sys_pipe2(int __user *fildes, int flags);
 /* fs/quota.c */
 asmlinkage long sys_quotactl(unsigned int cmd, const char __user *special,
 				qid_t id, void __user *addr);
+asmlinkage long sys_quotactl_path(unsigned int cmd, const char __user *mountpoint,
+				  qid_t id, void __user *addr);
 
 /* fs/readdir.c */
 asmlinkage long sys_getdents64(unsigned int fd,
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index ce58cff99b66..739c839d28fe 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -863,9 +863,11 @@ __SYSCALL(__NR_process_madvise, sys_process_madvise)
 __SC_COMP(__NR_epoll_pwait2, sys_epoll_pwait2, compat_sys_epoll_pwait2)
 #define __NR_mount_setattr 442
 __SYSCALL(__NR_mount_setattr, sys_mount_setattr)
+#define __NR_quotactl_path 443
+__SYSCALL(__NR_quotactl_path, sys_quotactl_path)
 
 #undef __NR_syscalls
-#define __NR_syscalls 443
+#define __NR_syscalls 444
 
 /*
  * 32 bit systems traditionally used different
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 19aa806890d5..d24431782414 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -99,6 +99,7 @@ COND_SYSCALL(flock);
 
 /* fs/quota.c */
 COND_SYSCALL(quotactl);
+COND_SYSCALL(quotactl_path);
 
 /* fs/readdir.c */
 
-- 
2.29.2

[PATCH] quotactl.2: Add documentation for quotactl_path()

[Sascha Hauer]

Expand the quotactl.2 manpage with a description for quotactl_path()
that takes a mountpoint path instead of a path to a block device.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 man2/quotactl.2      | 31 ++++++++++++++++++++++++++++---
 man2/quotactl_path.2 |  1 +
 2 files changed, 29 insertions(+), 3 deletions(-)
 create mode 100644 man2/quotactl_path.2

diff --git a/man2/quotactl.2 b/man2/quotactl.2
index 7869c64ea..76505c668 100644
--- a/man2/quotactl.2
+++ b/man2/quotactl.2
@@ -34,6 +34,8 @@ quotactl \- manipulate disk quotas
 .PP
 .BI "int quotactl(int " cmd ", const char *" special ", int " id \
 ", caddr_t " addr );
+.BI "int quotactl_path(int " cmd ", const char *" mountpoint ", int " id \
+", caddr_t " addr );
 .fi
 .SH DESCRIPTION
 The quota system can be used to set per-user, per-group, and per-project limits
@@ -48,7 +50,11 @@ after this, the soft limit counts as a hard limit.
 .PP
 The
 .BR quotactl ()
-call manipulates disk quotas.
+and
+.BR quotactl_path ()
+calls manipulate disk quotas. The difference between both functions is the way
+how the filesystem being manipulated is specified, see description of the arguments
+below.
 The
 .I cmd
 argument indicates a command to be applied to the user or
@@ -75,10 +81,19 @@ value is described below.
 .PP
 The
 .I special
-argument is a pointer to a null-terminated string containing the pathname
+argument to
+.BR quotactl ()
+is a pointer to a null-terminated string containing the pathname
 of the (mounted) block special device for the filesystem being manipulated.
 .PP
 The
+.I mountpoint
+argument to
+.BR quotactl_path ()
+is a pointer to a null-terminated string containing the pathname
+of the mountpoint for the filesystem being manipulated.
+.PP
+The
 .I addr
 argument is the address of an optional, command-specific, data structure
 that is copied in or out of the system.
@@ -133,7 +148,17 @@ flag in the
 .I dqi_flags
 field returned by the
 .B Q_GETINFO
-operation.
+operation. The
+.BR quotactl_path ()
+variant of this syscall generally ignores the
+.IR addr
+and
+.IR id
+arguments, so the
+.B Q_QUOTAON
+operation of
+.BR quotactl_path ()
+is only suitable for work with hidden system inodes.
 .IP
 This operation requires privilege
 .RB ( CAP_SYS_ADMIN ).
diff --git a/man2/quotactl_path.2 b/man2/quotactl_path.2
new file mode 100644
index 000000000..5f63187c6
--- /dev/null
+++ b/man2/quotactl_path.2
@@ -0,0 +1 @@
+.so man2/quotactl.2
-- 
2.20.1

Re: [PATCH 2/2] quota: wire up quotactl_path

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 19839 bytes --]

Hi Sascha,

I love your patch! Perhaps something to improve:

[auto build test WARNING on m68k/for-next]
[also build test WARNING on hp-parisc/for-next powerpc/next s390/features sparc/master linus/master v5.12-rc1]
[cannot apply to arm64/for-next/core tip/x86/asm]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Sascha-Hauer/quota-Add-mountpath-based-quota-support/20210304-204157
base:   https://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k.git for-next
config: x86_64-randconfig-m001-20210304 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/4c5e71a8aad3e3e1f2eb339eec24d563d0d6acbe
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Sascha-Hauer/quota-Add-mountpath-based-quota-support/20210304-204157
        git checkout 4c5e71a8aad3e3e1f2eb339eec24d563d0d6acbe
        # save the attached .config to linux build tree
        make W=1 ARCH=x86_64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

         |  ^~~~~~~~~~~~~~~~~~
   kernel/sys_ni.c:69:1: note: in expansion of macro 'COND_SYSCALL'
      69 | COND_SYSCALL(epoll_pwait);
         | ^~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:83:14: warning: no previous prototype for '__x64_sys_epoll_pwait2' [-Wmissing-prototypes]
      83 |  __weak long __##abi##_##name(const struct pt_regs *__unused) \
         |              ^~
   arch/x86/include/asm/syscall_wrapper.h:100:2: note: in expansion of macro '__COND_SYSCALL'
     100 |  __COND_SYSCALL(x64, sys_##name)
         |  ^~~~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:256:2: note: in expansion of macro '__X64_COND_SYSCALL'
     256 |  __X64_COND_SYSCALL(name)     \
         |  ^~~~~~~~~~~~~~~~~~
   kernel/sys_ni.c:71:1: note: in expansion of macro 'COND_SYSCALL'
      71 | COND_SYSCALL(epoll_pwait2);
         | ^~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:83:14: warning: no previous prototype for '__x64_sys_inotify_init1' [-Wmissing-prototypes]
      83 |  __weak long __##abi##_##name(const struct pt_regs *__unused) \
         |              ^~
   arch/x86/include/asm/syscall_wrapper.h:100:2: note: in expansion of macro '__COND_SYSCALL'
     100 |  __COND_SYSCALL(x64, sys_##name)
         |  ^~~~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:256:2: note: in expansion of macro '__X64_COND_SYSCALL'
     256 |  __X64_COND_SYSCALL(name)     \
         |  ^~~~~~~~~~~~~~~~~~
   kernel/sys_ni.c:77:1: note: in expansion of macro 'COND_SYSCALL'
      77 | COND_SYSCALL(inotify_init1);
         | ^~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:83:14: warning: no previous prototype for '__x64_sys_inotify_add_watch' [-Wmissing-prototypes]
      83 |  __weak long __##abi##_##name(const struct pt_regs *__unused) \
         |              ^~
   arch/x86/include/asm/syscall_wrapper.h:100:2: note: in expansion of macro '__COND_SYSCALL'
     100 |  __COND_SYSCALL(x64, sys_##name)
         |  ^~~~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:256:2: note: in expansion of macro '__X64_COND_SYSCALL'
     256 |  __X64_COND_SYSCALL(name)     \
         |  ^~~~~~~~~~~~~~~~~~
   kernel/sys_ni.c:78:1: note: in expansion of macro 'COND_SYSCALL'
      78 | COND_SYSCALL(inotify_add_watch);
         | ^~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:83:14: warning: no previous prototype for '__x64_sys_inotify_rm_watch' [-Wmissing-prototypes]
      83 |  __weak long __##abi##_##name(const struct pt_regs *__unused) \
         |              ^~
   arch/x86/include/asm/syscall_wrapper.h:100:2: note: in expansion of macro '__COND_SYSCALL'
     100 |  __COND_SYSCALL(x64, sys_##name)
         |  ^~~~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:256:2: note: in expansion of macro '__X64_COND_SYSCALL'
     256 |  __X64_COND_SYSCALL(name)     \
         |  ^~~~~~~~~~~~~~~~~~
   kernel/sys_ni.c:79:1: note: in expansion of macro 'COND_SYSCALL'
      79 | COND_SYSCALL(inotify_rm_watch);
         | ^~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:83:14: warning: no previous prototype for '__x64_sys_ioprio_set' [-Wmissing-prototypes]
      83 |  __weak long __##abi##_##name(const struct pt_regs *__unused) \
         |              ^~
   arch/x86/include/asm/syscall_wrapper.h:100:2: note: in expansion of macro '__COND_SYSCALL'
     100 |  __COND_SYSCALL(x64, sys_##name)
         |  ^~~~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:256:2: note: in expansion of macro '__X64_COND_SYSCALL'
     256 |  __X64_COND_SYSCALL(name)     \
         |  ^~~~~~~~~~~~~~~~~~
   kernel/sys_ni.c:84:1: note: in expansion of macro 'COND_SYSCALL'
      84 | COND_SYSCALL(ioprio_set);
         | ^~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:83:14: warning: no previous prototype for '__x64_sys_ioprio_get' [-Wmissing-prototypes]
      83 |  __weak long __##abi##_##name(const struct pt_regs *__unused) \
         |              ^~
   arch/x86/include/asm/syscall_wrapper.h:100:2: note: in expansion of macro '__COND_SYSCALL'
     100 |  __COND_SYSCALL(x64, sys_##name)
         |  ^~~~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:256:2: note: in expansion of macro '__X64_COND_SYSCALL'
     256 |  __X64_COND_SYSCALL(name)     \
         |  ^~~~~~~~~~~~~~~~~~
   kernel/sys_ni.c:85:1: note: in expansion of macro 'COND_SYSCALL'
      85 | COND_SYSCALL(ioprio_get);
         | ^~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:83:14: warning: no previous prototype for '__x64_sys_flock' [-Wmissing-prototypes]
      83 |  __weak long __##abi##_##name(const struct pt_regs *__unused) \
         |              ^~
   arch/x86/include/asm/syscall_wrapper.h:100:2: note: in expansion of macro '__COND_SYSCALL'
     100 |  __COND_SYSCALL(x64, sys_##name)
         |  ^~~~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:256:2: note: in expansion of macro '__X64_COND_SYSCALL'
     256 |  __X64_COND_SYSCALL(name)     \
         |  ^~~~~~~~~~~~~~~~~~
   kernel/sys_ni.c:88:1: note: in expansion of macro 'COND_SYSCALL'
      88 | COND_SYSCALL(flock);
         | ^~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:83:14: warning: no previous prototype for '__x64_sys_quotactl' [-Wmissing-prototypes]
      83 |  __weak long __##abi##_##name(const struct pt_regs *__unused) \
         |              ^~
   arch/x86/include/asm/syscall_wrapper.h:100:2: note: in expansion of macro '__COND_SYSCALL'
     100 |  __COND_SYSCALL(x64, sys_##name)
         |  ^~~~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:256:2: note: in expansion of macro '__X64_COND_SYSCALL'
     256 |  __X64_COND_SYSCALL(name)     \
         |  ^~~~~~~~~~~~~~~~~~
   kernel/sys_ni.c:101:1: note: in expansion of macro 'COND_SYSCALL'
     101 | COND_SYSCALL(quotactl);
         | ^~~~~~~~~~~~
>> arch/x86/include/asm/syscall_wrapper.h:83:14: warning: no previous prototype for '__x64_sys_quotactl_path' [-Wmissing-prototypes]
      83 |  __weak long __##abi##_##name(const struct pt_regs *__unused) \
         |              ^~
   arch/x86/include/asm/syscall_wrapper.h:100:2: note: in expansion of macro '__COND_SYSCALL'
     100 |  __COND_SYSCALL(x64, sys_##name)
         |  ^~~~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:256:2: note: in expansion of macro '__X64_COND_SYSCALL'
     256 |  __X64_COND_SYSCALL(name)     \
         |  ^~~~~~~~~~~~~~~~~~
   kernel/sys_ni.c:102:1: note: in expansion of macro 'COND_SYSCALL'
     102 | COND_SYSCALL(quotactl_path);
         | ^~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:83:14: warning: no previous prototype for '__x64_sys_signalfd4' [-Wmissing-prototypes]
      83 |  __weak long __##abi##_##name(const struct pt_regs *__unused) \
         |              ^~
   arch/x86/include/asm/syscall_wrapper.h:100:2: note: in expansion of macro '__COND_SYSCALL'
     100 |  __COND_SYSCALL(x64, sys_##name)
         |  ^~~~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:256:2: note: in expansion of macro '__X64_COND_SYSCALL'
     256 |  __X64_COND_SYSCALL(name)     \
         |  ^~~~~~~~~~~~~~~~~~
   kernel/sys_ni.c:113:1: note: in expansion of macro 'COND_SYSCALL'
     113 | COND_SYSCALL(signalfd4);
         | ^~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:83:14: warning: no previous prototype for '__x64_sys_timerfd_create' [-Wmissing-prototypes]
      83 |  __weak long __##abi##_##name(const struct pt_regs *__unused) \
         |              ^~
   arch/x86/include/asm/syscall_wrapper.h:100:2: note: in expansion of macro '__COND_SYSCALL'
     100 |  __COND_SYSCALL(x64, sys_##name)
         |  ^~~~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:256:2: note: in expansion of macro '__X64_COND_SYSCALL'
     256 |  __X64_COND_SYSCALL(name)     \
         |  ^~~~~~~~~~~~~~~~~~
   kernel/sys_ni.c:123:1: note: in expansion of macro 'COND_SYSCALL'
     123 | COND_SYSCALL(timerfd_create);
         | ^~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:83:14: warning: no previous prototype for '__x64_sys_timerfd_settime' [-Wmissing-prototypes]
      83 |  __weak long __##abi##_##name(const struct pt_regs *__unused) \
         |              ^~
   arch/x86/include/asm/syscall_wrapper.h:100:2: note: in expansion of macro '__COND_SYSCALL'
     100 |  __COND_SYSCALL(x64, sys_##name)
         |  ^~~~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:256:2: note: in expansion of macro '__X64_COND_SYSCALL'
     256 |  __X64_COND_SYSCALL(name)     \
         |  ^~~~~~~~~~~~~~~~~~
   kernel/sys_ni.c:124:1: note: in expansion of macro 'COND_SYSCALL'
     124 | COND_SYSCALL(timerfd_settime);
         | ^~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:83:14: warning: no previous prototype for '__x64_sys_timerfd_settime32' [-Wmissing-prototypes]
      83 |  __weak long __##abi##_##name(const struct pt_regs *__unused) \
         |              ^~
   arch/x86/include/asm/syscall_wrapper.h:100:2: note: in expansion of macro '__COND_SYSCALL'
     100 |  __COND_SYSCALL(x64, sys_##name)
         |  ^~~~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:256:2: note: in expansion of macro '__X64_COND_SYSCALL'
     256 |  __X64_COND_SYSCALL(name)     \
         |  ^~~~~~~~~~~~~~~~~~
   kernel/sys_ni.c:125:1: note: in expansion of macro 'COND_SYSCALL'
     125 | COND_SYSCALL(timerfd_settime32);
         | ^~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:83:14: warning: no previous prototype for '__x64_sys_timerfd_gettime' [-Wmissing-prototypes]
      83 |  __weak long __##abi##_##name(const struct pt_regs *__unused) \
         |              ^~
   arch/x86/include/asm/syscall_wrapper.h:100:2: note: in expansion of macro '__COND_SYSCALL'
     100 |  __COND_SYSCALL(x64, sys_##name)
         |  ^~~~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:256:2: note: in expansion of macro '__X64_COND_SYSCALL'
     256 |  __X64_COND_SYSCALL(name)     \
         |  ^~~~~~~~~~~~~~~~~~
   kernel/sys_ni.c:126:1: note: in expansion of macro 'COND_SYSCALL'
     126 | COND_SYSCALL(timerfd_gettime);
         | ^~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:83:14: warning: no previous prototype for '__x64_sys_timerfd_gettime32' [-Wmissing-prototypes]
      83 |  __weak long __##abi##_##name(const struct pt_regs *__unused) \
         |              ^~
   arch/x86/include/asm/syscall_wrapper.h:100:2: note: in expansion of macro '__COND_SYSCALL'
     100 |  __COND_SYSCALL(x64, sys_##name)
         |  ^~~~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:256:2: note: in expansion of macro '__X64_COND_SYSCALL'
     256 |  __X64_COND_SYSCALL(name)     \
         |  ^~~~~~~~~~~~~~~~~~
   kernel/sys_ni.c:127:1: note: in expansion of macro 'COND_SYSCALL'
     127 | COND_SYSCALL(timerfd_gettime32);
         | ^~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:83:14: warning: no previous prototype for '__x64_sys_acct' [-Wmissing-prototypes]
      83 |  __weak long __##abi##_##name(const struct pt_regs *__unused) \
         |              ^~
   arch/x86/include/asm/syscall_wrapper.h:100:2: note: in expansion of macro '__COND_SYSCALL'
     100 |  __COND_SYSCALL(x64, sys_##name)
         |  ^~~~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:256:2: note: in expansion of macro '__X64_COND_SYSCALL'
     256 |  __X64_COND_SYSCALL(name)     \
         |  ^~~~~~~~~~~~~~~~~~
   kernel/sys_ni.c:132:1: note: in expansion of macro 'COND_SYSCALL'
     132 | COND_SYSCALL(acct);
         | ^~~~~~~~~~~~
   arch/x86/include/asm/syscall_wrapper.h:83:14: warning: no previous prototype for '__x64_sys_capget' [-Wmissing-prototypes]
      83 |  __weak long __##abi##_##name(const struct pt_regs *__unused) \
         |              ^~
   arch/x86/include/asm/syscall_wrapper.h:100:2: note: in expansion of macro '__COND_SYSCALL'
     100 |  __COND_SYSCALL(x64, sys_##name)


vim +/__x64_sys_quotactl_path +83 arch/x86/include/asm/syscall_wrapper.h

cc42c045af1ff4de Brian Gerst       2020-03-13  13  
25c619e59b395a8c Brian Gerst       2020-03-13  14  /*
25c619e59b395a8c Brian Gerst       2020-03-13  15   * Instead of the generic __SYSCALL_DEFINEx() definition, the x86 version takes
25c619e59b395a8c Brian Gerst       2020-03-13  16   * struct pt_regs *regs as the only argument of the syscall stub(s) named as:
25c619e59b395a8c Brian Gerst       2020-03-13  17   * __x64_sys_*()         - 64-bit native syscall
25c619e59b395a8c Brian Gerst       2020-03-13  18   * __ia32_sys_*()        - 32-bit native syscall or common compat syscall
25c619e59b395a8c Brian Gerst       2020-03-13  19   * __ia32_compat_sys_*() - 32-bit compat syscall
25c619e59b395a8c Brian Gerst       2020-03-13  20   * __x32_compat_sys_*()  - 64-bit X32 compat syscall
25c619e59b395a8c Brian Gerst       2020-03-13  21   *
25c619e59b395a8c Brian Gerst       2020-03-13  22   * The registers are decoded according to the ABI:
25c619e59b395a8c Brian Gerst       2020-03-13  23   * 64-bit: RDI, RSI, RDX, R10, R8, R9
25c619e59b395a8c Brian Gerst       2020-03-13  24   * 32-bit: EBX, ECX, EDX, ESI, EDI, EBP
25c619e59b395a8c Brian Gerst       2020-03-13  25   *
25c619e59b395a8c Brian Gerst       2020-03-13  26   * The stub then passes the decoded arguments to the __se_sys_*() wrapper to
25c619e59b395a8c Brian Gerst       2020-03-13  27   * perform sign-extension (omitted for zero-argument syscalls).  Finally the
25c619e59b395a8c Brian Gerst       2020-03-13  28   * arguments are passed to the __do_sys_*() function which is the actual
25c619e59b395a8c Brian Gerst       2020-03-13  29   * syscall.  These wrappers are marked as inline so the compiler can optimize
25c619e59b395a8c Brian Gerst       2020-03-13  30   * the functions where appropriate.
25c619e59b395a8c Brian Gerst       2020-03-13  31   *
25c619e59b395a8c Brian Gerst       2020-03-13  32   * Example assembly (slightly re-ordered for better readability):
25c619e59b395a8c Brian Gerst       2020-03-13  33   *
25c619e59b395a8c Brian Gerst       2020-03-13  34   * <__x64_sys_recv>:		<-- syscall with 4 parameters
25c619e59b395a8c Brian Gerst       2020-03-13  35   *	callq	<__fentry__>
25c619e59b395a8c Brian Gerst       2020-03-13  36   *
25c619e59b395a8c Brian Gerst       2020-03-13  37   *	mov	0x70(%rdi),%rdi	<-- decode regs->di
25c619e59b395a8c Brian Gerst       2020-03-13  38   *	mov	0x68(%rdi),%rsi	<-- decode regs->si
25c619e59b395a8c Brian Gerst       2020-03-13  39   *	mov	0x60(%rdi),%rdx	<-- decode regs->dx
25c619e59b395a8c Brian Gerst       2020-03-13  40   *	mov	0x38(%rdi),%rcx	<-- decode regs->r10
25c619e59b395a8c Brian Gerst       2020-03-13  41   *
25c619e59b395a8c Brian Gerst       2020-03-13  42   *	xor	%r9d,%r9d	<-- clear %r9
25c619e59b395a8c Brian Gerst       2020-03-13  43   *	xor	%r8d,%r8d	<-- clear %r8
25c619e59b395a8c Brian Gerst       2020-03-13  44   *
25c619e59b395a8c Brian Gerst       2020-03-13  45   *	callq	__sys_recvfrom	<-- do the actual work in __sys_recvfrom()
25c619e59b395a8c Brian Gerst       2020-03-13  46   *				    which takes 6 arguments
25c619e59b395a8c Brian Gerst       2020-03-13  47   *
25c619e59b395a8c Brian Gerst       2020-03-13  48   *	cltq			<-- extend return value to 64-bit
25c619e59b395a8c Brian Gerst       2020-03-13  49   *	retq			<-- return
25c619e59b395a8c Brian Gerst       2020-03-13  50   *
25c619e59b395a8c Brian Gerst       2020-03-13  51   * This approach avoids leaking random user-provided register content down
25c619e59b395a8c Brian Gerst       2020-03-13  52   * the call chain.
25c619e59b395a8c Brian Gerst       2020-03-13  53   */
25c619e59b395a8c Brian Gerst       2020-03-13  54  
ebeb8c82ffaf9443 Dominik Brodowski 2018-04-05  55  /* Mapping of registers to parameters for syscalls on x86-64 and x32 */
ebeb8c82ffaf9443 Dominik Brodowski 2018-04-05  56  #define SC_X86_64_REGS_TO_ARGS(x, ...)					\
ebeb8c82ffaf9443 Dominik Brodowski 2018-04-05  57  	__MAP(x,__SC_ARGS						\
ebeb8c82ffaf9443 Dominik Brodowski 2018-04-05  58  		,,regs->di,,regs->si,,regs->dx				\
ebeb8c82ffaf9443 Dominik Brodowski 2018-04-05  59  		,,regs->r10,,regs->r8,,regs->r9)			\
ebeb8c82ffaf9443 Dominik Brodowski 2018-04-05  60  
ebeb8c82ffaf9443 Dominik Brodowski 2018-04-05  61  /* Mapping of registers to parameters for syscalls on i386 */
ebeb8c82ffaf9443 Dominik Brodowski 2018-04-05  62  #define SC_IA32_REGS_TO_ARGS(x, ...)					\
ebeb8c82ffaf9443 Dominik Brodowski 2018-04-05  63  	__MAP(x,__SC_ARGS						\
ebeb8c82ffaf9443 Dominik Brodowski 2018-04-05  64  	      ,,(unsigned int)regs->bx,,(unsigned int)regs->cx		\
ebeb8c82ffaf9443 Dominik Brodowski 2018-04-05  65  	      ,,(unsigned int)regs->dx,,(unsigned int)regs->si		\
ebeb8c82ffaf9443 Dominik Brodowski 2018-04-05  66  	      ,,(unsigned int)regs->di,,(unsigned int)regs->bp)
ebeb8c82ffaf9443 Dominik Brodowski 2018-04-05  67  
d2b5de495ee9838b Brian Gerst       2020-03-13  68  #define __SYS_STUB0(abi, name)						\
0f78ff17112d8b34 Brian Gerst       2020-03-13  69  	long __##abi##_##name(const struct pt_regs *regs);		\
d2b5de495ee9838b Brian Gerst       2020-03-13  70  	ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO);			\
0f78ff17112d8b34 Brian Gerst       2020-03-13  71  	long __##abi##_##name(const struct pt_regs *regs)		\
d2b5de495ee9838b Brian Gerst       2020-03-13  72  		__alias(__do_##name);
d2b5de495ee9838b Brian Gerst       2020-03-13  73  
4399e0cf494f739a Brian Gerst       2020-03-13  74  #define __SYS_STUBx(abi, name, ...)					\
0f78ff17112d8b34 Brian Gerst       2020-03-13  75  	long __##abi##_##name(const struct pt_regs *regs);		\
4399e0cf494f739a Brian Gerst       2020-03-13  76  	ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO);			\
0f78ff17112d8b34 Brian Gerst       2020-03-13  77  	long __##abi##_##name(const struct pt_regs *regs)		\
4399e0cf494f739a Brian Gerst       2020-03-13  78  	{								\
4399e0cf494f739a Brian Gerst       2020-03-13  79  		return __se_##name(__VA_ARGS__);			\
4399e0cf494f739a Brian Gerst       2020-03-13  80  	}
4399e0cf494f739a Brian Gerst       2020-03-13  81  
6cc8d2b286d9e716 Brian Gerst       2020-03-13  82  #define __COND_SYSCALL(abi, name)					\
0f78ff17112d8b34 Brian Gerst       2020-03-13 @83  	__weak long __##abi##_##name(const struct pt_regs *__unused)	\
6cc8d2b286d9e716 Brian Gerst       2020-03-13  84  	{								\
6cc8d2b286d9e716 Brian Gerst       2020-03-13  85  		return sys_ni_syscall();				\
6cc8d2b286d9e716 Brian Gerst       2020-03-13  86  	}
6cc8d2b286d9e716 Brian Gerst       2020-03-13  87  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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Re: [PATCH 2/2] quota: wire up quotactl_path

[kernel test robot]

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Hi Sascha,

I love your patch! Perhaps something to improve:

[auto build test WARNING on m68k/for-next]
[also build test WARNING on hp-parisc/for-next powerpc/next s390/features sparc/master linus/master v5.12-rc1]
[cannot apply to arm64/for-next/core tip/x86/asm]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Sascha-Hauer/quota-Add-mountpath-based-quota-support/20210304-204157
base:   https://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k.git for-next
config: arm64-randconfig-r002-20210304 (attached as .config)
compiler: aarch64-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/4c5e71a8aad3e3e1f2eb339eec24d563d0d6acbe
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Sascha-Hauer/quota-Add-mountpath-based-quota-support/20210304-204157
        git checkout 4c5e71a8aad3e3e1f2eb339eec24d563d0d6acbe
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arm64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:53:1: note: in expansion of macro 'COND_SYSCALL'
      53 | COND_SYSCALL(io_uring_register);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_lookup_dcookie' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:60:1: note: in expansion of macro 'COND_SYSCALL'
      60 | COND_SYSCALL(lookup_dcookie);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:41:25: warning: no previous prototype for '__arm64_compat_sys_lookup_dcookie' [-Wmissing-prototypes]
      41 |  asmlinkage long __weak __arm64_compat_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~~~~~~~~
   kernel/sys_ni.c:61:1: note: in expansion of macro 'COND_SYSCALL_COMPAT'
      61 | COND_SYSCALL_COMPAT(lookup_dcookie);
         | ^~~~~~~~~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_eventfd2' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:64:1: note: in expansion of macro 'COND_SYSCALL'
      64 | COND_SYSCALL(eventfd2);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_epoll_create1' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:67:1: note: in expansion of macro 'COND_SYSCALL'
      67 | COND_SYSCALL(epoll_create1);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_epoll_ctl' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:68:1: note: in expansion of macro 'COND_SYSCALL'
      68 | COND_SYSCALL(epoll_ctl);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_epoll_pwait' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:69:1: note: in expansion of macro 'COND_SYSCALL'
      69 | COND_SYSCALL(epoll_pwait);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:41:25: warning: no previous prototype for '__arm64_compat_sys_epoll_pwait' [-Wmissing-prototypes]
      41 |  asmlinkage long __weak __arm64_compat_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~~~~~~~~
   kernel/sys_ni.c:70:1: note: in expansion of macro 'COND_SYSCALL_COMPAT'
      70 | COND_SYSCALL_COMPAT(epoll_pwait);
         | ^~~~~~~~~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_epoll_pwait2' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:71:1: note: in expansion of macro 'COND_SYSCALL'
      71 | COND_SYSCALL(epoll_pwait2);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:41:25: warning: no previous prototype for '__arm64_compat_sys_epoll_pwait2' [-Wmissing-prototypes]
      41 |  asmlinkage long __weak __arm64_compat_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~~~~~~~~
   kernel/sys_ni.c:72:1: note: in expansion of macro 'COND_SYSCALL_COMPAT'
      72 | COND_SYSCALL_COMPAT(epoll_pwait2);
         | ^~~~~~~~~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_inotify_init1' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:77:1: note: in expansion of macro 'COND_SYSCALL'
      77 | COND_SYSCALL(inotify_init1);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_inotify_add_watch' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:78:1: note: in expansion of macro 'COND_SYSCALL'
      78 | COND_SYSCALL(inotify_add_watch);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_inotify_rm_watch' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:79:1: note: in expansion of macro 'COND_SYSCALL'
      79 | COND_SYSCALL(inotify_rm_watch);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_ioprio_set' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:84:1: note: in expansion of macro 'COND_SYSCALL'
      84 | COND_SYSCALL(ioprio_set);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_ioprio_get' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:85:1: note: in expansion of macro 'COND_SYSCALL'
      85 | COND_SYSCALL(ioprio_get);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_flock' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:88:1: note: in expansion of macro 'COND_SYSCALL'
      88 | COND_SYSCALL(flock);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_quotactl' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:101:1: note: in expansion of macro 'COND_SYSCALL'
     101 | COND_SYSCALL(quotactl);
         | ^~~~~~~~~~~~
>> arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_quotactl_path' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:102:1: note: in expansion of macro 'COND_SYSCALL'
     102 | COND_SYSCALL(quotactl_path);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_signalfd4' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:113:1: note: in expansion of macro 'COND_SYSCALL'
     113 | COND_SYSCALL(signalfd4);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:41:25: warning: no previous prototype for '__arm64_compat_sys_signalfd4' [-Wmissing-prototypes]
      41 |  asmlinkage long __weak __arm64_compat_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~~~~~~~~
   kernel/sys_ni.c:114:1: note: in expansion of macro 'COND_SYSCALL_COMPAT'
     114 | COND_SYSCALL_COMPAT(signalfd4);
         | ^~~~~~~~~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_timerfd_create' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:123:1: note: in expansion of macro 'COND_SYSCALL'
     123 | COND_SYSCALL(timerfd_create);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_timerfd_settime' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:124:1: note: in expansion of macro 'COND_SYSCALL'
     124 | COND_SYSCALL(timerfd_settime);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_timerfd_settime32' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:125:1: note: in expansion of macro 'COND_SYSCALL'
     125 | COND_SYSCALL(timerfd_settime32);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_timerfd_gettime' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:126:1: note: in expansion of macro 'COND_SYSCALL'
     126 | COND_SYSCALL(timerfd_gettime);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_timerfd_gettime32' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:127:1: note: in expansion of macro 'COND_SYSCALL'
     127 | COND_SYSCALL(timerfd_gettime32);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_acct' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:132:1: note: in expansion of macro 'COND_SYSCALL'
     132 | COND_SYSCALL(acct);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_capget' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:135:1: note: in expansion of macro 'COND_SYSCALL'
     135 | COND_SYSCALL(capget);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_capset' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:136:1: note: in expansion of macro 'COND_SYSCALL'
     136 | COND_SYSCALL(capset);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_clone3' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:144:1: note: in expansion of macro 'COND_SYSCALL'
     144 | COND_SYSCALL(clone3);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_futex' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:147:1: note: in expansion of macro 'COND_SYSCALL'
     147 | COND_SYSCALL(futex);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_futex_time32' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:148:1: note: in expansion of macro 'COND_SYSCALL'
     148 | COND_SYSCALL(futex_time32);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_set_robust_list' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:149:1: note: in expansion of macro 'COND_SYSCALL'
     149 | COND_SYSCALL(set_robust_list);
         | ^~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:41:25: warning: no previous prototype for '__arm64_compat_sys_set_robust_list' [-Wmissing-prototypes]
      41 |  asmlinkage long __weak __arm64_compat_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~~~~~~~~
   kernel/sys_ni.c:150:1: note: in expansion of macro 'COND_SYSCALL_COMPAT'
     150 | COND_SYSCALL_COMPAT(set_robust_list);
         | ^~~~~~~~~~~~~~~~~~~
   arch/arm64/include/asm/syscall_wrapper.h:76:25: warning: no previous prototype for '__arm64_sys_get_robust_list' [-Wmissing-prototypes]
      76 |  asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
         |                         ^~~~~~~~~~~~
   kernel/sys_ni.c:151:1: note: in expansion of macro 'COND_SYSCALL'
     151 | COND_SYSCALL(get_robust_list);


vim +/__arm64_sys_quotactl_path +76 arch/arm64/include/asm/syscall_wrapper.h

4378a7d4be30ec Mark Rutland  2018-07-11  50  
4378a7d4be30ec Mark Rutland  2018-07-11  51  #define __SYSCALL_DEFINEx(x, name, ...)						\
4378a7d4be30ec Mark Rutland  2018-07-11  52  	asmlinkage long __arm64_sys##name(const struct pt_regs *regs);		\
4378a7d4be30ec Mark Rutland  2018-07-11  53  	ALLOW_ERROR_INJECTION(__arm64_sys##name, ERRNO);			\
4378a7d4be30ec Mark Rutland  2018-07-11  54  	static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__));		\
4378a7d4be30ec Mark Rutland  2018-07-11  55  	static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));	\
4378a7d4be30ec Mark Rutland  2018-07-11  56  	asmlinkage long __arm64_sys##name(const struct pt_regs *regs)		\
4378a7d4be30ec Mark Rutland  2018-07-11  57  	{									\
4378a7d4be30ec Mark Rutland  2018-07-11  58  		return __se_sys##name(SC_ARM64_REGS_TO_ARGS(x,__VA_ARGS__));	\
4378a7d4be30ec Mark Rutland  2018-07-11  59  	}									\
4378a7d4be30ec Mark Rutland  2018-07-11  60  	static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__))		\
4378a7d4be30ec Mark Rutland  2018-07-11  61  	{									\
4378a7d4be30ec Mark Rutland  2018-07-11  62  		long ret = __do_sys##name(__MAP(x,__SC_CAST,__VA_ARGS__));	\
4378a7d4be30ec Mark Rutland  2018-07-11  63  		__MAP(x,__SC_TEST,__VA_ARGS__);					\
4378a7d4be30ec Mark Rutland  2018-07-11  64  		__PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__));		\
4378a7d4be30ec Mark Rutland  2018-07-11  65  		return ret;							\
4378a7d4be30ec Mark Rutland  2018-07-11  66  	}									\
4378a7d4be30ec Mark Rutland  2018-07-11  67  	static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
4378a7d4be30ec Mark Rutland  2018-07-11  68  
4378a7d4be30ec Mark Rutland  2018-07-11  69  #define SYSCALL_DEFINE0(sname)							\
4378a7d4be30ec Mark Rutland  2018-07-11  70  	SYSCALL_METADATA(_##sname, 0);						\
0e358bd7b7ebd2 Sami Tolvanen 2019-05-24  71  	asmlinkage long __arm64_sys_##sname(const struct pt_regs *__unused);	\
4378a7d4be30ec Mark Rutland  2018-07-11  72  	ALLOW_ERROR_INJECTION(__arm64_sys_##sname, ERRNO);			\
0e358bd7b7ebd2 Sami Tolvanen 2019-05-24  73  	asmlinkage long __arm64_sys_##sname(const struct pt_regs *__unused)
4378a7d4be30ec Mark Rutland  2018-07-11  74  
c27eccfe4d6c74 Sami Tolvanen 2019-09-10  75  #define COND_SYSCALL(name)							\
c27eccfe4d6c74 Sami Tolvanen 2019-09-10 @76  	asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs)	\
c27eccfe4d6c74 Sami Tolvanen 2019-09-10  77  	{									\
c27eccfe4d6c74 Sami Tolvanen 2019-09-10  78  		return sys_ni_syscall();					\
c27eccfe4d6c74 Sami Tolvanen 2019-09-10  79  	}
4378a7d4be30ec Mark Rutland  2018-07-11  80  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 23215 bytes --]

Re: [PATCH v3 0/2] quota: Add mountpath based quota support

[Jan Kara]

On Thu 04-03-21 13:35:38, Sascha Hauer wrote:
> Current quotactl syscall uses a path to a block device to specify the
> filesystem to work on which makes it unsuitable for filesystems that
> do not have a block device. This series adds a new syscall quotactl_path()
> which replaces the path to the block device with a mountpath, but otherwise
> behaves like original quotactl.
> 
> This is done to add quota support to UBIFS. UBIFS quota support has been
> posted several times with different approaches to put the mountpath into
> the existing quotactl() syscall until it has been suggested to make it a
> new syscall instead, so here it is.
> 
> I'm not posting the full UBIFS quota series here as it remains unchanged
> and I'd like to get feedback to the new syscall first. For those interested
> the most recent series can be found here: https://lwn.net/Articles/810463/

Thanks. I've merged the two patches into my tree and will push them to
Linus for the next merge window.

								Honza

> 
> Changes since v2:
> - Rebase on v5.12-rc1
> - replace mountpath.dentry->d_inode->i_sb with mountpath.mnt->mnt_sb
> - fix wrong macro usage in arch/x86/entry/syscalls/syscall_32.tbl
> - +Cc linux-api@vger.kernel.org
> 
> Changes since (implicit) v1:
> - Ignore second path argument to Q_QUOTAON. With this quotactl_path() can
>   only do the Q_QUOTAON operation on filesystems which use hidden inodes
>   for quota metadata storage
> - Drop unnecessary quotactl_cmd_onoff() check
> 
> Sascha Hauer (2):
>   quota: Add mountpath based quota support
>   quota: wire up quotactl_path
> 
>  arch/alpha/kernel/syscalls/syscall.tbl      |  1 +
>  arch/arm/tools/syscall.tbl                  |  1 +
>  arch/arm64/include/asm/unistd.h             |  2 +-
>  arch/arm64/include/asm/unistd32.h           |  2 +
>  arch/ia64/kernel/syscalls/syscall.tbl       |  1 +
>  arch/m68k/kernel/syscalls/syscall.tbl       |  1 +
>  arch/microblaze/kernel/syscalls/syscall.tbl |  1 +
>  arch/mips/kernel/syscalls/syscall_n32.tbl   |  1 +
>  arch/mips/kernel/syscalls/syscall_n64.tbl   |  1 +
>  arch/mips/kernel/syscalls/syscall_o32.tbl   |  1 +
>  arch/parisc/kernel/syscalls/syscall.tbl     |  1 +
>  arch/powerpc/kernel/syscalls/syscall.tbl    |  1 +
>  arch/s390/kernel/syscalls/syscall.tbl       |  1 +
>  arch/sh/kernel/syscalls/syscall.tbl         |  1 +
>  arch/sparc/kernel/syscalls/syscall.tbl      |  1 +
>  arch/x86/entry/syscalls/syscall_32.tbl      |  1 +
>  arch/x86/entry/syscalls/syscall_64.tbl      |  1 +
>  arch/xtensa/kernel/syscalls/syscall.tbl     |  1 +
>  fs/quota/quota.c                            | 49 +++++++++++++++++++--
>  include/linux/syscalls.h                    |  2 +
>  include/uapi/asm-generic/unistd.h           |  4 +-
>  kernel/sys_ni.c                             |  1 +
>  22 files changed, 71 insertions(+), 5 deletions(-)
> 
> -- 
> 2.29.2
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH v3 0/2] quota: Add mountpath based quota support

[Sascha Hauer]

On Tue, Mar 16, 2021 at 12:29:16PM +0100, Jan Kara wrote:
> On Thu 04-03-21 13:35:38, Sascha Hauer wrote:
> > Current quotactl syscall uses a path to a block device to specify the
> > filesystem to work on which makes it unsuitable for filesystems that
> > do not have a block device. This series adds a new syscall quotactl_path()
> > which replaces the path to the block device with a mountpath, but otherwise
> > behaves like original quotactl.
> > 
> > This is done to add quota support to UBIFS. UBIFS quota support has been
> > posted several times with different approaches to put the mountpath into
> > the existing quotactl() syscall until it has been suggested to make it a
> > new syscall instead, so here it is.
> > 
> > I'm not posting the full UBIFS quota series here as it remains unchanged
> > and I'd like to get feedback to the new syscall first. For those interested
> > the most recent series can be found here: https://lwn.net/Articles/810463/
> 
> Thanks. I've merged the two patches into my tree and will push them to
> Linus for the next merge window.

Thanks by the way. Now that these patches are merged I'll respin my
UBIFS quota series soon.

Sascha

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

Re: [PATCH v3 0/2] quota: Add mountpath based quota support

[Jan Kara]

Added a few more CCs.

On Tue 16-03-21 12:29:16, Jan Kara wrote:
> On Thu 04-03-21 13:35:38, Sascha Hauer wrote:
> > Current quotactl syscall uses a path to a block device to specify the
> > filesystem to work on which makes it unsuitable for filesystems that
> > do not have a block device. This series adds a new syscall quotactl_path()
> > which replaces the path to the block device with a mountpath, but otherwise
> > behaves like original quotactl.
> > 
> > This is done to add quota support to UBIFS. UBIFS quota support has been
> > posted several times with different approaches to put the mountpath into
> > the existing quotactl() syscall until it has been suggested to make it a
> > new syscall instead, so here it is.
> > 
> > I'm not posting the full UBIFS quota series here as it remains unchanged
> > and I'd like to get feedback to the new syscall first. For those interested
> > the most recent series can be found here: https://lwn.net/Articles/810463/
> 
> Thanks. I've merged the two patches into my tree and will push them to
> Linus for the next merge window.

So there are some people at LWN whining that quotactl_path() has no dirfd
and flags arguments for specifying the target. Somewhat late in the game
but since there's no major release with the syscall and no userspace using
it, I think we could still change that. What do you think? What they
suggest does make some sense. But then, rather then supporting API for
million-and-one ways in which I may wish to lookup a fs object, won't it be
better to just pass 'fd' in the new syscall (it may well be just O_PATH fd
AFAICT) and be done with that?

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH v3 0/2] quota: Add mountpath based quota support

[Christian Brauner]

On Wed, May 12, 2021 at 01:01:49PM +0200, Jan Kara wrote:
> Added a few more CCs.
> 
> On Tue 16-03-21 12:29:16, Jan Kara wrote:
> > On Thu 04-03-21 13:35:38, Sascha Hauer wrote:
> > > Current quotactl syscall uses a path to a block device to specify the
> > > filesystem to work on which makes it unsuitable for filesystems that
> > > do not have a block device. This series adds a new syscall quotactl_path()
> > > which replaces the path to the block device with a mountpath, but otherwise
> > > behaves like original quotactl.
> > > 
> > > This is done to add quota support to UBIFS. UBIFS quota support has been
> > > posted several times with different approaches to put the mountpath into
> > > the existing quotactl() syscall until it has been suggested to make it a
> > > new syscall instead, so here it is.
> > > 
> > > I'm not posting the full UBIFS quota series here as it remains unchanged
> > > and I'd like to get feedback to the new syscall first. For those interested
> > > the most recent series can be found here: https://lwn.net/Articles/810463/
> > 
> > Thanks. I've merged the two patches into my tree and will push them to
> > Linus for the next merge window.
> 
> So there are some people at LWN whining that quotactl_path() has no dirfd
> and flags arguments for specifying the target. Somewhat late in the game
> but since there's no major release with the syscall and no userspace using
> it, I think we could still change that. What do you think? What they
> suggest does make some sense. But then, rather then supporting API for
> million-and-one ways in which I may wish to lookup a fs object, won't it be
> better to just pass 'fd' in the new syscall (it may well be just O_PATH fd
> AFAICT) and be done with that?

I think adding a dirfd argument makes a lot of sense (Unless there are
some restrictions around quotas I'm misunderstanding.).

If I may: in general, I think we should aim to not add additional system
calls that operate on paths only. Purely path-based apis tend to be the
source of security issues especially when scoped lookups are really
important which given the ubiquity of sandboxing solutions nowadays is
quite often actually.
For example, when openat2() landed it gave such a boost in lookup
capabilities that I switched some libraries over to only ever do scoped
lookups, i.e. I decide on a starting point that gets opened path-based
and then explicitly express how I want that lookup to proceed ultimately
opening the final path component on which I want to perform operations.
Combined with the mount API almost everything can be done purely fd
based.

In addition to that dirfd-scopable system calls allow for a much nicer
api experience when programming in userspace.

Christian

Re: [PATCH v3 0/2] quota: Add mountpath based quota support

[Jan Kara]

On Wed 12-05-21 14:53:10, Christian Brauner wrote:
> On Wed, May 12, 2021 at 01:01:49PM +0200, Jan Kara wrote:
> > Added a few more CCs.
> > 
> > On Tue 16-03-21 12:29:16, Jan Kara wrote:
> > > On Thu 04-03-21 13:35:38, Sascha Hauer wrote:
> > > > Current quotactl syscall uses a path to a block device to specify the
> > > > filesystem to work on which makes it unsuitable for filesystems that
> > > > do not have a block device. This series adds a new syscall quotactl_path()
> > > > which replaces the path to the block device with a mountpath, but otherwise
> > > > behaves like original quotactl.
> > > > 
> > > > This is done to add quota support to UBIFS. UBIFS quota support has been
> > > > posted several times with different approaches to put the mountpath into
> > > > the existing quotactl() syscall until it has been suggested to make it a
> > > > new syscall instead, so here it is.
> > > > 
> > > > I'm not posting the full UBIFS quota series here as it remains unchanged
> > > > and I'd like to get feedback to the new syscall first. For those interested
> > > > the most recent series can be found here: https://lwn.net/Articles/810463/
> > > 
> > > Thanks. I've merged the two patches into my tree and will push them to
> > > Linus for the next merge window.
> > 
> > So there are some people at LWN whining that quotactl_path() has no dirfd
> > and flags arguments for specifying the target. Somewhat late in the game
> > but since there's no major release with the syscall and no userspace using
> > it, I think we could still change that. What do you think? What they
> > suggest does make some sense. But then, rather then supporting API for
> > million-and-one ways in which I may wish to lookup a fs object, won't it be
> > better to just pass 'fd' in the new syscall (it may well be just O_PATH fd
> > AFAICT) and be done with that?
> 
> I think adding a dirfd argument makes a lot of sense (Unless there are
> some restrictions around quotas I'm misunderstanding.).
> 
> If I may: in general, I think we should aim to not add additional system
> calls that operate on paths only. Purely path-based apis tend to be the
> source of security issues especially when scoped lookups are really
> important which given the ubiquity of sandboxing solutions nowadays is
> quite often actually.
> For example, when openat2() landed it gave such a boost in lookup
> capabilities that I switched some libraries over to only ever do scoped
> lookups, i.e. I decide on a starting point that gets opened path-based
> and then explicitly express how I want that lookup to proceed ultimately
> opening the final path component on which I want to perform operations.
> Combined with the mount API almost everything can be done purely fd
> based.
> 
> In addition to that dirfd-scopable system calls allow for a much nicer
> api experience when programming in userspace.

OK, thanks for your insights. But when we add 'dirfd' I wonder whether we
still need the 'path' component then. I mean you can always do fd =
openat2(), quotactl_fd(fd, ...). After all ioctl() works exactly that way
since the beginning. The only advantage of quotactl_xxx() taking path would
be saving the open(2) call. That is somewhat convenient for simple cases
(but also error prone in complex setups as you point out) and can be also
sligthly faster (but quotactl is hardly a performance sensitive thing)...

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH v3 0/2] quota: Add mountpath based quota support

[Sascha Hauer]

On Wed, May 12, 2021 at 01:01:49PM +0200, Jan Kara wrote:
> Added a few more CCs.
> 
> On Tue 16-03-21 12:29:16, Jan Kara wrote:
> > On Thu 04-03-21 13:35:38, Sascha Hauer wrote:
> > > Current quotactl syscall uses a path to a block device to specify the
> > > filesystem to work on which makes it unsuitable for filesystems that
> > > do not have a block device. This series adds a new syscall quotactl_path()
> > > which replaces the path to the block device with a mountpath, but otherwise
> > > behaves like original quotactl.
> > > 
> > > This is done to add quota support to UBIFS. UBIFS quota support has been
> > > posted several times with different approaches to put the mountpath into
> > > the existing quotactl() syscall until it has been suggested to make it a
> > > new syscall instead, so here it is.
> > > 
> > > I'm not posting the full UBIFS quota series here as it remains unchanged
> > > and I'd like to get feedback to the new syscall first. For those interested
> > > the most recent series can be found here: https://lwn.net/Articles/810463/
> > 
> > Thanks. I've merged the two patches into my tree and will push them to
> > Linus for the next merge window.
> 
> So there are some people at LWN whining that quotactl_path() has no dirfd
> and flags arguments for specifying the target. Somewhat late in the game
> but since there's no major release with the syscall and no userspace using
> it, I think we could still change that. What do you think? What they
> suggest does make some sense. But then, rather then supporting API for
> million-and-one ways in which I may wish to lookup a fs object, won't it be
> better to just pass 'fd' in the new syscall (it may well be just O_PATH fd
> AFAICT) and be done with that?

This sounds like a much cleaner interface to me. If we agree on this I
wouldn't mind spinning this patch for another few rounds.

Sascha

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

Re: [PATCH v3 0/2] quota: Add mountpath based quota support

[Christian Brauner]

On Wed, May 12, 2021 at 03:14:29PM +0200, Jan Kara wrote:
> On Wed 12-05-21 14:53:10, Christian Brauner wrote:
> > On Wed, May 12, 2021 at 01:01:49PM +0200, Jan Kara wrote:
> > > Added a few more CCs.
> > > 
> > > On Tue 16-03-21 12:29:16, Jan Kara wrote:
> > > > On Thu 04-03-21 13:35:38, Sascha Hauer wrote:
> > > > > Current quotactl syscall uses a path to a block device to specify the
> > > > > filesystem to work on which makes it unsuitable for filesystems that
> > > > > do not have a block device. This series adds a new syscall quotactl_path()
> > > > > which replaces the path to the block device with a mountpath, but otherwise
> > > > > behaves like original quotactl.
> > > > > 
> > > > > This is done to add quota support to UBIFS. UBIFS quota support has been
> > > > > posted several times with different approaches to put the mountpath into
> > > > > the existing quotactl() syscall until it has been suggested to make it a
> > > > > new syscall instead, so here it is.
> > > > > 
> > > > > I'm not posting the full UBIFS quota series here as it remains unchanged
> > > > > and I'd like to get feedback to the new syscall first. For those interested
> > > > > the most recent series can be found here: https://lwn.net/Articles/810463/
> > > > 
> > > > Thanks. I've merged the two patches into my tree and will push them to
> > > > Linus for the next merge window.
> > > 
> > > So there are some people at LWN whining that quotactl_path() has no dirfd
> > > and flags arguments for specifying the target. Somewhat late in the game
> > > but since there's no major release with the syscall and no userspace using
> > > it, I think we could still change that. What do you think? What they
> > > suggest does make some sense. But then, rather then supporting API for
> > > million-and-one ways in which I may wish to lookup a fs object, won't it be
> > > better to just pass 'fd' in the new syscall (it may well be just O_PATH fd
> > > AFAICT) and be done with that?
> > 
> > I think adding a dirfd argument makes a lot of sense (Unless there are
> > some restrictions around quotas I'm misunderstanding.).
> > 
> > If I may: in general, I think we should aim to not add additional system
> > calls that operate on paths only. Purely path-based apis tend to be the
> > source of security issues especially when scoped lookups are really
> > important which given the ubiquity of sandboxing solutions nowadays is
> > quite often actually.
> > For example, when openat2() landed it gave such a boost in lookup
> > capabilities that I switched some libraries over to only ever do scoped
> > lookups, i.e. I decide on a starting point that gets opened path-based
> > and then explicitly express how I want that lookup to proceed ultimately
> > opening the final path component on which I want to perform operations.
> > Combined with the mount API almost everything can be done purely fd
> > based.
> > 
> > In addition to that dirfd-scopable system calls allow for a much nicer
> > api experience when programming in userspace.
> 
> OK, thanks for your insights. But when we add 'dirfd' I wonder whether we
> still need the 'path' component then. I mean you can always do fd =
> openat2(), quotactl_fd(fd, ...). After all ioctl() works exactly that way
> since the beginning. The only advantage of quotactl_xxx() taking path would
> be saving the open(2) call. That is somewhat convenient for simple cases
> (but also error prone in complex setups as you point out) and can be also
> sligthly faster (but quotactl is hardly a performance sensitive thing)...

That's a bit tricky indeed. It would feel consistent to add a path
argument as most of our fs apis seems to work that way even stuff like
fanotify_mark() but indeed a fd-only based api would be fine too. I
would try to follow recent additions/prior art here, I think.

Re: [PATCH v3 0/2] quota: Add mountpath based quota support

[Jan Kara]

[-- Attachment #1: Type: text/plain, Size: 4429 bytes --]

On Wed 12-05-21 17:36:21, Christian Brauner wrote:
> On Wed, May 12, 2021 at 03:14:29PM +0200, Jan Kara wrote:
> > On Wed 12-05-21 14:53:10, Christian Brauner wrote:
> > > On Wed, May 12, 2021 at 01:01:49PM +0200, Jan Kara wrote:
> > > > Added a few more CCs.
> > > > 
> > > > On Tue 16-03-21 12:29:16, Jan Kara wrote:
> > > > > On Thu 04-03-21 13:35:38, Sascha Hauer wrote:
> > > > > > Current quotactl syscall uses a path to a block device to specify the
> > > > > > filesystem to work on which makes it unsuitable for filesystems that
> > > > > > do not have a block device. This series adds a new syscall quotactl_path()
> > > > > > which replaces the path to the block device with a mountpath, but otherwise
> > > > > > behaves like original quotactl.
> > > > > > 
> > > > > > This is done to add quota support to UBIFS. UBIFS quota support has been
> > > > > > posted several times with different approaches to put the mountpath into
> > > > > > the existing quotactl() syscall until it has been suggested to make it a
> > > > > > new syscall instead, so here it is.
> > > > > > 
> > > > > > I'm not posting the full UBIFS quota series here as it remains unchanged
> > > > > > and I'd like to get feedback to the new syscall first. For those interested
> > > > > > the most recent series can be found here: https://lwn.net/Articles/810463/
> > > > > 
> > > > > Thanks. I've merged the two patches into my tree and will push them to
> > > > > Linus for the next merge window.
> > > > 
> > > > So there are some people at LWN whining that quotactl_path() has no dirfd
> > > > and flags arguments for specifying the target. Somewhat late in the game
> > > > but since there's no major release with the syscall and no userspace using
> > > > it, I think we could still change that. What do you think? What they
> > > > suggest does make some sense. But then, rather then supporting API for
> > > > million-and-one ways in which I may wish to lookup a fs object, won't it be
> > > > better to just pass 'fd' in the new syscall (it may well be just O_PATH fd
> > > > AFAICT) and be done with that?
> > > 
> > > I think adding a dirfd argument makes a lot of sense (Unless there are
> > > some restrictions around quotas I'm misunderstanding.).
> > > 
> > > If I may: in general, I think we should aim to not add additional system
> > > calls that operate on paths only. Purely path-based apis tend to be the
> > > source of security issues especially when scoped lookups are really
> > > important which given the ubiquity of sandboxing solutions nowadays is
> > > quite often actually.
> > > For example, when openat2() landed it gave such a boost in lookup
> > > capabilities that I switched some libraries over to only ever do scoped
> > > lookups, i.e. I decide on a starting point that gets opened path-based
> > > and then explicitly express how I want that lookup to proceed ultimately
> > > opening the final path component on which I want to perform operations.
> > > Combined with the mount API almost everything can be done purely fd
> > > based.
> > > 
> > > In addition to that dirfd-scopable system calls allow for a much nicer
> > > api experience when programming in userspace.
> > 
> > OK, thanks for your insights. But when we add 'dirfd' I wonder whether we
> > still need the 'path' component then. I mean you can always do fd =
> > openat2(), quotactl_fd(fd, ...). After all ioctl() works exactly that way
> > since the beginning. The only advantage of quotactl_xxx() taking path would
> > be saving the open(2) call. That is somewhat convenient for simple cases
> > (but also error prone in complex setups as you point out) and can be also
> > sligthly faster (but quotactl is hardly a performance sensitive thing)...
> 
> That's a bit tricky indeed. It would feel consistent to add a path
> argument as most of our fs apis seems to work that way even stuff like
> fanotify_mark() but indeed a fd-only based api would be fine too. I
> would try to follow recent additions/prior art here, I think.

Thanks for opinion Christian. Sasha, I've decided to disable the syscall
for now (I plan to push attached patch to Linus later this week). Will you
please update the syscall to just take 'fd' argument instead of the path to
leave dealing with path pitfalls to syscalls such as openat2()? Probably
renaming to quotactl_fd() would be also good. Thanks!

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

[-- Attachment #2: 0001-quota-Disable-quotactl_path-syscall.patch --]
[-- Type: text/x-patch, Size: 13112 bytes --]

From 5b9fedb31e476693c90d8ee040e7d4c51b3e7cc4 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Mon, 17 May 2021 14:39:56 +0200
Subject: [PATCH] quota: Disable quotactl_path syscall

In commit fa8b90070a80 ("quota: wire up quotactl_path") we have wired up
new quotactl_path syscall. However some people in LWN discussion have
objected that the path based syscall is missing dirfd and flags argument
which is mostly standard for contemporary path based syscalls. Indeed
they have a point and after a discussion with Christian Brauner and
Sascha Hauer I've decided to disable the syscall for now and update its
API. Since there is no userspace currently using that syscall and it
hasn't been released in any major release, we should be fine.

CC: Christian Brauner <christian.brauner@ubuntu.com>
CC: Sascha Hauer <s.hauer@pengutronix.de>
Link: https://lore.kernel.org/lkml/20210512153621.n5u43jsytbik4yze@wittgenstein
Signed-off-by: Jan Kara <jack@suse.cz>
---
 arch/alpha/kernel/syscalls/syscall.tbl      | 2 +-
 arch/arm/tools/syscall.tbl                  | 2 +-
 arch/arm64/include/asm/unistd32.h           | 3 +--
 arch/ia64/kernel/syscalls/syscall.tbl       | 2 +-
 arch/m68k/kernel/syscalls/syscall.tbl       | 2 +-
 arch/microblaze/kernel/syscalls/syscall.tbl | 2 +-
 arch/mips/kernel/syscalls/syscall_n32.tbl   | 2 +-
 arch/mips/kernel/syscalls/syscall_n64.tbl   | 2 +-
 arch/mips/kernel/syscalls/syscall_o32.tbl   | 2 +-
 arch/parisc/kernel/syscalls/syscall.tbl     | 2 +-
 arch/powerpc/kernel/syscalls/syscall.tbl    | 2 +-
 arch/s390/kernel/syscalls/syscall.tbl       | 2 +-
 arch/sh/kernel/syscalls/syscall.tbl         | 2 +-
 arch/sparc/kernel/syscalls/syscall.tbl      | 2 +-
 arch/x86/entry/syscalls/syscall_32.tbl      | 2 +-
 arch/x86/entry/syscalls/syscall_64.tbl      | 2 +-
 arch/xtensa/kernel/syscalls/syscall.tbl     | 2 +-
 17 files changed, 17 insertions(+), 18 deletions(-)

diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
index 5622578742fd..3000a2e8ee21 100644
--- a/arch/alpha/kernel/syscalls/syscall.tbl
+++ b/arch/alpha/kernel/syscalls/syscall.tbl
@@ -482,7 +482,7 @@
 550	common	process_madvise			sys_process_madvise
 551	common	epoll_pwait2			sys_epoll_pwait2
 552	common	mount_setattr			sys_mount_setattr
-553	common	quotactl_path			sys_quotactl_path
+# 553 reserved for quotactl_path
 554	common	landlock_create_ruleset		sys_landlock_create_ruleset
 555	common	landlock_add_rule		sys_landlock_add_rule
 556	common	landlock_restrict_self		sys_landlock_restrict_self
diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
index c7679d7db98b..28e03b5fec00 100644
--- a/arch/arm/tools/syscall.tbl
+++ b/arch/arm/tools/syscall.tbl
@@ -456,7 +456,7 @@
 440	common	process_madvise			sys_process_madvise
 441	common	epoll_pwait2			sys_epoll_pwait2
 442	common	mount_setattr			sys_mount_setattr
-443	common	quotactl_path			sys_quotactl_path
+# 443 reserved for quotactl_path
 444	common	landlock_create_ruleset		sys_landlock_create_ruleset
 445	common	landlock_add_rule		sys_landlock_add_rule
 446	common	landlock_restrict_self		sys_landlock_restrict_self
diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
index 7859749d6628..5dab69d2c22b 100644
--- a/arch/arm64/include/asm/unistd32.h
+++ b/arch/arm64/include/asm/unistd32.h
@@ -893,8 +893,7 @@ __SYSCALL(__NR_process_madvise, sys_process_madvise)
 __SYSCALL(__NR_epoll_pwait2, compat_sys_epoll_pwait2)
 #define __NR_mount_setattr 442
 __SYSCALL(__NR_mount_setattr, sys_mount_setattr)
-#define __NR_quotactl_path 443
-__SYSCALL(__NR_quotactl_path, sys_quotactl_path)
+/* 443 is reserved for quotactl_path */
 #define __NR_landlock_create_ruleset 444
 __SYSCALL(__NR_landlock_create_ruleset, sys_landlock_create_ruleset)
 #define __NR_landlock_add_rule 445
diff --git a/arch/ia64/kernel/syscalls/syscall.tbl b/arch/ia64/kernel/syscalls/syscall.tbl
index 1ee8e736a48e..bb11fe4c875a 100644
--- a/arch/ia64/kernel/syscalls/syscall.tbl
+++ b/arch/ia64/kernel/syscalls/syscall.tbl
@@ -363,7 +363,7 @@
 440	common	process_madvise			sys_process_madvise
 441	common	epoll_pwait2			sys_epoll_pwait2
 442	common	mount_setattr			sys_mount_setattr
-443	common	quotactl_path			sys_quotactl_path
+# 443 reserved for quotactl_path
 444	common	landlock_create_ruleset		sys_landlock_create_ruleset
 445	common	landlock_add_rule		sys_landlock_add_rule
 446	common	landlock_restrict_self		sys_landlock_restrict_self
diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl
index 0dd019dc2136..79c2d24c89dd 100644
--- a/arch/m68k/kernel/syscalls/syscall.tbl
+++ b/arch/m68k/kernel/syscalls/syscall.tbl
@@ -442,7 +442,7 @@
 440	common	process_madvise			sys_process_madvise
 441	common	epoll_pwait2			sys_epoll_pwait2
 442	common	mount_setattr			sys_mount_setattr
-443	common	quotactl_path			sys_quotactl_path
+# 443 reserved for quotactl_path
 444	common	landlock_create_ruleset		sys_landlock_create_ruleset
 445	common	landlock_add_rule		sys_landlock_add_rule
 446	common	landlock_restrict_self		sys_landlock_restrict_self
diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl
index 2ac716984ca2..b11395a20c20 100644
--- a/arch/microblaze/kernel/syscalls/syscall.tbl
+++ b/arch/microblaze/kernel/syscalls/syscall.tbl
@@ -448,7 +448,7 @@
 440	common	process_madvise			sys_process_madvise
 441	common	epoll_pwait2			sys_epoll_pwait2
 442	common	mount_setattr			sys_mount_setattr
-443	common	quotactl_path			sys_quotactl_path
+# 443 reserved for quotactl_path
 444	common	landlock_create_ruleset		sys_landlock_create_ruleset
 445	common	landlock_add_rule		sys_landlock_add_rule
 446	common	landlock_restrict_self		sys_landlock_restrict_self
diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
index 5e0096657251..9220909526f9 100644
--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -381,7 +381,7 @@
 440	n32	process_madvise			sys_process_madvise
 441	n32	epoll_pwait2			compat_sys_epoll_pwait2
 442	n32	mount_setattr			sys_mount_setattr
-443	n32	quotactl_path			sys_quotactl_path
+# 443 reserved for quotactl_path
 444	n32	landlock_create_ruleset		sys_landlock_create_ruleset
 445	n32	landlock_add_rule		sys_landlock_add_rule
 446	n32	landlock_restrict_self		sys_landlock_restrict_self
diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
index 9974f5f8e49b..9cd1c34f31b5 100644
--- a/arch/mips/kernel/syscalls/syscall_n64.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
@@ -357,7 +357,7 @@
 440	n64	process_madvise			sys_process_madvise
 441	n64	epoll_pwait2			sys_epoll_pwait2
 442	n64	mount_setattr			sys_mount_setattr
-443	n64	quotactl_path			sys_quotactl_path
+# 443 reserved for quotactl_path
 444	n64	landlock_create_ruleset		sys_landlock_create_ruleset
 445	n64	landlock_add_rule		sys_landlock_add_rule
 446	n64	landlock_restrict_self		sys_landlock_restrict_self
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
index 39d6e71e57b6..d560c467a8c6 100644
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -430,7 +430,7 @@
 440	o32	process_madvise			sys_process_madvise
 441	o32	epoll_pwait2			sys_epoll_pwait2		compat_sys_epoll_pwait2
 442	o32	mount_setattr			sys_mount_setattr
-443	o32	quotactl_path			sys_quotactl_path
+# 443 reserved for quotactl_path
 444	o32	landlock_create_ruleset		sys_landlock_create_ruleset
 445	o32	landlock_add_rule		sys_landlock_add_rule
 446	o32	landlock_restrict_self		sys_landlock_restrict_self
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
index 5ac80b83d745..aabc37f8cae3 100644
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -440,7 +440,7 @@
 440	common	process_madvise			sys_process_madvise
 441	common	epoll_pwait2			sys_epoll_pwait2		compat_sys_epoll_pwait2
 442	common	mount_setattr			sys_mount_setattr
-443	common	quotactl_path			sys_quotactl_path
+# 443 reserved for quotactl_path
 444	common	landlock_create_ruleset		sys_landlock_create_ruleset
 445	common	landlock_add_rule		sys_landlock_add_rule
 446	common	landlock_restrict_self		sys_landlock_restrict_self
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
index 2e68fbb57cc6..8f052ff4058c 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -522,7 +522,7 @@
 440	common	process_madvise			sys_process_madvise
 441	common	epoll_pwait2			sys_epoll_pwait2		compat_sys_epoll_pwait2
 442	common	mount_setattr			sys_mount_setattr
-443	common	quotactl_path			sys_quotactl_path
+# 443 reserved for quotactl_path
 444	common	landlock_create_ruleset		sys_landlock_create_ruleset
 445	common	landlock_add_rule		sys_landlock_add_rule
 446	common	landlock_restrict_self		sys_landlock_restrict_self
diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
index 7e4a2aba366d..0690263df1dd 100644
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -445,7 +445,7 @@
 440  common	process_madvise		sys_process_madvise		sys_process_madvise
 441  common	epoll_pwait2		sys_epoll_pwait2		compat_sys_epoll_pwait2
 442  common	mount_setattr		sys_mount_setattr		sys_mount_setattr
-443  common	quotactl_path		sys_quotactl_path		sys_quotactl_path
+# 443 reserved for quotactl_path
 444  common	landlock_create_ruleset	sys_landlock_create_ruleset	sys_landlock_create_ruleset
 445  common	landlock_add_rule	sys_landlock_add_rule		sys_landlock_add_rule
 446  common	landlock_restrict_self	sys_landlock_restrict_self	sys_landlock_restrict_self
diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl
index f47a0dc55445..0b91499ebdcf 100644
--- a/arch/sh/kernel/syscalls/syscall.tbl
+++ b/arch/sh/kernel/syscalls/syscall.tbl
@@ -445,7 +445,7 @@
 440	common	process_madvise			sys_process_madvise
 441	common	epoll_pwait2			sys_epoll_pwait2
 442	common	mount_setattr			sys_mount_setattr
-443	common	quotactl_path			sys_quotactl_path
+# 443 reserved for quotactl_path
 444	common	landlock_create_ruleset		sys_landlock_create_ruleset
 445	common	landlock_add_rule		sys_landlock_add_rule
 446	common	landlock_restrict_self		sys_landlock_restrict_self
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
index b9e1c0e735b7..e34cc30ef22c 100644
--- a/arch/sparc/kernel/syscalls/syscall.tbl
+++ b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -488,7 +488,7 @@
 440	common	process_madvise			sys_process_madvise
 441	common	epoll_pwait2			sys_epoll_pwait2		compat_sys_epoll_pwait2
 442	common	mount_setattr			sys_mount_setattr
-443	common	quotactl_path			sys_quotactl_path
+# 443 reserved for quotactl_path
 444	common	landlock_create_ruleset		sys_landlock_create_ruleset
 445	common	landlock_add_rule		sys_landlock_add_rule
 446	common	landlock_restrict_self		sys_landlock_restrict_self
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 28a1423ce32e..4bbc267fb36b 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -447,7 +447,7 @@
 440	i386	process_madvise		sys_process_madvise
 441	i386	epoll_pwait2		sys_epoll_pwait2		compat_sys_epoll_pwait2
 442	i386	mount_setattr		sys_mount_setattr
-443	i386	quotactl_path		sys_quotactl_path
+# 443 reserved for quotactl_path
 444	i386	landlock_create_ruleset	sys_landlock_create_ruleset
 445	i386	landlock_add_rule	sys_landlock_add_rule
 446	i386	landlock_restrict_self	sys_landlock_restrict_self
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index ecd551b08d05..ce18119ea0d0 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -364,7 +364,7 @@
 440	common	process_madvise		sys_process_madvise
 441	common	epoll_pwait2		sys_epoll_pwait2
 442	common	mount_setattr		sys_mount_setattr
-443	common	quotactl_path		sys_quotactl_path
+# 443 reserved for quotactl_path
 444	common	landlock_create_ruleset	sys_landlock_create_ruleset
 445	common	landlock_add_rule	sys_landlock_add_rule
 446	common	landlock_restrict_self	sys_landlock_restrict_self
diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl
index 9d76d433d3d6..fd2f30227d96 100644
--- a/arch/xtensa/kernel/syscalls/syscall.tbl
+++ b/arch/xtensa/kernel/syscalls/syscall.tbl
@@ -413,7 +413,7 @@
 440	common	process_madvise			sys_process_madvise
 441	common	epoll_pwait2			sys_epoll_pwait2
 442	common	mount_setattr			sys_mount_setattr
-443	common	quotactl_path			sys_quotactl_path
+# 443 reserved for quotactl_path
 444	common	landlock_create_ruleset		sys_landlock_create_ruleset
 445	common	landlock_add_rule		sys_landlock_add_rule
 446	common	landlock_restrict_self		sys_landlock_restrict_self
-- 
2.26.2

Re: [PATCH v3 0/2] quota: Add mountpath based quota support

[Jan Kara]

On Wed 12-05-21 17:03:46, Sascha Hauer wrote:
> On Wed, May 12, 2021 at 01:01:49PM +0200, Jan Kara wrote:
> > Added a few more CCs.
> > 
> > On Tue 16-03-21 12:29:16, Jan Kara wrote:
> > > On Thu 04-03-21 13:35:38, Sascha Hauer wrote:
> > > > Current quotactl syscall uses a path to a block device to specify the
> > > > filesystem to work on which makes it unsuitable for filesystems that
> > > > do not have a block device. This series adds a new syscall quotactl_path()
> > > > which replaces the path to the block device with a mountpath, but otherwise
> > > > behaves like original quotactl.
> > > > 
> > > > This is done to add quota support to UBIFS. UBIFS quota support has been
> > > > posted several times with different approaches to put the mountpath into
> > > > the existing quotactl() syscall until it has been suggested to make it a
> > > > new syscall instead, so here it is.
> > > > 
> > > > I'm not posting the full UBIFS quota series here as it remains unchanged
> > > > and I'd like to get feedback to the new syscall first. For those interested
> > > > the most recent series can be found here: https://lwn.net/Articles/810463/
> > > 
> > > Thanks. I've merged the two patches into my tree and will push them to
> > > Linus for the next merge window.
> > 
> > So there are some people at LWN whining that quotactl_path() has no dirfd
> > and flags arguments for specifying the target. Somewhat late in the game
> > but since there's no major release with the syscall and no userspace using
> > it, I think we could still change that. What do you think? What they
> > suggest does make some sense. But then, rather then supporting API for
> > million-and-one ways in which I may wish to lookup a fs object, won't it be
> > better to just pass 'fd' in the new syscall (it may well be just O_PATH fd
> > AFAICT) and be done with that?
> 
> This sounds like a much cleaner interface to me. If we agree on this I
> wouldn't mind spinning this patch for another few rounds.

So the syscall is currently disabled in Linus' tree. Will you send a patch
for new fd-based quotactl variant?

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH v3 0/2] quota: Add mountpath based quota support

[Sascha Hauer]

On Mon, May 24, 2021 at 10:49:12AM +0200, Jan Kara wrote:
> On Wed 12-05-21 17:03:46, Sascha Hauer wrote:
> > On Wed, May 12, 2021 at 01:01:49PM +0200, Jan Kara wrote:
> > > Added a few more CCs.
> > > 
> > > On Tue 16-03-21 12:29:16, Jan Kara wrote:
> > > > On Thu 04-03-21 13:35:38, Sascha Hauer wrote:
> > > > > Current quotactl syscall uses a path to a block device to specify the
> > > > > filesystem to work on which makes it unsuitable for filesystems that
> > > > > do not have a block device. This series adds a new syscall quotactl_path()
> > > > > which replaces the path to the block device with a mountpath, but otherwise
> > > > > behaves like original quotactl.
> > > > > 
> > > > > This is done to add quota support to UBIFS. UBIFS quota support has been
> > > > > posted several times with different approaches to put the mountpath into
> > > > > the existing quotactl() syscall until it has been suggested to make it a
> > > > > new syscall instead, so here it is.
> > > > > 
> > > > > I'm not posting the full UBIFS quota series here as it remains unchanged
> > > > > and I'd like to get feedback to the new syscall first. For those interested
> > > > > the most recent series can be found here: https://lwn.net/Articles/810463/
> > > > 
> > > > Thanks. I've merged the two patches into my tree and will push them to
> > > > Linus for the next merge window.
> > > 
> > > So there are some people at LWN whining that quotactl_path() has no dirfd
> > > and flags arguments for specifying the target. Somewhat late in the game
> > > but since there's no major release with the syscall and no userspace using
> > > it, I think we could still change that. What do you think? What they
> > > suggest does make some sense. But then, rather then supporting API for
> > > million-and-one ways in which I may wish to lookup a fs object, won't it be
> > > better to just pass 'fd' in the new syscall (it may well be just O_PATH fd
> > > AFAICT) and be done with that?
> > 
> > This sounds like a much cleaner interface to me. If we agree on this I
> > wouldn't mind spinning this patch for another few rounds.
> 
> So the syscall is currently disabled in Linus' tree. Will you send a patch
> for new fd-based quotactl variant?

I'll sure do that, but I don't know when I can find a timeslot for it.
I hope I can come up with something next month.

Sascha

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

Re: [PATCH v3 0/2] quota: Add mountpath based quota support

[Christoph Hellwig]

Adding the dfd argument should be as simple as this patch (which also
moves the cmd argument later to match typical calling conventions).

It might be worth to rename the syscall to quotactlat to better match
other syscalls.  A flags argument doesn't make much sense here, as the
cmd argument can be used for extensions and is properly checked for
unknown values.

diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index 05e4bd9ab6d6..940101396feb 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -968,8 +968,8 @@ SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
 	return ret;
 }
 
-SYSCALL_DEFINE4(quotactl_path, unsigned int, cmd, const char __user *,
-		mountpoint, qid_t, id, void __user *, addr)
+SYSCALL_DEFINE5(quotactl_path, int, dfd, const char __user *, mountpoint,
+		unsigned int, cmd, qid_t, id, void __user *, addr)
 {
 	struct super_block *sb;
 	struct path mountpath;
@@ -980,8 +980,8 @@ SYSCALL_DEFINE4(quotactl_path, unsigned int, cmd, const char __user *,
 	if (type >= MAXQUOTAS)
 		return -EINVAL;
 
-	ret = user_path_at(AT_FDCWD, mountpoint,
-			     LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT, &mountpath);
+	ret = user_path_at(dfd, mountpoint, LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT,
+			   &mountpath);
 	if (ret)
 		return ret;
 
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index a672bbe28577..ae34984e2ab9 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -483,8 +483,8 @@ asmlinkage long sys_pipe2(int __user *fildes, int flags);
 /* fs/quota.c */
 asmlinkage long sys_quotactl(unsigned int cmd, const char __user *special,
 				qid_t id, void __user *addr);
-asmlinkage long sys_quotactl_path(unsigned int cmd, const char __user *mountpoint,
-				  qid_t id, void __user *addr);
+asmlinkage long sys_quotactl_path(int dfd, const char __user *mountpoint,
+		unsigned int cmd, qid_t id, void __user *addr);
 
 /* fs/readdir.c */
 asmlinkage long sys_getdents64(unsigned int fd,

Re: [PATCH v3 0/2] quota: Add mountpath based quota support

[Jan Kara]

[-- Attachment #1: Type: text/plain, Size: 705 bytes --]

On Tue 25-05-21 09:05:50, Christoph Hellwig wrote:
> Adding the dfd argument should be as simple as this patch (which also
> moves the cmd argument later to match typical calling conventions).
> 
> It might be worth to rename the syscall to quotactlat to better match
> other syscalls.  A flags argument doesn't make much sense here, as the
> cmd argument can be used for extensions and is properly checked for
> unknown values.

Thanks for the patch! So I was actually thinking about going to completely
fd-based syscall like ioctl(2) and then we don't have to worry about lookup
flags or paths at all. What do people thing about attached patch?

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

[-- Attachment #2: 0001-quota-Change-quotactl_path-systcall-to-an-fd-based-o.patch --]
[-- Type: text/x-patch, Size: 3346 bytes --]

From 359222f02ff7b69668a493207e3b84d53195f818 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Tue, 25 May 2021 16:07:48 +0200
Subject: [PATCH] quota: Change quotactl_path() systcall to an fd-based one

Some users have pointed out that path-based syscalls are problematic in
some environments and at least directory fd argument and possibly also
resolve flags are desirable for such syscalls. Rather than
reimplementing all details of pathname lookup and following where it may
eventually evolve, let's go for full file descriptor based syscall
similar to how ioctl(2) works since the beginning. Managing of quotas
isn't performance sensitive so the extra overhead of open does not
matter and we are able to consume O_PATH descriptors as well which makes
open cheap anyway. Also for frequent operations (such as retrieving
usage information for all users) we can reuse single fd and in fact get
even better performance as well as avoiding races with possible remounts
etc.

Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/quota/quota.c         | 27 ++++++++++++---------------
 include/linux/syscalls.h |  4 ++--
 2 files changed, 14 insertions(+), 17 deletions(-)

diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index 05e4bd9ab6d6..8450bb6186f4 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -968,31 +968,29 @@ SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
 	return ret;
 }
 
-SYSCALL_DEFINE4(quotactl_path, unsigned int, cmd, const char __user *,
-		mountpoint, qid_t, id, void __user *, addr)
+SYSCALL_DEFINE4(quotactl_fd, unsigned int, fd, unsigned int, cmd,
+		qid_t, id, void __user *, addr)
 {
 	struct super_block *sb;
-	struct path mountpath;
 	unsigned int cmds = cmd >> SUBCMDSHIFT;
 	unsigned int type = cmd & SUBCMDMASK;
+	struct fd f = fdget_raw(fd);
 	int ret;
 
-	if (type >= MAXQUOTAS)
-		return -EINVAL;
+	if (!f.file)
+		return -EBADF;
 
-	ret = user_path_at(AT_FDCWD, mountpoint,
-			     LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT, &mountpath);
-	if (ret)
-		return ret;
-
-	sb = mountpath.mnt->mnt_sb;
+	ret = -EINVAL;
+	if (type >= MAXQUOTAS)
+		goto out;
 
 	if (quotactl_cmd_write(cmds)) {
-		ret = mnt_want_write(mountpath.mnt);
+		ret = mnt_want_write(f.file->f_path.mnt);
 		if (ret)
 			goto out;
 	}
 
+	sb = f.file->f_path.mnt->mnt_sb;
 	if (quotactl_cmd_onoff(cmds))
 		down_write(&sb->s_umount);
 	else
@@ -1006,9 +1004,8 @@ SYSCALL_DEFINE4(quotactl_path, unsigned int, cmd, const char __user *,
 		up_read(&sb->s_umount);
 
 	if (quotactl_cmd_write(cmds))
-		mnt_drop_write(mountpath.mnt);
+		mnt_drop_write(f.file->f_path.mnt);
 out:
-	path_put(&mountpath);
-
+	fdput(f);
 	return ret;
 }
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 050511e8f1f8..586128d5c3b8 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -485,8 +485,8 @@ asmlinkage long sys_pipe2(int __user *fildes, int flags);
 /* fs/quota.c */
 asmlinkage long sys_quotactl(unsigned int cmd, const char __user *special,
 				qid_t id, void __user *addr);
-asmlinkage long sys_quotactl_path(unsigned int cmd, const char __user *mountpoint,
-				  qid_t id, void __user *addr);
+asmlinkage long sys_quotactl_fd(unsigned int fd, unsigned int cmd, qid_t id,
+				void __user *addr);
 
 /* fs/readdir.c */
 asmlinkage long sys_getdents64(unsigned int fd,
-- 
2.26.2

Re: [PATCH 1/2] quota: Add mountpath based quota support

[Al Viro]

On Thu, Feb 11, 2021 at 04:30:22PM +0100, Sascha Hauer wrote:

> +	sb = mountpath.dentry->d_inode->i_sb;

Minor nit: mountpath.mnt->mnt_sb, please.

Re: [PATCH 1/2] quota: Add mountpath based quota support

[Jan Kara]

On Fri 12-02-21 11:29:00, Sascha Hauer wrote:
> On Fri, Feb 12, 2021 at 11:05:05AM +0100, Jan Kara wrote:
> > On Fri 12-02-21 09:38:35, Sascha Hauer wrote:
> > > On Thu, Feb 11, 2021 at 03:38:13PM +0000, Christoph Hellwig wrote:
> > > > > +	if (!mountpoint)
> > > > > +		return -ENODEV;
> > > > > +
> > > > > +	ret = user_path_at(AT_FDCWD, mountpoint,
> > > > > +			     LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT, &mountpath);
> > > > 
> > > > user_path_at handles an empty path, although you'll get EFAULT instead.
> > > > Do we care about the -ENODEV here?
> > > 
> > > The quotactl manpage documents EFAULT as error code for invalid addr or
> > > special argument, so we really should return -EFAULT here.
> > > 
> > > Existing quotactl gets this wrong as well:
> > > 
> > > 	if (!special) {
> > > 		if (cmds == Q_SYNC)
> > > 			return quota_sync_all(type);
> > > 		return -ENODEV;
> > > 	}
> > > 
> > > Should we fix this or is there userspace code that is confused by a changed
> > > return value?
> > 
> > I'd leave the original quotactl(2) as is. There's no strong reason to risk
> > breaking some userspace. For the new syscall, I agree we can just
> > standardize the return value, there ENODEV makes even less sense since
> > there's no device in that call.
> 
> Ok, will do. Who can pick this series up? Anyone else I need to Cc next
> round?

I guess I can pick up both kernel patches (the manpage patch needs to be
submitted to the manpage list) but please CC linux-api@vger as well so that
interested people are aware of the new syscall.

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH 1/2] quota: Add mountpath based quota support

[Sascha Hauer]

On Fri, Feb 12, 2021 at 11:05:05AM +0100, Jan Kara wrote:
> On Fri 12-02-21 09:38:35, Sascha Hauer wrote:
> > On Thu, Feb 11, 2021 at 03:38:13PM +0000, Christoph Hellwig wrote:
> > > > +	if (!mountpoint)
> > > > +		return -ENODEV;
> > > > +
> > > > +	ret = user_path_at(AT_FDCWD, mountpoint,
> > > > +			     LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT, &mountpath);
> > > 
> > > user_path_at handles an empty path, although you'll get EFAULT instead.
> > > Do we care about the -ENODEV here?
> > 
> > The quotactl manpage documents EFAULT as error code for invalid addr or
> > special argument, so we really should return -EFAULT here.
> > 
> > Existing quotactl gets this wrong as well:
> > 
> > 	if (!special) {
> > 		if (cmds == Q_SYNC)
> > 			return quota_sync_all(type);
> > 		return -ENODEV;
> > 	}
> > 
> > Should we fix this or is there userspace code that is confused by a changed
> > return value?
> 
> I'd leave the original quotactl(2) as is. There's no strong reason to risk
> breaking some userspace. For the new syscall, I agree we can just
> standardize the return value, there ENODEV makes even less sense since
> there's no device in that call.

Ok, will do. Who can pick this series up? Anyone else I need to Cc next
round?

Sascha

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

Re: [PATCH 1/2] quota: Add mountpath based quota support

[Jan Kara]

On Fri 12-02-21 09:38:35, Sascha Hauer wrote:
> On Thu, Feb 11, 2021 at 03:38:13PM +0000, Christoph Hellwig wrote:
> > > +	if (!mountpoint)
> > > +		return -ENODEV;
> > > +
> > > +	ret = user_path_at(AT_FDCWD, mountpoint,
> > > +			     LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT, &mountpath);
> > 
> > user_path_at handles an empty path, although you'll get EFAULT instead.
> > Do we care about the -ENODEV here?
> 
> The quotactl manpage documents EFAULT as error code for invalid addr or
> special argument, so we really should return -EFAULT here.
> 
> Existing quotactl gets this wrong as well:
> 
> 	if (!special) {
> 		if (cmds == Q_SYNC)
> 			return quota_sync_all(type);
> 		return -ENODEV;
> 	}
> 
> Should we fix this or is there userspace code that is confused by a changed
> return value?

I'd leave the original quotactl(2) as is. There's no strong reason to risk
breaking some userspace. For the new syscall, I agree we can just
standardize the return value, there ENODEV makes even less sense since
there's no device in that call.

								Honza

-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH 1/2] quota: Add mountpath based quota support

[Sascha Hauer]

On Thu, Feb 11, 2021 at 03:38:13PM +0000, Christoph Hellwig wrote:
> > +	if (!mountpoint)
> > +		return -ENODEV;
> > +
> > +	ret = user_path_at(AT_FDCWD, mountpoint,
> > +			     LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT, &mountpath);
> 
> user_path_at handles an empty path, although you'll get EFAULT instead.
> Do we care about the -ENODEV here?

The quotactl manpage documents EFAULT as error code for invalid addr or
special argument, so we really should return -EFAULT here.

Existing quotactl gets this wrong as well:

	if (!special) {
		if (cmds == Q_SYNC)
			return quota_sync_all(type);
		return -ENODEV;
	}

Should we fix this or is there userspace code that is confused by a changed
return value?

Sascha

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

Re: [PATCH 1/2] quota: Add mountpath based quota support

[kernel test robot]

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Hi Sascha,

I love your patch! Yet something to improve:

[auto build test ERROR on arm64/for-next/core]
[also build test ERROR on tip/x86/asm m68k/for-next hp-parisc/for-next powerpc/next s390/features linus/master v5.11-rc7 next-20210211]
[cannot apply to sparc/master]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Sascha-Hauer/quota-Add-mountpath-based-quota-support/20210211-233912
base:   https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/core
config: x86_64-randconfig-a012-20210209 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project c9439ca36342fb6013187d0a69aef92736951476)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install x86_64 cross compiling tool for clang build
        # apt-get install binutils-x86-64-linux-gnu
        # https://github.com/0day-ci/linux/commit/4b7a3df11dd2ca215a6e9b24d81c98d6951476b6
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Sascha-Hauer/quota-Add-mountpath-based-quota-support/20210211-233912
        git checkout 4b7a3df11dd2ca215a6e9b24d81c98d6951476b6
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> fs/quota/quota.c:995:6: error: implicit declaration of function 'quotactl_cmd_write' [-Werror,-Wimplicit-function-declaration]
           if (quotactl_cmd_write(cmds)) {
               ^
   fs/quota/quota.c:995:6: note: did you mean 'quotactl_cmd_onoff'?
   fs/quota/quota.c:857:13: note: 'quotactl_cmd_onoff' declared here
   static bool quotactl_cmd_onoff(int cmd)
               ^
   1 error generated.


vim +/quotactl_cmd_write +995 fs/quota/quota.c

   972	
   973	SYSCALL_DEFINE4(quotactl_path, unsigned int, cmd, const char __user *,
   974			mountpoint, qid_t, id, void __user *, addr)
   975	{
   976		struct super_block *sb;
   977		struct path mountpath;
   978		unsigned int cmds = cmd >> SUBCMDSHIFT;
   979		unsigned int type = cmd & SUBCMDMASK;
   980		int ret;
   981	
   982		if (type >= MAXQUOTAS)
   983			return -EINVAL;
   984	
   985		if (!mountpoint)
   986			return -ENODEV;
   987	
   988		ret = user_path_at(AT_FDCWD, mountpoint,
   989				     LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT, &mountpath);
   990		if (ret)
   991			return ret;
   992	
   993		sb = mountpath.dentry->d_inode->i_sb;
   994	
 > 995		if (quotactl_cmd_write(cmds)) {

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 34205 bytes --]

Re: [PATCH 1/2] quota: Add mountpath based quota support

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 3091 bytes --]

Hi Sascha,

I love your patch! Yet something to improve:

[auto build test ERROR on arm64/for-next/core]
[also build test ERROR on tip/x86/asm m68k/for-next hp-parisc/for-next powerpc/next s390/features linus/master v5.11-rc7 next-20210211]
[cannot apply to sparc/master]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Sascha-Hauer/quota-Add-mountpath-based-quota-support/20210211-233912
base:   https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/core
config: x86_64-randconfig-a012-20210209 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project c9439ca36342fb6013187d0a69aef92736951476)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install x86_64 cross compiling tool for clang build
        # apt-get install binutils-x86-64-linux-gnu
        # https://github.com/0day-ci/linux/commit/4b7a3df11dd2ca215a6e9b24d81c98d6951476b6
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Sascha-Hauer/quota-Add-mountpath-based-quota-support/20210211-233912
        git checkout 4b7a3df11dd2ca215a6e9b24d81c98d6951476b6
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> fs/quota/quota.c:995:6: error: implicit declaration of function 'quotactl_cmd_write' [-Werror,-Wimplicit-function-declaration]
           if (quotactl_cmd_write(cmds)) {
               ^
   fs/quota/quota.c:995:6: note: did you mean 'quotactl_cmd_onoff'?
   fs/quota/quota.c:857:13: note: 'quotactl_cmd_onoff' declared here
   static bool quotactl_cmd_onoff(int cmd)
               ^
   1 error generated.


vim +/quotactl_cmd_write +995 fs/quota/quota.c

   972	
   973	SYSCALL_DEFINE4(quotactl_path, unsigned int, cmd, const char __user *,
   974			mountpoint, qid_t, id, void __user *, addr)
   975	{
   976		struct super_block *sb;
   977		struct path mountpath;
   978		unsigned int cmds = cmd >> SUBCMDSHIFT;
   979		unsigned int type = cmd & SUBCMDMASK;
   980		int ret;
   981	
   982		if (type >= MAXQUOTAS)
   983			return -EINVAL;
   984	
   985		if (!mountpoint)
   986			return -ENODEV;
   987	
   988		ret = user_path_at(AT_FDCWD, mountpoint,
   989				     LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT, &mountpath);
   990		if (ret)
   991			return ret;
   992	
   993		sb = mountpath.dentry->d_inode->i_sb;
   994	
 > 995		if (quotactl_cmd_write(cmds)) {

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

[-- Attachment #2: config.gz --]
[-- Type: application/gzip, Size: 34205 bytes --]

Re: [PATCH 1/2] quota: Add mountpath based quota support

[Christoph Hellwig]

> +	if (!mountpoint)
> +		return -ENODEV;
> +
> +	ret = user_path_at(AT_FDCWD, mountpoint,
> +			     LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT, &mountpath);

user_path_at handles an empty path, although you'll get EFAULT instead.
Do we care about the -ENODEV here?

Otherwise this looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

[PATCH 1/2] quota: Add mountpath based quota support

[Sascha Hauer]

Add syscall quotactl_path, a variant of quotactl which allows to specify
the mountpath instead of a path of to a block device.

The quotactl syscall expects a path to the mounted block device to
specify the filesystem to work on. This limits usage to filesystems
which actually have a block device. quotactl_path replaces the path
to the block device with a path where the filesystem is mounted at.

The global Q_SYNC command to sync all filesystems is not supported for
this new syscall, otherwise quotactl_path behaves like quotactl.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 fs/quota/quota.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index 6d16b2be5ac4..6f1df32abeea 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -17,6 +17,7 @@
 #include <linux/capability.h>
 #include <linux/quotaops.h>
 #include <linux/types.h>
+#include <linux/mount.h>
 #include <linux/writeback.h>
 #include <linux/nospec.h>
 #include "compat.h"
@@ -968,3 +969,51 @@ SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
 		path_put(pathp);
 	return ret;
 }
+
+SYSCALL_DEFINE4(quotactl_path, unsigned int, cmd, const char __user *,
+		mountpoint, qid_t, id, void __user *, addr)
+{
+	struct super_block *sb;
+	struct path mountpath;
+	unsigned int cmds = cmd >> SUBCMDSHIFT;
+	unsigned int type = cmd & SUBCMDMASK;
+	int ret;
+
+	if (type >= MAXQUOTAS)
+		return -EINVAL;
+
+	if (!mountpoint)
+		return -ENODEV;
+
+	ret = user_path_at(AT_FDCWD, mountpoint,
+			     LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT, &mountpath);
+	if (ret)
+		return ret;
+
+	sb = mountpath.dentry->d_inode->i_sb;
+
+	if (quotactl_cmd_write(cmds)) {
+		ret = mnt_want_write(mountpath.mnt);
+		if (ret)
+			goto out;
+	}
+
+	if (quotactl_cmd_onoff(cmds))
+		down_write(&sb->s_umount);
+	else
+		down_read(&sb->s_umount);
+
+	ret = do_quotactl(sb, type, cmds, id, addr, ERR_PTR(-EINVAL));
+
+	if (quotactl_cmd_onoff(cmds))
+		up_write(&sb->s_umount);
+	else
+		up_read(&sb->s_umount);
+
+	if (quotactl_cmd_write(cmds))
+		mnt_drop_write(mountpath.mnt);
+out:
+	path_put(&mountpath);
+
+	return ret;
+}
-- 
2.20.1

Re: [PATCH 1/2] quota: Add mountpath based quota support

[Jan Kara]

On Tue 09-02-21 08:51:01, Christoph Hellwig wrote:
> On Thu, Feb 04, 2021 at 01:53:50PM +0100, Jan Kara wrote:
> > Now quota data stored in a normal file is a setup we try to deprecate
> > anyway so another option is to just leave quotactl_path() only for those
> > setups where quota metadata is managed by the filesystem so we don't need
> > to pass quota files to Q_QUOTAON?
> 
> I'd be perfectly fine with that.

OK, then this looks like the best way forward to me. We can always extend
the quotactl_path() syscall later if we find this is problematic for some
real usecases.

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH 1/2] quota: Add mountpath based quota support

[Christoph Hellwig]

On Thu, Feb 04, 2021 at 01:53:50PM +0100, Jan Kara wrote:
> Now quota data stored in a normal file is a setup we try to deprecate
> anyway so another option is to just leave quotactl_path() only for those
> setups where quota metadata is managed by the filesystem so we don't need
> to pass quota files to Q_QUOTAON?

I'd be perfectly fine with that.

Re: [PATCH 1/2] quota: Add mountpath based quota support

[Jan Kara]

On Thu 04-02-21 07:34:14, Christoph Hellwig wrote:
> On Tue, Feb 02, 2021 at 07:02:41PM +0100, Jan Kara wrote:
> > Hum, let me think out loud. The path we pass to Q_QUOTAON is a path to
> > quota file - unless the filesystem stores quota in hidden files in which
> > case this argument is just ignored. You're right we could require that
> > specifically for Q_QUOTAON, the mountpoint path would actually need to
> > point to the quota file if it is relevant, otherwise anywhere in the
> > appropriate filesystem. We don't allow quota file to reside on a different
> > filesystem (for a past decade or so) so it should work fine.
> > 
> > So the only problem I have is whether requiring the mountpoint argument to
> > point quota file for Q_QUOTAON isn't going to be somewhat confusing to
> > users. At the very least it would require some careful explanation in the
> > manpage to explain the difference between quotactl_path() and quotactl()
> > in this regard. But is saving the second path for Q_QUOTAON really worth the
> > bother?
> 
> I find the doubled path argument a really horrible API, so I'd pretty
> strongly prefer to avoid that.

Honestly, I don't understand why is it so horrible. The paths point to
different things... The first path identifies the filesystem to operate on,
the second path identifies the file which contains quota accounting data.
In the ancient times, the file with quota accounting data could even be
stored on a different filesystem (these were still times when filesystem
metadata journalling was a new thing - like late 90's).  But later I just
disallowed that because it was not very useful (and luckily even used) and
just complicated matters.
 
Anyway, back to 2021 :). What I find somewhat confusing about a single path
for Q_QUOTAON is that for any other quotactl, any path on the filesystem is
fine. Similarly if quota data is stored in the hidden file, any path on the
filesystem is fine. It is only for Q_QUOTAON on a filesystem where quota
data is stored in a normal file, where we suddently require that the path
has to point to it.

Now quota data stored in a normal file is a setup we try to deprecate
anyway so another option is to just leave quotactl_path() only for those
setups where quota metadata is managed by the filesystem so we don't need
to pass quota files to Q_QUOTAON?

> > > Given how cheap quotactl_cmd_onoff and quotactl_cmd_write are we
> > > could probably simplify this down do:
> > > 
> > > 	if (quotactl_cmd_write(cmd)) {
> > 
> > This needs to be (quotactl_cmd_write(cmd) || quotactl_cmd_onoff(cmd)).
> > Otherwise I agree what you suggest is somewhat more readable given how
> > small the function is.
> 
> The way I read quotactl_cmd_write, it only special cases a few commands
> and returns 0 there, so we should not need the extra quotactl_cmd_onoff
> call, as all those commands are not explicitly listed.

Right, sorry, I was mistaken.

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH 1/2] quota: Add mountpath based quota support

[Christoph Hellwig]

On Tue, Feb 02, 2021 at 07:02:41PM +0100, Jan Kara wrote:
> Hum, let me think out loud. The path we pass to Q_QUOTAON is a path to
> quota file - unless the filesystem stores quota in hidden files in which
> case this argument is just ignored. You're right we could require that
> specifically for Q_QUOTAON, the mountpoint path would actually need to
> point to the quota file if it is relevant, otherwise anywhere in the
> appropriate filesystem. We don't allow quota file to reside on a different
> filesystem (for a past decade or so) so it should work fine.
> 
> So the only problem I have is whether requiring the mountpoint argument to
> point quota file for Q_QUOTAON isn't going to be somewhat confusing to
> users. At the very least it would require some careful explanation in the
> manpage to explain the difference between quotactl_path() and quotactl()
> in this regard. But is saving the second path for Q_QUOTAON really worth the
> bother?

I find the doubled path argument a really horrible API, so I'd pretty
strongly prefer to avoid that.

> > Given how cheap quotactl_cmd_onoff and quotactl_cmd_write are we
> > could probably simplify this down do:
> > 
> > 	if (quotactl_cmd_write(cmd)) {
> 
> This needs to be (quotactl_cmd_write(cmd) || quotactl_cmd_onoff(cmd)).
> Otherwise I agree what you suggest is somewhat more readable given how
> small the function is.

The way I read quotactl_cmd_write, it only special cases a few commands
and returns 0 there, so we should not need the extra quotactl_cmd_onoff
call, as all those commands are not explicitly listed.

Re: [PATCH 1/2] quota: Add mountpath based quota support

[Jan Kara]

On Thu 28-01-21 14:35:52, Christoph Hellwig wrote:
> > +	struct path path, *pathp = NULL;
> > +	struct path mountpath;
> > +	bool excl = false, thawed = false;
> > +	int ret;
> > +
> > +	cmds = cmd >> SUBCMDSHIFT;
> > +	type = cmd & SUBCMDMASK;
> 
> Personal pet peeve: it would be nice to just initialize cmds and
> type on their declaration line, or while we're at it declutter
> this a bit and remove the separate cmds variable:
> 
> 	unsigned int type = cmd & SUBCMDMASK;
> 
> 	cmd >>= SUBCMDSHIFT;

Yeah, whatever :)

> > +	/*
> > +	 * Path for quotaon has to be resolved before grabbing superblock
> > +	 * because that gets s_umount sem which is also possibly needed by path
> > +	 * resolution (think about autofs) and thus deadlocks could arise.
> > +	 */
> > +	if (cmds == Q_QUOTAON) {
> > +		ret = user_path_at(AT_FDCWD, addr,
> > +				   LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT, &path);
> > +		if (ret)
> > +			pathp = ERR_PTR(ret);
> > +		else
> > +			pathp = &path;
> > +	}
> > +
> > +	ret = user_path_at(AT_FDCWD, mountpoint,
> > +			     LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT, &mountpath);
> > +	if (ret)
> > +		goto out;
> 
> I don't think we need two path lookups here, we can path the same path
> to the command for quotaon.

Hum, let me think out loud. The path we pass to Q_QUOTAON is a path to
quota file - unless the filesystem stores quota in hidden files in which
case this argument is just ignored. You're right we could require that
specifically for Q_QUOTAON, the mountpoint path would actually need to
point to the quota file if it is relevant, otherwise anywhere in the
appropriate filesystem. We don't allow quota file to reside on a different
filesystem (for a past decade or so) so it should work fine.

So the only problem I have is whether requiring the mountpoint argument to
point quota file for Q_QUOTAON isn't going to be somewhat confusing to
users. At the very least it would require some careful explanation in the
manpage to explain the difference between quotactl_path() and quotactl()
in this regard. But is saving the second path for Q_QUOTAON really worth the
bother?

> > +	if (quotactl_cmd_onoff(cmds)) {
> > +		excl = true;
> > +		thawed = true;
> > +	} else if (quotactl_cmd_write(cmds)) {
> > +		thawed = true;
> > +	}
> > +
> > +	if (thawed) {
> > +		ret = mnt_want_write(mountpath.mnt);
> > +		if (ret)
> > +			goto out1;
> > +	}
> > +
> > +	sb = mountpath.dentry->d_inode->i_sb;
> > +
> > +	if (excl)
> > +		down_write(&sb->s_umount);
> > +	else
> > +		down_read(&sb->s_umount);
> 
> Given how cheap quotactl_cmd_onoff and quotactl_cmd_write are we
> could probably simplify this down do:
> 
> 	if (quotactl_cmd_write(cmd)) {

This needs to be (quotactl_cmd_write(cmd) || quotactl_cmd_onoff(cmd)).
Otherwise I agree what you suggest is somewhat more readable given how
small the function is.

> 		ret = mnt_want_write(path.mnt);
> 		if (ret)
> 			goto out1;
> 	}
> 	if (quotactl_cmd_onoff(cmd))
> 		down_write(&sb->s_umount);
> 	else
> 		down_read(&sb->s_umount);
> 
> and duplicate the checks after the do_quotactl call.

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH 1/2] quota: Add mountpath based quota support

[Christoph Hellwig]

> +	uint cmds, type;
> +	struct super_block *sb = NULL;

I don't think sb needs the NULL initialization.

> +	struct path path, *pathp = NULL;
> +	struct path mountpath;
> +	bool excl = false, thawed = false;
> +	int ret;
> +
> +	cmds = cmd >> SUBCMDSHIFT;
> +	type = cmd & SUBCMDMASK;

Personal pet peeve: it would be nice to just initialize cmds and
type on their declaration line, or while we're at it declutter
this a bit and remove the separate cmds variable:

	unsigned int type = cmd & SUBCMDMASK;


	cmd >>= SUBCMDSHIFT;

> +	/*
> +	 * Path for quotaon has to be resolved before grabbing superblock
> +	 * because that gets s_umount sem which is also possibly needed by path
> +	 * resolution (think about autofs) and thus deadlocks could arise.
> +	 */
> +	if (cmds == Q_QUOTAON) {
> +		ret = user_path_at(AT_FDCWD, addr,
> +				   LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT, &path);
> +		if (ret)
> +			pathp = ERR_PTR(ret);
> +		else
> +			pathp = &path;
> +	}
> +
> +	ret = user_path_at(AT_FDCWD, mountpoint,
> +			     LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT, &mountpath);
> +	if (ret)
> +		goto out;

I don't think we need two path lookups here, we can path the same path
to the command for quotaon.


> +	if (quotactl_cmd_onoff(cmds)) {
> +		excl = true;
> +		thawed = true;
> +	} else if (quotactl_cmd_write(cmds)) {
> +		thawed = true;
> +	}
> +
> +	if (thawed) {
> +		ret = mnt_want_write(mountpath.mnt);
> +		if (ret)
> +			goto out1;
> +	}
> +
> +	sb = mountpath.dentry->d_inode->i_sb;
> +
> +	if (excl)
> +		down_write(&sb->s_umount);
> +	else
> +		down_read(&sb->s_umount);

Given how cheap quotactl_cmd_onoff and quotactl_cmd_write are we
could probably simplify this down do:

	if (quotactl_cmd_write(cmd)) {
		ret = mnt_want_write(path.mnt);
		if (ret)
			goto out1;
	}
	if (quotactl_cmd_onoff(cmd))
		down_write(&sb->s_umount);
	else
		down_read(&sb->s_umount);

and duplicate the checks after the do_quotactl call.

[PATCH 1/2] quota: Add mountpath based quota support

[Sascha Hauer]

Add syscall quotactl_path, a variant of quotactl which allows to specify
the mountpath instead of a path of to a block device.

The quotactl syscall expects a path to the mounted block device to
specify the filesystem to work on. This limits usage to filesystems
which actually have a block device. quotactl_path replaces the path
to the block device with a path where the filesystem is mounted at.

The global Q_SYNC command to sync all filesystems is not supported for
this new syscall, otherwise quotactl_path behaves like quotactl.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 fs/quota/quota.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)

diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index 6d16b2be5ac4..9ac09e128686 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -17,6 +17,7 @@
 #include <linux/capability.h>
 #include <linux/quotaops.h>
 #include <linux/types.h>
+#include <linux/mount.h>
 #include <linux/writeback.h>
 #include <linux/nospec.h>
 #include "compat.h"
@@ -968,3 +969,79 @@ SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
 		path_put(pathp);
 	return ret;
 }
+
+SYSCALL_DEFINE4(quotactl_path, unsigned int, cmd, const char __user *,
+		mountpoint, qid_t, id, void __user *, addr)
+{
+	uint cmds, type;
+	struct super_block *sb = NULL;
+	struct path path, *pathp = NULL;
+	struct path mountpath;
+	bool excl = false, thawed = false;
+	int ret;
+
+	cmds = cmd >> SUBCMDSHIFT;
+	type = cmd & SUBCMDMASK;
+
+	if (type >= MAXQUOTAS)
+		return -EINVAL;
+
+	if (!mountpoint)
+		return -ENODEV;
+
+	/*
+	 * Path for quotaon has to be resolved before grabbing superblock
+	 * because that gets s_umount sem which is also possibly needed by path
+	 * resolution (think about autofs) and thus deadlocks could arise.
+	 */
+	if (cmds == Q_QUOTAON) {
+		ret = user_path_at(AT_FDCWD, addr,
+				   LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT, &path);
+		if (ret)
+			pathp = ERR_PTR(ret);
+		else
+			pathp = &path;
+	}
+
+	ret = user_path_at(AT_FDCWD, mountpoint,
+			     LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT, &mountpath);
+	if (ret)
+		goto out;
+
+	if (quotactl_cmd_onoff(cmds)) {
+		excl = true;
+		thawed = true;
+	} else if (quotactl_cmd_write(cmds)) {
+		thawed = true;
+	}
+
+	if (thawed) {
+		ret = mnt_want_write(mountpath.mnt);
+		if (ret)
+			goto out1;
+	}
+
+	sb = mountpath.dentry->d_inode->i_sb;
+
+	if (excl)
+		down_write(&sb->s_umount);
+	else
+		down_read(&sb->s_umount);
+
+	ret = do_quotactl(sb, type, cmds, id, addr, pathp);
+
+	if (excl)
+		up_write(&sb->s_umount);
+	else
+		up_read(&sb->s_umount);
+
+	if (thawed)
+		mnt_drop_write(mountpath.mnt);
+out1:
+	path_put(&mountpath);
+
+out:
+	if (pathp && !IS_ERR(pathp))
+		path_put(pathp);
+	return ret;
+}
-- 
2.20.1