Got more comments below with private mail: On 2025-02-11 18:22:47, Andrey Albershteyn wrote: > From: Andrey Albershteyn <aalbersh@xxxxxxxxxx> > > Introduce getfsxattrat and setfsxattrat syscalls to manipulate inode > extended attributes/flags. The syscalls take parent directory fd and > path to the child together with struct fsxattr. > > This is an alternative to FS_IOC_FSSETXATTR ioctl with a difference > that file don't need to be open as we can reference it with a path > instead of fd. By having this we can manipulated inode extended > attributes not only on regular files but also on special ones. This > is not possible with FS_IOC_FSSETXATTR ioctl as with special files > we can not call ioctl() directly on the filesystem inode using fd. > > This patch adds two new syscalls which allows userspace to get/set > extended inode attributes on special files by using parent directory > and a path - *at() like syscall. > > Also, as vfs_fileattr_set() is now will be called on special files > too, let's forbid any other attributes except projid and nextents > (symlink can have an extent). > > CC: linux-api@xxxxxxxxxxxxxxx > CC: linux-fsdevel@xxxxxxxxxxxxxxx > CC: linux-xfs@xxxxxxxxxxxxxxx > Signed-off-by: Andrey Albershteyn <aalbersh@xxxxxxxxxx> > --- > v1: > https://lore.kernel.org/linuxppc-dev/20250109174540.893098-1-aalbersh@xxxxxxxxxx/ > > Previous discussion: > https://lore.kernel.org/linux-xfs/20240520164624.665269-2-aalbersh@xxxxxxxxxx/ > > XFS has project quotas which could be attached to a directory. All > new inodes in these directories inherit project ID set on parent > directory. > > The project is created from userspace by opening and calling > FS_IOC_FSSETXATTR on each inode. This is not possible for special > files such as FIFO, SOCK, BLK etc. Therefore, some inodes are left > with empty project ID. Those inodes then are not shown in the quota > accounting but still exist in the directory. Moreover, in the case > when special files are created in the directory with already > existing project quota, these inode inherit extended attributes. > This than leaves them with these attributes without the possibility > to clear them out. This, in turn, prevents userspace from > re-creating quota project on these existing files. > --- > Changes in v3: > - Remove unnecessary "dfd is dir" check as it checked in user_path_at() > - Remove unnecessary "same filesystem" check > - Use CLASS() instead of directly calling fdget/fdput > - Link to v2: https://lore.kernel.org/r/20250122-xattrat-syscall-v2-1-5b360d4fbcb2@xxxxxxxxxx > --- > arch/alpha/kernel/syscalls/syscall.tbl | 2 + > arch/arm/tools/syscall.tbl | 2 + > arch/arm64/tools/syscall_32.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 + > fs/inode.c | 75 +++++++++++++++++++++++++++++ > fs/ioctl.c | 16 +++++- > include/linux/fileattr.h | 1 + > include/linux/syscalls.h | 4 ++ > include/uapi/asm-generic/unistd.h | 8 ++- > 21 files changed, 133 insertions(+), 3 deletions(-) > > diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl > index c59d53d6d3f3490f976ca179ddfe02e69265ae4d..4b9e687494c16b60c6fd6ca1dc4d6564706a7e25 100644 > --- a/arch/alpha/kernel/syscalls/syscall.tbl > +++ b/arch/alpha/kernel/syscalls/syscall.tbl > @@ -506,3 +506,5 @@ > 574 common getxattrat sys_getxattrat > 575 common listxattrat sys_listxattrat > 576 common removexattrat sys_removexattrat > +577 common getfsxattrat sys_getfsxattrat > +578 common setfsxattrat sys_setfsxattrat > diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl > index 49eeb2ad8dbd8e074c6240417693f23fb328afa8..66466257f3c2debb3e2299f0b608c6740c98cab2 100644 > --- a/arch/arm/tools/syscall.tbl > +++ b/arch/arm/tools/syscall.tbl > @@ -481,3 +481,5 @@ > 464 common getxattrat sys_getxattrat > 465 common listxattrat sys_listxattrat > 466 common removexattrat sys_removexattrat > +467 common getfsxattrat sys_getfsxattrat > +468 common setfsxattrat sys_setfsxattrat > diff --git a/arch/arm64/tools/syscall_32.tbl b/arch/arm64/tools/syscall_32.tbl > index 69a829912a05eb8a3e21ed701d1030e31c0148bc..9c516118b154811d8d11d5696f32817430320dbf 100644 > --- a/arch/arm64/tools/syscall_32.tbl > +++ b/arch/arm64/tools/syscall_32.tbl > @@ -478,3 +478,5 @@ > 464 common getxattrat sys_getxattrat > 465 common listxattrat sys_listxattrat > 466 common removexattrat sys_removexattrat > +467 common getfsxattrat sys_getfsxattrat > +468 common setfsxattrat sys_setfsxattrat > diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl > index f5ed71f1910d09769c845c2d062d99ee0449437c..159476387f394a92ee5e29db89b118c630372db2 100644 > --- a/arch/m68k/kernel/syscalls/syscall.tbl > +++ b/arch/m68k/kernel/syscalls/syscall.tbl > @@ -466,3 +466,5 @@ > 464 common getxattrat sys_getxattrat > 465 common listxattrat sys_listxattrat > 466 common removexattrat sys_removexattrat > +467 common getfsxattrat sys_getfsxattrat > +468 common setfsxattrat sys_setfsxattrat > diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl > index 680f568b77f2cbefc3eacb2517f276041f229b1e..a6d59ee740b58cacf823702003cf9bad17c0d3b7 100644 > --- a/arch/microblaze/kernel/syscalls/syscall.tbl > +++ b/arch/microblaze/kernel/syscalls/syscall.tbl > @@ -472,3 +472,5 @@ > 464 common getxattrat sys_getxattrat > 465 common listxattrat sys_listxattrat > 466 common removexattrat sys_removexattrat > +467 common getfsxattrat sys_getfsxattrat > +468 common setfsxattrat sys_setfsxattrat > diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl > index 0b9b7e25b69ad592642f8533bee9ccfe95ce9626..cfe38fcebe1a0279e11751378d3e71c5ec6b6569 100644 > --- a/arch/mips/kernel/syscalls/syscall_n32.tbl > +++ b/arch/mips/kernel/syscalls/syscall_n32.tbl > @@ -405,3 +405,5 @@ > 464 n32 getxattrat sys_getxattrat > 465 n32 listxattrat sys_listxattrat > 466 n32 removexattrat sys_removexattrat > +467 n32 getfsxattrat sys_getfsxattrat > +468 n32 setfsxattrat sys_setfsxattrat > diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl > index c844cd5cda620b2809a397cdd6f4315ab6a1bfe2..29a0c5974d1aa2f01e33edc0252d75fb97abe230 100644 > --- a/arch/mips/kernel/syscalls/syscall_n64.tbl > +++ b/arch/mips/kernel/syscalls/syscall_n64.tbl > @@ -381,3 +381,5 @@ > 464 n64 getxattrat sys_getxattrat > 465 n64 listxattrat sys_listxattrat > 466 n64 removexattrat sys_removexattrat > +467 n64 getfsxattrat sys_getfsxattrat > +468 n64 setfsxattrat sys_setfsxattrat > diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl > index 349b8aad1159f404103bd2057a1e64e9bf309f18..6c00436807c57c492ba957fcd59af1202231cf80 100644 > --- a/arch/mips/kernel/syscalls/syscall_o32.tbl > +++ b/arch/mips/kernel/syscalls/syscall_o32.tbl > @@ -454,3 +454,5 @@ > 464 o32 getxattrat sys_getxattrat > 465 o32 listxattrat sys_listxattrat > 466 o32 removexattrat sys_removexattrat > +467 o32 getfsxattrat sys_getfsxattrat > +468 o32 setfsxattrat sys_setfsxattrat > diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl > index d9fc94c869657fcfbd7aca1d5f5abc9fae2fb9d8..b3578fac43d6b65167787fcc97d2d09f5a9828e7 100644 > --- a/arch/parisc/kernel/syscalls/syscall.tbl > +++ b/arch/parisc/kernel/syscalls/syscall.tbl > @@ -465,3 +465,5 @@ > 464 common getxattrat sys_getxattrat > 465 common listxattrat sys_listxattrat > 466 common removexattrat sys_removexattrat > +467 common getfsxattrat sys_getfsxattrat > +468 common setfsxattrat sys_setfsxattrat > diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl > index d8b4ab78bef076bd50d49b87dea5060fd8c1686a..808045d82c9465c3bfa96b15947546efe5851e9a 100644 > --- a/arch/powerpc/kernel/syscalls/syscall.tbl > +++ b/arch/powerpc/kernel/syscalls/syscall.tbl > @@ -557,3 +557,5 @@ > 464 common getxattrat sys_getxattrat > 465 common listxattrat sys_listxattrat > 466 common removexattrat sys_removexattrat > +467 common getfsxattrat sys_getfsxattrat > +468 common setfsxattrat sys_setfsxattrat > diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl > index e9115b4d8b635b846e5c9ad6ce229605323723a5..78dfc2c184d4815baf8a9e61c546c9936d58a47c 100644 > --- a/arch/s390/kernel/syscalls/syscall.tbl > +++ b/arch/s390/kernel/syscalls/syscall.tbl > @@ -469,3 +469,5 @@ > 464 common getxattrat sys_getxattrat sys_getxattrat > 465 common listxattrat sys_listxattrat sys_listxattrat > 466 common removexattrat sys_removexattrat sys_removexattrat > +467 common getfsxattrat sys_getfsxattrat sys_getfsxattrat > +468 common setfsxattrat sys_setfsxattrat sys_setfsxattrat > diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl > index c8cad33bf250ea110de37bd1407f5a43ec5e38f2..d5a5c8339f0ed25ea07c4aba90351d352033c8a0 100644 > --- a/arch/sh/kernel/syscalls/syscall.tbl > +++ b/arch/sh/kernel/syscalls/syscall.tbl > @@ -470,3 +470,5 @@ > 464 common getxattrat sys_getxattrat > 465 common listxattrat sys_listxattrat > 466 common removexattrat sys_removexattrat > +467 common getfsxattrat sys_getfsxattrat > +468 common setfsxattrat sys_setfsxattrat > diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl > index 727f99d333b304b3db0711953a3d91ece18a28eb..817dcd8603bcbffc47f3f59aa3b74b16486453d0 100644 > --- a/arch/sparc/kernel/syscalls/syscall.tbl > +++ b/arch/sparc/kernel/syscalls/syscall.tbl > @@ -512,3 +512,5 @@ > 464 common getxattrat sys_getxattrat > 465 common listxattrat sys_listxattrat > 466 common removexattrat sys_removexattrat > +467 common getfsxattrat sys_getfsxattrat > +468 common setfsxattrat sys_setfsxattrat > diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl > index 4d0fb2fba7e208ae9455459afe11e277321d9f74..b4842c027c5d00c0236b2ba89387c5e2267447bd 100644 > --- a/arch/x86/entry/syscalls/syscall_32.tbl > +++ b/arch/x86/entry/syscalls/syscall_32.tbl > @@ -472,3 +472,5 @@ > 464 i386 getxattrat sys_getxattrat > 465 i386 listxattrat sys_listxattrat > 466 i386 removexattrat sys_removexattrat > +467 i386 getfsxattrat sys_getfsxattrat > +468 i386 setfsxattrat sys_setfsxattrat > diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl > index 5eb708bff1c791debd6cfc5322583b2ae53f6437..b6f0a7236aaee624cf9b484239a1068085a8ffe1 100644 > --- a/arch/x86/entry/syscalls/syscall_64.tbl > +++ b/arch/x86/entry/syscalls/syscall_64.tbl > @@ -390,6 +390,8 @@ > 464 common getxattrat sys_getxattrat > 465 common listxattrat sys_listxattrat > 466 common removexattrat sys_removexattrat > +467 common getfsxattrat sys_getfsxattrat > +468 common setfsxattrat sys_setfsxattrat > > # > # 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 37effc1b134eea061f2c350c1d68b4436b65a4dd..425d56be337d1de22f205ac503df61ff86224fee 100644 > --- a/arch/xtensa/kernel/syscalls/syscall.tbl > +++ b/arch/xtensa/kernel/syscalls/syscall.tbl > @@ -437,3 +437,5 @@ > 464 common getxattrat sys_getxattrat > 465 common listxattrat sys_listxattrat > 466 common removexattrat sys_removexattrat > +467 common getfsxattrat sys_getfsxattrat > +468 common setfsxattrat sys_setfsxattrat > diff --git a/fs/inode.c b/fs/inode.c > index 6b4c77268fc0ecace4ac78a9ca777fbffc277f4a..b2dddd9db4fabaf67a6cbf541a86978b290411ec 100644 > --- a/fs/inode.c > +++ b/fs/inode.c > @@ -23,6 +23,9 @@ > #include <linux/rw_hint.h> > #include <linux/seq_file.h> > #include <linux/debugfs.h> > +#include <linux/syscalls.h> > +#include <linux/fileattr.h> > +#include <linux/namei.h> > #include <trace/events/writeback.h> > #define CREATE_TRACE_POINTS > #include <trace/events/timestamp.h> > @@ -2953,3 +2956,75 @@ umode_t mode_strip_sgid(struct mnt_idmap *idmap, > return mode & ~S_ISGID; > } > EXPORT_SYMBOL(mode_strip_sgid); > + > +SYSCALL_DEFINE4(getfsxattrat, int, dfd, const char __user *, filename, > + struct fsxattr __user *, fsx, unsigned int, at_flags) > +{ > + CLASS(fd, dir)(dfd); > + struct fileattr fa; > + struct path filepath; > + int error; > + unsigned int lookup_flags = 0; > + > + if ((at_flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0) > + return -EINVAL; > + > + if (at_flags & AT_SYMLINK_FOLLOW) > + lookup_flags |= LOOKUP_FOLLOW; > + > + if (at_flags & AT_EMPTY_PATH) > + lookup_flags |= LOOKUP_EMPTY; > + > + if (fd_empty(dir)) > + return -EBADF; > + > + error = user_path_at(dfd, filename, lookup_flags, &filepath); > + if (error) > + return error; > + > + error = vfs_fileattr_get(filepath.dentry, &fa); vfs_fileattr_get() returns ENOIOCTLCMD, where EOPNOTSUPP is more appropriate > + if (!error) > + error = copy_fsxattr_to_user(&fa, fsx); > + > + path_put(&filepath); > + return error; > +} > + > +SYSCALL_DEFINE4(setfsxattrat, int, dfd, const char __user *, filename, > + struct fsxattr __user *, fsx, unsigned int, at_flags) ^ can be const > +{ > + CLASS(fd, dir)(dfd); > + struct fileattr fa; > + struct path filepath; > + int error; > + unsigned int lookup_flags = 0; > + > + if ((at_flags & ~(AT_SYMLINK_FOLLOW | AT_EMPTY_PATH)) != 0) > + return -EINVAL; > + > + if (at_flags & AT_SYMLINK_FOLLOW) > + lookup_flags |= LOOKUP_FOLLOW; > + > + if (at_flags & AT_EMPTY_PATH) > + lookup_flags |= LOOKUP_EMPTY; > + > + if (fd_empty(dir)) > + return -EBADF; > + > + if (copy_fsxattr_from_user(&fa, fsx)) > + return -EFAULT; > + > + error = user_path_at(dfd, filename, lookup_flags, &filepath); > + if (error) > + return error; > + > + error = mnt_want_write(filepath.mnt); > + if (!error) { > + error = vfs_fileattr_set(file_mnt_idmap(fd_file(dir)), > + filepath.dentry, &fa); same here with returned error -- - Andrey
