Implement new system calls to provide enhanced file stats and enhanced filesystem stats. The patches can be found here: http://git.kernel.org/cgit/linux/kernel/git/dhowells/linux-fs.git/log/?h=xstat =========== DESCRIPTION =========== The third patch provides this new system call: long ret = statx(int dfd, const char *filename, unsigned atflag, unsigned mask, struct statx *buffer); This is an enhanced file stat function that provides a number of useful features, in summary: (1) More information: creation time, data version number, flags/attributes. A subset of these is available through a number of filesystems (such as CIFS, NFS, AFS, Ext4 and BTRFS). (2) Lightweight stat (AT_NO_ATTR_SYNC): Ask for just those details of interest, and allow a network fs to approximate anything not of interest, without going to the server. (3) Heavyweight stat (AT_FORCE_ATTR_SYNC): Force a network fs to flush buffers and go to the server, even if it thinks its cached attributes are up to date. (4) Allow the filesystem to indicate what it can/cannot provide: A filesystem can now say it doesn't support a standard stat feature if that isn't available. (5) Make the fields a consistent size on all arches, and make them large. (6) Can be extended by using more request flags and using up the padding space in the statx struct. Note that no lstat() equivalent is required as that can be implemented through statx() with atflag == 0. There is also no fstat() equivalent as that can be implemented through statx() with filename == NULL and the relevant fd passed as dfd. The seventh patch provides another new system call: long ret = fsinfo(int dfd, const char *filename, unsigned atflag, unsigned request, void *buffer); This is an enhanced filesystem stat and information retrieval function that provides more information, in summary: (1) All the information provided by statfs() and more. The fields are made large. (2) Provides information about timestamp range and resolution to complement statx(). (3) Provides information about IOC flags supported in statx()'s return. (4) Provides volume binary IDs and UUIDs. (5) Provides the filesystem name according to the kernel as a string (eg. "ext4" or "nfs3") in addition to the magic number. (6) Provides information obtained from network filesystems, such as volume and domain names. (7) Has lots of spare space that can be used for future extenstions and a bit mask indicating what was provided. Note that I've added a 'request' identifier. This is to select the set of data to be returned. The idea is that 'buffer' points to a fixed-size struct selected by request. Currently only 0 is available and this refers to 'struct fsinfo'. However, I could split up the buffer into say 3: (0) statfs-type information (1) Timestamp and IOC flags info. (2) Network fs strings. However, some of this might be better retrieved through getxattr(). ======= TESTING ======= Test programs are added into samples/statx/ by the appropriate patches. David --- David Howells (12): Ext4: Fix extended timestamp encoding and decoding statx: Provide IOC flags for Windows fs attributes statx: Add a system call to make enhanced file info available statx: AFS: Return enhanced file attributes statx: Ext4: Return enhanced file attributes statx: NFS: Return enhanced file attributes statx: CIFS: Return enhanced attributes fsinfo: Add a system call to make enhanced filesystem info available fsinfo: Ext4: Return information through the filesystem info syscall fsinfo: AFS: Return information through the filesystem info syscall fsinfo: NFS: Return information through the filesystem info syscall fsinfo: CIFS: Return information through the filesystem info syscall arch/x86/entry/syscalls/syscall_32.tbl | 2 arch/x86/entry/syscalls/syscall_64.tbl | 2 fs/afs/inode.c | 23 ++ fs/afs/super.c | 39 ++++ fs/cifs/cifsfs.c | 25 +++ fs/cifs/cifsfs.h | 4 fs/cifs/cifsglob.h | 8 + fs/cifs/dir.c | 2 fs/cifs/inode.c | 124 ++++++++++--- fs/cifs/netmisc.c | 4 fs/exportfs/expfs.c | 4 fs/ext4/ext4.h | 24 ++- fs/ext4/file.c | 2 fs/ext4/inode.c | 31 +++ fs/ext4/namei.c | 2 fs/ext4/super.c | 39 ++++ fs/ext4/symlink.c | 2 fs/nfs/inode.c | 45 ++++- fs/nfs/internal.h | 1 fs/nfs/nfs4super.c | 1 fs/nfs/super.c | 58 ++++++ fs/ntfs/time.h | 2 fs/stat.c | 305 +++++++++++++++++++++++++++++--- fs/statfs.c | 218 +++++++++++++++++++++++ include/linux/fs.h | 7 + include/linux/stat.h | 14 + include/linux/syscalls.h | 6 + include/linux/time64.h | 2 include/uapi/linux/fcntl.h | 2 include/uapi/linux/fs.h | 7 + include/uapi/linux/stat.h | 185 +++++++++++++++++++ samples/Makefile | 3 samples/statx/Makefile | 13 + samples/statx/test-fsinfo.c | 179 +++++++++++++++++++ samples/statx/test-statx.c | 273 +++++++++++++++++++++++++++++ 35 files changed, 1558 insertions(+), 100 deletions(-) create mode 100644 samples/statx/Makefile create mode 100644 samples/statx/test-fsinfo.c create mode 100644 samples/statx/test-statx.c -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
