Merge tag 'for-linus-hexagon-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel...

[linux-stable.git] / include / uapi / linux / fs.h

/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
#ifndef _UAPI_LINUX_FS_H
#define _UAPI_LINUX_FS_H

/*
 * This file has definitions for some important file table structures
 * and constants and structures used by various generic file system
 * ioctl's.  Please do not make any changes in this file before
 * sending patches for review to linux-fsdevel@vger.kernel.org and
 * linux-api@vger.kernel.org.
 */

#include <linux/limits.h>
#include <linux/ioctl.h>
#include <linux/types.h>
#ifndef __KERNEL__
#include <linux/fscrypt.h>
#endif

/* Use of MS_* flags within the kernel is restricted to core mount(2) code. */
#if !defined(__KERNEL__)
#include <linux/mount.h>
#endif

/*
 * It's silly to have NR_OPEN bigger than NR_FILE, but you can change
 * the file limit at runtime and only root can increase the per-process
 * nr_file rlimit, so it's safe to set up a ridiculously high absolute
 * upper limit on files-per-process.
 *
 * Some programs (notably those using select()) may have to be 
 * recompiled to take full advantage of the new limits..  
 */

/* Fixed constants first: */
#undef NR_OPEN
#define INR_OPEN_CUR 1024       /* Initial setting for nfile rlimits */
#define INR_OPEN_MAX 4096       /* Hard limit for nfile rlimits */

#define BLOCK_SIZE_BITS 10
#define BLOCK_SIZE (1<<BLOCK_SIZE_BITS)

/* flags for integrity meta */
#define IO_INTEGRITY_CHK_GUARD          (1U << 0) /* enforce guard check */
#define IO_INTEGRITY_CHK_REFTAG         (1U << 1) /* enforce ref check */
#define IO_INTEGRITY_CHK_APPTAG         (1U << 2) /* enforce app check */

#define IO_INTEGRITY_VALID_FLAGS (IO_INTEGRITY_CHK_GUARD | \
                                  IO_INTEGRITY_CHK_REFTAG | \
                                  IO_INTEGRITY_CHK_APPTAG)

#define SEEK_SET        0       /* seek relative to beginning of file */
#define SEEK_CUR        1       /* seek relative to current file position */
#define SEEK_END        2       /* seek relative to end of file */
#define SEEK_DATA       3       /* seek to the next data */
#define SEEK_HOLE       4       /* seek to the next hole */
#define SEEK_MAX        SEEK_HOLE

#define RENAME_NOREPLACE        (1 << 0)        /* Don't overwrite target */
#define RENAME_EXCHANGE         (1 << 1)        /* Exchange source and dest */
#define RENAME_WHITEOUT         (1 << 2)        /* Whiteout source */

struct file_clone_range {
        __s64 src_fd;
        __u64 src_offset;
        __u64 src_length;
        __u64 dest_offset;
};

struct fstrim_range {
        __u64 start;
        __u64 len;
        __u64 minlen;
};

/*
 * We include a length field because some filesystems (vfat) have an identifier
 * that we do want to expose as a UUID, but doesn't have the standard length.
 *
 * We use a fixed size buffer beacuse this interface will, by fiat, never
 * support "UUIDs" longer than 16 bytes; we don't want to force all downstream
 * users to have to deal with that.
 */
struct fsuuid2 {
        __u8    len;
        __u8    uuid[16];
};

struct fs_sysfs_path {
        __u8                    len;
        __u8                    name[128];
};

/* extent-same (dedupe) ioctls; these MUST match the btrfs ioctl definitions */
#define FILE_DEDUPE_RANGE_SAME          0
#define FILE_DEDUPE_RANGE_DIFFERS       1

/* from struct btrfs_ioctl_file_extent_same_info */
struct file_dedupe_range_info {
        __s64 dest_fd;          /* in - destination file */
        __u64 dest_offset;      /* in - start of extent in destination */
        __u64 bytes_deduped;    /* out - total # of bytes we were able
                                 * to dedupe from this file. */
        /* status of this dedupe operation:
         * < 0 for error
         * == FILE_DEDUPE_RANGE_SAME if dedupe succeeds
         * == FILE_DEDUPE_RANGE_DIFFERS if data differs
         */
        __s32 status;           /* out - see above description */
        __u32 reserved;         /* must be zero */
};

/* from struct btrfs_ioctl_file_extent_same_args */
struct file_dedupe_range {
        __u64 src_offset;       /* in - start of extent in source */
        __u64 src_length;       /* in - length of extent */
        __u16 dest_count;       /* in - total elements in info array */
        __u16 reserved1;        /* must be zero */
        __u32 reserved2;        /* must be zero */
        struct file_dedupe_range_info info[];
};

/* And dynamically-tunable limits and defaults: */
struct files_stat_struct {
        unsigned long nr_files;         /* read only */
        unsigned long nr_free_files;    /* read only */
        unsigned long max_files;                /* tunable */
};

struct inodes_stat_t {
        long nr_inodes;
        long nr_unused;
        long dummy[5];          /* padding for sysctl ABI compatibility */
};


#define NR_FILE  8192   /* this can well be larger on a larger system */

/*
 * Structure for FS_IOC_FSGETXATTR[A] and FS_IOC_FSSETXATTR.
 */
struct fsxattr {
        __u32           fsx_xflags;     /* xflags field value (get/set) */
        __u32           fsx_extsize;    /* extsize field value (get/set)*/
        __u32           fsx_nextents;   /* nextents field value (get)   */
        __u32           fsx_projid;     /* project identifier (get/set) */
        __u32           fsx_cowextsize; /* CoW extsize field value (get/set)*/
        unsigned char   fsx_pad[8];
};

/*
 * Flags for the fsx_xflags field
 */
#define FS_XFLAG_REALTIME       0x00000001      /* data in realtime volume */
#define FS_XFLAG_PREALLOC       0x00000002      /* preallocated file extents */
#define FS_XFLAG_IMMUTABLE      0x00000008      /* file cannot be modified */
#define FS_XFLAG_APPEND         0x00000010      /* all writes append */
#define FS_XFLAG_SYNC           0x00000020      /* all writes synchronous */
#define FS_XFLAG_NOATIME        0x00000040      /* do not update access time */
#define FS_XFLAG_NODUMP         0x00000080      /* do not include in backups */
#define FS_XFLAG_RTINHERIT      0x00000100      /* create with rt bit set */
#define FS_XFLAG_PROJINHERIT    0x00000200      /* create with parents projid */
#define FS_XFLAG_NOSYMLINKS     0x00000400      /* disallow symlink creation */
#define FS_XFLAG_EXTSIZE        0x00000800      /* extent size allocator hint */
#define FS_XFLAG_EXTSZINHERIT   0x00001000      /* inherit inode extent size */
#define FS_XFLAG_NODEFRAG       0x00002000      /* do not defragment */
#define FS_XFLAG_FILESTREAM     0x00004000      /* use filestream allocator */
#define FS_XFLAG_DAX            0x00008000      /* use DAX for IO */
#define FS_XFLAG_COWEXTSIZE     0x00010000      /* CoW extent size allocator hint */
#define FS_XFLAG_HASATTR        0x80000000      /* no DIFLAG for this   */

/* the read-only stuff doesn't really belong here, but any other place is
   probably as bad and I don't want to create yet another include file. */

#define BLKROSET   _IO(0x12,93) /* set device read-only (0 = read-write) */
#define BLKROGET   _IO(0x12,94) /* get read-only status (0 = read_write) */
#define BLKRRPART  _IO(0x12,95) /* re-read partition table */
#define BLKGETSIZE _IO(0x12,96) /* return device size /512 (long *arg) */
#define BLKFLSBUF  _IO(0x12,97) /* flush buffer cache */
#define BLKRASET   _IO(0x12,98) /* set read ahead for block device */
#define BLKRAGET   _IO(0x12,99) /* get current read ahead setting */
#define BLKFRASET  _IO(0x12,100)/* set filesystem (mm/filemap.c) read-ahead */
#define BLKFRAGET  _IO(0x12,101)/* get filesystem (mm/filemap.c) read-ahead */
#define BLKSECTSET _IO(0x12,102)/* set max sectors per request (ll_rw_blk.c) */
#define BLKSECTGET _IO(0x12,103)/* get max sectors per request (ll_rw_blk.c) */
#define BLKSSZGET  _IO(0x12,104)/* get block device sector size */
#if 0
#define BLKPG      _IO(0x12,105)/* See blkpg.h */

/* Some people are morons.  Do not use sizeof! */

#define BLKELVGET  _IOR(0x12,106,size_t)/* elevator get */
#define BLKELVSET  _IOW(0x12,107,size_t)/* elevator set */
/* This was here just to show that the number is taken -
   probably all these _IO(0x12,*) ioctls should be moved to blkpg.h. */
#endif
/* A jump here: 108-111 have been used for various private purposes. */
#define BLKBSZGET  _IOR(0x12,112,size_t)
#define BLKBSZSET  _IOW(0x12,113,size_t)
#define BLKGETSIZE64 _IOR(0x12,114,size_t)      /* return device size in bytes (u64 *arg) */
#define BLKTRACESETUP _IOWR(0x12,115,struct blk_user_trace_setup)
#define BLKTRACESTART _IO(0x12,116)
#define BLKTRACESTOP _IO(0x12,117)
#define BLKTRACETEARDOWN _IO(0x12,118)
#define BLKDISCARD _IO(0x12,119)
#define BLKIOMIN _IO(0x12,120)
#define BLKIOOPT _IO(0x12,121)
#define BLKALIGNOFF _IO(0x12,122)
#define BLKPBSZGET _IO(0x12,123)
#define BLKDISCARDZEROES _IO(0x12,124)
#define BLKSECDISCARD _IO(0x12,125)
#define BLKROTATIONAL _IO(0x12,126)
#define BLKZEROOUT _IO(0x12,127)
#define BLKGETDISKSEQ _IOR(0x12,128,__u64)
/*
 * A jump here: 130-136 are reserved for zoned block devices
 * (see uapi/linux/blkzoned.h)
 */

#define BMAP_IOCTL 1            /* obsolete - kept for compatibility */
#define FIBMAP     _IO(0x00,1)  /* bmap access */
#define FIGETBSZ   _IO(0x00,2)  /* get the block size used for bmap */
#define FIFREEZE        _IOWR('X', 119, int)    /* Freeze */
#define FITHAW          _IOWR('X', 120, int)    /* Thaw */
#define FITRIM          _IOWR('X', 121, struct fstrim_range)    /* Trim */
#define FICLONE         _IOW(0x94, 9, int)
#define FICLONERANGE    _IOW(0x94, 13, struct file_clone_range)
#define FIDEDUPERANGE   _IOWR(0x94, 54, struct file_dedupe_range)

#define FSLABEL_MAX 256 /* Max chars for the interface; each fs may differ */

#define FS_IOC_GETFLAGS                 _IOR('f', 1, long)
#define FS_IOC_SETFLAGS                 _IOW('f', 2, long)
#define FS_IOC_GETVERSION               _IOR('v', 1, long)
#define FS_IOC_SETVERSION               _IOW('v', 2, long)
#define FS_IOC_FIEMAP                   _IOWR('f', 11, struct fiemap)
#define FS_IOC32_GETFLAGS               _IOR('f', 1, int)
#define FS_IOC32_SETFLAGS               _IOW('f', 2, int)
#define FS_IOC32_GETVERSION             _IOR('v', 1, int)
#define FS_IOC32_SETVERSION             _IOW('v', 2, int)
#define FS_IOC_FSGETXATTR               _IOR('X', 31, struct fsxattr)
#define FS_IOC_FSSETXATTR               _IOW('X', 32, struct fsxattr)
#define FS_IOC_GETFSLABEL               _IOR(0x94, 49, char[FSLABEL_MAX])
#define FS_IOC_SETFSLABEL               _IOW(0x94, 50, char[FSLABEL_MAX])
/* Returns the external filesystem UUID, the same one blkid returns */
#define FS_IOC_GETFSUUID                _IOR(0x15, 0, struct fsuuid2)
/*
 * Returns the path component under /sys/fs/ that refers to this filesystem;
 * also /sys/kernel/debug/ for filesystems with debugfs exports
 */
#define FS_IOC_GETFSSYSFSPATH           _IOR(0x15, 1, struct fs_sysfs_path)

/*
 * Inode flags (FS_IOC_GETFLAGS / FS_IOC_SETFLAGS)
 *
 * Note: for historical reasons, these flags were originally used and
 * defined for use by ext2/ext3, and then other file systems started
 * using these flags so they wouldn't need to write their own version
 * of chattr/lsattr (which was shipped as part of e2fsprogs).  You
 * should think twice before trying to use these flags in new
 * contexts, or trying to assign these flags, since they are used both
 * as the UAPI and the on-disk encoding for ext2/3/4.  Also, we are
 * almost out of 32-bit flags.  :-)
 *
 * We have recently hoisted FS_IOC_FSGETXATTR / FS_IOC_FSSETXATTR from
 * XFS to the generic FS level interface.  This uses a structure that
 * has padding and hence has more room to grow, so it may be more
 * appropriate for many new use cases.
 *
 * Please do not change these flags or interfaces before checking with
 * linux-fsdevel@vger.kernel.org and linux-api@vger.kernel.org.
 */
#define FS_SECRM_FL                     0x00000001 /* Secure deletion */
#define FS_UNRM_FL                      0x00000002 /* Undelete */
#define FS_COMPR_FL                     0x00000004 /* Compress file */
#define FS_SYNC_FL                      0x00000008 /* Synchronous updates */
#define FS_IMMUTABLE_FL                 0x00000010 /* Immutable file */
#define FS_APPEND_FL                    0x00000020 /* writes to file may only append */
#define FS_NODUMP_FL                    0x00000040 /* do not dump file */
#define FS_NOATIME_FL                   0x00000080 /* do not update atime */
/* Reserved for compression usage... */
#define FS_DIRTY_FL                     0x00000100
#define FS_COMPRBLK_FL                  0x00000200 /* One or more compressed clusters */
#define FS_NOCOMP_FL                    0x00000400 /* Don't compress */
/* End compression flags --- maybe not all used */
#define FS_ENCRYPT_FL                   0x00000800 /* Encrypted file */
#define FS_BTREE_FL                     0x00001000 /* btree format dir */
#define FS_INDEX_FL                     0x00001000 /* hash-indexed directory */
#define FS_IMAGIC_FL                    0x00002000 /* AFS directory */
#define FS_JOURNAL_DATA_FL              0x00004000 /* Reserved for ext3 */
#define FS_NOTAIL_FL                    0x00008000 /* file tail should not be merged */
#define FS_DIRSYNC_FL                   0x00010000 /* dirsync behaviour (directories only) */
#define FS_TOPDIR_FL                    0x00020000 /* Top of directory hierarchies*/
#define FS_HUGE_FILE_FL                 0x00040000 /* Reserved for ext4 */
#define FS_EXTENT_FL                    0x00080000 /* Extents */
#define FS_VERITY_FL                    0x00100000 /* Verity protected inode */
#define FS_EA_INODE_FL                  0x00200000 /* Inode used for large EA */
#define FS_EOFBLOCKS_FL                 0x00400000 /* Reserved for ext4 */
#define FS_NOCOW_FL                     0x00800000 /* Do not cow file */
#define FS_DAX_FL                       0x02000000 /* Inode is DAX */
#define FS_INLINE_DATA_FL               0x10000000 /* Reserved for ext4 */
#define FS_PROJINHERIT_FL               0x20000000 /* Create with parents projid */
#define FS_CASEFOLD_FL                  0x40000000 /* Folder is case insensitive */
#define FS_RESERVED_FL                  0x80000000 /* reserved for ext2 lib */

#define FS_FL_USER_VISIBLE              0x0003DFFF /* User visible flags */
#define FS_FL_USER_MODIFIABLE           0x000380FF /* User modifiable flags */


#define SYNC_FILE_RANGE_WAIT_BEFORE     1
#define SYNC_FILE_RANGE_WRITE           2
#define SYNC_FILE_RANGE_WAIT_AFTER      4
#define SYNC_FILE_RANGE_WRITE_AND_WAIT  (SYNC_FILE_RANGE_WRITE | \
                                         SYNC_FILE_RANGE_WAIT_BEFORE | \
                                         SYNC_FILE_RANGE_WAIT_AFTER)

/*
 * Flags for preadv2/pwritev2:
 */

typedef int __bitwise __kernel_rwf_t;

/* high priority request, poll if possible */
#define RWF_HIPRI       ((__force __kernel_rwf_t)0x00000001)

/* per-IO O_DSYNC */
#define RWF_DSYNC       ((__force __kernel_rwf_t)0x00000002)

/* per-IO O_SYNC */
#define RWF_SYNC        ((__force __kernel_rwf_t)0x00000004)

/* per-IO, return -EAGAIN if operation would block */
#define RWF_NOWAIT      ((__force __kernel_rwf_t)0x00000008)

/* per-IO O_APPEND */
#define RWF_APPEND      ((__force __kernel_rwf_t)0x00000010)

/* per-IO negation of O_APPEND */
#define RWF_NOAPPEND    ((__force __kernel_rwf_t)0x00000020)

/* Atomic Write */
#define RWF_ATOMIC      ((__force __kernel_rwf_t)0x00000040)

/* buffered IO that drops the cache after reading or writing data */
#define RWF_DONTCACHE   ((__force __kernel_rwf_t)0x00000080)

/* mask of flags supported by the kernel */
#define RWF_SUPPORTED   (RWF_HIPRI | RWF_DSYNC | RWF_SYNC | RWF_NOWAIT |\
                         RWF_APPEND | RWF_NOAPPEND | RWF_ATOMIC |\
                         RWF_DONTCACHE)

#define PROCFS_IOCTL_MAGIC 'f'

/* Pagemap ioctl */
#define PAGEMAP_SCAN    _IOWR(PROCFS_IOCTL_MAGIC, 16, struct pm_scan_arg)

/* Bitmasks provided in pm_scan_args masks and reported in page_region.categories. */
#define PAGE_IS_WPALLOWED       (1 << 0)
#define PAGE_IS_WRITTEN         (1 << 1)
#define PAGE_IS_FILE            (1 << 2)
#define PAGE_IS_PRESENT         (1 << 3)
#define PAGE_IS_SWAPPED         (1 << 4)
#define PAGE_IS_PFNZERO         (1 << 5)
#define PAGE_IS_HUGE            (1 << 6)
#define PAGE_IS_SOFT_DIRTY      (1 << 7)

/*
 * struct page_region - Page region with flags
 * @start:      Start of the region
 * @end:        End of the region (exclusive)
 * @categories: PAGE_IS_* category bitmask for the region
 */
struct page_region {
        __u64 start;
        __u64 end;
        __u64 categories;
};

/* Flags for PAGEMAP_SCAN ioctl */
#define PM_SCAN_WP_MATCHING     (1 << 0)        /* Write protect the pages matched. */
#define PM_SCAN_CHECK_WPASYNC   (1 << 1)        /* Abort the scan when a non-WP-enabled page is found. */

/*
 * struct pm_scan_arg - Pagemap ioctl argument
 * @size:               Size of the structure
 * @flags:              Flags for the IOCTL
 * @start:              Starting address of the region
 * @end:                Ending address of the region
 * @walk_end            Address where the scan stopped (written by kernel).
 *                      walk_end == end (address tags cleared) informs that the scan completed on entire range.
 * @vec:                Address of page_region struct array for output
 * @vec_len:            Length of the page_region struct array
 * @max_pages:          Optional limit for number of returned pages (0 = disabled)
 * @category_inverted:  PAGE_IS_* categories which values match if 0 instead of 1
 * @category_mask:      Skip pages for which any category doesn't match
 * @category_anyof_mask: Skip pages for which no category matches
 * @return_mask:        PAGE_IS_* categories that are to be reported in `page_region`s returned
 */
struct pm_scan_arg {
        __u64 size;
        __u64 flags;
        __u64 start;
        __u64 end;
        __u64 walk_end;
        __u64 vec;
        __u64 vec_len;
        __u64 max_pages;
        __u64 category_inverted;
        __u64 category_mask;
        __u64 category_anyof_mask;
        __u64 return_mask;
};

/* /proc/<pid>/maps ioctl */
#define PROCMAP_QUERY   _IOWR(PROCFS_IOCTL_MAGIC, 17, struct procmap_query)

enum procmap_query_flags {
        /*
         * VMA permission flags.
         *
         * Can be used as part of procmap_query.query_flags field to look up
         * only VMAs satisfying specified subset of permissions. E.g., specifying
         * PROCMAP_QUERY_VMA_READABLE only will return both readable and read/write VMAs,
         * while having PROCMAP_QUERY_VMA_READABLE | PROCMAP_QUERY_VMA_WRITABLE will only
         * return read/write VMAs, though both executable/non-executable and
         * private/shared will be ignored.
         *
         * PROCMAP_QUERY_VMA_* flags are also returned in procmap_query.vma_flags
         * field to specify actual VMA permissions.
         */
        PROCMAP_QUERY_VMA_READABLE              = 0x01,
        PROCMAP_QUERY_VMA_WRITABLE              = 0x02,
        PROCMAP_QUERY_VMA_EXECUTABLE            = 0x04,
        PROCMAP_QUERY_VMA_SHARED                = 0x08,
        /*
         * Query modifier flags.
         *
         * By default VMA that covers provided address is returned, or -ENOENT
         * is returned. With PROCMAP_QUERY_COVERING_OR_NEXT_VMA flag set, closest
         * VMA with vma_start > addr will be returned if no covering VMA is
         * found.
         *
         * PROCMAP_QUERY_FILE_BACKED_VMA instructs query to consider only VMAs that
         * have file backing. Can be combined with PROCMAP_QUERY_COVERING_OR_NEXT_VMA
         * to iterate all VMAs with file backing.
         */
        PROCMAP_QUERY_COVERING_OR_NEXT_VMA      = 0x10,
        PROCMAP_QUERY_FILE_BACKED_VMA           = 0x20,
};

/*
 * Input/output argument structured passed into ioctl() call. It can be used
 * to query a set of VMAs (Virtual Memory Areas) of a process.
 *
 * Each field can be one of three kinds, marked in a short comment to the
 * right of the field:
 *   - "in", input argument, user has to provide this value, kernel doesn't modify it;
 *   - "out", output argument, kernel sets this field with VMA data;
 *   - "in/out", input and output argument; user provides initial value (used
 *     to specify maximum allowable buffer size), and kernel sets it to actual
 *     amount of data written (or zero, if there is no data).
 *
 * If matching VMA is found (according to criterias specified by
 * query_addr/query_flags, all the out fields are filled out, and ioctl()
 * returns 0. If there is no matching VMA, -ENOENT will be returned.
 * In case of any other error, negative error code other than -ENOENT is
 * returned.
 *
 * Most of the data is similar to the one returned as text in /proc/<pid>/maps
 * file, but procmap_query provides more querying flexibility. There are no
 * consistency guarantees between subsequent ioctl() calls, but data returned
 * for matched VMA is self-consistent.
 */
struct procmap_query {
        /* Query struct size, for backwards/forward compatibility */
        __u64 size;
        /*
         * Query flags, a combination of enum procmap_query_flags values.
         * Defines query filtering and behavior, see enum procmap_query_flags.
         *
         * Input argument, provided by user. Kernel doesn't modify it.
         */
        __u64 query_flags;              /* in */
        /*
         * Query address. By default, VMA that covers this address will
         * be looked up. PROCMAP_QUERY_* flags above modify this default
         * behavior further.
         *
         * Input argument, provided by user. Kernel doesn't modify it.
         */
        __u64 query_addr;               /* in */
        /* VMA starting (inclusive) and ending (exclusive) address, if VMA is found. */
        __u64 vma_start;                /* out */
        __u64 vma_end;                  /* out */
        /* VMA permissions flags. A combination of PROCMAP_QUERY_VMA_* flags. */
        __u64 vma_flags;                /* out */
        /* VMA backing page size granularity. */
        __u64 vma_page_size;            /* out */
        /*
         * VMA file offset. If VMA has file backing, this specifies offset
         * within the file that VMA's start address corresponds to.
         * Is set to zero if VMA has no backing file.
         */
        __u64 vma_offset;               /* out */
        /* Backing file's inode number, or zero, if VMA has no backing file. */
        __u64 inode;                    /* out */
        /* Backing file's device major/minor number, or zero, if VMA has no backing file. */
        __u32 dev_major;                /* out */
        __u32 dev_minor;                /* out */
        /*
         * If set to non-zero value, signals the request to return VMA name
         * (i.e., VMA's backing file's absolute path, with " (deleted)" suffix
         * appended, if file was unlinked from FS) for matched VMA. VMA name
         * can also be some special name (e.g., "[heap]", "[stack]") or could
         * be even user-supplied with prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME).
         *
         * Kernel will set this field to zero, if VMA has no associated name.
         * Otherwise kernel will return actual amount of bytes filled in
         * user-supplied buffer (see vma_name_addr field below), including the
         * terminating zero.
         *
         * If VMA name is longer that user-supplied maximum buffer size,
         * -E2BIG error is returned.
         *
         * If this field is set to non-zero value, vma_name_addr should point
         * to valid user space memory buffer of at least vma_name_size bytes.
         * If set to zero, vma_name_addr should be set to zero as well
         */
        __u32 vma_name_size;            /* in/out */
        /*
         * If set to non-zero value, signals the request to extract and return
         * VMA's backing file's build ID, if the backing file is an ELF file
         * and it contains embedded build ID.
         *
         * Kernel will set this field to zero, if VMA has no backing file,
         * backing file is not an ELF file, or ELF file has no build ID
         * embedded.
         *
         * Build ID is a binary value (not a string). Kernel will set
         * build_id_size field to exact number of bytes used for build ID.
         * If build ID is requested and present, but needs more bytes than
         * user-supplied maximum buffer size (see build_id_addr field below),
         * -E2BIG error will be returned.
         *
         * If this field is set to non-zero value, build_id_addr should point
         * to valid user space memory buffer of at least build_id_size bytes.
         * If set to zero, build_id_addr should be set to zero as well
         */
        __u32 build_id_size;            /* in/out */
        /*
         * User-supplied address of a buffer of at least vma_name_size bytes
         * for kernel to fill with matched VMA's name (see vma_name_size field
         * description above for details).
         *
         * Should be set to zero if VMA name should not be returned.
         */
        __u64 vma_name_addr;            /* in */
        /*
         * User-supplied address of a buffer of at least build_id_size bytes
         * for kernel to fill with matched VMA's ELF build ID, if available
         * (see build_id_size field description above for details).
         *
         * Should be set to zero if build ID should not be returned.
         */
        __u64 build_id_addr;            /* in */
};

#endif /* _UAPI_LINUX_FS_H */