From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3EED73876BA; Thu, 6 Aug 2026 05:24:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785993892; cv=none; b=IoWgVsDHGvTP5W/RnV28fUbqO7HSe6y7fvnPWxR1VfQNgO0+1osPTkfNVBRl/7XrKz9PT+0U5n9ECq3+TMgmXpssQxX3pjRykR7kX1Jf+zehPOh93EMQw0uxJQ4bZCFE+NrSvS6ZPbooNbHIvsBzqVqdDdSFYlf3AArwLj+kTFo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785993892; c=relaxed/simple; bh=m4AiYVxLzSTdKgPcsDUD7fNjqKESQ9EX1BmCuInblps=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kVv/l9MFHPZfGwdhlBwf00LmCzXjpC6n2iDn3UnLcaG9/3jh2RW8gVdkPBHTkBw5MplrUvFLb4F9nqthhAQguZxPlW1rI5R0VA2XZYH4M4A1kFPXiQ9ecTWXEZLjJBFpqA5csIdZoK1nPOZeGfQRCZwhCCY6OZ02+FlZG0RGJ24= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=g3WNmJkk; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="g3WNmJkk" Received: by smtp.kernel.org (Postfix) with UTF8SMTPSA id C71EB1F000E9; Thu, 6 Aug 2026 05:24:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785993889; bh=F1J+hDxLJ0+emdzvqZFW9KihFBAmAAYMZb4CYh8BOlQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=g3WNmJkk3P03I5fvLT4G3tACYxDVkynacZ8yby7PAQayuCBiEtsitD7EEy0iuOixW jmTYJilozVsqswkEFPNZ8wl5xFAHUKZoXlTOyXPQnMl1chG/ssHrD39P+SwkjpJWs4 gMAeiy3iQjxU8s/Tcxh02bnXbjUyQZMZ0DlVSxKhWWMw0e6QW5bmTTDvihhI7xOYWk JNfeJ9lhryWrmvGcPrnMtv5qex95yHApwArj+l4IH0ek5ynmOsmHorQxNRu26ckNDx RXOq2QaTtMuQgUHwu0Y+pboBus28AHBU4OEp47+1+s8sD92XPqw2kcsq8Grly4ULq3 ZxqzxTttdJY9Q== Date: Wed, 5 Aug 2026 22:24:49 -0700 From: "Darrick J. Wong" To: John Groves Cc: John Groves , Miklos Szeredi , Dan Williams , Bernd Schubert , Alison Schofield , John Groves , Jonathan Corbet , Jake Edge , Shuah Khan , Vishal Verma , Dave Jiang , Matthew Wilcox , Jan Kara , Alexander Viro , David Hildenbrand , Christian Brauner , Randy Dunlap , Jeff Layton , Amir Goldstein , Jonathan Cameron , Stefan Hajnoczi , Joanne Koong , Josef Bacik , Bagas Sanjaya , Chen Linxuan , James Morse , Fuad Tabba , Sean Christopherson , Shivank Garg , Ackerley Tng , Gregory Price , Andrew Morton , Namjae Jeon , Lorenzo Stoakes , Greg Kroah-Hartman , Ira Weiny , Pasha Tatashin , Haren Myneni , Pratyush Yadav , Giovanni Cabiddu , Jiri Slaby , Ethan Nelson-Moore , Gabriel Whigham , Aravind Ramesh , Ajay Joshi , "venkataravis@micron.com" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "nvdimm@lists.linux.dev" , "linux-cxl@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "fuse-devel@lists.linux.dev" Subject: Re: [PATCH V12 07/12] famfs: MAP_CREATE ioctl and fmap ingest (ABI 44) Message-ID: <20260806052449.GG3560084@frogsfrogsfrogs> References: <0100019fc572ca94-ec363dd7-3a77-484b-b4b7-f2503a0931a6-000000@email.amazonses.com> <20260803022919.75875-1-john@jagalactic.com> <0100019fc5746312-6cfe9a07-a658-4aba-b1e9-5233b0ddfcf4-000000@email.amazonses.com> Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0100019fc5746312-6cfe9a07-a658-4aba-b1e9-5233b0ddfcf4-000000@email.amazonses.com> On Mon, Aug 03, 2026 at 02:29:26AM +0000, John Groves wrote: > From: John Groves > > Add the famfs file ioctl handler (FAMFSIOC_NOP, FAMFSIOC_MAP_CREATE) and > the KABI-44 self-describing fmap message: the wire ABI in famfs_ioctl.h > (famfs_ioc_fmap_header plus the simple and interleaved extent structs), the > in-core famfs_file_meta, and famfs_file_init_dax(), which copies the > message in, parses both the simple-extent and interleaved (striped) wire > forms into inode->i_private, and sets S_DAX. > > Resolving those mappings to dax-device offsets (iomap_begin) is added in > the following commit; the read/write/fault paths keep their NULL iomap_ops > stub until then. > > Also add famfs ioctls to ioctl-number.rst > > Signed-off-by: John Groves > --- > .../userspace-api/ioctl/ioctl-number.rst | 1 + > fs/famfs/famfs_file.c | 326 +++++++++++++++++- > fs/famfs/famfs_inode.c | 1 + > fs/famfs/famfs_internal.h | 46 +++ > include/uapi/linux/famfs_ioctl.h | 91 +++++ > 5 files changed, 462 insertions(+), 3 deletions(-) > create mode 100644 include/uapi/linux/famfs_ioctl.h > > diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst > index 3f0ef1e27eb0..5e244dec1b98 100644 > --- a/Documentation/userspace-api/ioctl/ioctl-number.rst > +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst > @@ -299,6 +299,7 @@ Code Seq# Include File Comments > 'u' 00-2F linux/ublk_cmd.h conflict! > 'u' 20-3F linux/uvcvideo.h USB video class host driver > 'u' 40-4f linux/udmabuf.h userspace dma-buf misc device > +'u' 50-5F linux/famfs_ioctl.h famfs shared memory file system > 'v' 00-1F linux/ext2_fs.h conflict! > 'v' 00-1F linux/fs.h conflict! > 'v' 00-0F linux/sonypi.h conflict! > diff --git a/fs/famfs/famfs_file.c b/fs/famfs/famfs_file.c > index 678f2035fd5f..d710c8a0c923 100644 > --- a/fs/famfs/famfs_file.c > +++ b/fs/famfs/famfs_file.c > @@ -13,9 +13,313 @@ > #include > #include > #include > +#include > > +#include > #include "famfs_internal.h" > > +/* Expose famfs kernel abi version as a read-only module parameter */ > +static int famfs_kabi_version = FAMFS_KABI_VERSION; > +module_param(famfs_kabi_version, int, 0444); > +MODULE_PARM_DESC(famfs_kabi_version, "famfs kernel abi version"); Maybe make the "NOP" ioctl a geometry ioctl that tells you the abi version and (I guess) the page and pmd size? :D > +void > +famfs_meta_free(struct famfs_file_meta *map) > +{ > + if (map) { > + switch (map->fm_extent_type) { > + case FAMFS_IOC_EXT_SIMPLE: > + kfree(map->se); > + break; > + case FAMFS_IOC_EXT_INTERLEAVE: > + if (map->ie) { > + u32 i; > + > + for (i = 0; i < map->fm_niext; i++) > + kfree(map->ie[i].ie_strips); > + } > + kfree(map->ie); > + break; > + default: > + break; > + } > + } > + kfree(map); > +} > + > +/** > + * famfs_file_init_dax() - FAMFSIOC_MAP_CREATE ioctl handler > + * @file: the un-initialized file > + * @arg: user pointer to a self-describing fmap message > + * > + * The map-create ioctl carries the fmap as a self-describing message: a > + * struct famfs_ioc_fmap_header followed by an extent list. The message is > + * copied in, parsed into a famfs_file_meta, and published on inode->i_private. > + * Both the simple-extent and the interleaved (striped) wire forms are handled. > + * The wire layout byte-matches the fmap carried in a fuse famfs GET_FMAP reply. > + */ This kerneldoc is for the next function? > +static int > +famfs_check_ext_alignment(struct famfs_meta_simple_ext *se) > +{ > + int errs = 0; > + > + if (!IS_ALIGNED(se->ext_offset, PMD_SIZE)) > + errs++; > + if (!IS_ALIGNED(se->ext_len, PMD_SIZE)) > + errs++; Does this need to check the dax dev index is valid? Or is it ok to just fail an IO if that index is garbage? > + > + return errs; > +} > + > +static int > +famfs_file_init_dax(struct file *file, void __user *arg) > +{ > + struct famfs_ioc_fmap_header fmh; > + struct famfs_file_meta *meta = NULL; > + struct famfs_fs_info *fsi; > + struct super_block *sb; > + struct inode *inode; > + void *fmap_buf = NULL; > + size_t extent_total = 0; > + size_t next_offset; > + int errs = 0; > + int rc; > + u32 i, j; > + > + inode = file_inode(file); > + if (!inode) > + return -EBADF; > + if (inode->i_private) > + return -EEXIST; > + > + sb = inode->i_sb; > + fsi = sb->s_fs_info; > + if (fsi->deverror) > + return -ENODEV; > + if (!famfs_opt_enabled(fsi, FAMFS_OPT_MAP_CREATE)) > + return -EPERM; > + > + if (copy_from_user(&fmh, arg, sizeof(fmh))) > + return -EFAULT; > + > + if (fmh.fmap_version != FAMFS_FMAP_VERSION) > + return -EINVAL; > + if (fmh.fmap_size < sizeof(fmh)) > + return -EINVAL; > + if (fmh.fmap_size > FAMFS_FMAP_MSG_MAX) > + return -EFBIG; > + if (fmh.nextents < 1) > + return -EINVAL; > + > + fmap_buf = kvmalloc(fmh.fmap_size, GFP_KERNEL); > + if (!fmap_buf) > + return -ENOMEM; > + > + if (copy_from_user(fmap_buf, arg, fmh.fmap_size)) { > + rc = -EFAULT; > + goto out; > + } > + next_offset = sizeof(fmh); /* start of the extent list */ > + > + meta = kzalloc_obj(*meta, GFP_KERNEL); > + if (!meta) { > + rc = -ENOMEM; > + goto out; > + } > + > + meta->error = false; > + meta->file_type = fmh.file_type; > + meta->file_size = fmh.file_size; > + meta->fm_extent_type = fmh.ext_type; > + > + switch (fmh.ext_type) { > + case FAMFS_IOC_EXT_SIMPLE: { > + struct famfs_ioc_simple_ext *se_in = fmap_buf + next_offset; > + > + next_offset += (size_t)fmh.nextents * sizeof(*se_in); > + if (next_offset > fmh.fmap_size) { > + rc = -EINVAL; > + goto out; > + } > + > + meta->fm_nextents = fmh.nextents; > + meta->se = kcalloc(meta->fm_nextents, sizeof(*meta->se), > + GFP_KERNEL); > + if (!meta->se) { > + rc = -ENOMEM; > + goto out; > + } > + > + for (i = 0; i < fmh.nextents; i++) { > + meta->se[i].dev_index = se_in[i].se_devindex; > + meta->se[i].ext_offset = se_in[i].se_offset; > + meta->se[i].ext_len = se_in[i].se_len; > + > + if (meta->se[i].dev_index >= FAMFS_MAX_DAXDEVS) { > + rc = -EINVAL; > + goto out; > + } > + meta->dev_bitmap |= BIT_ULL(meta->se[i].dev_index); > + errs += famfs_check_ext_alignment(&meta->se[i]); > + extent_total += meta->se[i].ext_len; > + } > + break; > + } > + > + case FAMFS_IOC_EXT_INTERLEAVE: { > + s64 size_remainder = meta->file_size; > + u32 niext = fmh.nextents; > + > + meta->fm_niext = niext; > + meta->ie = kcalloc(niext, sizeof(*meta->ie), GFP_KERNEL); > + if (!meta->ie) { > + rc = -ENOMEM; > + goto out; > + } > + > + /* Outer loop is over the separate interleaved extents */ > + for (i = 0; i < niext; i++) { > + struct famfs_ioc_iext *ie_in = fmap_buf + next_offset; > + struct famfs_ioc_simple_ext *sie_in; > + u64 nstrips; > + > + next_offset += sizeof(*ie_in); > + if (next_offset > fmh.fmap_size) { > + rc = -EINVAL; > + goto out; > + } > + > + if (ie_in->ie_chunk_size == 0 || > + !IS_ALIGNED(ie_in->ie_chunk_size, PMD_SIZE)) { > + rc = -EINVAL; > + goto out; > + } > + if (ie_in->ie_nbytes == 0) { > + rc = -EINVAL; > + goto out; > + } > + > + nstrips = ie_in->ie_nstrips; > + if (nstrips < 1) { > + rc = -EINVAL; > + goto out; > + } > + > + meta->ie[i].fie_chunk_size = ie_in->ie_chunk_size; > + meta->ie[i].fie_nstrips = ie_in->ie_nstrips; > + meta->ie[i].fie_nbytes = ie_in->ie_nbytes; > + > + /* The strip extents follow the interleaved-ext header */ > + sie_in = fmap_buf + next_offset; > + next_offset += nstrips * sizeof(*sie_in); > + if (next_offset > fmh.fmap_size) { > + rc = -EINVAL; > + goto out; > + } > + > + meta->ie[i].ie_strips = > + kcalloc(nstrips, sizeof(meta->ie[i].ie_strips[0]), > + GFP_KERNEL); > + if (!meta->ie[i].ie_strips) { > + rc = -ENOMEM; > + goto out; > + } > + > + /* Inner loop is over the strips */ > + for (j = 0; j < nstrips; j++) { > + struct famfs_meta_simple_ext *so = > + &meta->ie[i].ie_strips[j]; > + > + so->dev_index = sie_in[j].se_devindex; > + so->ext_offset = sie_in[j].se_offset; > + so->ext_len = sie_in[j].se_len; > + > + if (so->dev_index >= FAMFS_MAX_DAXDEVS) { > + rc = -EINVAL; > + goto out; > + } > + meta->dev_bitmap |= BIT_ULL(so->dev_index); > + errs += famfs_check_ext_alignment(so); > + extent_total += so->ext_len; > + size_remainder -= so->ext_len; This is a lot of indenting, maybe each case should be a separate helper function? --D > + } > + } > + > + if (size_remainder > 0) { > + /* Strips do not cover the whole file */ > + rc = -EINVAL; > + goto out; > + } > + break; > + } > + > + default: > + rc = -EINVAL; > + goto out; > + } > + > + if (errs > 0) { > + rc = -EINVAL; > + goto out; > + } > + if (extent_total < meta->file_size) { > + rc = -EINVAL; > + goto out; > + } > + > + /* Publish the famfs metadata on inode->i_private */ > + inode_lock(inode); > + if (inode->i_private) { > + rc = -EEXIST; /* file already has famfs metadata */ > + } else { > + inode->i_private = meta; > + i_size_write(inode, meta->file_size); > + inode->i_flags |= S_DAX; > + meta = NULL; /* owned by the inode now */ > + rc = 0; > + } > + inode_unlock(inode); > + > +out: > + kvfree(fmap_buf); > + if (meta) > + famfs_meta_free(meta); > + return rc; > +} > + > +/** > + * famfs_file_ioctl() - Top-level famfs file ioctl handler > + * @file: the file > + * @cmd: ioctl opcode > + * @arg: ioctl opcode argument (if any) > + */ > +static long > +famfs_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg) > +{ > + struct inode *inode = file_inode(file); > + struct famfs_fs_info *fsi = inode->i_sb->s_fs_info; > + long rc; > + > + if (fsi->deverror && (cmd != FAMFSIOC_NOP)) > + return -ENODEV; > + > + switch (cmd) { > + case FAMFSIOC_NOP: > + rc = 0; > + break; > + > + case FAMFSIOC_MAP_CREATE: > + rc = famfs_file_init_dax(file, (void __user *)arg); > + break; > + > + default: > + rc = -ENOTTY; > + break; > + } > + > + return rc; > +} > + > /********************************************************************* > * vm_operations > */ > @@ -93,9 +397,25 @@ const struct vm_operations_struct famfs_file_vm_ops = { > static ssize_t > famfs_file_invalid(struct inode *inode) > { > + struct famfs_file_meta *meta = inode->i_private; > + size_t i_size = i_size_read(inode); > + > + if (!meta) { > + pr_debug("%s: un-initialized famfs file\n", __func__); > + return -EIO; > + } > + if (meta->error) { > + pr_debug("%s: previously detected metadata errors\n", __func__); > + return -EIO; > + } > + if (i_size != meta->file_size) { > + pr_warn("%s: i_size overwritten from %ld to %ld\n", > + __func__, meta->file_size, i_size); > + meta->error = true; > + return -ENXIO; > + } > if (!IS_DAX(inode)) { > - pr_debug("%s: inode %llx IS_DAX is false\n", > - __func__, (u64)inode); > + pr_debug("%s: inode %llx IS_DAX is false\n", __func__, (u64)inode); > return -ENXIO; > } > return 0; > @@ -222,7 +542,7 @@ const struct file_operations famfs_file_operations = { > /* Custom famfs operations */ > .write_iter = famfs_dax_write_iter, > .read_iter = famfs_dax_read_iter, > - .unlocked_ioctl = NULL /*famfs_file_ioctl*/, > + .unlocked_ioctl = famfs_file_ioctl, > .mmap = famfs_file_mmap, > > /* Force PMD alignment for mmap */ > diff --git a/fs/famfs/famfs_inode.c b/fs/famfs/famfs_inode.c > index 910a143dad30..a6c3b4574e69 100644 > --- a/fs/famfs/famfs_inode.c > +++ b/fs/famfs/famfs_inode.c > @@ -300,6 +300,7 @@ static int famfs_show_options(struct seq_file *m, struct dentry *root) > > static void famfs_evict_inode(struct inode *inode) > { > + famfs_meta_free((struct famfs_file_meta *)inode->i_private); > inode->i_private = NULL; > dax_break_layout_final(inode); > truncate_inode_pages_final(&inode->i_data); > diff --git a/fs/famfs/famfs_internal.h b/fs/famfs/famfs_internal.h > index 26f5abda96dc..b5f9c8d0349f 100644 > --- a/fs/famfs/famfs_internal.h > +++ b/fs/famfs/famfs_internal.h > @@ -15,8 +15,52 @@ > #include > #include > > +#include > + > extern const struct file_operations famfs_file_operations; > > +/* > + * Internal sanity bound on a FAMFSIOC_MAP_CREATE fmap message. The ABI does > + * not advertise a maximum (the message is self-describing); this only guards > + * the copy-in against an unreasonable allocation. Oversize is rejected with > + * -EFBIG. > + */ > +#define FAMFS_FMAP_MSG_MAX (4 * 1024 * 1024) > + > +struct famfs_meta_simple_ext { > + u64 dev_index; > + u64 ext_offset; > + u64 ext_len; > +}; > + > +struct famfs_meta_interleaved_ext { > + u64 fie_nstrips; > + u64 fie_chunk_size; > + u64 fie_nbytes; > + struct famfs_meta_simple_ext *ie_strips; > +}; > + > +/* > + * Each famfs dax file has this hanging from its inode->i_private. > + */ > +struct famfs_file_meta { > + bool error; > + enum famfs_file_type file_type; > + size_t file_size; > + enum famfs_ioc_ext_type fm_extent_type; > + u64 dev_bitmap; /* referenced daxdev indices */ > + union { /* This will make code a bit more readable */ > + struct { > + size_t fm_nextents; > + struct famfs_meta_simple_ext *se; > + }; > + struct { > + size_t fm_niext; > + struct famfs_meta_interleaved_ext *ie; > + }; > + }; > +}; > + > struct famfs_mount_opts { > umode_t mode; > }; > @@ -83,4 +127,6 @@ int famfs_devlist_alloc(struct famfs_fs_info *fsi); > int famfs_install_daxdev(struct famfs_fs_info *fsi, struct super_block *sb, > u64 index, dev_t devno, const char *name); > > +void famfs_meta_free(struct famfs_file_meta *map); > + > #endif /* FAMFS_INTERNAL_H */ > diff --git a/include/uapi/linux/famfs_ioctl.h b/include/uapi/linux/famfs_ioctl.h > new file mode 100644 > index 000000000000..b4eb373c1ade > --- /dev/null > +++ b/include/uapi/linux/famfs_ioctl.h > @@ -0,0 +1,91 @@ > +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ > +/* > + * famfs - dax file system for shared fabric-attached memory > + * > + * Copyright 2023-2024 Micron Technology, Inc. > + * > + * This file system, originally based on ramfs the dax support from xfs, > + * is intended to allow multiple host systems to mount a common file system > + * view of dax files that map to shared memory. > + */ > +#ifndef FAMFS_IOCTL_H > +#define FAMFS_IOCTL_H > + > +#include > +#include > + > +#define FAMFS_KABI_VERSION 44 > + > +enum famfs_file_type { > + FAMFS_REG, > + FAMFS_SUPERBLOCK, > + FAMFS_LOG, > +}; > + > +/* > + * Extent type in a famfs fmap message, and of the in-core map > + * (famfs_file_meta.fm_extent_type). > + */ > +enum famfs_ioc_ext_type { > + FAMFS_IOC_EXT_SIMPLE, > + FAMFS_IOC_EXT_INTERLEAVE, > +}; > + > +/* > + * The FAMFSIOC_MAP_CREATE payload is a self-describing fmap message: a > + * struct famfs_ioc_fmap_header immediately followed by @nextents extent > + * records. @fmap_size gives the total message length, so a reader is > + * self-delimiting. > + * > + * For ext_type == FAMFS_IOC_EXT_SIMPLE the records are an array of > + * @nextents famfs_ioc_simple_ext. For ext_type == FAMFS_IOC_EXT_INTERLEAVE > + * each of the @nextents records is a famfs_ioc_iext header immediately > + * followed by ie_nstrips famfs_ioc_simple_ext strip extents. > + * > + * This wire layout is byte-identical to the fmap carried in a fuse famfs > + * GET_FMAP reply, so the same userspace serializer emits both. > + * > + * The message is self-describing (@fmap_size bounds it), so neither the extent > + * and strip counts nor the total size are capped by this ABI. The kernel > + * applies an internal sanity limit to the copy-in and returns -EFBIG for a > + * message larger than it will accept. > + */ > +#define FAMFS_FMAP_VERSION 1 > + > +struct famfs_ioc_simple_ext { > + __u32 se_devindex; > + __u32 reserved; > + __u64 se_offset; > + __u64 se_len; > +}; > + > +struct famfs_ioc_iext { /* interleaved (striped) extent */ > + __u32 ie_nstrips; > + __u32 ie_chunk_size; > + __u64 ie_nbytes; /* total bytes mapped by this interleaved extent */ > + __u64 reserved; > +}; > + > +struct famfs_ioc_fmap_header { > + __u8 file_type; /* enum famfs_file_type */ > + __u8 reserved; > + __u16 fmap_version; /* FAMFS_FMAP_VERSION */ > + __u32 ext_type; /* enum famfs_ioc_ext_type */ > + __u32 nextents; > + __u32 fmap_size; /* total message bytes, including this header */ > + __u64 file_size; > + __u64 reserved1; > +}; > + > +#define FAMFSIOC_MAGIC 'u' > + > +/* famfs file ioctl opcodes */ > +#define FAMFSIOC_NOP _IO(FAMFSIOC_MAGIC, 0x50) > + > +/* > + * MAP_CREATE carries the self-describing fmap message - struct > + * famfs_ioc_fmap_header followed by the extent list (see above). > + */ > +#define FAMFSIOC_MAP_CREATE _IOW(FAMFSIOC_MAGIC, 0x51, struct famfs_ioc_fmap_header) > + > +#endif /* FAMFS_IOCTL_H */ > -- > 2.53.0 > > >