| Message ID | a5d0969403ca02af6593b6789a21b230b2436800.1708709155.git.john@groves.net (mailing list archive) |
|---|---|
| State | Handled Elsewhere, archived |
| Headers | show |
| Series | Introduce the famfs shared-memory file system | expand |
On Fri, 23 Feb 2024 11:41:59 -0600 John Groves <John@Groves.net> wrote: > This commit introduces the per-file ioctl function famfs_file_ioctl() > into struct file_operations, and introduces the famfs_file_init_dax() > function (which is called by famfs_file_ioct()) > > famfs_file_init_dax() associates a dax extent list with a file, making > it into a proper famfs file. It is called from the FAMFSIOC_MAP_CREATE > ioctl. Starting with an empty file (which is basically a ramfs file), > this turns the file into a DAX file backed by the specified extent list. > > The other ioctls are: > > FAMFSIOC_NOP - A convenient way for user space to verify it's a famfs file > FAMFSIOC_MAP_GET - Get the header of the metadata for a file > FAMFSIOC_MAP_GETEXT - Get the extents for a file > > The latter two, together, are comparable to xfs_bmap. Our user space tools > use them primarly in testing. > > Signed-off-by: John Groves <john@groves.net> A few more comments inline. Nothing fundamental just nice to have simplifications of the code. > --- > fs/famfs/famfs_file.c | 226 ++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 226 insertions(+) > > diff --git a/fs/famfs/famfs_file.c b/fs/famfs/famfs_file.c > index 5228e9de1e3b..fd42d5966982 100644 > --- a/fs/famfs/famfs_file.c > +++ b/fs/famfs/famfs_file.c > @@ -19,6 +19,231 @@ > #include <uapi/linux/famfs_ioctl.h> > #include "famfs_internal.h" > > +/** > + * famfs_map_meta_alloc() - Allocate famfs file metadata > + * @mapp: Pointer to an mcache_map_meta pointer > + * @ext_count: The number of extents needed > + */ > +static int > +famfs_meta_alloc( > + struct famfs_file_meta **metap, > + size_t ext_count) > +{ > + struct famfs_file_meta *meta; > + size_t metasz; > + > + *metap = NULL; Not responsibility of caller? > + > + metasz = sizeof(*meta) + sizeof(*(meta->tfs_extents)) * ext_count; Looks like struct_size() would be appropriate. > + > + meta = kzalloc(metasz, GFP_KERNEL); > + if (!meta) > + return -ENOMEM; > + > + meta->tfs_extent_ct = ext_count; > + *metap = meta; > + > + return 0; > +} > + > +static void > +famfs_meta_free( > + struct famfs_file_meta *map) > +{ > + kfree(map); Given this is just kfree you can use __free magic to simplify things below. > +} > + > +/** > + * famfs_file_init_dax() - FAMFSIOC_MAP_CREATE ioctl handler > + * @file: > + * @arg: ptr to struct mcioc_map in user space > + * > + * Setup the dax mapping for a file. Files are created empty, and then function is called > + * (by famfs_file_ioctl()) to setup the mapping and set the file size. > + */ > +static int > +famfs_file_init_dax( > + struct file *file, > + void __user *arg) > +{ > + struct famfs_extent *tfs_extents = NULL; > + struct famfs_file_meta *meta = NULL; > + struct inode *inode; > + struct famfs_ioc_map imap; > + struct famfs_fs_info *fsi; > + struct super_block *sb; > + int alignment_errs = 0; > + size_t extent_total = 0; > + size_t ext_count; > + int rc = 0; > + int i; > + > + rc = copy_from_user(&imap, arg, sizeof(imap)); > + if (rc) > + return -EFAULT; > + > + ext_count = imap.ext_list_count; > + if (ext_count < 1) { > + rc = -ENOSPC; > + goto errout; meta data not yet allocated. return -ENOSPC; > + } > + > + if (ext_count > FAMFS_MAX_EXTENTS) { > + rc = -E2BIG; > + goto errout; return > + } > + > + inode = file_inode(file); > + if (!inode) { > + rc = -EBADF; > + goto errout; return; > + } > + sb = inode->i_sb; > + fsi = inode->i_sb->s_fs_info; > + > + tfs_extents = &imap.ext_list[0]; > + > + rc = famfs_meta_alloc(&meta, ext_count); > + if (rc) > + goto errout; return ... only after this point should there be any meta data to free on exit? > + > + meta->file_type = imap.file_type; > + meta->file_size = imap.file_size; > + > + /* Fill in the internal file metadata structure */ > + for (i = 0; i < imap.ext_list_count; i++) { > + size_t len; > + off_t offset; > + > + offset = imap.ext_list[i].offset; > + len = imap.ext_list[i].len; > + > + extent_total += len; > + > + if (WARN_ON(offset == 0 && meta->file_type != FAMFS_SUPERBLOCK)) { > + rc = -EINVAL; > + goto errout; > + } > + > + meta->tfs_extents[i].offset = offset; > + meta->tfs_extents[i].len = len; > + > + /* All extent addresses/offsets must be 2MiB aligned, > + * and all but the last length must be a 2MiB multiple. > + */ > + if (!IS_ALIGNED(offset, PMD_SIZE)) { > + pr_err("%s: error ext %d hpa %lx not aligned\n", > + __func__, i, offset); > + alignment_errs++; > + } > + if (i < (imap.ext_list_count - 1) && !IS_ALIGNED(len, PMD_SIZE)) { > + pr_err("%s: error ext %d length %ld not aligned\n", > + __func__, i, len); > + alignment_errs++; > + } > + } > + > + /* > + * File size can be <= ext list size, since extent sizes are constrained > + * to PMD multiples > + */ > + if (imap.file_size > extent_total) { > + pr_err("%s: file size %lld larger than ext list size %lld\n", > + __func__, (u64)imap.file_size, (u64)extent_total); > + rc = -EINVAL; > + goto errout; > + } > + > + if (alignment_errs > 0) { > + pr_err("%s: there were %d alignment errors in the extent list\n", > + __func__, alignment_errs); > + rc = -EINVAL; > + goto errout; > + } > + > + /* Publish the famfs metadata on inode->i_private */ > + inode_lock(inode); Easy to add a guard definition - maybe useful enough to bother as can then do this which makes the error handling align with other cases. scoped_guard(inode_sem, inode) { if (inode->i_private) { rc = -EEXIST; goto errout; } inode->... } > + if (inode->i_private) { > + rc = -EEXIST; /* file already has famfs metadata */ > + } else { > + inode->i_private = meta; You could use __free on the meta data and inode->i_private = no_ptr_free(meta); here. Then all your earlier error paths become direct returns. > + i_size_write(inode, imap.file_size); > + inode->i_flags |= S_DAX; > + } > + inode_unlock(inode); > + > + errout: > + if (rc) > + famfs_meta_free(meta); A separate error path is going to be easier to follow as no if (rc) > + > + return rc; > +} > + > +/** > + * famfs_file_ioctl() - top-level famfs file ioctl handler > + * @file: > + * @cmd: > + * @arg: > + */ > +static > +long > +famfs_file_ioctl( > + struct file *file, > + unsigned int cmd, > + unsigned long arg) > +{ > + long rc; > + > + switch (cmd) { > + case FAMFSIOC_NOP: > + rc = 0; return 0; > + break; > + > + case FAMFSIOC_MAP_CREATE: > + rc = famfs_file_init_dax(file, (void *)arg); return famfs_file_init_dax() > + break; > + > + case FAMFSIOC_MAP_GET: { > + struct inode *inode = file_inode(file); > + struct famfs_file_meta *meta = inode->i_private; > + struct famfs_ioc_map umeta; > + > + memset(&umeta, 0, sizeof(umeta)); > + > + if (meta) { > + /* TODO: do more to harmonize these structures */ > + umeta.extent_type = meta->tfs_extent_type; > + umeta.file_size = i_size_read(inode); > + umeta.ext_list_count = meta->tfs_extent_ct; > + > + rc = copy_to_user((void __user *)arg, &umeta, sizeof(umeta)); > + if (rc) > + pr_err("%s: copy_to_user returned %ld\n", __func__, rc); > + > + } else { > + rc = -EINVAL; > + } Flip logic. if (!meta) return -EINVAL; umeta ... return 0; > + } > + break; > + case FAMFSIOC_MAP_GETEXT: { > + struct inode *inode = file_inode(file); > + struct famfs_file_meta *meta = inode->i_private; > + > + if (meta) > + rc = copy_to_user((void __user *)arg, meta->tfs_extents, > + meta->tfs_extent_ct * sizeof(struct famfs_extent)); > + else > + rc = -EINVAL; if (!meta) return -EINVAL; return copy_to_user > + } > + break; > + default: > + rc = -ENOTTY; return -ENOTTY; > + break; > + } > + > + return rc; Early returns will simplify the flow for anyone reading this. > +}
diff --git a/fs/famfs/famfs_file.c b/fs/famfs/famfs_file.c index 5228e9de1e3b..fd42d5966982 100644 --- a/fs/famfs/famfs_file.c +++ b/fs/famfs/famfs_file.c @@ -19,6 +19,231 @@ #include <uapi/linux/famfs_ioctl.h> #include "famfs_internal.h" +/** + * famfs_map_meta_alloc() - Allocate famfs file metadata + * @mapp: Pointer to an mcache_map_meta pointer + * @ext_count: The number of extents needed + */ +static int +famfs_meta_alloc( + struct famfs_file_meta **metap, + size_t ext_count) +{ + struct famfs_file_meta *meta; + size_t metasz; + + *metap = NULL; + + metasz = sizeof(*meta) + sizeof(*(meta->tfs_extents)) * ext_count; + + meta = kzalloc(metasz, GFP_KERNEL); + if (!meta) + return -ENOMEM; + + meta->tfs_extent_ct = ext_count; + *metap = meta; + + return 0; +} + +static void +famfs_meta_free( + struct famfs_file_meta *map) +{ + kfree(map); +} + +/** + * famfs_file_init_dax() - FAMFSIOC_MAP_CREATE ioctl handler + * @file: + * @arg: ptr to struct mcioc_map in user space + * + * Setup the dax mapping for a file. Files are created empty, and then function is called + * (by famfs_file_ioctl()) to setup the mapping and set the file size. + */ +static int +famfs_file_init_dax( + struct file *file, + void __user *arg) +{ + struct famfs_extent *tfs_extents = NULL; + struct famfs_file_meta *meta = NULL; + struct inode *inode; + struct famfs_ioc_map imap; + struct famfs_fs_info *fsi; + struct super_block *sb; + int alignment_errs = 0; + size_t extent_total = 0; + size_t ext_count; + int rc = 0; + int i; + + rc = copy_from_user(&imap, arg, sizeof(imap)); + if (rc) + return -EFAULT; + + ext_count = imap.ext_list_count; + if (ext_count < 1) { + rc = -ENOSPC; + goto errout; + } + + if (ext_count > FAMFS_MAX_EXTENTS) { + rc = -E2BIG; + goto errout; + } + + inode = file_inode(file); + if (!inode) { + rc = -EBADF; + goto errout; + } + sb = inode->i_sb; + fsi = inode->i_sb->s_fs_info; + + tfs_extents = &imap.ext_list[0]; + + rc = famfs_meta_alloc(&meta, ext_count); + if (rc) + goto errout; + + meta->file_type = imap.file_type; + meta->file_size = imap.file_size; + + /* Fill in the internal file metadata structure */ + for (i = 0; i < imap.ext_list_count; i++) { + size_t len; + off_t offset; + + offset = imap.ext_list[i].offset; + len = imap.ext_list[i].len; + + extent_total += len; + + if (WARN_ON(offset == 0 && meta->file_type != FAMFS_SUPERBLOCK)) { + rc = -EINVAL; + goto errout; + } + + meta->tfs_extents[i].offset = offset; + meta->tfs_extents[i].len = len; + + /* All extent addresses/offsets must be 2MiB aligned, + * and all but the last length must be a 2MiB multiple. + */ + if (!IS_ALIGNED(offset, PMD_SIZE)) { + pr_err("%s: error ext %d hpa %lx not aligned\n", + __func__, i, offset); + alignment_errs++; + } + if (i < (imap.ext_list_count - 1) && !IS_ALIGNED(len, PMD_SIZE)) { + pr_err("%s: error ext %d length %ld not aligned\n", + __func__, i, len); + alignment_errs++; + } + } + + /* + * File size can be <= ext list size, since extent sizes are constrained + * to PMD multiples + */ + if (imap.file_size > extent_total) { + pr_err("%s: file size %lld larger than ext list size %lld\n", + __func__, (u64)imap.file_size, (u64)extent_total); + rc = -EINVAL; + goto errout; + } + + if (alignment_errs > 0) { + pr_err("%s: there were %d alignment errors in the extent list\n", + __func__, alignment_errs); + rc = -EINVAL; + goto errout; + } + + /* 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, imap.file_size); + inode->i_flags |= S_DAX; + } + inode_unlock(inode); + + errout: + if (rc) + famfs_meta_free(meta); + + return rc; +} + +/** + * famfs_file_ioctl() - top-level famfs file ioctl handler + * @file: + * @cmd: + * @arg: + */ +static +long +famfs_file_ioctl( + struct file *file, + unsigned int cmd, + unsigned long arg) +{ + long rc; + + switch (cmd) { + case FAMFSIOC_NOP: + rc = 0; + break; + + case FAMFSIOC_MAP_CREATE: + rc = famfs_file_init_dax(file, (void *)arg); + break; + + case FAMFSIOC_MAP_GET: { + struct inode *inode = file_inode(file); + struct famfs_file_meta *meta = inode->i_private; + struct famfs_ioc_map umeta; + + memset(&umeta, 0, sizeof(umeta)); + + if (meta) { + /* TODO: do more to harmonize these structures */ + umeta.extent_type = meta->tfs_extent_type; + umeta.file_size = i_size_read(inode); + umeta.ext_list_count = meta->tfs_extent_ct; + + rc = copy_to_user((void __user *)arg, &umeta, sizeof(umeta)); + if (rc) + pr_err("%s: copy_to_user returned %ld\n", __func__, rc); + + } else { + rc = -EINVAL; + } + } + break; + case FAMFSIOC_MAP_GETEXT: { + struct inode *inode = file_inode(file); + struct famfs_file_meta *meta = inode->i_private; + + if (meta) + rc = copy_to_user((void __user *)arg, meta->tfs_extents, + meta->tfs_extent_ct * sizeof(struct famfs_extent)); + else + rc = -EINVAL; + } + break; + default: + rc = -ENOTTY; + break; + } + + return rc; +} + /********************************************************************* * file_operations */ @@ -143,6 +368,7 @@ const struct file_operations famfs_file_operations = { /* Custom famfs operations */ .write_iter = famfs_dax_write_iter, .read_iter = famfs_dax_read_iter, + .unlocked_ioctl = famfs_file_ioctl, .mmap = famfs_file_mmap, /* Force PMD alignment for mmap */
This commit introduces the per-file ioctl function famfs_file_ioctl() into struct file_operations, and introduces the famfs_file_init_dax() function (which is called by famfs_file_ioct()) famfs_file_init_dax() associates a dax extent list with a file, making it into a proper famfs file. It is called from the FAMFSIOC_MAP_CREATE ioctl. Starting with an empty file (which is basically a ramfs file), this turns the file into a DAX file backed by the specified extent list. The other ioctls are: FAMFSIOC_NOP - A convenient way for user space to verify it's a famfs file FAMFSIOC_MAP_GET - Get the header of the metadata for a file FAMFSIOC_MAP_GETEXT - Get the extents for a file The latter two, together, are comparable to xfs_bmap. Our user space tools use them primarly in testing. Signed-off-by: John Groves <john@groves.net> --- fs/famfs/famfs_file.c | 226 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 226 insertions(+)