diff options
Diffstat (limited to 'fs/libfs.c')
-rw-r--r-- | fs/libfs.c | 364 |
1 files changed, 311 insertions, 53 deletions
diff --git a/fs/libfs.c b/fs/libfs.c index 5b851315eeed..37f2d34ee090 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -33,7 +33,7 @@ int simple_getattr(struct mnt_idmap *idmap, const struct path *path, unsigned int query_flags) { struct inode *inode = d_inode(path->dentry); - generic_fillattr(&nop_mnt_idmap, inode, stat); + generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat); stat->blocks = inode->i_mapping->nrpages << (PAGE_SHIFT - 9); return 0; } @@ -239,6 +239,254 @@ const struct inode_operations simple_dir_inode_operations = { }; EXPORT_SYMBOL(simple_dir_inode_operations); +static void offset_set(struct dentry *dentry, u32 offset) +{ + dentry->d_fsdata = (void *)((uintptr_t)(offset)); +} + +static u32 dentry2offset(struct dentry *dentry) +{ + return (u32)((uintptr_t)(dentry->d_fsdata)); +} + +static struct lock_class_key simple_offset_xa_lock; + +/** + * simple_offset_init - initialize an offset_ctx + * @octx: directory offset map to be initialized + * + */ +void simple_offset_init(struct offset_ctx *octx) +{ + xa_init_flags(&octx->xa, XA_FLAGS_ALLOC1); + lockdep_set_class(&octx->xa.xa_lock, &simple_offset_xa_lock); + + /* 0 is '.', 1 is '..', so always start with offset 2 */ + octx->next_offset = 2; +} + +/** + * simple_offset_add - Add an entry to a directory's offset map + * @octx: directory offset ctx to be updated + * @dentry: new dentry being added + * + * Returns zero on success. @so_ctx and the dentry offset are updated. + * Otherwise, a negative errno value is returned. + */ +int simple_offset_add(struct offset_ctx *octx, struct dentry *dentry) +{ + static const struct xa_limit limit = XA_LIMIT(2, U32_MAX); + u32 offset; + int ret; + + if (dentry2offset(dentry) != 0) + return -EBUSY; + + ret = xa_alloc_cyclic(&octx->xa, &offset, dentry, limit, + &octx->next_offset, GFP_KERNEL); + if (ret < 0) + return ret; + + offset_set(dentry, offset); + return 0; +} + +/** + * simple_offset_remove - Remove an entry to a directory's offset map + * @octx: directory offset ctx to be updated + * @dentry: dentry being removed + * + */ +void simple_offset_remove(struct offset_ctx *octx, struct dentry *dentry) +{ + u32 offset; + + offset = dentry2offset(dentry); + if (offset == 0) + return; + + xa_erase(&octx->xa, offset); + offset_set(dentry, 0); +} + +/** + * simple_offset_rename_exchange - exchange rename with directory offsets + * @old_dir: parent of dentry being moved + * @old_dentry: dentry being moved + * @new_dir: destination parent + * @new_dentry: destination dentry + * + * Returns zero on success. Otherwise a negative errno is returned and the + * rename is rolled back. + */ +int simple_offset_rename_exchange(struct inode *old_dir, + struct dentry *old_dentry, + struct inode *new_dir, + struct dentry *new_dentry) +{ + struct offset_ctx *old_ctx = old_dir->i_op->get_offset_ctx(old_dir); + struct offset_ctx *new_ctx = new_dir->i_op->get_offset_ctx(new_dir); + u32 old_index = dentry2offset(old_dentry); + u32 new_index = dentry2offset(new_dentry); + int ret; + + simple_offset_remove(old_ctx, old_dentry); + simple_offset_remove(new_ctx, new_dentry); + + ret = simple_offset_add(new_ctx, old_dentry); + if (ret) + goto out_restore; + + ret = simple_offset_add(old_ctx, new_dentry); + if (ret) { + simple_offset_remove(new_ctx, old_dentry); + goto out_restore; + } + + ret = simple_rename_exchange(old_dir, old_dentry, new_dir, new_dentry); + if (ret) { + simple_offset_remove(new_ctx, old_dentry); + simple_offset_remove(old_ctx, new_dentry); + goto out_restore; + } + return 0; + +out_restore: + offset_set(old_dentry, old_index); + xa_store(&old_ctx->xa, old_index, old_dentry, GFP_KERNEL); + offset_set(new_dentry, new_index); + xa_store(&new_ctx->xa, new_index, new_dentry, GFP_KERNEL); + return ret; +} + +/** + * simple_offset_destroy - Release offset map + * @octx: directory offset ctx that is about to be destroyed + * + * During fs teardown (eg. umount), a directory's offset map might still + * contain entries. xa_destroy() cleans out anything that remains. + */ +void simple_offset_destroy(struct offset_ctx *octx) +{ + xa_destroy(&octx->xa); +} + +/** + * offset_dir_llseek - Advance the read position of a directory descriptor + * @file: an open directory whose position is to be updated + * @offset: a byte offset + * @whence: enumerator describing the starting position for this update + * + * SEEK_END, SEEK_DATA, and SEEK_HOLE are not supported for directories. + * + * Returns the updated read position if successful; otherwise a + * negative errno is returned and the read position remains unchanged. + */ +static loff_t offset_dir_llseek(struct file *file, loff_t offset, int whence) +{ + switch (whence) { + case SEEK_CUR: + offset += file->f_pos; + fallthrough; + case SEEK_SET: + if (offset >= 0) + break; + fallthrough; + default: + return -EINVAL; + } + + return vfs_setpos(file, offset, U32_MAX); +} + +static struct dentry *offset_find_next(struct xa_state *xas) +{ + struct dentry *child, *found = NULL; + + rcu_read_lock(); + child = xas_next_entry(xas, U32_MAX); + if (!child) + goto out; + spin_lock(&child->d_lock); + if (simple_positive(child)) + found = dget_dlock(child); + spin_unlock(&child->d_lock); +out: + rcu_read_unlock(); + return found; +} + +static bool offset_dir_emit(struct dir_context *ctx, struct dentry *dentry) +{ + u32 offset = dentry2offset(dentry); + struct inode *inode = d_inode(dentry); + + return ctx->actor(ctx, dentry->d_name.name, dentry->d_name.len, offset, + inode->i_ino, fs_umode_to_dtype(inode->i_mode)); +} + +static void offset_iterate_dir(struct inode *inode, struct dir_context *ctx) +{ + struct offset_ctx *so_ctx = inode->i_op->get_offset_ctx(inode); + XA_STATE(xas, &so_ctx->xa, ctx->pos); + struct dentry *dentry; + + while (true) { + dentry = offset_find_next(&xas); + if (!dentry) + break; + + if (!offset_dir_emit(ctx, dentry)) { + dput(dentry); + break; + } + + dput(dentry); + ctx->pos = xas.xa_index + 1; + } +} + +/** + * offset_readdir - Emit entries starting at offset @ctx->pos + * @file: an open directory to iterate over + * @ctx: directory iteration context + * + * Caller must hold @file's i_rwsem to prevent insertion or removal of + * entries during this call. + * + * On entry, @ctx->pos contains an offset that represents the first entry + * to be read from the directory. + * + * The operation continues until there are no more entries to read, or + * until the ctx->actor indicates there is no more space in the caller's + * output buffer. + * + * On return, @ctx->pos contains an offset that will read the next entry + * in this directory when offset_readdir() is called again with @ctx. + * + * Return values: + * %0 - Complete + */ +static int offset_readdir(struct file *file, struct dir_context *ctx) +{ + struct dentry *dir = file->f_path.dentry; + + lockdep_assert_held(&d_inode(dir)->i_rwsem); + + if (!dir_emit_dots(file, ctx)) + return 0; + + offset_iterate_dir(d_inode(dir), ctx); + return 0; +} + +const struct file_operations simple_offset_dir_operations = { + .llseek = offset_dir_llseek, + .iterate_shared = offset_readdir, + .read = generic_read_dir, + .fsync = noop_fsync, +}; + static struct dentry *find_next_child(struct dentry *parent, struct dentry *prev) { struct dentry *child = NULL; @@ -275,7 +523,7 @@ void simple_recursive_removal(struct dentry *dentry, while ((child = find_next_child(this, victim)) == NULL) { // kill and ascend // update metadata while it's still locked - inode->i_ctime = current_time(inode); + inode_set_ctime_current(inode); clear_nlink(inode); inode_unlock(inode); victim = this; @@ -293,8 +541,7 @@ void simple_recursive_removal(struct dentry *dentry, dput(victim); // unpin it } if (victim == dentry) { - inode->i_ctime = inode->i_mtime = - current_time(inode); + inode->i_mtime = inode_set_ctime_current(inode); if (d_is_dir(dentry)) drop_nlink(inode); inode_unlock(inode); @@ -335,7 +582,7 @@ static int pseudo_fs_fill_super(struct super_block *s, struct fs_context *fc) */ root->i_ino = 1; root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; - root->i_atime = root->i_mtime = root->i_ctime = current_time(root); + root->i_atime = root->i_mtime = inode_set_ctime_current(root); s->s_root = d_make_root(root); if (!s->s_root) return -ENOMEM; @@ -391,7 +638,8 @@ int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *den { struct inode *inode = d_inode(old_dentry); - inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode); + dir->i_mtime = inode_set_ctime_to_ts(dir, + inode_set_ctime_current(inode)); inc_nlink(inode); ihold(inode); dget(dentry); @@ -425,7 +673,8 @@ int simple_unlink(struct inode *dir, struct dentry *dentry) { struct inode *inode = d_inode(dentry); - inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode); + dir->i_mtime = inode_set_ctime_to_ts(dir, + inode_set_ctime_current(inode)); drop_nlink(inode); dput(dentry); return 0; @@ -444,6 +693,31 @@ int simple_rmdir(struct inode *dir, struct dentry *dentry) } EXPORT_SYMBOL(simple_rmdir); +/** + * simple_rename_timestamp - update the various inode timestamps for rename + * @old_dir: old parent directory + * @old_dentry: dentry that is being renamed + * @new_dir: new parent directory + * @new_dentry: target for rename + * + * POSIX mandates that the old and new parent directories have their ctime and + * mtime updated, and that inodes of @old_dentry and @new_dentry (if any), have + * their ctime updated. + */ +void simple_rename_timestamp(struct inode *old_dir, struct dentry *old_dentry, + struct inode *new_dir, struct dentry *new_dentry) +{ + struct inode *newino = d_inode(new_dentry); + + old_dir->i_mtime = inode_set_ctime_current(old_dir); + if (new_dir != old_dir) + new_dir->i_mtime = inode_set_ctime_current(new_dir); + inode_set_ctime_current(d_inode(old_dentry)); + if (newino) + inode_set_ctime_current(newino); +} +EXPORT_SYMBOL_GPL(simple_rename_timestamp); + int simple_rename_exchange(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) { @@ -459,11 +733,7 @@ int simple_rename_exchange(struct inode *old_dir, struct dentry *old_dentry, inc_nlink(old_dir); } } - old_dir->i_ctime = old_dir->i_mtime = - new_dir->i_ctime = new_dir->i_mtime = - d_inode(old_dentry)->i_ctime = - d_inode(new_dentry)->i_ctime = current_time(old_dir); - + simple_rename_timestamp(old_dir, old_dentry, new_dir, new_dentry); return 0; } EXPORT_SYMBOL_GPL(simple_rename_exchange); @@ -472,7 +742,6 @@ int simple_rename(struct mnt_idmap *idmap, struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry, unsigned int flags) { - struct inode *inode = d_inode(old_dentry); int they_are_dirs = d_is_dir(old_dentry); if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) @@ -495,9 +764,7 @@ int simple_rename(struct mnt_idmap *idmap, struct inode *old_dir, inc_nlink(new_dir); } - old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = - new_dir->i_mtime = inode->i_ctime = current_time(old_dir); - + simple_rename_timestamp(old_dir, old_dentry, new_dir, new_dentry); return 0; } EXPORT_SYMBOL(simple_rename); @@ -548,21 +815,20 @@ int simple_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, struct page **pagep, void **fsdata) { - struct page *page; - pgoff_t index; - - index = pos >> PAGE_SHIFT; + struct folio *folio; - page = grab_cache_page_write_begin(mapping, index); - if (!page) - return -ENOMEM; + folio = __filemap_get_folio(mapping, pos / PAGE_SIZE, FGP_WRITEBEGIN, + mapping_gfp_mask(mapping)); + if (IS_ERR(folio)) + return PTR_ERR(folio); - *pagep = page; + *pagep = &folio->page; - if (!PageUptodate(page) && (len != PAGE_SIZE)) { - unsigned from = pos & (PAGE_SIZE - 1); + if (!folio_test_uptodate(folio) && (len != folio_size(folio))) { + size_t from = offset_in_folio(folio, pos); - zero_user_segments(page, 0, from, from + len, PAGE_SIZE); + folio_zero_segments(folio, 0, from, + from + len, folio_size(folio)); } return 0; } @@ -594,17 +860,18 @@ static int simple_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { - struct inode *inode = page->mapping->host; + struct folio *folio = page_folio(page); + struct inode *inode = folio->mapping->host; loff_t last_pos = pos + copied; - /* zero the stale part of the page if we did a short copy */ - if (!PageUptodate(page)) { + /* zero the stale part of the folio if we did a short copy */ + if (!folio_test_uptodate(folio)) { if (copied < len) { - unsigned from = pos & (PAGE_SIZE - 1); + size_t from = offset_in_folio(folio, pos); - zero_user(page, from + copied, len - copied); + folio_zero_range(folio, from + copied, len - copied); } - SetPageUptodate(page); + folio_mark_uptodate(folio); } /* * No need to use i_size_read() here, the i_size @@ -613,9 +880,9 @@ static int simple_write_end(struct file *file, struct address_space *mapping, if (last_pos > inode->i_size) i_size_write(inode, last_pos); - set_page_dirty(page); - unlock_page(page); - put_page(page); + folio_mark_dirty(folio); + folio_unlock(folio); + folio_put(folio); return copied; } @@ -659,7 +926,7 @@ int simple_fill_super(struct super_block *s, unsigned long magic, */ inode->i_ino = 1; inode->i_mode = S_IFDIR | 0755; - inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); + inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode); inode->i_op = &simple_dir_inode_operations; inode->i_fop = &simple_dir_operations; set_nlink(inode, 2); @@ -685,7 +952,7 @@ int simple_fill_super(struct super_block *s, unsigned long magic, goto out; } inode->i_mode = S_IFREG | files->mode; - inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); + inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode); inode->i_fop = files->ops; inode->i_ino = i; d_add(dentry, inode); @@ -1253,7 +1520,7 @@ struct inode *alloc_anon_inode(struct super_block *s) inode->i_uid = current_fsuid(); inode->i_gid = current_fsgid(); inode->i_flags |= S_PRIVATE; - inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); + inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode); return inode; } EXPORT_SYMBOL(alloc_anon_inode); @@ -1269,7 +1536,7 @@ EXPORT_SYMBOL(alloc_anon_inode); * All arguments are ignored and it just returns -EINVAL. */ int -simple_nosetlease(struct file *filp, long arg, struct file_lock **flp, +simple_nosetlease(struct file *filp, int arg, struct file_lock **flp, void **priv) { return -EINVAL; @@ -1315,7 +1582,7 @@ static int empty_dir_getattr(struct mnt_idmap *idmap, u32 request_mask, unsigned int query_flags) { struct inode *inode = d_inode(path->dentry); - generic_fillattr(&nop_mnt_idmap, inode, stat); + generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat); return 0; } @@ -1381,16 +1648,6 @@ bool is_empty_dir_inode(struct inode *inode) } #if IS_ENABLED(CONFIG_UNICODE) -/* - * Determine if the name of a dentry should be casefolded. - * - * Return: if names will need casefolding - */ -static bool needs_casefold(const struct inode *dir) -{ - return IS_CASEFOLDED(dir) && dir->i_sb->s_encoding; -} - /** * generic_ci_d_compare - generic d_compare implementation for casefolding filesystems * @dentry: dentry whose name we are checking against @@ -1411,7 +1668,7 @@ static int generic_ci_d_compare(const struct dentry *dentry, unsigned int len, char strbuf[DNAME_INLINE_LEN]; int ret; - if (!dir || !needs_casefold(dir)) + if (!dir || !IS_CASEFOLDED(dir)) goto fallback; /* * If the dentry name is stored in-line, then it may be concurrently @@ -1453,7 +1710,7 @@ static int generic_ci_d_hash(const struct dentry *dentry, struct qstr *str) const struct unicode_map *um = sb->s_encoding; int ret = 0; - if (!dir || !needs_casefold(dir)) + if (!dir || !IS_CASEFOLDED(dir)) return 0; ret = utf8_casefold_hash(um, dentry, str); @@ -1646,6 +1903,7 @@ ssize_t direct_write_fallback(struct kiocb *iocb, struct iov_iter *iter, * We don't know how much we wrote, so just return the number of * bytes which were direct-written */ + iocb->ki_pos -= buffered_written; if (direct_written) return direct_written; return err; |