diff options
Diffstat (limited to 'kernel/fs/logfs/readwrite.c')
| -rw-r--r-- | kernel/fs/logfs/readwrite.c | 2298 |
1 files changed, 2298 insertions, 0 deletions
diff --git a/kernel/fs/logfs/readwrite.c b/kernel/fs/logfs/readwrite.c new file mode 100644 index 000000000..380d86e1a --- /dev/null +++ b/kernel/fs/logfs/readwrite.c @@ -0,0 +1,2298 @@ +/* + * fs/logfs/readwrite.c + * + * As should be obvious for Linux kernel code, license is GPLv2 + * + * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org> + * + * + * Actually contains five sets of very similar functions: + * read read blocks from a file + * seek_hole find next hole + * seek_data find next data block + * valid check whether a block still belongs to a file + * write write blocks to a file + * delete delete a block (for directories and ifile) + * rewrite move existing blocks of a file to a new location (gc helper) + * truncate truncate a file + */ +#include "logfs.h" +#include <linux/sched.h> +#include <linux/slab.h> + +static u64 adjust_bix(u64 bix, level_t level) +{ + switch (level) { + case 0: + return bix; + case LEVEL(1): + return max_t(u64, bix, I0_BLOCKS); + case LEVEL(2): + return max_t(u64, bix, I1_BLOCKS); + case LEVEL(3): + return max_t(u64, bix, I2_BLOCKS); + case LEVEL(4): + return max_t(u64, bix, I3_BLOCKS); + case LEVEL(5): + return max_t(u64, bix, I4_BLOCKS); + default: + WARN_ON(1); + return bix; + } +} + +static inline u64 maxbix(u8 height) +{ + return 1ULL << (LOGFS_BLOCK_BITS * height); +} + +/** + * The inode address space is cut in two halves. Lower half belongs to data + * pages, upper half to indirect blocks. If the high bit (INDIRECT_BIT) is + * set, the actual block index (bix) and level can be derived from the page + * index. + * + * The lowest three bits of the block index are set to 0 after packing and + * unpacking. Since the lowest n bits (9 for 4KiB blocksize) are ignored + * anyway this is harmless. + */ +#define ARCH_SHIFT (BITS_PER_LONG - 32) +#define INDIRECT_BIT (0x80000000UL << ARCH_SHIFT) +#define LEVEL_SHIFT (28 + ARCH_SHIFT) +static inline pgoff_t first_indirect_block(void) +{ + return INDIRECT_BIT | (1ULL << LEVEL_SHIFT); +} + +pgoff_t logfs_pack_index(u64 bix, level_t level) +{ + pgoff_t index; + + BUG_ON(bix >= INDIRECT_BIT); + if (level == 0) + return bix; + + index = INDIRECT_BIT; + index |= (__force long)level << LEVEL_SHIFT; + index |= bix >> ((__force u8)level * LOGFS_BLOCK_BITS); + return index; +} + +void logfs_unpack_index(pgoff_t index, u64 *bix, level_t *level) +{ + u8 __level; + + if (!(index & INDIRECT_BIT)) { + *bix = index; + *level = 0; + return; + } + + __level = (index & ~INDIRECT_BIT) >> LEVEL_SHIFT; + *level = LEVEL(__level); + *bix = (index << (__level * LOGFS_BLOCK_BITS)) & ~INDIRECT_BIT; + *bix = adjust_bix(*bix, *level); + return; +} +#undef ARCH_SHIFT +#undef INDIRECT_BIT +#undef LEVEL_SHIFT + +/* + * Time is stored as nanoseconds since the epoch. + */ +static struct timespec be64_to_timespec(__be64 betime) +{ + return ns_to_timespec(be64_to_cpu(betime)); +} + +static __be64 timespec_to_be64(struct timespec tsp) +{ + return cpu_to_be64((u64)tsp.tv_sec * NSEC_PER_SEC + tsp.tv_nsec); +} + +static void logfs_disk_to_inode(struct logfs_disk_inode *di, struct inode*inode) +{ + struct logfs_inode *li = logfs_inode(inode); + int i; + + inode->i_mode = be16_to_cpu(di->di_mode); + li->li_height = di->di_height; + li->li_flags = be32_to_cpu(di->di_flags); + i_uid_write(inode, be32_to_cpu(di->di_uid)); + i_gid_write(inode, be32_to_cpu(di->di_gid)); + inode->i_size = be64_to_cpu(di->di_size); + logfs_set_blocks(inode, be64_to_cpu(di->di_used_bytes)); + inode->i_atime = be64_to_timespec(di->di_atime); + inode->i_ctime = be64_to_timespec(di->di_ctime); + inode->i_mtime = be64_to_timespec(di->di_mtime); + set_nlink(inode, be32_to_cpu(di->di_refcount)); + inode->i_generation = be32_to_cpu(di->di_generation); + + switch (inode->i_mode & S_IFMT) { + case S_IFSOCK: /* fall through */ + case S_IFBLK: /* fall through */ + case S_IFCHR: /* fall through */ + case S_IFIFO: + inode->i_rdev = be64_to_cpu(di->di_data[0]); + break; + case S_IFDIR: /* fall through */ + case S_IFREG: /* fall through */ + case S_IFLNK: + for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++) + li->li_data[i] = be64_to_cpu(di->di_data[i]); + break; + default: + BUG(); + } +} + +static void logfs_inode_to_disk(struct inode *inode, struct logfs_disk_inode*di) +{ + struct logfs_inode *li = logfs_inode(inode); + int i; + + di->di_mode = cpu_to_be16(inode->i_mode); + di->di_height = li->li_height; + di->di_pad = 0; + di->di_flags = cpu_to_be32(li->li_flags); + di->di_uid = cpu_to_be32(i_uid_read(inode)); + di->di_gid = cpu_to_be32(i_gid_read(inode)); + di->di_size = cpu_to_be64(i_size_read(inode)); + di->di_used_bytes = cpu_to_be64(li->li_used_bytes); + di->di_atime = timespec_to_be64(inode->i_atime); + di->di_ctime = timespec_to_be64(inode->i_ctime); + di->di_mtime = timespec_to_be64(inode->i_mtime); + di->di_refcount = cpu_to_be32(inode->i_nlink); + di->di_generation = cpu_to_be32(inode->i_generation); + + switch (inode->i_mode & S_IFMT) { + case S_IFSOCK: /* fall through */ + case S_IFBLK: /* fall through */ + case S_IFCHR: /* fall through */ + case S_IFIFO: + di->di_data[0] = cpu_to_be64(inode->i_rdev); + break; + case S_IFDIR: /* fall through */ + case S_IFREG: /* fall through */ + case S_IFLNK: + for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++) + di->di_data[i] = cpu_to_be64(li->li_data[i]); + break; + default: + BUG(); + } +} + +static void __logfs_set_blocks(struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + struct logfs_inode *li = logfs_inode(inode); + + inode->i_blocks = ULONG_MAX; + if (li->li_used_bytes >> sb->s_blocksize_bits < ULONG_MAX) + inode->i_blocks = ALIGN(li->li_used_bytes, 512) >> 9; +} + +void logfs_set_blocks(struct inode *inode, u64 bytes) +{ + struct logfs_inode *li = logfs_inode(inode); + + li->li_used_bytes = bytes; + __logfs_set_blocks(inode); +} + +static void prelock_page(struct super_block *sb, struct page *page, int lock) +{ + struct logfs_super *super = logfs_super(sb); + + BUG_ON(!PageLocked(page)); + if (lock) { + BUG_ON(PagePreLocked(page)); + SetPagePreLocked(page); + } else { + /* We are in GC path. */ + if (PagePreLocked(page)) + super->s_lock_count++; + else + SetPagePreLocked(page); + } +} + +static void preunlock_page(struct super_block *sb, struct page *page, int lock) +{ + struct logfs_super *super = logfs_super(sb); + + BUG_ON(!PageLocked(page)); + if (lock) + ClearPagePreLocked(page); + else { + /* We are in GC path. */ + BUG_ON(!PagePreLocked(page)); + if (super->s_lock_count) + super->s_lock_count--; + else + ClearPagePreLocked(page); + } +} + +/* + * Logfs is prone to an AB-BA deadlock where one task tries to acquire + * s_write_mutex with a locked page and GC tries to get that page while holding + * s_write_mutex. + * To solve this issue logfs will ignore the page lock iff the page in question + * is waiting for s_write_mutex. We annotate this fact by setting PG_pre_locked + * in addition to PG_locked. + */ +void logfs_get_wblocks(struct super_block *sb, struct page *page, int lock) +{ + struct logfs_super *super = logfs_super(sb); + + if (page) + prelock_page(sb, page, lock); + + if (lock) { + mutex_lock(&super->s_write_mutex); + logfs_gc_pass(sb); + /* FIXME: We also have to check for shadowed space + * and mempool fill grade */ + } +} + +void logfs_put_wblocks(struct super_block *sb, struct page *page, int lock) +{ + struct logfs_super *super = logfs_super(sb); + + if (page) + preunlock_page(sb, page, lock); + /* Order matters - we must clear PG_pre_locked before releasing + * s_write_mutex or we could race against another task. */ + if (lock) + mutex_unlock(&super->s_write_mutex); +} + +static struct page *logfs_get_read_page(struct inode *inode, u64 bix, + level_t level) +{ + return find_or_create_page(inode->i_mapping, + logfs_pack_index(bix, level), GFP_NOFS); +} + +static void logfs_put_read_page(struct page *page) +{ + unlock_page(page); + page_cache_release(page); +} + +static void logfs_lock_write_page(struct page *page) +{ + int loop = 0; + + while (unlikely(!trylock_page(page))) { + if (loop++ > 0x1000) { + /* Has been observed once so far... */ + printk(KERN_ERR "stack at %p\n", &loop); + BUG(); + } + if (PagePreLocked(page)) { + /* Holder of page lock is waiting for us, it + * is safe to use this page. */ + break; + } + /* Some other process has this page locked and has + * nothing to do with us. Wait for it to finish. + */ + schedule(); + } + BUG_ON(!PageLocked(page)); +} + +static struct page *logfs_get_write_page(struct inode *inode, u64 bix, + level_t level) +{ + struct address_space *mapping = inode->i_mapping; + pgoff_t index = logfs_pack_index(bix, level); + struct page *page; + int err; + +repeat: + page = find_get_page(mapping, index); + if (!page) { + page = __page_cache_alloc(GFP_NOFS); + if (!page) + return NULL; + err = add_to_page_cache_lru(page, mapping, index, GFP_NOFS); + if (unlikely(err)) { + page_cache_release(page); + if (err == -EEXIST) + goto repeat; + return NULL; + } + } else logfs_lock_write_page(page); + BUG_ON(!PageLocked(page)); + return page; +} + +static void logfs_unlock_write_page(struct page *page) +{ + if (!PagePreLocked(page)) + unlock_page(page); +} + +static void logfs_put_write_page(struct page *page) +{ + logfs_unlock_write_page(page); + page_cache_release(page); +} + +static struct page *logfs_get_page(struct inode *inode, u64 bix, level_t level, + int rw) +{ + if (rw == READ) + return logfs_get_read_page(inode, bix, level); + else + return logfs_get_write_page(inode, bix, level); +} + +static void logfs_put_page(struct page *page, int rw) +{ + if (rw == READ) + logfs_put_read_page(page); + else + logfs_put_write_page(page); +} + +static unsigned long __get_bits(u64 val, int skip, int no) +{ + u64 ret = val; + + ret >>= skip * no; + ret <<= 64 - no; + ret >>= 64 - no; + return ret; +} + +static unsigned long get_bits(u64 val, level_t skip) +{ + return __get_bits(val, (__force int)skip, LOGFS_BLOCK_BITS); +} + +static inline void init_shadow_tree(struct super_block *sb, + struct shadow_tree *tree) +{ + struct logfs_super *super = logfs_super(sb); + + btree_init_mempool64(&tree->new, super->s_btree_pool); + btree_init_mempool64(&tree->old, super->s_btree_pool); +} + +static void indirect_write_block(struct logfs_block *block) +{ + struct page *page; + struct inode *inode; + int ret; + + page = block->page; + inode = page->mapping->host; + logfs_lock_write_page(page); + ret = logfs_write_buf(inode, page, 0); + logfs_unlock_write_page(page); + /* + * This needs some rework. Unless you want your filesystem to run + * completely synchronously (you don't), the filesystem will always + * report writes as 'successful' before the actual work has been + * done. The actual work gets done here and this is where any errors + * will show up. And there isn't much we can do about it, really. + * + * Some attempts to fix the errors (move from bad blocks, retry io,...) + * have already been done, so anything left should be either a broken + * device or a bug somewhere in logfs itself. Being relatively new, + * the odds currently favor a bug, so for now the line below isn't + * entirely tasteles. + */ + BUG_ON(ret); +} + +static void inode_write_block(struct logfs_block *block) +{ + struct inode *inode; + int ret; + + inode = block->inode; + if (inode->i_ino == LOGFS_INO_MASTER) + logfs_write_anchor(inode->i_sb); + else { + ret = __logfs_write_inode(inode, NULL, 0); + /* see indirect_write_block comment */ + BUG_ON(ret); + } +} + +/* + * This silences a false, yet annoying gcc warning. I hate it when my editor + * jumps into bitops.h each time I recompile this file. + * TODO: Complain to gcc folks about this and upgrade compiler. + */ +static unsigned long fnb(const unsigned long *addr, + unsigned long size, unsigned long offset) +{ + return find_next_bit(addr, size, offset); +} + +static __be64 inode_val0(struct inode *inode) +{ + struct logfs_inode *li = logfs_inode(inode); + u64 val; + + /* + * Explicit shifting generates good code, but must match the format + * of the structure. Add some paranoia just in case. + */ + BUILD_BUG_ON(offsetof(struct logfs_disk_inode, di_mode) != 0); + BUILD_BUG_ON(offsetof(struct logfs_disk_inode, di_height) != 2); + BUILD_BUG_ON(offsetof(struct logfs_disk_inode, di_flags) != 4); + + val = (u64)inode->i_mode << 48 | + (u64)li->li_height << 40 | + (u64)li->li_flags; + return cpu_to_be64(val); +} + +static int inode_write_alias(struct super_block *sb, + struct logfs_block *block, write_alias_t *write_one_alias) +{ + struct inode *inode = block->inode; + struct logfs_inode *li = logfs_inode(inode); + unsigned long pos; + u64 ino , bix; + __be64 val; + level_t level; + int err; + + for (pos = 0; ; pos++) { + pos = fnb(block->alias_map, LOGFS_BLOCK_FACTOR, pos); + if (pos >= LOGFS_EMBEDDED_FIELDS + INODE_POINTER_OFS) + return 0; + + switch (pos) { + case INODE_HEIGHT_OFS: + val = inode_val0(inode); + break; + case INODE_USED_OFS: + val = cpu_to_be64(li->li_used_bytes); + break; + case INODE_SIZE_OFS: + val = cpu_to_be64(i_size_read(inode)); + break; + case INODE_POINTER_OFS ... INODE_POINTER_OFS + LOGFS_EMBEDDED_FIELDS - 1: + val = cpu_to_be64(li->li_data[pos - INODE_POINTER_OFS]); + break; + default: + BUG(); + } + + ino = LOGFS_INO_MASTER; + bix = inode->i_ino; + level = LEVEL(0); + err = write_one_alias(sb, ino, bix, level, pos, val); + if (err) + return err; + } +} + +static int indirect_write_alias(struct super_block *sb, + struct logfs_block *block, write_alias_t *write_one_alias) +{ + unsigned long pos; + struct page *page = block->page; + u64 ino , bix; + __be64 *child, val; + level_t level; + int err; + + for (pos = 0; ; pos++) { + pos = fnb(block->alias_map, LOGFS_BLOCK_FACTOR, pos); + if (pos >= LOGFS_BLOCK_FACTOR) + return 0; + + ino = page->mapping->host->i_ino; + logfs_unpack_index(page->index, &bix, &level); + child = kmap_atomic(page); + val = child[pos]; + kunmap_atomic(child); + err = write_one_alias(sb, ino, bix, level, pos, val); + if (err) + return err; + } +} + +int logfs_write_obj_aliases_pagecache(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_block *block; + int err; + + list_for_each_entry(block, &super->s_object_alias, alias_list) { + err = block->ops->write_alias(sb, block, write_alias_journal); + if (err) + return err; + } + return 0; +} + +void __free_block(struct super_block *sb, struct logfs_block *block) +{ + BUG_ON(!list_empty(&block->item_list)); + list_del(&block->alias_list); + mempool_free(block, logfs_super(sb)->s_block_pool); +} + +static void inode_free_block(struct super_block *sb, struct logfs_block *block) +{ + struct inode *inode = block->inode; + + logfs_inode(inode)->li_block = NULL; + __free_block(sb, block); +} + +static void indirect_free_block(struct super_block *sb, + struct logfs_block *block) +{ + struct page *page = block->page; + + if (PagePrivate(page)) { + ClearPagePrivate(page); + page_cache_release(page); + set_page_private(page, 0); + } + __free_block(sb, block); +} + + +static struct logfs_block_ops inode_block_ops = { + .write_block = inode_write_block, + .free_block = inode_free_block, + .write_alias = inode_write_alias, +}; + +struct logfs_block_ops indirect_block_ops = { + .write_block = indirect_write_block, + .free_block = indirect_free_block, + .write_alias = indirect_write_alias, +}; + +struct logfs_block *__alloc_block(struct super_block *sb, + u64 ino, u64 bix, level_t level) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_block *block; + + block = mempool_alloc(super->s_block_pool, GFP_NOFS); + memset(block, 0, sizeof(*block)); + INIT_LIST_HEAD(&block->alias_list); + INIT_LIST_HEAD(&block->item_list); + block->sb = sb; + block->ino = ino; + block->bix = bix; + block->level = level; + return block; +} + +static void alloc_inode_block(struct inode *inode) +{ + struct logfs_inode *li = logfs_inode(inode); + struct logfs_block *block; + + if (li->li_block) + return; + + block = __alloc_block(inode->i_sb, LOGFS_INO_MASTER, inode->i_ino, 0); + block->inode = inode; + li->li_block = block; + block->ops = &inode_block_ops; +} + +void initialize_block_counters(struct page *page, struct logfs_block *block, + __be64 *array, int page_is_empty) +{ + u64 ptr; + int i, start; + + block->partial = 0; + block->full = 0; + start = 0; + if (page->index < first_indirect_block()) { + /* Counters are pointless on level 0 */ + return; + } + if (page->index == first_indirect_block()) { + /* Skip unused pointers */ + start = I0_BLOCKS; + block->full = I0_BLOCKS; + } + if (!page_is_empty) { + for (i = start; i < LOGFS_BLOCK_FACTOR; i++) { + ptr = be64_to_cpu(array[i]); + if (ptr) + block->partial++; + if (ptr & LOGFS_FULLY_POPULATED) + block->full++; + } + } +} + +static void alloc_data_block(struct inode *inode, struct page *page) +{ + struct logfs_block *block; + u64 bix; + level_t level; + + if (PagePrivate(page)) + return; + + logfs_unpack_index(page->index, &bix, &level); + block = __alloc_block(inode->i_sb, inode->i_ino, bix, level); + block->page = page; + + SetPagePrivate(page); + page_cache_get(page); + set_page_private(page, (unsigned long) block); + + block->ops = &indirect_block_ops; +} + +static void alloc_indirect_block(struct inode *inode, struct page *page, + int page_is_empty) +{ + struct logfs_block *block; + __be64 *array; + + if (PagePrivate(page)) + return; + + alloc_data_block(inode, page); + + block = logfs_block(page); + array = kmap_atomic(page); + initialize_block_counters(page, block, array, page_is_empty); + kunmap_atomic(array); +} + +static void block_set_pointer(struct page *page, int index, u64 ptr) +{ + struct logfs_block *block = logfs_block(page); + __be64 *array; + u64 oldptr; + + BUG_ON(!block); + array = kmap_atomic(page); + oldptr = be64_to_cpu(array[index]); + array[index] = cpu_to_be64(ptr); + kunmap_atomic(array); + SetPageUptodate(page); + + block->full += !!(ptr & LOGFS_FULLY_POPULATED) + - !!(oldptr & LOGFS_FULLY_POPULATED); + block->partial += !!ptr - !!oldptr; +} + +static u64 block_get_pointer(struct page *page, int index) +{ + __be64 *block; + u64 ptr; + + block = kmap_atomic(page); + ptr = be64_to_cpu(block[index]); + kunmap_atomic(block); + return ptr; +} + +static int logfs_read_empty(struct page *page) +{ + zero_user_segment(page, 0, PAGE_CACHE_SIZE); + return 0; +} + +static int logfs_read_direct(struct inode *inode, struct page *page) +{ + struct logfs_inode *li = logfs_inode(inode); + pgoff_t index = page->index; + u64 block; + + block = li->li_data[index]; + if (!block) + return logfs_read_empty(page); + + return logfs_segment_read(inode, page, block, index, 0); +} + +static int logfs_read_loop(struct inode *inode, struct page *page, + int rw_context) +{ + struct logfs_inode *li = logfs_inode(inode); + u64 bix, bofs = li->li_data[INDIRECT_INDEX]; + level_t level, target_level; + int ret; + struct page *ipage; + + logfs_unpack_index(page->index, &bix, &target_level); + if (!bofs) + return logfs_read_empty(page); + + if (bix >= maxbix(li->li_height)) + return logfs_read_empty(page); + + for (level = LEVEL(li->li_height); + (__force u8)level > (__force u8)target_level; + level = SUBLEVEL(level)){ + ipage = logfs_get_page(inode, bix, level, rw_context); + if (!ipage) + return -ENOMEM; + + ret = logfs_segment_read(inode, ipage, bofs, bix, level); + if (ret) { + logfs_put_read_page(ipage); + return ret; + } + + bofs = block_get_pointer(ipage, get_bits(bix, SUBLEVEL(level))); + logfs_put_page(ipage, rw_context); + if (!bofs) + return logfs_read_empty(page); + } + + return logfs_segment_read(inode, page, bofs, bix, 0); +} + +static int logfs_read_block(struct inode *inode, struct page *page, + int rw_context) +{ + pgoff_t index = page->index; + + if (index < I0_BLOCKS) + return logfs_read_direct(inode, page); + return logfs_read_loop(inode, page, rw_context); +} + +static int logfs_exist_loop(struct inode *inode, u64 bix) +{ + struct logfs_inode *li = logfs_inode(inode); + u64 bofs = li->li_data[INDIRECT_INDEX]; + level_t level; + int ret; + struct page *ipage; + + if (!bofs) + return 0; + if (bix >= maxbix(li->li_height)) + return 0; + + for (level = LEVEL(li->li_height); level != 0; level = SUBLEVEL(level)) { + ipage = logfs_get_read_page(inode, bix, level); + if (!ipage) + return -ENOMEM; + + ret = logfs_segment_read(inode, ipage, bofs, bix, level); + if (ret) { + logfs_put_read_page(ipage); + return ret; + } + + bofs = block_get_pointer(ipage, get_bits(bix, SUBLEVEL(level))); + logfs_put_read_page(ipage); + if (!bofs) + return 0; + } + + return 1; +} + +int logfs_exist_block(struct inode *inode, u64 bix) +{ + struct logfs_inode *li = logfs_inode(inode); + + if (bix < I0_BLOCKS) + return !!li->li_data[bix]; + return logfs_exist_loop(inode, bix); +} + +static u64 seek_holedata_direct(struct inode *inode, u64 bix, int data) +{ + struct logfs_inode *li = logfs_inode(inode); + + for (; bix < I0_BLOCKS; bix++) + if (data ^ (li->li_data[bix] == 0)) + return bix; + return I0_BLOCKS; +} + +static u64 seek_holedata_loop(struct inode *inode, u64 bix, int data) +{ + struct logfs_inode *li = logfs_inode(inode); + __be64 *rblock; + u64 increment, bofs = li->li_data[INDIRECT_INDEX]; + level_t level; + int ret, slot; + struct page *page; + + BUG_ON(!bofs); + + for (level = LEVEL(li->li_height); level != 0; level = SUBLEVEL(level)) { + increment = 1 << (LOGFS_BLOCK_BITS * ((__force u8)level-1)); + page = logfs_get_read_page(inode, bix, level); + if (!page) + return bix; + + ret = logfs_segment_read(inode, page, bofs, bix, level); + if (ret) { + logfs_put_read_page(page); + return bix; + } + + slot = get_bits(bix, SUBLEVEL(level)); + rblock = kmap_atomic(page); + while (slot < LOGFS_BLOCK_FACTOR) { + if (data && (rblock[slot] != 0)) + break; + if (!data && !(be64_to_cpu(rblock[slot]) & LOGFS_FULLY_POPULATED)) + break; + slot++; + bix += increment; + bix &= ~(increment - 1); + } + if (slot >= LOGFS_BLOCK_FACTOR) { + kunmap_atomic(rblock); + logfs_put_read_page(page); + return bix; + } + bofs = be64_to_cpu(rblock[slot]); + kunmap_atomic(rblock); + logfs_put_read_page(page); + if (!bofs) { + BUG_ON(data); + return bix; + } + } + return bix; +} + +/** + * logfs_seek_hole - find next hole starting at a given block index + * @inode: inode to search in + * @bix: block index to start searching + * + * Returns next hole. If the file doesn't contain any further holes, the + * block address next to eof is returned instead. + */ +u64 logfs_seek_hole(struct inode *inode, u64 bix) +{ + struct logfs_inode *li = logfs_inode(inode); + + if (bix < I0_BLOCKS) { + bix = seek_holedata_direct(inode, bix, 0); + if (bix < I0_BLOCKS) + return bix; + } + + if (!li->li_data[INDIRECT_INDEX]) + return bix; + else if (li->li_data[INDIRECT_INDEX] & LOGFS_FULLY_POPULATED) + bix = maxbix(li->li_height); + else if (bix >= maxbix(li->li_height)) + return bix; + else { + bix = seek_holedata_loop(inode, bix, 0); + if (bix < maxbix(li->li_height)) + return bix; + /* Should not happen anymore. But if some port writes semi- + * corrupt images (as this one used to) we might run into it. + */ + WARN_ON_ONCE(bix == maxbix(li->li_height)); + } + + return bix; +} + +static u64 __logfs_seek_data(struct inode *inode, u64 bix) +{ + struct logfs_inode *li = logfs_inode(inode); + + if (bix < I0_BLOCKS) { + bix = seek_holedata_direct(inode, bix, 1); + if (bix < I0_BLOCKS) + return bix; + } + + if (bix < maxbix(li->li_height)) { + if (!li->li_data[INDIRECT_INDEX]) + bix = maxbix(li->li_height); + else + return seek_holedata_loop(inode, bix, 1); + } + + return bix; +} + +/** + * logfs_seek_data - find next data block after a given block index + * @inode: inode to search in + * @bix: block index to start searching + * + * Returns next data block. If the file doesn't contain any further data + * blocks, the last block in the file is returned instead. + */ +u64 logfs_seek_data(struct inode *inode, u64 bix) +{ + struct super_block *sb = inode->i_sb; + u64 ret, end; + + ret = __logfs_seek_data(inode, bix); + end = i_size_read(inode) >> sb->s_blocksize_bits; + if (ret >= end) + ret = max(bix, end); + return ret; +} + +static int logfs_is_valid_direct(struct logfs_inode *li, u64 bix, u64 ofs) +{ + return pure_ofs(li->li_data[bix]) == ofs; +} + +static int __logfs_is_valid_loop(struct inode *inode, u64 bix, + u64 ofs, u64 bofs) +{ + struct logfs_inode *li = logfs_inode(inode); + level_t level; + int ret; + struct page *page; + + for (level = LEVEL(li->li_height); level != 0; level = SUBLEVEL(level)){ + page = logfs_get_write_page(inode, bix, level); + BUG_ON(!page); + + ret = logfs_segment_read(inode, page, bofs, bix, level); + if (ret) { + logfs_put_write_page(page); + return 0; + } + + bofs = block_get_pointer(page, get_bits(bix, SUBLEVEL(level))); + logfs_put_write_page(page); + if (!bofs) + return 0; + + if (pure_ofs(bofs) == ofs) + return 1; + } + return 0; +} + +static int logfs_is_valid_loop(struct inode *inode, u64 bix, u64 ofs) +{ + struct logfs_inode *li = logfs_inode(inode); + u64 bofs = li->li_data[INDIRECT_INDEX]; + + if (!bofs) + return 0; + + if (bix >= maxbix(li->li_height)) + return 0; + + if (pure_ofs(bofs) == ofs) + return 1; + + return __logfs_is_valid_loop(inode, bix, ofs, bofs); +} + +static int __logfs_is_valid_block(struct inode *inode, u64 bix, u64 ofs) +{ + struct logfs_inode *li = logfs_inode(inode); + + if ((inode->i_nlink == 0) && atomic_read(&inode->i_count) == 1) + return 0; + + if (bix < I0_BLOCKS) + return logfs_is_valid_direct(li, bix, ofs); + return logfs_is_valid_loop(inode, bix, ofs); +} + +/** + * logfs_is_valid_block - check whether this block is still valid + * + * @sb: superblock + * @ofs: block physical offset + * @ino: block inode number + * @bix: block index + * @gc_level: block level + * + * Returns 0 if the block is invalid, 1 if it is valid and 2 if it will + * become invalid once the journal is written. + */ +int logfs_is_valid_block(struct super_block *sb, u64 ofs, u64 ino, u64 bix, + gc_level_t gc_level) +{ + struct logfs_super *super = logfs_super(sb); + struct inode *inode; + int ret, cookie; + + /* Umount closes a segment with free blocks remaining. Those + * blocks are by definition invalid. */ + if (ino == -1) + return 0; + + LOGFS_BUG_ON((u64)(u_long)ino != ino, sb); + + inode = logfs_safe_iget(sb, ino, &cookie); + if (IS_ERR(inode)) + goto invalid; + + ret = __logfs_is_valid_block(inode, bix, ofs); + logfs_safe_iput(inode, cookie); + if (ret) + return ret; + +invalid: + /* Block is nominally invalid, but may still sit in the shadow tree, + * waiting for a journal commit. + */ + if (btree_lookup64(&super->s_shadow_tree.old, ofs)) + return 2; + return 0; +} + +int logfs_readpage_nolock(struct page *page) +{ + struct inode *inode = page->mapping->host; + int ret = -EIO; + + ret = logfs_read_block(inode, page, READ); + + if (ret) { + ClearPageUptodate(page); + SetPageError(page); + } else { + SetPageUptodate(page); + ClearPageError(page); + } + flush_dcache_page(page); + + return ret; +} + +static int logfs_reserve_bytes(struct inode *inode, int bytes) +{ + struct logfs_super *super = logfs_super(inode->i_sb); + u64 available = super->s_free_bytes + super->s_dirty_free_bytes + - super->s_dirty_used_bytes - super->s_dirty_pages; + + if (!bytes) + return 0; + + if (available < bytes) + return -ENOSPC; + + if (available < bytes + super->s_root_reserve && + !capable(CAP_SYS_RESOURCE)) + return -ENOSPC; + + return 0; +} + +int get_page_reserve(struct inode *inode, struct page *page) +{ + struct logfs_super *super = logfs_super(inode->i_sb); + struct logfs_block *block = logfs_block(page); + int ret; + + if (block && block->reserved_bytes) + return 0; + + logfs_get_wblocks(inode->i_sb, page, WF_LOCK); + while ((ret = logfs_reserve_bytes(inode, 6 * LOGFS_MAX_OBJECTSIZE)) && + !list_empty(&super->s_writeback_list)) { + block = list_entry(super->s_writeback_list.next, + struct logfs_block, alias_list); + block->ops->write_block(block); + } + if (!ret) { + alloc_data_block(inode, page); + block = logfs_block(page); + block->reserved_bytes += 6 * LOGFS_MAX_OBJECTSIZE; + super->s_dirty_pages += 6 * LOGFS_MAX_OBJECTSIZE; + list_move_tail(&block->alias_list, &super->s_writeback_list); + } + logfs_put_wblocks(inode->i_sb, page, WF_LOCK); + return ret; +} + +/* + * We are protected by write lock. Push victims up to superblock level + * and release transaction when appropriate. + */ +/* FIXME: This is currently called from the wrong spots. */ +static void logfs_handle_transaction(struct inode *inode, + struct logfs_transaction *ta) +{ + struct logfs_super *super = logfs_super(inode->i_sb); + + if (!ta) + return; + logfs_inode(inode)->li_block->ta = NULL; + + if (inode->i_ino != LOGFS_INO_MASTER) { + BUG(); /* FIXME: Yes, this needs more thought */ + /* just remember the transaction until inode is written */ + //BUG_ON(logfs_inode(inode)->li_transaction); + //logfs_inode(inode)->li_transaction = ta; + return; + } + + switch (ta->state) { + case CREATE_1: /* fall through */ + case UNLINK_1: + BUG_ON(super->s_victim_ino); + super->s_victim_ino = ta->ino; + break; + case CREATE_2: /* fall through */ + case UNLINK_2: + BUG_ON(super->s_victim_ino != ta->ino); + super->s_victim_ino = 0; + /* transaction ends here - free it */ + kfree(ta); + break; + case CROSS_RENAME_1: + BUG_ON(super->s_rename_dir); + BUG_ON(super->s_rename_pos); + super->s_rename_dir = ta->dir; + super->s_rename_pos = ta->pos; + break; + case CROSS_RENAME_2: + BUG_ON(super->s_rename_dir != ta->dir); + BUG_ON(super->s_rename_pos != ta->pos); + super->s_rename_dir = 0; + super->s_rename_pos = 0; + kfree(ta); + break; + case TARGET_RENAME_1: + BUG_ON(super->s_rename_dir); + BUG_ON(super->s_rename_pos); + BUG_ON(super->s_victim_ino); + super->s_rename_dir = ta->dir; + super->s_rename_pos = ta->pos; + super->s_victim_ino = ta->ino; + break; + case TARGET_RENAME_2: + BUG_ON(super->s_rename_dir != ta->dir); + BUG_ON(super->s_rename_pos != ta->pos); + BUG_ON(super->s_victim_ino != ta->ino); + super->s_rename_dir = 0; + super->s_rename_pos = 0; + break; + case TARGET_RENAME_3: + BUG_ON(super->s_rename_dir); + BUG_ON(super->s_rename_pos); + BUG_ON(super->s_victim_ino != ta->ino); + super->s_victim_ino = 0; + kfree(ta); + break; + default: + BUG(); + } +} + +/* + * Not strictly a reservation, but rather a check that we still have enough + * space to satisfy the write. + */ +static int logfs_reserve_blocks(struct inode *inode, int blocks) +{ + return logfs_reserve_bytes(inode, blocks * LOGFS_MAX_OBJECTSIZE); +} + +struct write_control { + u64 ofs; + long flags; +}; + +static struct logfs_shadow *alloc_shadow(struct inode *inode, u64 bix, + level_t level, u64 old_ofs) +{ + struct logfs_super *super = logfs_super(inode->i_sb); + struct logfs_shadow *shadow; + + shadow = mempool_alloc(super->s_shadow_pool, GFP_NOFS); + memset(shadow, 0, sizeof(*shadow)); + shadow->ino = inode->i_ino; + shadow->bix = bix; + shadow->gc_level = expand_level(inode->i_ino, level); + shadow->old_ofs = old_ofs & ~LOGFS_FULLY_POPULATED; + return shadow; +} + +static void free_shadow(struct inode *inode, struct logfs_shadow *shadow) +{ + struct logfs_super *super = logfs_super(inode->i_sb); + + mempool_free(shadow, super->s_shadow_pool); +} + +static void mark_segment(struct shadow_tree *tree, u32 segno) +{ + int err; + + if (!btree_lookup32(&tree->segment_map, segno)) { + err = btree_insert32(&tree->segment_map, segno, (void *)1, + GFP_NOFS); + BUG_ON(err); + tree->no_shadowed_segments++; + } +} + +/** + * fill_shadow_tree - Propagate shadow tree changes due to a write + * @inode: Inode owning the page + * @page: Struct page that was written + * @shadow: Shadow for the current write + * + * Writes in logfs can result in two semi-valid objects. The old object + * is still valid as long as it can be reached by following pointers on + * the medium. Only when writes propagate all the way up to the journal + * has the new object safely replaced the old one. + * + * To handle this problem, a struct logfs_shadow is used to represent + * every single write. It is attached to the indirect block, which is + * marked dirty. When the indirect block is written, its shadows are + * handed up to the next indirect block (or inode). Untimately they + * will reach the master inode and be freed upon journal commit. + * + * This function handles a single step in the propagation. It adds the + * shadow for the current write to the tree, along with any shadows in + * the page's tree, in case it was an indirect block. If a page is + * written, the inode parameter is left NULL, if an inode is written, + * the page parameter is left NULL. + */ +static void fill_shadow_tree(struct inode *inode, struct page *page, + struct logfs_shadow *shadow) +{ + struct logfs_super *super = logfs_super(inode->i_sb); + struct logfs_block *block = logfs_block(page); + struct shadow_tree *tree = &super->s_shadow_tree; + + if (PagePrivate(page)) { + if (block->alias_map) + super->s_no_object_aliases -= bitmap_weight( + block->alias_map, LOGFS_BLOCK_FACTOR); + logfs_handle_transaction(inode, block->ta); + block->ops->free_block(inode->i_sb, block); + } + if (shadow) { + if (shadow->old_ofs) + btree_insert64(&tree->old, shadow->old_ofs, shadow, + GFP_NOFS); + else + btree_insert64(&tree->new, shadow->new_ofs, shadow, + GFP_NOFS); + + super->s_dirty_used_bytes += shadow->new_len; + super->s_dirty_free_bytes += shadow->old_len; + mark_segment(tree, shadow->old_ofs >> super->s_segshift); + mark_segment(tree, shadow->new_ofs >> super->s_segshift); + } +} + +static void logfs_set_alias(struct super_block *sb, struct logfs_block *block, + long child_no) +{ + struct logfs_super *super = logfs_super(sb); + + if (block->inode && block->inode->i_ino == LOGFS_INO_MASTER) { + /* Aliases in the master inode are pointless. */ + return; + } + + if (!test_bit(child_no, block->alias_map)) { + set_bit(child_no, block->alias_map); + super->s_no_object_aliases++; + } + list_move_tail(&block->alias_list, &super->s_object_alias); +} + +/* + * Object aliases can and often do change the size and occupied space of a + * file. So not only do we have to change the pointers, we also have to + * change inode->i_size and li->li_used_bytes. Which is done by setting + * another two object aliases for the inode itself. + */ +static void set_iused(struct inode *inode, struct logfs_shadow *shadow) +{ + struct logfs_inode *li = logfs_inode(inode); + + if (shadow->new_len == shadow->old_len) + return; + + alloc_inode_block(inode); + li->li_used_bytes += shadow->new_len - shadow->old_len; + __logfs_set_blocks(inode); + logfs_set_alias(inode->i_sb, li->li_block, INODE_USED_OFS); + logfs_set_alias(inode->i_sb, li->li_block, INODE_SIZE_OFS); +} + +static int logfs_write_i0(struct inode *inode, struct page *page, + struct write_control *wc) +{ + struct logfs_shadow *shadow; + u64 bix; + level_t level; + int full, err = 0; + + logfs_unpack_index(page->index, &bix, &level); + if (wc->ofs == 0) + if (logfs_reserve_blocks(inode, 1)) + return -ENOSPC; + + shadow = alloc_shadow(inode, bix, level, wc->ofs); + if (wc->flags & WF_WRITE) + err = logfs_segment_write(inode, page, shadow); + if (wc->flags & WF_DELETE) + logfs_segment_delete(inode, shadow); + if (err) { + free_shadow(inode, shadow); + return err; + } + + set_iused(inode, shadow); + full = 1; + if (level != 0) { + alloc_indirect_block(inode, page, 0); + full = logfs_block(page)->full == LOGFS_BLOCK_FACTOR; + } + fill_shadow_tree(inode, page, shadow); + wc->ofs = shadow->new_ofs; + if (wc->ofs && full) + wc->ofs |= LOGFS_FULLY_POPULATED; + return 0; +} + +static int logfs_write_direct(struct inode *inode, struct page *page, + long flags) +{ + struct logfs_inode *li = logfs_inode(inode); + struct write_control wc = { + .ofs = li->li_data[page->index], + .flags = flags, + }; + int err; + + alloc_inode_block(inode); + + err = logfs_write_i0(inode, page, &wc); + if (err) + return err; + + li->li_data[page->index] = wc.ofs; + logfs_set_alias(inode->i_sb, li->li_block, + page->index + INODE_POINTER_OFS); + return 0; +} + +static int ptr_change(u64 ofs, struct page *page) +{ + struct logfs_block *block = logfs_block(page); + int empty0, empty1, full0, full1; + + empty0 = ofs == 0; + empty1 = block->partial == 0; + if (empty0 != empty1) + return 1; + + /* The !! is necessary to shrink result to int */ + full0 = !!(ofs & LOGFS_FULLY_POPULATED); + full1 = block->full == LOGFS_BLOCK_FACTOR; + if (full0 != full1) + return 1; + return 0; +} + +static int __logfs_write_rec(struct inode *inode, struct page *page, + struct write_control *this_wc, + pgoff_t bix, level_t target_level, level_t level) +{ + int ret, page_empty = 0; + int child_no = get_bits(bix, SUBLEVEL(level)); + struct page *ipage; + struct write_control child_wc = { + .flags = this_wc->flags, + }; + + ipage = logfs_get_write_page(inode, bix, level); + if (!ipage) + return -ENOMEM; + + if (this_wc->ofs) { + ret = logfs_segment_read(inode, ipage, this_wc->ofs, bix, level); + if (ret) + goto out; + } else if (!PageUptodate(ipage)) { + page_empty = 1; + logfs_read_empty(ipage); + } + + child_wc.ofs = block_get_pointer(ipage, child_no); + + if ((__force u8)level-1 > (__force u8)target_level) + ret = __logfs_write_rec(inode, page, &child_wc, bix, + target_level, SUBLEVEL(level)); + else + ret = logfs_write_i0(inode, page, &child_wc); + + if (ret) + goto out; + + alloc_indirect_block(inode, ipage, page_empty); + block_set_pointer(ipage, child_no, child_wc.ofs); + /* FIXME: first condition seems superfluous */ + if (child_wc.ofs || logfs_block(ipage)->partial) + this_wc->flags |= WF_WRITE; + /* the condition on this_wc->ofs ensures that we won't consume extra + * space for indirect blocks in the future, which we cannot reserve */ + if (!this_wc->ofs || ptr_change(this_wc->ofs, ipage)) + ret = logfs_write_i0(inode, ipage, this_wc); + else + logfs_set_alias(inode->i_sb, logfs_block(ipage), child_no); +out: + logfs_put_write_page(ipage); + return ret; +} + +static int logfs_write_rec(struct inode *inode, struct page *page, + pgoff_t bix, level_t target_level, long flags) +{ + struct logfs_inode *li = logfs_inode(inode); + struct write_control wc = { + .ofs = li->li_data[INDIRECT_INDEX], + .flags = flags, + }; + int ret; + + alloc_inode_block(inode); + + if (li->li_height > (__force u8)target_level) + ret = __logfs_write_rec(inode, page, &wc, bix, target_level, + LEVEL(li->li_height)); + else + ret = logfs_write_i0(inode, page, &wc); + if (ret) + return ret; + + if (li->li_data[INDIRECT_INDEX] != wc.ofs) { + li->li_data[INDIRECT_INDEX] = wc.ofs; + logfs_set_alias(inode->i_sb, li->li_block, + INDIRECT_INDEX + INODE_POINTER_OFS); + } + return ret; +} + +void logfs_add_transaction(struct inode *inode, struct logfs_transaction *ta) +{ + alloc_inode_block(inode); + logfs_inode(inode)->li_block->ta = ta; +} + +void logfs_del_transaction(struct inode *inode, struct logfs_transaction *ta) +{ + struct logfs_block *block = logfs_inode(inode)->li_block; + + if (block && block->ta) + block->ta = NULL; +} + +static int grow_inode(struct inode *inode, u64 bix, level_t level) +{ + struct logfs_inode *li = logfs_inode(inode); + u8 height = (__force u8)level; + struct page *page; + struct write_control wc = { + .flags = WF_WRITE, + }; + int err; + + BUG_ON(height > 5 || li->li_height > 5); + while (height > li->li_height || bix >= maxbix(li->li_height)) { + page = logfs_get_write_page(inode, I0_BLOCKS + 1, + LEVEL(li->li_height + 1)); + if (!page) + return -ENOMEM; + logfs_read_empty(page); + alloc_indirect_block(inode, page, 1); + block_set_pointer(page, 0, li->li_data[INDIRECT_INDEX]); + err = logfs_write_i0(inode, page, &wc); + logfs_put_write_page(page); + if (err) + return err; + li->li_data[INDIRECT_INDEX] = wc.ofs; + wc.ofs = 0; + li->li_height++; + logfs_set_alias(inode->i_sb, li->li_block, INODE_HEIGHT_OFS); + } + return 0; +} + +static int __logfs_write_buf(struct inode *inode, struct page *page, long flags) +{ + struct logfs_super *super = logfs_super(inode->i_sb); + pgoff_t index = page->index; + u64 bix; + level_t level; + int err; + + flags |= WF_WRITE | WF_DELETE; + inode->i_ctime = inode->i_mtime = CURRENT_TIME; + + logfs_unpack_index(index, &bix, &level); + if (logfs_block(page) && logfs_block(page)->reserved_bytes) + super->s_dirty_pages -= logfs_block(page)->reserved_bytes; + + if (index < I0_BLOCKS) + return logfs_write_direct(inode, page, flags); + + bix = adjust_bix(bix, level); + err = grow_inode(inode, bix, level); + if (err) + return err; + return logfs_write_rec(inode, page, bix, level, flags); +} + +int logfs_write_buf(struct inode *inode, struct page *page, long flags) +{ + struct super_block *sb = inode->i_sb; + int ret; + + logfs_get_wblocks(sb, page, flags & WF_LOCK); + ret = __logfs_write_buf(inode, page, flags); + logfs_put_wblocks(sb, page, flags & WF_LOCK); + return ret; +} + +static int __logfs_delete(struct inode *inode, struct page *page) +{ + long flags = WF_DELETE; + int err; + + inode->i_ctime = inode->i_mtime = CURRENT_TIME; + + if (page->index < I0_BLOCKS) + return logfs_write_direct(inode, page, flags); + err = grow_inode(inode, page->index, 0); + if (err) + return err; + return logfs_write_rec(inode, page, page->index, 0, flags); +} + +int logfs_delete(struct inode *inode, pgoff_t index, + struct shadow_tree *shadow_tree) +{ + struct super_block *sb = inode->i_sb; + struct page *page; + int ret; + + page = logfs_get_read_page(inode, index, 0); + if (!page) + return -ENOMEM; + + logfs_get_wblocks(sb, page, 1); + ret = __logfs_delete(inode, page); + logfs_put_wblocks(sb, page, 1); + + logfs_put_read_page(page); + + return ret; +} + +int logfs_rewrite_block(struct inode *inode, u64 bix, u64 ofs, + gc_level_t gc_level, long flags) +{ + level_t level = shrink_level(gc_level); + struct page *page; + int err; + + page = logfs_get_write_page(inode, bix, level); + if (!page) + return -ENOMEM; + + err = logfs_segment_read(inode, page, ofs, bix, level); + if (!err) { + if (level != 0) + alloc_indirect_block(inode, page, 0); + err = logfs_write_buf(inode, page, flags); + if (!err && shrink_level(gc_level) == 0) { + /* Rewrite cannot mark the inode dirty but has to + * write it immediately. + * Q: Can't we just create an alias for the inode + * instead? And if not, why not? + */ + if (inode->i_ino == LOGFS_INO_MASTER) + logfs_write_anchor(inode->i_sb); + else { + err = __logfs_write_inode(inode, page, flags); + } + } + } + logfs_put_write_page(page); + return err; +} + +static int truncate_data_block(struct inode *inode, struct page *page, + u64 ofs, struct logfs_shadow *shadow, u64 size) +{ + loff_t pageofs = page->index << inode->i_sb->s_blocksize_bits; + u64 bix; + level_t level; + int err; + + /* Does truncation happen within this page? */ + if (size <= pageofs || size - pageofs >= PAGE_SIZE) + return 0; + + logfs_unpack_index(page->index, &bix, &level); + BUG_ON(level != 0); + + err = logfs_segment_read(inode, page, ofs, bix, level); + if (err) + return err; + + zero_user_segment(page, size - pageofs, PAGE_CACHE_SIZE); + return logfs_segment_write(inode, page, shadow); +} + +static int logfs_truncate_i0(struct inode *inode, struct page *page, + struct write_control *wc, u64 size) +{ + struct logfs_shadow *shadow; + u64 bix; + level_t level; + int err = 0; + + logfs_unpack_index(page->index, &bix, &level); + BUG_ON(level != 0); + shadow = alloc_shadow(inode, bix, level, wc->ofs); + + err = truncate_data_block(inode, page, wc->ofs, shadow, size); + if (err) { + free_shadow(inode, shadow); + return err; + } + + logfs_segment_delete(inode, shadow); + set_iused(inode, shadow); + fill_shadow_tree(inode, page, shadow); + wc->ofs = shadow->new_ofs; + return 0; +} + +static int logfs_truncate_direct(struct inode *inode, u64 size) +{ + struct logfs_inode *li = logfs_inode(inode); + struct write_control wc; + struct page *page; + int e; + int err; + + alloc_inode_block(inode); + + for (e = I0_BLOCKS - 1; e >= 0; e--) { + if (size > (e+1) * LOGFS_BLOCKSIZE) + break; + + wc.ofs = li->li_data[e]; + if (!wc.ofs) + continue; + + page = logfs_get_write_page(inode, e, 0); + if (!page) + return -ENOMEM; + err = logfs_segment_read(inode, page, wc.ofs, e, 0); + if (err) { + logfs_put_write_page(page); + return err; + } + err = logfs_truncate_i0(inode, page, &wc, size); + logfs_put_write_page(page); + if (err) + return err; + + li->li_data[e] = wc.ofs; + } + return 0; +} + +/* FIXME: these need to become per-sb once we support different blocksizes */ +static u64 __logfs_step[] = { + 1, + I1_BLOCKS, + I2_BLOCKS, + I3_BLOCKS, +}; + +static u64 __logfs_start_index[] = { + I0_BLOCKS, + I1_BLOCKS, + I2_BLOCKS, + I3_BLOCKS +}; + +static inline u64 logfs_step(level_t level) +{ + return __logfs_step[(__force u8)level]; +} + +static inline u64 logfs_factor(u8 level) +{ + return __logfs_step[level] * LOGFS_BLOCKSIZE; +} + +static inline u64 logfs_start_index(level_t level) +{ + return __logfs_start_index[(__force u8)level]; +} + +static void logfs_unpack_raw_index(pgoff_t index, u64 *bix, level_t *level) +{ + logfs_unpack_index(index, bix, level); + if (*bix <= logfs_start_index(SUBLEVEL(*level))) + *bix = 0; +} + +static int __logfs_truncate_rec(struct inode *inode, struct page *ipage, + struct write_control *this_wc, u64 size) +{ + int truncate_happened = 0; + int e, err = 0; + u64 bix, child_bix, next_bix; + level_t level; + struct page *page; + struct write_control child_wc = { /* FIXME: flags */ }; + + logfs_unpack_raw_index(ipage->index, &bix, &level); + err = logfs_segment_read(inode, ipage, this_wc->ofs, bix, level); + if (err) + return err; + + for (e = LOGFS_BLOCK_FACTOR - 1; e >= 0; e--) { + child_bix = bix + e * logfs_step(SUBLEVEL(level)); + next_bix = child_bix + logfs_step(SUBLEVEL(level)); + if (size > next_bix * LOGFS_BLOCKSIZE) + break; + + child_wc.ofs = pure_ofs(block_get_pointer(ipage, e)); + if (!child_wc.ofs) + continue; + + page = logfs_get_write_page(inode, child_bix, SUBLEVEL(level)); + if (!page) + return -ENOMEM; + + if ((__force u8)level > 1) + err = __logfs_truncate_rec(inode, page, &child_wc, size); + else + err = logfs_truncate_i0(inode, page, &child_wc, size); + logfs_put_write_page(page); + if (err) + return err; + + truncate_happened = 1; + alloc_indirect_block(inode, ipage, 0); + block_set_pointer(ipage, e, child_wc.ofs); + } + + if (!truncate_happened) { + printk("ineffectual truncate (%lx, %lx, %llx)\n", inode->i_ino, ipage->index, size); + return 0; + } + + this_wc->flags = WF_DELETE; + if (logfs_block(ipage)->partial) + this_wc->flags |= WF_WRITE; + + return logfs_write_i0(inode, ipage, this_wc); +} + +static int logfs_truncate_rec(struct inode *inode, u64 size) +{ + struct logfs_inode *li = logfs_inode(inode); + struct write_control wc = { + .ofs = li->li_data[INDIRECT_INDEX], + }; + struct page *page; + int err; + + alloc_inode_block(inode); + + if (!wc.ofs) + return 0; + + page = logfs_get_write_page(inode, 0, LEVEL(li->li_height)); + if (!page) + return -ENOMEM; + + err = __logfs_truncate_rec(inode, page, &wc, size); + logfs_put_write_page(page); + if (err) + return err; + + if (li->li_data[INDIRECT_INDEX] != wc.ofs) + li->li_data[INDIRECT_INDEX] = wc.ofs; + return 0; +} + +static int __logfs_truncate(struct inode *inode, u64 size) +{ + int ret; + + if (size >= logfs_factor(logfs_inode(inode)->li_height)) + return 0; + + ret = logfs_truncate_rec(inode, size); + if (ret) + return ret; + + return logfs_truncate_direct(inode, size); +} + +/* + * Truncate, by changing the segment file, can consume a fair amount + * of resources. So back off from time to time and do some GC. + * 8 or 2048 blocks should be well within safety limits even if + * every single block resided in a different segment. + */ +#define TRUNCATE_STEP (8 * 1024 * 1024) +int logfs_truncate(struct inode *inode, u64 target) +{ + struct super_block *sb = inode->i_sb; + u64 size = i_size_read(inode); + int err = 0; + + size = ALIGN(size, TRUNCATE_STEP); + while (size > target) { + if (size > TRUNCATE_STEP) + size -= TRUNCATE_STEP; + else + size = 0; + if (size < target) + size = target; + + logfs_get_wblocks(sb, NULL, 1); + err = __logfs_truncate(inode, size); + if (!err) + err = __logfs_write_inode(inode, NULL, 0); + logfs_put_wblocks(sb, NULL, 1); + } + + if (!err) { + err = inode_newsize_ok(inode, target); + if (err) + goto out; + + truncate_setsize(inode, target); + } + + out: + /* I don't trust error recovery yet. */ + WARN_ON(err); + return err; +} + +static void move_page_to_inode(struct inode *inode, struct page *page) +{ + struct logfs_inode *li = logfs_inode(inode); + struct logfs_block *block = logfs_block(page); + + if (!block) + return; + + log_blockmove("move_page_to_inode(%llx, %llx, %x)\n", + block->ino, block->bix, block->level); + BUG_ON(li->li_block); + block->ops = &inode_block_ops; + block->inode = inode; + li->li_block = block; + + block->page = NULL; + if (PagePrivate(page)) { + ClearPagePrivate(page); + page_cache_release(page); + set_page_private(page, 0); + } +} + +static void move_inode_to_page(struct page *page, struct inode *inode) +{ + struct logfs_inode *li = logfs_inode(inode); + struct logfs_block *block = li->li_block; + + if (!block) + return; + + log_blockmove("move_inode_to_page(%llx, %llx, %x)\n", + block->ino, block->bix, block->level); + BUG_ON(PagePrivate(page)); + block->ops = &indirect_block_ops; + block->page = page; + + if (!PagePrivate(page)) { + SetPagePrivate(page); + page_cache_get(page); + set_page_private(page, (unsigned long) block); + } + + block->inode = NULL; + li->li_block = NULL; +} + +int logfs_read_inode(struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + struct logfs_super *super = logfs_super(sb); + struct inode *master_inode = super->s_master_inode; + struct page *page; + struct logfs_disk_inode *di; + u64 ino = inode->i_ino; + + if (ino << sb->s_blocksize_bits > i_size_read(master_inode)) + return -ENODATA; + if (!logfs_exist_block(master_inode, ino)) + return -ENODATA; + + page = read_cache_page(master_inode->i_mapping, ino, + (filler_t *)logfs_readpage, NULL); + if (IS_ERR(page)) + return PTR_ERR(page); + + di = kmap_atomic(page); + logfs_disk_to_inode(di, inode); + kunmap_atomic(di); + move_page_to_inode(inode, page); + page_cache_release(page); + return 0; +} + +/* Caller must logfs_put_write_page(page); */ +static struct page *inode_to_page(struct inode *inode) +{ + struct inode *master_inode = logfs_super(inode->i_sb)->s_master_inode; + struct logfs_disk_inode *di; + struct page *page; + + BUG_ON(inode->i_ino == LOGFS_INO_MASTER); + + page = logfs_get_write_page(master_inode, inode->i_ino, 0); + if (!page) + return NULL; + + di = kmap_atomic(page); + logfs_inode_to_disk(inode, di); + kunmap_atomic(di); + move_inode_to_page(page, inode); + return page; +} + +static int do_write_inode(struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + struct inode *master_inode = logfs_super(sb)->s_master_inode; + loff_t size = (inode->i_ino + 1) << inode->i_sb->s_blocksize_bits; + struct page *page; + int err; + + BUG_ON(inode->i_ino == LOGFS_INO_MASTER); + /* FIXME: lock inode */ + + if (i_size_read(master_inode) < size) + i_size_write(master_inode, size); + + /* TODO: Tell vfs this inode is clean now */ + + page = inode_to_page(inode); + if (!page) + return -ENOMEM; + + /* FIXME: transaction is part of logfs_block now. Is that enough? */ + err = logfs_write_buf(master_inode, page, 0); + if (err) + move_page_to_inode(inode, page); + + logfs_put_write_page(page); + return err; +} + +static void logfs_mod_segment_entry(struct super_block *sb, u32 segno, + int write, + void (*change_se)(struct logfs_segment_entry *, long), + long arg) +{ + struct logfs_super *super = logfs_super(sb); + struct inode *inode; + struct page *page; + struct logfs_segment_entry *se; + pgoff_t page_no; + int child_no; + + page_no = segno >> (sb->s_blocksize_bits - 3); + child_no = segno & ((sb->s_blocksize >> 3) - 1); + + inode = super->s_segfile_inode; + page = logfs_get_write_page(inode, page_no, 0); + BUG_ON(!page); /* FIXME: We need some reserve page for this case */ + if (!PageUptodate(page)) + logfs_read_block(inode, page, WRITE); + + if (write) + alloc_indirect_block(inode, page, 0); + se = kmap_atomic(page); + change_se(se + child_no, arg); + if (write) { + logfs_set_alias(sb, logfs_block(page), child_no); + BUG_ON((int)be32_to_cpu(se[child_no].valid) > super->s_segsize); + } + kunmap_atomic(se); + + logfs_put_write_page(page); +} + +static void __get_segment_entry(struct logfs_segment_entry *se, long _target) +{ + struct logfs_segment_entry *target = (void *)_target; + + *target = *se; +} + +void logfs_get_segment_entry(struct super_block *sb, u32 segno, + struct logfs_segment_entry *se) +{ + logfs_mod_segment_entry(sb, segno, 0, __get_segment_entry, (long)se); +} + +static void __set_segment_used(struct logfs_segment_entry *se, long increment) +{ + u32 valid; + + valid = be32_to_cpu(se->valid); + valid += increment; + se->valid = cpu_to_be32(valid); +} + +void logfs_set_segment_used(struct super_block *sb, u64 ofs, int increment) +{ + struct logfs_super *super = logfs_super(sb); + u32 segno = ofs >> super->s_segshift; + + if (!increment) + return; + + logfs_mod_segment_entry(sb, segno, 1, __set_segment_used, increment); +} + +static void __set_segment_erased(struct logfs_segment_entry *se, long ec_level) +{ + se->ec_level = cpu_to_be32(ec_level); +} + +void logfs_set_segment_erased(struct super_block *sb, u32 segno, u32 ec, + gc_level_t gc_level) +{ + u32 ec_level = ec << 4 | (__force u8)gc_level; + + logfs_mod_segment_entry(sb, segno, 1, __set_segment_erased, ec_level); +} + +static void __set_segment_reserved(struct logfs_segment_entry *se, long ignore) +{ + se->valid = cpu_to_be32(RESERVED); +} + +void logfs_set_segment_reserved(struct super_block *sb, u32 segno) +{ + logfs_mod_segment_entry(sb, segno, 1, __set_segment_reserved, 0); +} + +static void __set_segment_unreserved(struct logfs_segment_entry *se, + long ec_level) +{ + se->valid = 0; + se->ec_level = cpu_to_be32(ec_level); +} + +void logfs_set_segment_unreserved(struct super_block *sb, u32 segno, u32 ec) +{ + u32 ec_level = ec << 4; + + logfs_mod_segment_entry(sb, segno, 1, __set_segment_unreserved, + ec_level); +} + +int __logfs_write_inode(struct inode *inode, struct page *page, long flags) +{ + struct super_block *sb = inode->i_sb; + int ret; + + logfs_get_wblocks(sb, page, flags & WF_LOCK); + ret = do_write_inode(inode); + logfs_put_wblocks(sb, page, flags & WF_LOCK); + return ret; +} + +static int do_delete_inode(struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + struct inode *master_inode = logfs_super(sb)->s_master_inode; + struct page *page; + int ret; + + page = logfs_get_write_page(master_inode, inode->i_ino, 0); + if (!page) + return -ENOMEM; + + move_inode_to_page(page, inode); + + logfs_get_wblocks(sb, page, 1); + ret = __logfs_delete(master_inode, page); + logfs_put_wblocks(sb, page, 1); + + logfs_put_write_page(page); + return ret; +} + +/* + * ZOMBIE inodes have already been deleted before and should remain dead, + * if it weren't for valid checking. No need to kill them again here. + */ +void logfs_evict_inode(struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + struct logfs_inode *li = logfs_inode(inode); + struct logfs_block *block = li->li_block; + struct page *page; + + if (!inode->i_nlink) { + if (!(li->li_flags & LOGFS_IF_ZOMBIE)) { + li->li_flags |= LOGFS_IF_ZOMBIE; + if (i_size_read(inode) > 0) + logfs_truncate(inode, 0); + do_delete_inode(inode); + } + } + truncate_inode_pages_final(&inode->i_data); + clear_inode(inode); + + /* Cheaper version of write_inode. All changes are concealed in + * aliases, which are moved back. No write to the medium happens. + */ + /* Only deleted files may be dirty at this point */ + BUG_ON(inode->i_state & I_DIRTY && inode->i_nlink); + if (!block) + return; + if ((logfs_super(sb)->s_flags & LOGFS_SB_FLAG_SHUTDOWN)) { + block->ops->free_block(inode->i_sb, block); + return; + } + + page = inode_to_page(inode); + BUG_ON(!page); /* FIXME: Use emergency page */ + logfs_put_write_page(page); +} + +void btree_write_block(struct logfs_block *block) +{ + struct inode *inode; + struct page *page; + int err, cookie; + + inode = logfs_safe_iget(block->sb, block->ino, &cookie); + page = logfs_get_write_page(inode, block->bix, block->level); + + err = logfs_readpage_nolock(page); + BUG_ON(err); + BUG_ON(!PagePrivate(page)); + BUG_ON(logfs_block(page) != block); + err = __logfs_write_buf(inode, page, 0); + BUG_ON(err); + BUG_ON(PagePrivate(page) || page->private); + + logfs_put_write_page(page); + logfs_safe_iput(inode, cookie); +} + +/** + * logfs_inode_write - write inode or dentry objects + * + * @inode: parent inode (ifile or directory) + * @buf: object to write (inode or dentry) + * @count: object size + * @bix: block index + * @flags: write flags + * @shadow_tree: shadow below this inode + * + * FIXME: All caller of this put a 200-300 byte variable on the stack, + * only to call here and do a memcpy from that stack variable. A good + * example of wasted performance and stack space. + */ +int logfs_inode_write(struct inode *inode, const void *buf, size_t count, + loff_t bix, long flags, struct shadow_tree *shadow_tree) +{ + loff_t pos = bix << inode->i_sb->s_blocksize_bits; + int err; + struct page *page; + void *pagebuf; + + BUG_ON(pos & (LOGFS_BLOCKSIZE-1)); + BUG_ON(count > LOGFS_BLOCKSIZE); + page = logfs_get_write_page(inode, bix, 0); + if (!page) + return -ENOMEM; + + pagebuf = kmap_atomic(page); + memcpy(pagebuf, buf, count); + flush_dcache_page(page); + kunmap_atomic(pagebuf); + + if (i_size_read(inode) < pos + LOGFS_BLOCKSIZE) + i_size_write(inode, pos + LOGFS_BLOCKSIZE); + + err = logfs_write_buf(inode, page, flags); + logfs_put_write_page(page); + return err; +} + +int logfs_open_segfile(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + struct inode *inode; + + inode = logfs_read_meta_inode(sb, LOGFS_INO_SEGFILE); + if (IS_ERR(inode)) + return PTR_ERR(inode); + super->s_segfile_inode = inode; + return 0; +} + +int logfs_init_rw(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + int min_fill = 3 * super->s_no_blocks; + + INIT_LIST_HEAD(&super->s_object_alias); + INIT_LIST_HEAD(&super->s_writeback_list); + mutex_init(&super->s_write_mutex); + super->s_block_pool = mempool_create_kmalloc_pool(min_fill, + sizeof(struct logfs_block)); + super->s_shadow_pool = mempool_create_kmalloc_pool(min_fill, + sizeof(struct logfs_shadow)); + return 0; +} + +void logfs_cleanup_rw(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + + logfs_mempool_destroy(super->s_block_pool); + logfs_mempool_destroy(super->s_shadow_pool); +} |