diff options
Diffstat (limited to 'fs/logfs/dir.c')
-rw-r--r-- | fs/logfs/dir.c | 801 |
1 files changed, 0 insertions, 801 deletions
diff --git a/fs/logfs/dir.c b/fs/logfs/dir.c deleted file mode 100644 index c87ea52de3d9..000000000000 --- a/fs/logfs/dir.c +++ /dev/null @@ -1,801 +0,0 @@ -/* - * fs/logfs/dir.c - directory-related code - * - * As should be obvious for Linux kernel code, license is GPLv2 - * - * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org> - */ -#include "logfs.h" -#include <linux/slab.h> - -/* - * Atomic dir operations - * - * Directory operations are by default not atomic. Dentries and Inodes are - * created/removed/altered in separate operations. Therefore we need to do - * a small amount of journaling. - * - * Create, link, mkdir, mknod and symlink all share the same function to do - * the work: __logfs_create. This function works in two atomic steps: - * 1. allocate inode (remember in journal) - * 2. allocate dentry (clear journal) - * - * As we can only get interrupted between the two, when the inode we just - * created is simply stored in the anchor. On next mount, if we were - * interrupted, we delete the inode. From a users point of view the - * operation never happened. - * - * Unlink and rmdir also share the same function: unlink. Again, this - * function works in two atomic steps - * 1. remove dentry (remember inode in journal) - * 2. unlink inode (clear journal) - * - * And again, on the next mount, if we were interrupted, we delete the inode. - * From a users point of view the operation succeeded. - * - * Rename is the real pain to deal with, harder than all the other methods - * combined. Depending on the circumstances we can run into three cases. - * A "target rename" where the target dentry already existed, a "local - * rename" where both parent directories are identical or a "cross-directory - * rename" in the remaining case. - * - * Local rename is atomic, as the old dentry is simply rewritten with a new - * name. - * - * Cross-directory rename works in two steps, similar to __logfs_create and - * logfs_unlink: - * 1. Write new dentry (remember old dentry in journal) - * 2. Remove old dentry (clear journal) - * - * Here we remember a dentry instead of an inode. On next mount, if we were - * interrupted, we delete the dentry. From a users point of view, the - * operation succeeded. - * - * Target rename works in three atomic steps: - * 1. Attach old inode to new dentry (remember old dentry and new inode) - * 2. Remove old dentry (still remember the new inode) - * 3. Remove victim inode - * - * Here we remember both an inode an a dentry. If we get interrupted - * between steps 1 and 2, we delete both the dentry and the inode. If - * we get interrupted between steps 2 and 3, we delete just the inode. - * In either case, the remaining objects are deleted on next mount. From - * a users point of view, the operation succeeded. - */ - -static int write_dir(struct inode *dir, struct logfs_disk_dentry *dd, - loff_t pos) -{ - return logfs_inode_write(dir, dd, sizeof(*dd), pos, WF_LOCK, NULL); -} - -static int write_inode(struct inode *inode) -{ - return __logfs_write_inode(inode, NULL, WF_LOCK); -} - -static s64 dir_seek_data(struct inode *inode, s64 pos) -{ - s64 new_pos = logfs_seek_data(inode, pos); - - return max(pos, new_pos - 1); -} - -static int beyond_eof(struct inode *inode, loff_t bix) -{ - loff_t pos = bix << inode->i_sb->s_blocksize_bits; - return pos >= i_size_read(inode); -} - -/* - * Prime value was chosen to be roughly 256 + 26. r5 hash uses 11, - * so short names (len <= 9) don't even occupy the complete 32bit name - * space. A prime >256 ensures short names quickly spread the 32bit - * name space. Add about 26 for the estimated amount of information - * of each character and pick a prime nearby, preferably a bit-sparse - * one. - */ -static u32 logfs_hash_32(const char *s, int len, u32 seed) -{ - u32 hash = seed; - int i; - - for (i = 0; i < len; i++) - hash = hash * 293 + s[i]; - return hash; -} - -/* - * We have to satisfy several conflicting requirements here. Small - * directories should stay fairly compact and not require too many - * indirect blocks. The number of possible locations for a given hash - * should be small to make lookup() fast. And we should try hard not - * to overflow the 32bit name space or nfs and 32bit host systems will - * be unhappy. - * - * So we use the following scheme. First we reduce the hash to 0..15 - * and try a direct block. If that is occupied we reduce the hash to - * 16..255 and try an indirect block. Same for 2x and 3x indirect - * blocks. Lastly we reduce the hash to 0x800_0000 .. 0xffff_ffff, - * but use buckets containing eight entries instead of a single one. - * - * Using 16 entries should allow for a reasonable amount of hash - * collisions, so the 32bit name space can be packed fairly tight - * before overflowing. Oh and currently we don't overflow but return - * and error. - * - * How likely are collisions? Doing the appropriate math is beyond me - * and the Bronstein textbook. But running a test program to brute - * force collisions for a couple of days showed that on average the - * first collision occurs after 598M entries, with 290M being the - * smallest result. Obviously 21 entries could already cause a - * collision if all entries are carefully chosen. - */ -static pgoff_t hash_index(u32 hash, int round) -{ - u32 i0_blocks = I0_BLOCKS; - u32 i1_blocks = I1_BLOCKS; - u32 i2_blocks = I2_BLOCKS; - u32 i3_blocks = I3_BLOCKS; - - switch (round) { - case 0: - return hash % i0_blocks; - case 1: - return i0_blocks + hash % (i1_blocks - i0_blocks); - case 2: - return i1_blocks + hash % (i2_blocks - i1_blocks); - case 3: - return i2_blocks + hash % (i3_blocks - i2_blocks); - case 4 ... 19: - return i3_blocks + 16 * (hash % (((1<<31) - i3_blocks) / 16)) - + round - 4; - } - BUG(); -} - -static struct page *logfs_get_dd_page(struct inode *dir, struct dentry *dentry) -{ - const struct qstr *name = &dentry->d_name; - struct page *page; - struct logfs_disk_dentry *dd; - u32 hash = logfs_hash_32(name->name, name->len, 0); - pgoff_t index; - int round; - - if (name->len > LOGFS_MAX_NAMELEN) - return ERR_PTR(-ENAMETOOLONG); - - for (round = 0; round < 20; round++) { - index = hash_index(hash, round); - - if (beyond_eof(dir, index)) - return NULL; - if (!logfs_exist_block(dir, index)) - continue; - page = read_cache_page(dir->i_mapping, index, - (filler_t *)logfs_readpage, NULL); - if (IS_ERR(page)) - return page; - dd = kmap_atomic(page); - BUG_ON(dd->namelen == 0); - - if (name->len != be16_to_cpu(dd->namelen) || - memcmp(name->name, dd->name, name->len)) { - kunmap_atomic(dd); - put_page(page); - continue; - } - - kunmap_atomic(dd); - return page; - } - return NULL; -} - -static int logfs_remove_inode(struct inode *inode) -{ - int ret; - - drop_nlink(inode); - ret = write_inode(inode); - LOGFS_BUG_ON(ret, inode->i_sb); - return ret; -} - -static void abort_transaction(struct inode *inode, struct logfs_transaction *ta) -{ - if (logfs_inode(inode)->li_block) - logfs_inode(inode)->li_block->ta = NULL; - kfree(ta); -} - -static int logfs_unlink(struct inode *dir, struct dentry *dentry) -{ - struct logfs_super *super = logfs_super(dir->i_sb); - struct inode *inode = d_inode(dentry); - struct logfs_transaction *ta; - struct page *page; - pgoff_t index; - int ret; - - ta = kzalloc(sizeof(*ta), GFP_KERNEL); - if (!ta) - return -ENOMEM; - - ta->state = UNLINK_1; - ta->ino = inode->i_ino; - - inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode); - - page = logfs_get_dd_page(dir, dentry); - if (!page) { - kfree(ta); - return -ENOENT; - } - if (IS_ERR(page)) { - kfree(ta); - return PTR_ERR(page); - } - index = page->index; - put_page(page); - - mutex_lock(&super->s_dirop_mutex); - logfs_add_transaction(dir, ta); - - ret = logfs_delete(dir, index, NULL); - if (!ret) - ret = write_inode(dir); - - if (ret) { - abort_transaction(dir, ta); - printk(KERN_ERR"LOGFS: unable to delete inode\n"); - goto out; - } - - ta->state = UNLINK_2; - logfs_add_transaction(inode, ta); - ret = logfs_remove_inode(inode); -out: - mutex_unlock(&super->s_dirop_mutex); - return ret; -} - -static inline int logfs_empty_dir(struct inode *dir) -{ - u64 data; - - data = logfs_seek_data(dir, 0) << dir->i_sb->s_blocksize_bits; - return data >= i_size_read(dir); -} - -static int logfs_rmdir(struct inode *dir, struct dentry *dentry) -{ - struct inode *inode = d_inode(dentry); - - if (!logfs_empty_dir(inode)) - return -ENOTEMPTY; - - return logfs_unlink(dir, dentry); -} - -/* FIXME: readdir currently has it's own dir_walk code. I don't see a good - * way to combine the two copies */ -static int logfs_readdir(struct file *file, struct dir_context *ctx) -{ - struct inode *dir = file_inode(file); - loff_t pos; - struct page *page; - struct logfs_disk_dentry *dd; - - if (ctx->pos < 0) - return -EINVAL; - - if (!dir_emit_dots(file, ctx)) - return 0; - - pos = ctx->pos - 2; - BUG_ON(pos < 0); - for (;; pos++, ctx->pos++) { - bool full; - if (beyond_eof(dir, pos)) - break; - if (!logfs_exist_block(dir, pos)) { - /* deleted dentry */ - pos = dir_seek_data(dir, pos); - continue; - } - page = read_cache_page(dir->i_mapping, pos, - (filler_t *)logfs_readpage, NULL); - if (IS_ERR(page)) - return PTR_ERR(page); - dd = kmap(page); - BUG_ON(dd->namelen == 0); - - full = !dir_emit(ctx, (char *)dd->name, - be16_to_cpu(dd->namelen), - be64_to_cpu(dd->ino), dd->type); - kunmap(page); - put_page(page); - if (full) - break; - } - return 0; -} - -static void logfs_set_name(struct logfs_disk_dentry *dd, const struct qstr *name) -{ - dd->namelen = cpu_to_be16(name->len); - memcpy(dd->name, name->name, name->len); -} - -static struct dentry *logfs_lookup(struct inode *dir, struct dentry *dentry, - unsigned int flags) -{ - struct page *page; - struct logfs_disk_dentry *dd; - pgoff_t index; - u64 ino = 0; - struct inode *inode; - - page = logfs_get_dd_page(dir, dentry); - if (IS_ERR(page)) - return ERR_CAST(page); - if (!page) { - d_add(dentry, NULL); - return NULL; - } - index = page->index; - dd = kmap_atomic(page); - ino = be64_to_cpu(dd->ino); - kunmap_atomic(dd); - put_page(page); - - inode = logfs_iget(dir->i_sb, ino); - if (IS_ERR(inode)) - printk(KERN_ERR"LogFS: Cannot read inode #%llx for dentry (%lx, %lx)n", - ino, dir->i_ino, index); - return d_splice_alias(inode, dentry); -} - -static void grow_dir(struct inode *dir, loff_t index) -{ - index = (index + 1) << dir->i_sb->s_blocksize_bits; - if (i_size_read(dir) < index) - i_size_write(dir, index); -} - -static int logfs_write_dir(struct inode *dir, struct dentry *dentry, - struct inode *inode) -{ - struct page *page; - struct logfs_disk_dentry *dd; - u32 hash = logfs_hash_32(dentry->d_name.name, dentry->d_name.len, 0); - pgoff_t index; - int round, err; - - for (round = 0; round < 20; round++) { - index = hash_index(hash, round); - - if (logfs_exist_block(dir, index)) - continue; - page = find_or_create_page(dir->i_mapping, index, GFP_KERNEL); - if (!page) - return -ENOMEM; - - dd = kmap_atomic(page); - memset(dd, 0, sizeof(*dd)); - dd->ino = cpu_to_be64(inode->i_ino); - dd->type = logfs_type(inode); - logfs_set_name(dd, &dentry->d_name); - kunmap_atomic(dd); - - err = logfs_write_buf(dir, page, WF_LOCK); - unlock_page(page); - put_page(page); - if (!err) - grow_dir(dir, index); - return err; - } - /* FIXME: Is there a better return value? In most cases neither - * the filesystem nor the directory are full. But we have had - * too many collisions for this particular hash and no fallback. - */ - return -ENOSPC; -} - -static int __logfs_create(struct inode *dir, struct dentry *dentry, - struct inode *inode, const char *dest, long destlen) -{ - struct logfs_super *super = logfs_super(dir->i_sb); - struct logfs_inode *li = logfs_inode(inode); - struct logfs_transaction *ta; - int ret; - - ta = kzalloc(sizeof(*ta), GFP_KERNEL); - if (!ta) { - drop_nlink(inode); - iput(inode); - return -ENOMEM; - } - - ta->state = CREATE_1; - ta->ino = inode->i_ino; - mutex_lock(&super->s_dirop_mutex); - logfs_add_transaction(inode, ta); - - if (dest) { - /* symlink */ - ret = logfs_inode_write(inode, dest, destlen, 0, WF_LOCK, NULL); - if (!ret) - ret = write_inode(inode); - } else { - /* creat/mkdir/mknod */ - ret = write_inode(inode); - } - if (ret) { - abort_transaction(inode, ta); - li->li_flags |= LOGFS_IF_STILLBORN; - /* FIXME: truncate symlink */ - drop_nlink(inode); - iput(inode); - goto out; - } - - ta->state = CREATE_2; - logfs_add_transaction(dir, ta); - ret = logfs_write_dir(dir, dentry, inode); - /* sync directory */ - if (!ret) - ret = write_inode(dir); - - if (ret) { - logfs_del_transaction(dir, ta); - ta->state = CREATE_2; - logfs_add_transaction(inode, ta); - logfs_remove_inode(inode); - iput(inode); - goto out; - } - d_instantiate(dentry, inode); -out: - mutex_unlock(&super->s_dirop_mutex); - return ret; -} - -static int logfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) -{ - struct inode *inode; - - /* - * FIXME: why do we have to fill in S_IFDIR, while the mode is - * correct for mknod, creat, etc.? Smells like the vfs *should* - * do it for us but for some reason fails to do so. - */ - inode = logfs_new_inode(dir, S_IFDIR | mode); - if (IS_ERR(inode)) - return PTR_ERR(inode); - - inode->i_op = &logfs_dir_iops; - inode->i_fop = &logfs_dir_fops; - - return __logfs_create(dir, dentry, inode, NULL, 0); -} - -static int logfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, - bool excl) -{ - struct inode *inode; - - inode = logfs_new_inode(dir, mode); - if (IS_ERR(inode)) - return PTR_ERR(inode); - - inode->i_op = &logfs_reg_iops; - inode->i_fop = &logfs_reg_fops; - inode->i_mapping->a_ops = &logfs_reg_aops; - - return __logfs_create(dir, dentry, inode, NULL, 0); -} - -static int logfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, - dev_t rdev) -{ - struct inode *inode; - - if (dentry->d_name.len > LOGFS_MAX_NAMELEN) - return -ENAMETOOLONG; - - inode = logfs_new_inode(dir, mode); - if (IS_ERR(inode)) - return PTR_ERR(inode); - - init_special_inode(inode, mode, rdev); - - return __logfs_create(dir, dentry, inode, NULL, 0); -} - -static int logfs_symlink(struct inode *dir, struct dentry *dentry, - const char *target) -{ - struct inode *inode; - size_t destlen = strlen(target) + 1; - - if (destlen > dir->i_sb->s_blocksize) - return -ENAMETOOLONG; - - inode = logfs_new_inode(dir, S_IFLNK | 0777); - if (IS_ERR(inode)) - return PTR_ERR(inode); - - inode->i_op = &page_symlink_inode_operations; - inode_nohighmem(inode); - inode->i_mapping->a_ops = &logfs_reg_aops; - - return __logfs_create(dir, dentry, inode, target, destlen); -} - -static int logfs_link(struct dentry *old_dentry, struct inode *dir, - struct dentry *dentry) -{ - struct inode *inode = d_inode(old_dentry); - - inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode); - ihold(inode); - inc_nlink(inode); - mark_inode_dirty_sync(inode); - - return __logfs_create(dir, dentry, inode, NULL, 0); -} - -static int logfs_get_dd(struct inode *dir, struct dentry *dentry, - struct logfs_disk_dentry *dd, loff_t *pos) -{ - struct page *page; - void *map; - - page = logfs_get_dd_page(dir, dentry); - if (IS_ERR(page)) - return PTR_ERR(page); - *pos = page->index; - map = kmap_atomic(page); - memcpy(dd, map, sizeof(*dd)); - kunmap_atomic(map); - put_page(page); - return 0; -} - -static int logfs_delete_dd(struct inode *dir, loff_t pos) -{ - /* - * Getting called with pos somewhere beyond eof is either a goofup - * within this file or means someone maliciously edited the - * (crc-protected) journal. - */ - BUG_ON(beyond_eof(dir, pos)); - dir->i_ctime = dir->i_mtime = current_time(dir); - log_dir(" Delete dentry (%lx, %llx)\n", dir->i_ino, pos); - return logfs_delete(dir, pos, NULL); -} - -/* - * Cross-directory rename, target does not exist. Just a little nasty. - * Create a new dentry in the target dir, then remove the old dentry, - * all the while taking care to remember our operation in the journal. - */ -static int logfs_rename_cross(struct inode *old_dir, struct dentry *old_dentry, - struct inode *new_dir, struct dentry *new_dentry) -{ - struct logfs_super *super = logfs_super(old_dir->i_sb); - struct logfs_disk_dentry dd; - struct logfs_transaction *ta; - loff_t pos; - int err; - - /* 1. locate source dd */ - err = logfs_get_dd(old_dir, old_dentry, &dd, &pos); - if (err) - return err; - - ta = kzalloc(sizeof(*ta), GFP_KERNEL); - if (!ta) - return -ENOMEM; - - ta->state = CROSS_RENAME_1; - ta->dir = old_dir->i_ino; - ta->pos = pos; - - /* 2. write target dd */ - mutex_lock(&super->s_dirop_mutex); - logfs_add_transaction(new_dir, ta); - err = logfs_write_dir(new_dir, new_dentry, d_inode(old_dentry)); - if (!err) - err = write_inode(new_dir); - - if (err) { - super->s_rename_dir = 0; - super->s_rename_pos = 0; - abort_transaction(new_dir, ta); - goto out; - } - - /* 3. remove source dd */ - ta->state = CROSS_RENAME_2; - logfs_add_transaction(old_dir, ta); - err = logfs_delete_dd(old_dir, pos); - if (!err) - err = write_inode(old_dir); - LOGFS_BUG_ON(err, old_dir->i_sb); -out: - mutex_unlock(&super->s_dirop_mutex); - return err; -} - -static int logfs_replace_inode(struct inode *dir, struct dentry *dentry, - struct logfs_disk_dentry *dd, struct inode *inode) -{ - loff_t pos; - int err; - - err = logfs_get_dd(dir, dentry, dd, &pos); - if (err) - return err; - dd->ino = cpu_to_be64(inode->i_ino); - dd->type = logfs_type(inode); - - err = write_dir(dir, dd, pos); - if (err) - return err; - log_dir("Replace dentry (%lx, %llx) %s -> %llx\n", dir->i_ino, pos, - dd->name, be64_to_cpu(dd->ino)); - return write_inode(dir); -} - -/* Target dentry exists - the worst case. We need to attach the source - * inode to the target dentry, then remove the orphaned target inode and - * source dentry. - */ -static int logfs_rename_target(struct inode *old_dir, struct dentry *old_dentry, - struct inode *new_dir, struct dentry *new_dentry) -{ - struct logfs_super *super = logfs_super(old_dir->i_sb); - struct inode *old_inode = d_inode(old_dentry); - struct inode *new_inode = d_inode(new_dentry); - int isdir = S_ISDIR(old_inode->i_mode); - struct logfs_disk_dentry dd; - struct logfs_transaction *ta; - loff_t pos; - int err; - - BUG_ON(isdir != S_ISDIR(new_inode->i_mode)); - if (isdir) { - if (!logfs_empty_dir(new_inode)) - return -ENOTEMPTY; - } - - /* 1. locate source dd */ - err = logfs_get_dd(old_dir, old_dentry, &dd, &pos); - if (err) - return err; - - ta = kzalloc(sizeof(*ta), GFP_KERNEL); - if (!ta) - return -ENOMEM; - - ta->state = TARGET_RENAME_1; - ta->dir = old_dir->i_ino; - ta->pos = pos; - ta->ino = new_inode->i_ino; - - /* 2. attach source inode to target dd */ - mutex_lock(&super->s_dirop_mutex); - logfs_add_transaction(new_dir, ta); - err = logfs_replace_inode(new_dir, new_dentry, &dd, old_inode); - if (err) { - super->s_rename_dir = 0; - super->s_rename_pos = 0; - super->s_victim_ino = 0; - abort_transaction(new_dir, ta); - goto out; - } - - /* 3. remove source dd */ - ta->state = TARGET_RENAME_2; - logfs_add_transaction(old_dir, ta); - err = logfs_delete_dd(old_dir, pos); - if (!err) - err = write_inode(old_dir); - LOGFS_BUG_ON(err, old_dir->i_sb); - - /* 4. remove target inode */ - ta->state = TARGET_RENAME_3; - logfs_add_transaction(new_inode, ta); - err = logfs_remove_inode(new_inode); - -out: - mutex_unlock(&super->s_dirop_mutex); - return err; -} - -static int logfs_rename(struct inode *old_dir, struct dentry *old_dentry, - struct inode *new_dir, struct dentry *new_dentry, - unsigned int flags) -{ - if (flags & ~RENAME_NOREPLACE) - return -EINVAL; - - if (d_really_is_positive(new_dentry)) - return logfs_rename_target(old_dir, old_dentry, - new_dir, new_dentry); - return logfs_rename_cross(old_dir, old_dentry, new_dir, new_dentry); -} - -/* No locking done here, as this is called before .get_sb() returns. */ -int logfs_replay_journal(struct super_block *sb) -{ - struct logfs_super *super = logfs_super(sb); - struct inode *inode; - u64 ino, pos; - int err; - - if (super->s_victim_ino) { - /* delete victim inode */ - ino = super->s_victim_ino; - printk(KERN_INFO"LogFS: delete unmapped inode #%llx\n", ino); - inode = logfs_iget(sb, ino); - if (IS_ERR(inode)) - goto fail; - - LOGFS_BUG_ON(i_size_read(inode) > 0, sb); - super->s_victim_ino = 0; - err = logfs_remove_inode(inode); - iput(inode); - if (err) { - super->s_victim_ino = ino; - goto fail; - } - } - if (super->s_rename_dir) { - /* delete old dd from rename */ - ino = super->s_rename_dir; - pos = super->s_rename_pos; - printk(KERN_INFO"LogFS: delete unbacked dentry (%llx, %llx)\n", - ino, pos); - inode = logfs_iget(sb, ino); - if (IS_ERR(inode)) - goto fail; - - super->s_rename_dir = 0; - super->s_rename_pos = 0; - err = logfs_delete_dd(inode, pos); - iput(inode); - if (err) { - super->s_rename_dir = ino; - super->s_rename_pos = pos; - goto fail; - } - } - return 0; -fail: - LOGFS_BUG(sb); - return -EIO; -} - -const struct inode_operations logfs_dir_iops = { - .create = logfs_create, - .link = logfs_link, - .lookup = logfs_lookup, - .mkdir = logfs_mkdir, - .mknod = logfs_mknod, - .rename = logfs_rename, - .rmdir = logfs_rmdir, - .symlink = logfs_symlink, - .unlink = logfs_unlink, -}; -const struct file_operations logfs_dir_fops = { - .fsync = logfs_fsync, - .unlocked_ioctl = logfs_ioctl, - .iterate_shared = logfs_readdir, - .read = generic_read_dir, - .llseek = generic_file_llseek, -}; |