nilfs2: avoid rec_len overflow with 64KB block size
With 64KB blocksize, a directory entry can have size 64KB which does not fit into 16 bits we have for entry length. So this patch stores 0xffff instead and converts value when read from / written to disk. Nilfs derives its directory implementation from ext2 filesystem, and this draws upon the corresponding change on ext2. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
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@ -141,7 +141,7 @@ static void nilfs_check_page(struct page *page)
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}
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for (offs = 0; offs <= limit - NILFS_DIR_REC_LEN(1); offs += rec_len) {
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p = (struct nilfs_dir_entry *)(kaddr + offs);
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rec_len = le16_to_cpu(p->rec_len);
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rec_len = nilfs_rec_len_from_disk(p->rec_len);
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if (rec_len < NILFS_DIR_REC_LEN(1))
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goto Eshort;
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@ -235,7 +235,8 @@ nilfs_match(int len, const unsigned char *name, struct nilfs_dir_entry *de)
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*/
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static struct nilfs_dir_entry *nilfs_next_entry(struct nilfs_dir_entry *p)
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{
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return (struct nilfs_dir_entry *)((char *)p + le16_to_cpu(p->rec_len));
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return (struct nilfs_dir_entry *)((char *)p +
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nilfs_rec_len_from_disk(p->rec_len));
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}
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static unsigned char
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@ -326,7 +327,7 @@ static int nilfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
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goto success;
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}
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}
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filp->f_pos += le16_to_cpu(de->rec_len);
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filp->f_pos += nilfs_rec_len_from_disk(de->rec_len);
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}
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nilfs_put_page(page);
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}
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@ -441,7 +442,7 @@ void nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de,
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struct page *page, struct inode *inode)
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{
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unsigned from = (char *) de - (char *) page_address(page);
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unsigned to = from + le16_to_cpu(de->rec_len);
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unsigned to = from + nilfs_rec_len_from_disk(de->rec_len);
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struct address_space *mapping = page->mapping;
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int err;
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@ -497,7 +498,7 @@ int nilfs_add_link(struct dentry *dentry, struct inode *inode)
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/* We hit i_size */
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name_len = 0;
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rec_len = chunk_size;
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de->rec_len = cpu_to_le16(chunk_size);
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de->rec_len = nilfs_rec_len_to_disk(chunk_size);
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de->inode = 0;
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goto got_it;
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}
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@ -511,7 +512,7 @@ int nilfs_add_link(struct dentry *dentry, struct inode *inode)
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if (nilfs_match(namelen, name, de))
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goto out_unlock;
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name_len = NILFS_DIR_REC_LEN(de->name_len);
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rec_len = le16_to_cpu(de->rec_len);
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rec_len = nilfs_rec_len_from_disk(de->rec_len);
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if (!de->inode && rec_len >= reclen)
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goto got_it;
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if (rec_len >= name_len + reclen)
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@ -534,8 +535,8 @@ got_it:
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struct nilfs_dir_entry *de1;
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de1 = (struct nilfs_dir_entry *)((char *)de + name_len);
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de1->rec_len = cpu_to_le16(rec_len - name_len);
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de->rec_len = cpu_to_le16(name_len);
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de1->rec_len = nilfs_rec_len_to_disk(rec_len - name_len);
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de->rec_len = nilfs_rec_len_to_disk(name_len);
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de = de1;
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}
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de->name_len = namelen;
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@ -566,7 +567,8 @@ int nilfs_delete_entry(struct nilfs_dir_entry *dir, struct page *page)
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struct inode *inode = mapping->host;
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char *kaddr = page_address(page);
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unsigned from = ((char *)dir - kaddr) & ~(nilfs_chunk_size(inode) - 1);
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unsigned to = ((char *)dir - kaddr) + le16_to_cpu(dir->rec_len);
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unsigned to = ((char *)dir - kaddr) +
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nilfs_rec_len_from_disk(dir->rec_len);
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struct nilfs_dir_entry *pde = NULL;
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struct nilfs_dir_entry *de = (struct nilfs_dir_entry *)(kaddr + from);
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int err;
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@ -587,7 +589,7 @@ int nilfs_delete_entry(struct nilfs_dir_entry *dir, struct page *page)
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err = nilfs_prepare_chunk(page, mapping, from, to);
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BUG_ON(err);
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if (pde)
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pde->rec_len = cpu_to_le16(to - from);
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pde->rec_len = nilfs_rec_len_to_disk(to - from);
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dir->inode = 0;
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nilfs_commit_chunk(page, mapping, from, to);
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inode->i_ctime = inode->i_mtime = CURRENT_TIME;
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@ -621,14 +623,14 @@ int nilfs_make_empty(struct inode *inode, struct inode *parent)
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memset(kaddr, 0, chunk_size);
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de = (struct nilfs_dir_entry *)kaddr;
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de->name_len = 1;
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de->rec_len = cpu_to_le16(NILFS_DIR_REC_LEN(1));
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de->rec_len = nilfs_rec_len_to_disk(NILFS_DIR_REC_LEN(1));
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memcpy(de->name, ".\0\0", 4);
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de->inode = cpu_to_le64(inode->i_ino);
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nilfs_set_de_type(de, inode);
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de = (struct nilfs_dir_entry *)(kaddr + NILFS_DIR_REC_LEN(1));
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de->name_len = 2;
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de->rec_len = cpu_to_le16(chunk_size - NILFS_DIR_REC_LEN(1));
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de->rec_len = nilfs_rec_len_to_disk(chunk_size - NILFS_DIR_REC_LEN(1));
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de->inode = cpu_to_le64(parent->i_ino);
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memcpy(de->name, "..\0", 4);
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nilfs_set_de_type(de, inode);
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@ -326,7 +326,25 @@ enum {
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#define NILFS_DIR_ROUND (NILFS_DIR_PAD - 1)
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#define NILFS_DIR_REC_LEN(name_len) (((name_len) + 12 + NILFS_DIR_ROUND) & \
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~NILFS_DIR_ROUND)
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#define NILFS_MAX_REC_LEN ((1<<16)-1)
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static inline unsigned nilfs_rec_len_from_disk(__le16 dlen)
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{
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unsigned len = le16_to_cpu(dlen);
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if (len == NILFS_MAX_REC_LEN)
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return 1 << 16;
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return len;
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}
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static inline __le16 nilfs_rec_len_to_disk(unsigned len)
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{
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if (len == (1 << 16))
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return cpu_to_le16(NILFS_MAX_REC_LEN);
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else if (len > (1 << 16))
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BUG();
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return cpu_to_le16(len);
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}
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/**
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* struct nilfs_finfo - file information
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