From 6cda9fa2575ec0869fe77b0bdf295c0e51868cab Mon Sep 17 00:00:00 2001 From: Ryusuke Konishi Date: Sun, 25 Jul 2010 20:39:03 +0900 Subject: 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 --- fs/nilfs2/dir.c | 26 ++++++++++++++------------ include/linux/nilfs2_fs.h | 18 ++++++++++++++++++ 2 files changed, 32 insertions(+), 12 deletions(-) diff --git a/fs/nilfs2/dir.c b/fs/nilfs2/dir.c index d8d183e6d095..b60277b44468 100644 --- a/fs/nilfs2/dir.c +++ b/fs/nilfs2/dir.c @@ -141,7 +141,7 @@ static void nilfs_check_page(struct page *page) } for (offs = 0; offs <= limit - NILFS_DIR_REC_LEN(1); offs += rec_len) { p = (struct nilfs_dir_entry *)(kaddr + offs); - rec_len = le16_to_cpu(p->rec_len); + rec_len = nilfs_rec_len_from_disk(p->rec_len); if (rec_len < NILFS_DIR_REC_LEN(1)) goto Eshort; @@ -235,7 +235,8 @@ nilfs_match(int len, const unsigned char *name, struct nilfs_dir_entry *de) */ static struct nilfs_dir_entry *nilfs_next_entry(struct nilfs_dir_entry *p) { - return (struct nilfs_dir_entry *)((char *)p + le16_to_cpu(p->rec_len)); + return (struct nilfs_dir_entry *)((char *)p + + nilfs_rec_len_from_disk(p->rec_len)); } static unsigned char @@ -326,7 +327,7 @@ static int nilfs_readdir(struct file *filp, void *dirent, filldir_t filldir) goto success; } } - filp->f_pos += le16_to_cpu(de->rec_len); + filp->f_pos += nilfs_rec_len_from_disk(de->rec_len); } nilfs_put_page(page); } @@ -441,7 +442,7 @@ void nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de, struct page *page, struct inode *inode) { unsigned from = (char *) de - (char *) page_address(page); - unsigned to = from + le16_to_cpu(de->rec_len); + unsigned to = from + nilfs_rec_len_from_disk(de->rec_len); struct address_space *mapping = page->mapping; int err; @@ -497,7 +498,7 @@ int nilfs_add_link(struct dentry *dentry, struct inode *inode) /* We hit i_size */ name_len = 0; rec_len = chunk_size; - de->rec_len = cpu_to_le16(chunk_size); + de->rec_len = nilfs_rec_len_to_disk(chunk_size); de->inode = 0; goto got_it; } @@ -511,7 +512,7 @@ int nilfs_add_link(struct dentry *dentry, struct inode *inode) if (nilfs_match(namelen, name, de)) goto out_unlock; name_len = NILFS_DIR_REC_LEN(de->name_len); - rec_len = le16_to_cpu(de->rec_len); + rec_len = nilfs_rec_len_from_disk(de->rec_len); if (!de->inode && rec_len >= reclen) goto got_it; if (rec_len >= name_len + reclen) @@ -534,8 +535,8 @@ got_it: struct nilfs_dir_entry *de1; de1 = (struct nilfs_dir_entry *)((char *)de + name_len); - de1->rec_len = cpu_to_le16(rec_len - name_len); - de->rec_len = cpu_to_le16(name_len); + de1->rec_len = nilfs_rec_len_to_disk(rec_len - name_len); + de->rec_len = nilfs_rec_len_to_disk(name_len); de = de1; } de->name_len = namelen; @@ -566,7 +567,8 @@ int nilfs_delete_entry(struct nilfs_dir_entry *dir, struct page *page) struct inode *inode = mapping->host; char *kaddr = page_address(page); unsigned from = ((char *)dir - kaddr) & ~(nilfs_chunk_size(inode) - 1); - unsigned to = ((char *)dir - kaddr) + le16_to_cpu(dir->rec_len); + unsigned to = ((char *)dir - kaddr) + + nilfs_rec_len_from_disk(dir->rec_len); struct nilfs_dir_entry *pde = NULL; struct nilfs_dir_entry *de = (struct nilfs_dir_entry *)(kaddr + from); int err; @@ -587,7 +589,7 @@ int nilfs_delete_entry(struct nilfs_dir_entry *dir, struct page *page) err = nilfs_prepare_chunk(page, mapping, from, to); BUG_ON(err); if (pde) - pde->rec_len = cpu_to_le16(to - from); + pde->rec_len = nilfs_rec_len_to_disk(to - from); dir->inode = 0; nilfs_commit_chunk(page, mapping, from, to); inode->i_ctime = inode->i_mtime = CURRENT_TIME; @@ -621,14 +623,14 @@ int nilfs_make_empty(struct inode *inode, struct inode *parent) memset(kaddr, 0, chunk_size); de = (struct nilfs_dir_entry *)kaddr; de->name_len = 1; - de->rec_len = cpu_to_le16(NILFS_DIR_REC_LEN(1)); + de->rec_len = nilfs_rec_len_to_disk(NILFS_DIR_REC_LEN(1)); memcpy(de->name, ".\0\0", 4); de->inode = cpu_to_le64(inode->i_ino); nilfs_set_de_type(de, inode); de = (struct nilfs_dir_entry *)(kaddr + NILFS_DIR_REC_LEN(1)); de->name_len = 2; - de->rec_len = cpu_to_le16(chunk_size - NILFS_DIR_REC_LEN(1)); + de->rec_len = nilfs_rec_len_to_disk(chunk_size - NILFS_DIR_REC_LEN(1)); de->inode = cpu_to_le64(parent->i_ino); memcpy(de->name, "..\0", 4); nilfs_set_de_type(de, inode); diff --git a/include/linux/nilfs2_fs.h b/include/linux/nilfs2_fs.h index 7dd4cd494490..970828a5ffc5 100644 --- a/include/linux/nilfs2_fs.h +++ b/include/linux/nilfs2_fs.h @@ -326,7 +326,25 @@ enum { #define NILFS_DIR_ROUND (NILFS_DIR_PAD - 1) #define NILFS_DIR_REC_LEN(name_len) (((name_len) + 12 + NILFS_DIR_ROUND) & \ ~NILFS_DIR_ROUND) +#define NILFS_MAX_REC_LEN ((1<<16)-1) +static inline unsigned nilfs_rec_len_from_disk(__le16 dlen) +{ + unsigned len = le16_to_cpu(dlen); + + if (len == NILFS_MAX_REC_LEN) + return 1 << 16; + return len; +} + +static inline __le16 nilfs_rec_len_to_disk(unsigned len) +{ + if (len == (1 << 16)) + return cpu_to_le16(NILFS_MAX_REC_LEN); + else if (len > (1 << 16)) + BUG(); + return cpu_to_le16(len); +} /** * struct nilfs_finfo - file information -- cgit v1.2.1