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>
diff --git a/fs/nilfs2/dir.c b/fs/nilfs2/dir.c
index d8d183e..b60277b 100644
--- a/fs/nilfs2/dir.c
+++ b/fs/nilfs2/dir.c
@@ -141,7 +141,7 @@
}
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 @@
*/
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 @@
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 @@
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 @@
/* 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 @@
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 @@
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 @@
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 @@
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 @@
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);
