/*
* routine to check that the specified directory is empty (for rmdir)
*/
static int empty_dir(struct inode * inode)
{
struct super_block * sb;
unsigned long pos, block, offset; /* pos = block * block_size + offset */
struct buffer_head * bh;
struct sysv_dir_entry * de;
if (!inode)
return 1;
block = 0;
bh = NULL;
pos = offset = 2*SYSV_DIRSIZE;
if (inode->i_size % SYSV_DIRSIZE)
goto bad_dir;
if (inode->i_size < pos)
goto bad_dir;
bh = sysv_file_bread(inode, 0, 0);
if (!bh)
goto bad_dir;
de = (struct sysv_dir_entry *) (bh->b_data + 0*SYSV_DIRSIZE);
if (!de->inode || strcmp(de->name,"."))
goto bad_dir;
de = (struct sysv_dir_entry *) (bh->b_data + 1*SYSV_DIRSIZE);
if (!de->inode || strcmp(de->name,".."))
goto bad_dir;
sb = inode->i_sb;
while (pos < inode->i_size) {
if (!bh) {
bh = sysv_file_bread(inode, block, 0);
if (!bh) {
/* offset = 0; */ block++;
pos += sb->sv_block_size;
continue;
}
}
de = (struct sysv_dir_entry *) (bh->b_data + offset);
pos += SYSV_DIRSIZE;
offset += SYSV_DIRSIZE;
if (de->inode) {
brelse(bh);
return 0;
}
if (offset < sb->sv_block_size)
continue;
brelse(bh);
bh = NULL;
offset = 0; block++;
}
brelse(bh);
return 1;
bad_dir:
brelse(bh);
printk("Bad directory on device %s\n",
kdevname(inode->i_dev));
return 1;
}
static int sysv_readlink(struct inode * inode, char * buffer, int buflen)
{
struct buffer_head * bh;
char * bh_data;
int i;
char c;
if (!S_ISLNK(inode->i_mode)) {
iput(inode);
return -EINVAL;
}
if (buflen > inode->i_sb->sv_block_size_1)
buflen = inode->i_sb->sv_block_size_1;
bh = sysv_file_bread(inode, 0, 0);
iput(inode);
if (!bh)
return 0;
bh_data = bh->b_data;
i = 0;
while (i<buflen && (c = bh_data[i])) {
i++;
put_fs_byte(c,buffer++);
}
brelse(bh);
return i;
}
int sysv_symlink(struct inode * dir, struct dentry * dentry,
const char * symname)
{
struct sysv_dir_entry * de;
struct inode * inode;
struct buffer_head * name_block;
char * name_block_data;
struct super_block * sb;
int i;
char c;
struct buffer_head * bh;
if (!(inode = sysv_new_inode(dir)))
return -ENOSPC;
inode->i_mode = S_IFLNK | 0777;
inode->i_op = &sysv_symlink_inode_operations;
name_block = sysv_file_bread(inode, 0, 1);
if (!name_block) {
inode->i_nlink--;
mark_inode_dirty(inode);
iput(inode);
return -ENOSPC;
}
sb = inode->i_sb;
name_block_data = name_block->b_data;
i = 0;
while (i < sb->sv_block_size_1 && (c = *(symname++)))
name_block_data[i++] = c;
name_block_data[i] = 0;
mark_buffer_dirty(name_block, 1);
brelse(name_block);
inode->i_size = i;
mark_inode_dirty(inode);
bh = sysv_find_entry(dir, dentry->d_name.name,
dentry->d_name.len, &de);
if (bh) {
inode->i_nlink--;
mark_inode_dirty(inode);
iput(inode);
brelse(bh);
return -EEXIST;
}
i = sysv_add_entry(dir, dentry->d_name.name,
dentry->d_name.len, &bh, &de);
if (i) {
inode->i_nlink--;
mark_inode_dirty(inode);
iput(inode);
return i;
}
de->inode = inode->i_ino;
mark_buffer_dirty(bh, 1);
brelse(bh);
d_instantiate(dentry, inode);
return 0;
}
int sysv_mkdir(struct inode * dir, struct dentry *dentry, int mode)
{
int error;
struct inode * inode;
struct buffer_head * bh, *dir_block;
struct sysv_dir_entry * de;
if (!dir)
return -EINVAL;
bh = sysv_find_entry(dir, dentry->d_name.name,
dentry->d_name.len, &de);
if (bh) {
brelse(bh);
return -EEXIST;
}
if (dir->i_nlink >= dir->i_sb->sv_link_max)
return -EMLINK;
inode = sysv_new_inode(dir);
if (!inode)
return -ENOSPC;
inode->i_op = &sysv_dir_inode_operations;
inode->i_size = 2 * SYSV_DIRSIZE;
dir_block = sysv_file_bread(inode,0,1);
if (!dir_block) {
inode->i_nlink--;
mark_inode_dirty(inode);
iput(inode);
return -ENOSPC;
}
de = (struct sysv_dir_entry *) (dir_block->b_data + 0*SYSV_DIRSIZE);
de->inode = inode->i_ino;
strcpy(de->name,"."); /* rest of de->name is zero, see sysv_new_block */
de = (struct sysv_dir_entry *) (dir_block->b_data + 1*SYSV_DIRSIZE);
de->inode = dir->i_ino;
strcpy(de->name,".."); /* rest of de->name is zero, see sysv_new_block */
inode->i_nlink = 2;
mark_buffer_dirty(dir_block, 1);
brelse(dir_block);
inode->i_mode = S_IFDIR | (mode & 0777 & ~current->fs->umask);
if (dir->i_mode & S_ISGID)
inode->i_mode |= S_ISGID;
mark_inode_dirty(inode);
error = sysv_add_entry(dir, dentry->d_name.name,
dentry->d_name.len, &bh, &de);
if (error) {
inode->i_nlink=0;
iput(inode);
return error;
}
de->inode = inode->i_ino;
mark_buffer_dirty(bh, 1);
dir->i_nlink++;
mark_inode_dirty(dir);
brelse(bh);
d_instantiate(dentry, inode);
return 0;
}
/*
* sysv_find_entry()
*
* finds an entry in the specified directory with the wanted name. It
* returns the cache buffer in which the entry was found, and the entry
* itself (as a parameter - res_dir). It does NOT read the inode of the
* entry - you'll have to do that yourself if you want to.
*/
static struct buffer_head * sysv_find_entry(struct inode * dir,
const char * name, int namelen, struct sysv_dir_entry ** res_dir)
{
struct super_block * sb;
unsigned long pos, block, offset; /* pos = block * block_size + offset */
struct buffer_head * bh;
*res_dir = NULL;
if (!dir)
return NULL;
sb = dir->i_sb;
if (namelen > SYSV_NAMELEN) {
if (sb->sv_truncate)
namelen = SYSV_NAMELEN;
else
return NULL;
}
bh = NULL;
pos = block = offset = 0;
while (pos < dir->i_size) {
if (!bh) {
bh = sysv_file_bread(dir, block, 0);
if (!bh) {
/* offset = 0; */ block++;
pos += sb->sv_block_size;
continue;
}
}
if (sysv_match(namelen, name,
*res_dir = (struct sysv_dir_entry *) (bh->b_data + offset) ))
return bh;
pos += SYSV_DIRSIZE;
offset += SYSV_DIRSIZE;
if (offset < sb->sv_block_size)
continue;
brelse(bh);
bh = NULL;
offset = 0; block++;
}
brelse(bh);
*res_dir = NULL;
return NULL;
}
static int sysv_follow_link(struct inode * dir, struct inode * inode,
int flag, int mode, struct inode ** res_inode)
{
int error;
struct buffer_head * bh;
*res_inode = NULL;
if (!dir) {
dir = current->fs->root;
dir->i_count++;
}
if (!inode) {
iput(dir);
return -ENOENT;
}
if (!S_ISLNK(inode->i_mode)) {
iput(dir);
*res_inode = inode;
return 0;
}
if (current->link_count > 5) {
iput(inode);
iput(dir);
return -ELOOP;
}
if (!(bh = sysv_file_bread(inode, 0, 0))) { /* is reading 1 block enough ?? */
iput(inode);
iput(dir);
return -EIO;
}
iput(inode);
current->link_count++;
error = open_namei(bh->b_data,flag,mode,res_inode,dir);
current->link_count--;
brelse(bh);
return error;
}
/*
* Anybody can rename anything with this: the permission checks are left to the
* higher-level routines.
*/
static int sysv_rename(struct inode * old_dir, struct dentry * old_dentry,
struct inode * new_dir, struct dentry * new_dentry)
{
struct inode * old_inode, * new_inode;
struct buffer_head * old_bh, * new_bh, * dir_bh;
struct sysv_dir_entry * old_de, * new_de;
int retval;
old_inode = old_dentry->d_inode;
new_inode = new_dentry->d_inode;
new_bh = dir_bh = NULL;
old_bh = sysv_find_entry(old_dir, old_dentry->d_name.name,
old_dentry->d_name.len, &old_de);
retval = -ENOENT;
if (!old_bh || old_de->inode != old_inode->i_ino)
goto end_rename;
retval = -EPERM;
new_bh = sysv_find_entry(new_dir, new_dentry->d_name.name,
new_dentry->d_name.len, &new_de);
if (new_bh) {
if (!new_inode) {
brelse(new_bh);
new_bh = NULL;
}
}
if (S_ISDIR(old_inode->i_mode)) {
if (new_inode) {
retval = -ENOTEMPTY;
if (!empty_dir(new_inode))
goto end_rename;
}
retval = -EIO;
dir_bh = sysv_file_bread(old_inode, 0, 0);
if (!dir_bh)
goto end_rename;
if (PARENT_INO(dir_bh->b_data) != old_dir->i_ino)
goto end_rename;
retval = -EMLINK;
if (!new_inode && new_dir != old_dir &&
new_dir->i_nlink >= new_dir->i_sb->sv_link_max)
goto end_rename;
}
if (!new_bh) {
retval = sysv_add_entry(new_dir, new_dentry->d_name.name,
new_dentry->d_name.len, &new_bh, &new_de);
if (retval)
goto end_rename;
}
new_de->inode = old_inode->i_ino;
old_de->inode = 0;
old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME;
mark_inode_dirty(old_dir);
new_dir->i_ctime = new_dir->i_mtime = CURRENT_TIME;
mark_inode_dirty(new_dir);
if (new_inode) {
new_inode->i_nlink--;
new_inode->i_ctime = CURRENT_TIME;
mark_inode_dirty(new_inode);
}
mark_buffer_dirty(old_bh);
mark_buffer_dirty(new_bh);
if (dir_bh) {
PARENT_INO(dir_bh->b_data) = new_dir->i_ino;
mark_buffer_dirty(dir_bh);
old_dir->i_nlink--;
mark_inode_dirty(old_dir);
if (new_inode) {
new_inode->i_nlink--;
mark_inode_dirty(new_inode);
} else {
new_dir->i_nlink++;
mark_inode_dirty(new_dir);
}
}
retval = 0;
end_rename:
brelse(dir_bh);
brelse(old_bh);
brelse(new_bh);
return retval;
}
/*
* sysv_add_entry()
*
* adds a file entry to the specified directory, returning a possible
* error value if it fails.
*
* NOTE!! The inode part of 'de' is left at 0 - which means you
* may not sleep between calling this and putting something into
* the entry, as someone else might have used it while you slept.
*/
static int sysv_add_entry(struct inode * dir,
const char * name, int namelen,
struct buffer_head ** res_buf,
struct sysv_dir_entry ** res_dir)
{
struct super_block * sb;
int i;
unsigned long pos, block, offset; /* pos = block * block_size + offset */
struct buffer_head * bh;
struct sysv_dir_entry * de;
*res_buf = NULL;
*res_dir = NULL;
sb = dir->i_sb;
if (namelen > SYSV_NAMELEN) {
if (sb->sv_truncate)
namelen = SYSV_NAMELEN;
else
return -ENAMETOOLONG;
}
if (!namelen)
return -ENOENT;
bh = NULL;
pos = block = offset = 0;
while (1) {
if (!bh) {
bh = sysv_file_bread(dir, block, 1);
if (!bh)
return -ENOSPC;
}
de = (struct sysv_dir_entry *) (bh->b_data + offset);
pos += SYSV_DIRSIZE;
offset += SYSV_DIRSIZE;
if (pos > dir->i_size) {
de->inode = 0;
dir->i_size = pos;
mark_inode_dirty(dir);
}
if (de->inode) {
if (namecompare(namelen, SYSV_NAMELEN, name, de->name)) {
brelse(bh);
return -EEXIST;
}
} else {
dir->i_mtime = dir->i_ctime = CURRENT_TIME;
mark_inode_dirty(dir);
for (i = 0; i < SYSV_NAMELEN ; i++)
de->name[i] = (i < namelen) ? name[i] : 0;
mark_buffer_dirty(bh);
*res_dir = de;
break;
}
if (offset < sb->sv_block_size)
continue;
brelse(bh);
bh = NULL;
offset = 0; block++;
}
*res_buf = bh;
return 0;
}
/*
* rename uses retrying to avoid race-conditions: at least they should be minimal.
* it tries to allocate all the blocks, then sanity-checks, and if the sanity-
* checks fail, it tries to restart itself again. Very practical - no changes
* are done until we know everything works ok.. and then all the changes can be
* done in one fell swoop when we have claimed all the buffers needed.
*
* Anybody can rename anything with this: the permission checks are left to the
* higher-level routines.
*/
static int do_sysv_rename(struct inode * old_dir, struct dentry * old_dentry,
struct inode * new_dir, struct dentry * new_dentry)
{
struct inode * old_inode, * new_inode;
struct buffer_head * old_bh, * new_bh, * dir_bh;
struct sysv_dir_entry * old_de, * new_de;
int retval;
goto start_up;
try_again:
brelse(old_bh);
brelse(new_bh);
brelse(dir_bh);
current->counter = 0;
schedule();
start_up:
old_inode = new_inode = NULL;
old_bh = new_bh = dir_bh = NULL;
old_bh = sysv_find_entry(old_dir, old_dentry->d_name.name,
old_dentry->d_name.len, &old_de);
retval = -ENOENT;
if (!old_bh)
goto end_rename;
old_inode = old_dentry->d_inode; /* don't cross mnt-points */
retval = -EPERM;
new_inode = new_dentry->d_inode;
new_bh = sysv_find_entry(new_dir, new_dentry->d_name.name,
new_dentry->d_name.len, &new_de);
if (new_bh) {
if (!new_inode) {
brelse(new_bh);
new_bh = NULL;
}
}
if (new_inode == old_inode) {
retval = 0;
goto end_rename;
}
if (S_ISDIR(old_inode->i_mode)) {
retval = -EINVAL;
if (is_subdir(new_dentry, old_dentry))
goto end_rename;
if (new_inode) {
if (new_dentry->d_count > 1)
shrink_dcache_parent(new_dentry);
retval = -EBUSY;
if (new_dentry->d_count > 1)
goto end_rename;
retval = -ENOTEMPTY;
if (!empty_dir(new_inode))
goto end_rename;
}
retval = -EIO;
dir_bh = sysv_file_bread(old_inode, 0, 0);
if (!dir_bh)
goto end_rename;
if (PARENT_INO(dir_bh->b_data) != old_dir->i_ino)
goto end_rename;
retval = -EMLINK;
if (!new_inode && new_dir->i_nlink >= new_dir->i_sb->sv_link_max)
goto end_rename;
}
if (!new_bh) {
retval = sysv_add_entry(new_dir, new_dentry->d_name.name,
new_dentry->d_name.len, &new_bh, &new_de);
if (retval)
goto end_rename;
}
/* sanity checking before doing the rename - avoid races */
if (new_inode && (new_de->inode != new_inode->i_ino))
goto try_again;
if (new_de->inode && !new_inode)
goto try_again;
if (old_de->inode != old_inode->i_ino)
goto try_again;
/* ok, that's it */
old_de->inode = 0;
new_de->inode = old_inode->i_ino;
old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME;
mark_inode_dirty(old_dir);
new_dir->i_ctime = new_dir->i_mtime = CURRENT_TIME;
mark_inode_dirty(new_dir);
if (new_inode) {
new_inode->i_nlink--;
new_inode->i_ctime = CURRENT_TIME;
mark_inode_dirty(new_inode);
}
mark_buffer_dirty(old_bh, 1);
mark_buffer_dirty(new_bh, 1);
if (dir_bh) {
PARENT_INO(dir_bh->b_data) = new_dir->i_ino;
mark_buffer_dirty(dir_bh, 1);
old_dir->i_nlink--;
mark_inode_dirty(old_dir);
if (new_inode) {
new_inode->i_nlink--;
mark_inode_dirty(new_inode);
} else {
new_dir->i_nlink++;
mark_inode_dirty(new_dir);
}
}
d_move(old_dentry, new_dentry);
retval = 0;
end_rename:
brelse(dir_bh);
brelse(old_bh);
brelse(new_bh);
return retval;
}
