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sys_readdir and memfs_readdir closer to targeted look and feel.

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We now have a single dirbuf of size PAGE_SIZE kept on the vnode. This is
to be used for directory contents only. The reason it's kept on FS0 is
because the contents are modified by calls such as mkdir or create, and otherwise
these would have been handled by mm0 on the page cache buffers, which wouldn't work.
This commit is contained in:
Bahadir Balban
2008-02-14 14:37:56 +00:00
parent 2440b5be61
commit a989e1f774
4 changed files with 46 additions and 22 deletions
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30
tasks/fs0/src/memfs/vnode.c
View File

@@ -211,21 +211,23 @@ int memfs_write_vnode(struct superblock *sb, struct vnode *v)
*
* TODO: Returns the list of posix-compliant dirent records in the buffer.
*/
void *memfs_vnode_readdir(struct vnode *v, void *dirbuf)
int memfs_vnode_readdir(struct vnode *v)
{
int err;
struct memfs_dentry *memfsd = dirbuf;
struct dentry *parent = list_entry(v->dentries.next, struct dentry,
vref);
u8 *dirbuf;
struct memfs_dentry *memfsd;
struct dentry *parent = list_entry(v->dentries.next,
struct dentry, vref);
/* Check directory type */
if (!vfs_isdir(v))
return PTR_ERR(-ENOTDIR);
return -ENOTDIR;
/* Allocate dirbuf if one is not provided by the upper layer */
if (!dirbuf) {
if (!v->dirbuf->buffer) {
/* This is as big as a page */
memfsd = dirbuf = vfs_alloc_dirpage();
v->dirbuf->buffer = vfs_alloc_dirbuf();
memfsd = dirbuf = v->dirbuf->buffer;
/*
* Fail if vnode size is bigger than a page. Since this allocation
@@ -234,18 +236,18 @@ void *memfs_vnode_readdir(struct vnode *v, void *dirbuf)
BUG_ON(v->size > PAGE_SIZE);
}
/* Read contents into the buffer */
/* Read memfsd contents into the buffer */
if ((err = v->fops.read(v, 0, 1, dirbuf)))
return PTR_ERR(err);
return err;
/* For each fs-specific directory entry */
/* Read fs-specific directory entry into vnode and dentry caches. */
for (int i = 0; i < (v->size / sizeof(struct memfs_dentry)); i++) {
struct dentry *newd;
struct vnode *newv;
/* Allocate a vfs dentry */
if (!(newd = vfs_alloc_dentry()))
return PTR_ERR(-ENOMEM);
return -ENOMEM;
/* Initialise it */
newd->ops = generic_dentry_operations;
@@ -264,8 +266,12 @@ void *memfs_vnode_readdir(struct vnode *v, void *dirbuf)
/* Copy fields into generic dentry */
memcpy(newd->name, memfsd[i].name, MEMFS_DNAME_MAX);
/* Add both vnode and dentry to their caches */
list_add(&newd->cache_list, &dentry_cache);
list_add(&newv->cache_list, &vnode_cache);
}
return dirbuf;
return 0;
}
struct vnode_ops memfs_vnode_operations = {

26
tasks/fs0/src/syscalls.c
View File

@@ -90,21 +90,39 @@ int sys_read(l4id_t sender, int fd, void *buf, int count)
*/
int sys_readdir(l4id_t sender, int fd, void *buf, int count)
{
unsigned long vnum;
struct vnode *v;
struct tcb *t;
struct dirbuf *db;
unsigned long nbytes;
int err;
/* Get the task */
BUG_ON(!(t = find_task(sender)));
/* Convert fd to vnode. */
BUG_ON(!(v = t->fd[fd]));
/* Convert fd to vnum. */
BUG_ON(!(vnum = t->fd[fd]));
/* Lookup vnode */
if (!(v = vfs_lookup_byvnum(vnum)))
return -EINVAL; /* No such vnode */
/* Ensure vnode is a directory */
if (!vfs_isdir(v))
return -ENOTDIR;
/* Simply read its contents */
v->ops.readdir(v, buf, count);
/* Read the whole content from fs, if haven't done so yet */
if ((err = v->ops.readdir(v)) < 0)
return err;
/* Bytes to read, minimum of vnode size and count requested */
nbytes = (v->size <= count) ? v->size : count;
/* Do we have those bytes at hand? */
if (v->dirbuf->buffer && (v->dirbuf->npages * PAGE_SIZE) >= nbytes) {
memcpy(buf, v->dirbuf->buffer, nbytes); /* Finish the job */
return nbytes;
}
return 0;
}