read/write support for shm fs

diff -uNr 2.4.0-shm_vm_locked-truncate/include/linux/fs.h 2.4.0-shm_vm_locked-truncate-rw/include/linux/fs.h
@@ -1198,6 +1198,7 @@
 	}
 	return inode;
 }
+extern void remove_suid(struct inode *inode);
 
 extern void insert_inode_hash(struct inode *);
 extern void remove_inode_hash(struct inode *);

@@ -1245,6 +1246,7 @@
 int block_truncate_page(struct address_space *, loff_t, get_block_t *);
 
 extern int generic_file_mmap(struct file *, struct vm_area_struct *);
+extern int file_read_actor(read_descriptor_t * desc, struct page *page, unsigned long offset, unsigned long size);
 extern ssize_t generic_file_read(struct file *, char *, size_t, loff_t *);
 extern ssize_t generic_file_write(struct file *, const char *, size_t, loff_t *);
 extern void do_generic_file_read(struct file *, loff_t *, read_descriptor_t *, read_actor_t);

diff -uNr 2.4.0-shm_vm_locked-truncate/include/linux/mm.h 2.4.0-shm_vm_locked-truncate-rw/include/linux/mm.h
@@ -200,8 +200,8 @@
 					smp_mb__before_clear_bit(); \
 					if (!test_and_clear_bit(PG_locked, &(page)->flags)) BUG(); \
 					smp_mb__after_clear_bit(); \
-					if (waitqueue_active(&page->wait)) \
-						wake_up(&page->wait); \
+					if (waitqueue_active(&(page)->wait)) \
+						wake_up(&(page)->wait); \
 				} while (0)
 #define PageError(page)		test_bit(PG_error, &(page)->flags)
 #define SetPageError(page)	set_bit(PG_error, &(page)->flags)

diff -uNr 2.4.0-shm_vm_locked-truncate/mm/filemap.c 2.4.0-shm_vm_locked-truncate-rw/mm/filemap.c
@@ -1212,7 +1212,7 @@
 	UPDATE_ATIME(inode);
 }
 
-static int file_read_actor(read_descriptor_t * desc, struct page *page, unsigned long offset, unsigned long size)
+int file_read_actor(read_descriptor_t * desc, struct page *page, unsigned long offset, unsigned long size)
 {
 	char *kaddr;
 	unsigned long left, count = desc->count;

@@ -2408,7 +2408,7 @@
 	return page;
 }
 
-static inline void remove_suid(struct inode *inode)
+inline void remove_suid(struct inode *inode)
 {
 	unsigned int mode;
 

474 lines not on this page · raw message

diff -uNr 2.4.0-shm_vm_locked-truncate-rw-swapfs/mm/shmem.c 2.4.0-shm_vm_locked-truncate-rw-swapfs-symlink/mm/shmem.c
@@ -39,6 +39,7 @@
 static struct inode_operations shmem_inode_operations;
 static struct file_operations shmem_dir_operations;
 static struct inode_operations shmem_dir_inode_operations;
+static struct inode_operations shmem_symlink_inode_operations;
 static struct vm_operations_struct shmem_vm_ops;
 
 LIST_HEAD (shmem_inodes);

@@ -127,7 +128,7 @@
 
 	spin_lock (&info->lock);
 	index = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
-	if (index >= info->max_index)
+	if (index > info->max_index)
 		goto out;
 
 	start = shmem_truncate_part (info->i_direct, SHMEM_NR_DIRECT, index, &freed);

@@ -419,7 +420,7 @@
 			inode->i_fop = &shmem_dir_operations;
 			break;
 		case S_IFLNK:
-			inode->i_op = &page_symlink_inode_operations;
+			inode->i_op = &shmem_symlink_inode_operations;
 			break;
 		}
 		spin_lock (&shmem_ilock);

@@ -787,14 +788,63 @@
 static int shmem_symlink(struct inode * dir, struct dentry *dentry, const char * symname)
 {
 	int error;
+	int len;
+	struct inode *inode;
+	struct page *page;
+	char *kaddr;
 
 	error = shmem_mknod(dir, dentry, S_IFLNK | S_IRWXUGO, 0);
-	if (!error) {
-		int l = strlen(symname)+1;
-		struct inode *inode = dentry->d_inode;
-		error = block_symlink(inode, symname, l);
-	}
-	return error;
+	if (error)
+		return error;
+
+	len = strlen(symname);
+	if (len > PAGE_SIZE)
+		return -ENAMETOOLONG;
+		
+	inode = dentry->d_inode;
+	down(&inode->i_sem);
+	page = shmem_getpage_locked(inode, 0);
+	if (IS_ERR(page))
+		goto fail;
+	kaddr = kmap(page);
+	memcpy(kaddr, symname, len);
+	kunmap(page);
+	inode->i_size = len;
+	SetPageDirty(page);
+	UnlockPage(page);
+	page_cache_release(page);
+	up(&inode->i_sem);
+	return 0;
+fail:
+	up(&inode->i_sem);
+	return PTR_ERR(page);
+}
+
+static int shmem_readlink(struct dentry *dentry, char *buffer, int buflen)
+{
+	struct page * page;
+	int res = shmem_getpage(dentry->d_inode, 0, &page);
+
+	if (res)
+		return res;
+
+	res = vfs_readlink(dentry,buffer,buflen, kmap(page));
+	kunmap(page);
+	page_cache_release(page);
+	return res;
+}
+
+static int shmem_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+	struct page * page;
+	int res = shmem_getpage(dentry->d_inode, 0, &page);
+	if (res)
+		return res;
+
+	res = vfs_follow_link(nd, kmap(page));
+	kunmap(page);
+	page_cache_release(page);
+	return res;
 }
 
 static int shmem_parse_options(char *options, int *mode, unsigned long * blocks, unsigned long *inodes)

@@ -912,6 +962,12 @@
 
 static struct inode_operations shmem_inode_operations = {
 	truncate:	shmem_truncate,
+};
+
+static struct inode_operations shmem_symlink_inode_operations = {
+	truncate:	shmem_truncate,
+	readlink:	shmem_readlink,
+	follow_link:	shmem_follow_link,
 };
 
 static struct file_operations shmem_dir_operations = {