patch-2.4.20 linux-2.4.20/mm/shmem.c

• Lines: 278
• Date: Thu Nov 28 15:53:15 2002
• Orig file: linux-2.4.19/mm/shmem.c
• Orig date: Fri Aug 2 17:39:46 2002

diff -urN linux-2.4.19/mm/shmem.c linux-2.4.20/mm/shmem.c
@@ -34,6 +34,14 @@
 #define TMPFS_MAGIC	0x01021994
 
 #define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long))
+#define BLOCKS_PER_PAGE  (PAGE_CACHE_SIZE/512)
+
+#define SHMEM_MAX_INDEX  (SHMEM_NR_DIRECT + ENTRIES_PER_PAGE * (ENTRIES_PER_PAGE/2) * (ENTRIES_PER_PAGE+1))
+#define SHMEM_MAX_BYTES  ((unsigned long long)SHMEM_MAX_INDEX << PAGE_CACHE_SHIFT)
+#define VM_ACCT(size)    (((size) + PAGE_CACHE_SIZE - 1) >> PAGE_SHIFT)
+
+/* Pretend that each entry is of this size in directory's i_size */
+#define BOGO_DIRENT_SIZE 20
 
 #define SHMEM_SB(sb) (&sb->u.shmem_sb)
 
@@ -50,8 +58,6 @@
 
 static struct page *shmem_getpage_locked(struct shmem_inode_info *, struct inode *, unsigned long);
 
-#define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512)
-
 /*
  * shmem_recalc_inode - recalculate the size of an inode
  *
@@ -127,9 +133,6 @@
  * 	      	       +-> 48-51
  * 	      	       +-> 52-55
  */
-
-#define SHMEM_MAX_BLOCKS (SHMEM_NR_DIRECT + ENTRIES_PER_PAGE * ENTRIES_PER_PAGE/2*(ENTRIES_PER_PAGE+1))
-
 static swp_entry_t * shmem_swp_entry (struct shmem_inode_info *info, unsigned long index, unsigned long page) 
 {
 	unsigned long offset;
@@ -182,7 +185,7 @@
 	unsigned long page = 0;
 	swp_entry_t * res;
 
-	if (index >= SHMEM_MAX_BLOCKS)
+	if (index >= SHMEM_MAX_INDEX)
 		return ERR_PTR(-EFBIG);
 
 	if (info->next_index <= index)
@@ -358,11 +361,11 @@
 {
 	struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
 
-	inode->i_size = 0;
-	if (inode->i_op->truncate == shmem_truncate){ 
+	if (inode->i_op->truncate == shmem_truncate) {
 		spin_lock (&shmem_ilock);
 		list_del (&SHMEM_I(inode)->list);
 		spin_unlock (&shmem_ilock);
+		inode->i_size = 0;
 		shmem_truncate (inode);
 	}
 	spin_lock (&sbinfo->stat_lock);
@@ -557,7 +560,7 @@
 		unsigned long flags;
 
 		/* Look it up and read it in.. */
-		page = find_get_page(&swapper_space, entry->val);
+		page = lookup_swap_cache(*entry);
 		if (!page) {
 			swp_entry_t swap = *entry;
 			spin_unlock (&info->lock);
@@ -612,6 +615,7 @@
 		if (!page)
 			return ERR_PTR(-ENOMEM);
 		clear_highpage(page);
+		flush_dcache_page(page);
 		inode->i_blocks += BLOCKS_PER_PAGE;
 		add_to_page_cache (page, mapping, idx);
 	}
@@ -731,11 +735,13 @@
 			inode->i_op = &shmem_inode_operations;
 			inode->i_fop = &shmem_file_operations;
 			spin_lock (&shmem_ilock);
-			list_add_tail(&SHMEM_I(inode)->list, &shmem_inodes);
+			list_add_tail(&info->list, &shmem_inodes);
 			spin_unlock (&shmem_ilock);
 			break;
 		case S_IFDIR:
 			inode->i_nlink++;
+			/* Some things misbehave if size == 0 on a directory */
+			inode->i_size = 2 * BOGO_DIRENT_SIZE;
 			inode->i_op = &shmem_dir_inode_operations;
 			inode->i_fop = &dcache_dir_ops;
 			break;
@@ -999,7 +1005,7 @@
 	buf->f_files = sbinfo->max_inodes;
 	buf->f_ffree = sbinfo->free_inodes;
 	spin_unlock (&sbinfo->stat_lock);
-	buf->f_namelen = 255;
+	buf->f_namelen = NAME_MAX;
 	return 0;
 }
 
@@ -1022,6 +1028,7 @@
 	int error = -ENOSPC;
 
 	if (inode) {
+		dir->i_size += BOGO_DIRENT_SIZE;
 		dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 		d_instantiate(dentry, inode);
 		dget(dentry); /* Extra count - pin the dentry in core */
@@ -1055,6 +1062,7 @@
 	if (S_ISDIR(inode->i_mode))
 		return -EPERM;
 
+	dir->i_size += BOGO_DIRENT_SIZE;
 	inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 	inode->i_nlink++;
 	atomic_inc(&inode->i_count);	/* New dentry reference */
@@ -1099,6 +1107,8 @@
 static int shmem_unlink(struct inode * dir, struct dentry *dentry)
 {
 	struct inode *inode = dentry->d_inode;
+
+	dir->i_size -= BOGO_DIRENT_SIZE;
 	inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 	inode->i_nlink--;
 	dput(dentry);	/* Undo the count from "create" - this does all the work */
@@ -1122,65 +1132,63 @@
  */
 static int shmem_rename(struct inode * old_dir, struct dentry *old_dentry, struct inode * new_dir,struct dentry *new_dentry)
 {
-	struct inode *inode;
+	struct inode *inode = old_dentry->d_inode;
+	int they_are_dirs = S_ISDIR(inode->i_mode);
 
 	if (!shmem_empty(new_dentry)) 
 		return -ENOTEMPTY;
 
-	inode = new_dentry->d_inode;
-	if (inode) {
-		inode->i_ctime = CURRENT_TIME;
-		inode->i_nlink--;
-		dput(new_dentry);
-	}
-	inode = old_dentry->d_inode;
-	if (S_ISDIR(inode->i_mode)) {
+	if (new_dentry->d_inode) {
+		(void) shmem_unlink(new_dir, new_dentry);
+		if (they_are_dirs)
+			old_dir->i_nlink--;
+	} else if (they_are_dirs) {
 		old_dir->i_nlink--;
 		new_dir->i_nlink++;
 	}
 
-	inode->i_ctime = old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME;
+	old_dir->i_size -= BOGO_DIRENT_SIZE;
+	new_dir->i_size += BOGO_DIRENT_SIZE;
+	old_dir->i_ctime = old_dir->i_mtime =
+	new_dir->i_ctime = new_dir->i_mtime =
+	inode->i_ctime = CURRENT_TIME;
 	return 0;
 }
 
 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;
 	struct shmem_inode_info * info;
 
-	error = shmem_mknod(dir, dentry, S_IFLNK | S_IRWXUGO, 0);
-	if (error)
-		return error;
-
 	len = strlen(symname) + 1;
-	inode = dentry->d_inode;
+	if (len > PAGE_CACHE_SIZE)
+		return -ENAMETOOLONG;
+
+	inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0);
+	if (!inode)
+		return -ENOSPC;
+
 	info = SHMEM_I(inode);
 	inode->i_size = len-1;
-	inode->i_op = &shmem_symlink_inline_operations;
-
 	if (len <= sizeof(struct shmem_inode_info)) {
 		/* do it inline */
 		memcpy(info, symname, len);
+		inode->i_op = &shmem_symlink_inline_operations;
 	} else {
-		if (len > PAGE_CACHE_SIZE) {
-			error = -ENAMETOOLONG;
-			goto rmnod;
-		}
-		inode->i_op = &shmem_symlink_inode_operations;
-		spin_lock (&shmem_ilock);
-		list_add_tail(&info->list, &shmem_inodes);
-		spin_unlock (&shmem_ilock);
 		down(&info->sem);
 		page = shmem_getpage_locked(info, inode, 0);
 		if (IS_ERR(page)) {
 			up(&info->sem);
-			error = PTR_ERR(page);
-			goto rmnod;
+			iput(inode);
+			return PTR_ERR(page);
 		}
+		inode->i_op = &shmem_symlink_inode_operations;
+		spin_lock (&shmem_ilock);
+		list_add_tail(&info->list, &shmem_inodes);
+		spin_unlock (&shmem_ilock);
 		kaddr = kmap(page);
 		memcpy(kaddr, symname, len);
 		kunmap(page);
@@ -1189,13 +1197,11 @@
 		page_cache_release(page);
 		up(&info->sem);
 	}
+	dir->i_size += BOGO_DIRENT_SIZE;
 	dir->i_ctime = dir->i_mtime = CURRENT_TIME;
+	d_instantiate(dentry, inode);
+	dget(dentry);
 	return 0;
-
-rmnod:
-	if (!shmem_unlink(dir, dentry))
-		d_delete(dentry);
-	return error;
 }
 
 static int shmem_readlink_inline(struct dentry *dentry, char *buffer, int buflen)
@@ -1355,7 +1361,7 @@
 	sbinfo->free_blocks = blocks;
 	sbinfo->max_inodes = inodes;
 	sbinfo->free_inodes = inodes;
-	sb->s_maxbytes = (unsigned long long) SHMEM_MAX_BLOCKS << PAGE_CACHE_SHIFT;
+	sb->s_maxbytes = SHMEM_MAX_BYTES;
 	sb->s_blocksize = PAGE_CACHE_SIZE;
 	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 	sb->s_magic = TMPFS_MAGIC;
@@ -1489,10 +1495,10 @@
 	struct qstr this;
 	int vm_enough_memory(long pages);
 
-	if (size > (unsigned long long) SHMEM_MAX_BLOCKS << PAGE_CACHE_SHIFT)
+	if (size > SHMEM_MAX_BYTES)
 		return ERR_PTR(-EINVAL);
 
-	if (!vm_enough_memory((size) >> PAGE_CACHE_SHIFT))
+	if (!vm_enough_memory(VM_ACCT(size)))
 		return ERR_PTR(-ENOMEM);
 
 	this.name = name;
@@ -1514,13 +1520,12 @@
 		goto close_file;
 
 	d_instantiate(dentry, inode);
-	dentry->d_inode->i_size = size;
-	shmem_truncate(inode);
+	inode->i_size = size;
+	inode->i_nlink = 0;	/* It is unlinked */
 	file->f_vfsmnt = mntget(shm_mnt);
 	file->f_dentry = dentry;
 	file->f_op = &shmem_file_operations;
 	file->f_mode = FMODE_WRITE | FMODE_READ;
-	inode->i_nlink = 0;	/* It is unlinked */
 	return(file);
 
 close_file:
@@ -1529,6 +1534,7 @@
 	dput (dentry);
 	return ERR_PTR(error);	
 }
+
 /*
  * shmem_zero_setup - setup a shared anonymous mapping
  *