Hi Linus,
the appended patch fixes several tmpfs problems:
1) writing out of a mapping of a tmpfs file into the same file can
deadlock
2) shmem_remount_fs garbles parameters which are not supplied
3) shmem_file_setup should check the maximum size
Please apply
Christoph
diff -uNr 6-pre5/include/linux/shmem_fs.h 6-pre5-fix/include/linux/shmem_fs.h
--- 6-pre5/include/linux/shmem_fs.h Sun Apr 29 20:33:00 2001
+++ 6-pre5-fix/include/linux/shmem_fs.h Thu Jun 21 15:52:25 2001
@@ -19,6 +19,7 @@
struct shmem_inode_info {
spinlock_t lock;
+ struct semaphore sem;
unsigned long max_index;
swp_entry_t i_direct[SHMEM_NR_DIRECT]; /* for the first blocks */
swp_entry_t **i_indirect; /* doubly indirect blocks */
diff -uNr 6-pre5/mm/shmem.c 6-pre5-fix/mm/shmem.c
--- 6-pre5/mm/shmem.c Tue Jun 12 09:49:28 2001
+++ 6-pre5-fix/mm/shmem.c Thu Jun 21 15:52:26 2001
@@ -3,7 +3,8 @@
*
* Copyright (C) 2000 Linus Torvalds.
* 2000 Transmeta Corp.
- * 2000 Christoph Rohland
+ * 2000-2001 Christoph Rohland
+ * 2000-2001 SAP AG
*
* This file is released under the GPL.
*/
@@ -33,7 +34,7 @@
#define TMPFS_MAGIC 0x01021994
#define ENTRIES_PER_PAGE (PAGE_SIZE/sizeof(unsigned long))
-#define NR_SINGLE (ENTRIES_PER_PAGE + SHMEM_NR_DIRECT)
+#define SHMEM_MAX_BLOCKS (SHMEM_NR_DIRECT + ENTRIES_PER_PAGE*ENTRIES_PER_PAGE)
static struct super_operations shmem_ops;
static struct address_space_operations shmem_aops;
@@ -161,6 +162,7 @@
swp_entry_t **base, **ptr, **last;
struct shmem_inode_info * info = &inode->u.shmem_i;
+ down(&info->sem);
inode->i_ctime = inode->i_mtime = CURRENT_TIME;
spin_lock (&info->lock);
index = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
@@ -193,10 +195,14 @@
}
out:
- info->max_index = index;
+ if (index <= SHMEM_MAX_BLOCKS)
+ info->max_index = index;
+ else
+ info->max_index = SHMEM_MAX_BLOCKS + 1;
info->swapped -= freed;
shmem_recalc_inode(inode);
spin_unlock (&info->lock);
+ up(&info->sem);
}
static void shmem_delete_inode(struct inode * inode)
@@ -281,15 +287,12 @@
* still need to guard against racing with shm_writepage(), which might
* be trying to move the page to the swap cache as we run.
*/
-static struct page * shmem_getpage_locked(struct inode * inode, unsigned long idx)
+static struct page * shmem_getpage_locked(struct shmem_inode_info *info, struct inode
+* inode, unsigned long idx)
{
struct address_space * mapping = inode->i_mapping;
- struct shmem_inode_info *info;
struct page * page;
swp_entry_t *entry;
- info = &inode->u.shmem_i;
-
repeat:
page = find_lock_page(mapping, idx);
if (page)
@@ -393,6 +396,7 @@
static int shmem_getpage(struct inode * inode, unsigned long idx, struct page **ptr)
{
+ struct shmem_inode_info *info;
struct address_space * mapping = inode->i_mapping;
int error;
@@ -407,27 +411,28 @@
page_cache_release(*ptr);
}
- down (&inode->i_sem);
- /* retest we may have slept */
+ info = &inode->u.shmem_i;
+ down (&info->sem);
+ /* retest we may have slept */
+
+ *ptr = ERR_PTR(-EFAULT);
if (inode->i_size < (loff_t) idx * PAGE_CACHE_SIZE)
- goto sigbus;
- *ptr = shmem_getpage_locked(inode, idx);
+ goto failed;
+
+ *ptr = shmem_getpage_locked(&inode->u.shmem_i, inode, idx);
if (IS_ERR (*ptr))
goto failed;
+
UnlockPage(*ptr);
- up (&inode->i_sem);
+ up (&info->sem);
return 0;
failed:
- up (&inode->i_sem);
+ up (&info->sem);
error = PTR_ERR(*ptr);
- *ptr = NOPAGE_OOM;
- if (error != -EFBIG)
- *ptr = NOPAGE_SIGBUS;
- return error;
-sigbus:
- up (&inode->i_sem);
*ptr = NOPAGE_SIGBUS;
- return -EFAULT;
+ if (error == -ENOMEM)
+ *ptr = NOPAGE_OOM;
+ return error;
}
struct page * shmem_nopage(struct vm_area_struct * vma, unsigned long address, int
no_share)
@@ -500,6 +505,7 @@
struct inode *shmem_get_inode(struct super_block *sb, int mode, int dev)
{
struct inode * inode;
+ struct shmem_inode_info *info;
spin_lock (&sb->u.shmem_sb.stat_lock);
if (!sb->u.shmem_sb.free_inodes) {
@@ -519,7 +525,9 @@
inode->i_rdev = NODEV;
inode->i_mapping->a_ops = &shmem_aops;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
- spin_lock_init (&inode->u.shmem_i.lock);
+ info = &inode->u.shmem_i;
+ spin_lock_init (&info->lock);
+ sema_init (&info->sem, 1);
switch (mode & S_IFMT) {
default:
init_special_inode(inode, mode, dev);
@@ -549,6 +557,7 @@
shmem_file_write(struct file *file,const char *buf,size_t count,loff_t *ppos)
{
struct inode *inode = file->f_dentry->d_inode;
+ struct shmem_inode_info *info;
unsigned long limit = current->rlim[RLIMIT_FSIZE].rlim_cur;
loff_t pos;
struct page *page;
@@ -624,7 +633,11 @@
__get_user(dummy, buf+bytes-1);
}
- page = shmem_getpage_locked(inode, index);
+ info = &inode->u.shmem_i;
+ down (&info->sem);
+ page = shmem_getpage_locked(info, inode, index);
+ up (&info->sem);
+
status = PTR_ERR(page);
if (IS_ERR(page))
break;
@@ -635,7 +648,6 @@
}
kaddr = kmap(page);
-// can this do a truncated write? cr
status = copy_from_user(kaddr+offset, buf, bytes);
kunmap(page);
if (status)
@@ -932,7 +944,7 @@
inode = dentry->d_inode;
down(&inode->i_sem);
- page = shmem_getpage_locked(inode, 0);
+ page = shmem_getpage_locked(&inode->u.shmem_i, inode, 0);
if (IS_ERR(page))
goto fail;
kaddr = kmap(page);
@@ -1027,6 +1039,8 @@
unsigned long max_inodes, inodes;
struct shmem_sb_info *info = &sb->u.shmem_sb;
+ max_blocks = info->max_blocks;
+ max_inodes = info->max_inodes;
if (shmem_parse_options (data, NULL, &max_blocks, &max_inodes))
return -EINVAL;
@@ -1074,7 +1088,7 @@
sb->u.shmem_sb.free_blocks = blocks;
sb->u.shmem_sb.max_inodes = inodes;
sb->u.shmem_sb.free_inodes = inodes;
- sb->s_maxbytes = (unsigned long long)(SHMEM_NR_DIRECT +
(ENTRIES_PER_PAGE*ENTRIES_PER_PAGE)) << PAGE_CACHE_SHIFT;
+ sb->s_maxbytes = (unsigned long long)SHMEM_MAX_BLOCKS << PAGE_CACHE_SHIFT;
sb->s_blocksize = PAGE_CACHE_SIZE;
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
sb->s_magic = TMPFS_MAGIC;
@@ -1282,9 +1296,11 @@
struct qstr this;
int vm_enough_memory(long pages);
- error = -ENOMEM;
+ if (size > (unsigned long long) SHMEM_MAX_BLOCKS << PAGE_CACHE_SHIFT)
+ return ERR_PTR(-EINVAL);
+
if (!vm_enough_memory((size) >> PAGE_SHIFT))
- goto out;
+ return ERR_PTR(-ENOMEM);
this.name = name;
this.len = strlen(name);
@@ -1292,7 +1308,7 @@
root = tmpfs_fs_type.kern_mnt->mnt_root;
dentry = d_alloc(root, &this);
if (!dentry)
- goto out;
+ return ERR_PTR(-ENOMEM);
error = -ENFILE;
file = get_empty_filp();
@@ -1318,7 +1334,6 @@
put_filp(file);
put_dentry:
dput (dentry);
-out:
return ERR_PTR(error);
}
/*
-
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