fly using a remount ('mount -o remount ...') of the filesystem. A tmpfs
filesystem can be resized but it cannot be resized to a size below its current
usage. tmpfs also supports POSIX ACLs, and extended attributes for the
-trusted.* and security.* namespaces. ramfs does not use swap and you cannot
-modify any parameter for a ramfs filesystem. The size limit of a ramfs
+trusted.*, security.* and user.* namespaces. ramfs does not use swap and you
+cannot modify any parameter for a ramfs filesystem. The size limit of a ramfs
filesystem is how much memory you have available, and so care must be taken if
used so to not run out of memory.
use up all the memory on the machine; but enhances the scalability of
that instance in a system with many CPUs making intensive use of it.
+If nr_inodes is not 0, that limited space for inodes is also used up by
+extended attributes: "df -i"'s IUsed and IUse% increase, IFree decreases.
+
tmpfs blocks may be swapped out, when there is a shortage of memory.
tmpfs has a mount option to disable its use of swap:
EXPORT_SYMBOL(xattr_full_name);
/**
+ * simple_xattr_space - estimate the memory used by a simple xattr
+ * @name: the full name of the xattr
+ * @size: the size of its value
+ *
+ * This takes no account of how much larger the two slab objects actually are:
+ * that would depend on the slab implementation, when what is required is a
+ * deterministic number, which grows with name length and size and quantity.
+ *
+ * Return: The approximate number of bytes of memory used by such an xattr.
+ */
+size_t simple_xattr_space(const char *name, size_t size)
+{
+ /*
+ * Use "40" instead of sizeof(struct simple_xattr), to return the
+ * same result on 32-bit and 64-bit, and even if simple_xattr grows.
+ */
+ return 40 + size + strlen(name);
+}
+
+/**
* simple_xattr_free - free an xattr object
* @xattr: the xattr object
*
/**
* simple_xattrs_free - free xattrs
* @xattrs: xattr header whose xattrs to destroy
+ * @freed_space: approximate number of bytes of memory freed from @xattrs
*
* Destroy all xattrs in @xattr. When this is called no one can hold a
* reference to any of the xattrs anymore.
*/
-void simple_xattrs_free(struct simple_xattrs *xattrs)
+void simple_xattrs_free(struct simple_xattrs *xattrs, size_t *freed_space)
{
struct rb_node *rbp;
+ if (freed_space)
+ *freed_space = 0;
rbp = rb_first(&xattrs->rb_root);
while (rbp) {
struct simple_xattr *xattr;
rbp_next = rb_next(rbp);
xattr = rb_entry(rbp, struct simple_xattr, rb_node);
rb_erase(&xattr->rb_node, &xattrs->rb_root);
+ if (freed_space)
+ *freed_space += simple_xattr_space(xattr->name,
+ xattr->size);
simple_xattr_free(xattr);
rbp = rbp_next;
}
return 0;
}
-static void shmem_free_inode(struct super_block *sb)
+static void shmem_free_inode(struct super_block *sb, size_t freed_ispace)
{
struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
if (sbinfo->max_inodes) {
raw_spin_lock(&sbinfo->stat_lock);
- sbinfo->free_ispace += BOGO_INODE_SIZE;
+ sbinfo->free_ispace += BOGO_INODE_SIZE + freed_ispace;
raw_spin_unlock(&sbinfo->stat_lock);
}
}
{
struct shmem_inode_info *info = SHMEM_I(inode);
struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
+ size_t freed = 0;
if (shmem_mapping(inode->i_mapping)) {
shmem_unacct_size(info->flags, inode->i_size);
}
}
- simple_xattrs_free(&info->xattrs);
+ simple_xattrs_free(&info->xattrs, sbinfo->max_inodes ? &freed : NULL);
+ shmem_free_inode(inode->i_sb, freed);
WARN_ON(inode->i_blocks);
- shmem_free_inode(inode->i_sb);
clear_inode(inode);
#ifdef CONFIG_TMPFS_QUOTA
dquot_free_inode(inode);
inode = new_inode(sb);
if (!inode) {
- shmem_free_inode(sb);
+ shmem_free_inode(sb, 0);
return ERR_PTR(-ENOSPC);
}
ret = simple_offset_add(shmem_get_offset_ctx(dir), dentry);
if (ret) {
if (inode->i_nlink)
- shmem_free_inode(inode->i_sb);
+ shmem_free_inode(inode->i_sb, 0);
goto out;
}
struct inode *inode = d_inode(dentry);
if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode))
- shmem_free_inode(inode->i_sb);
+ shmem_free_inode(inode->i_sb, 0);
simple_offset_remove(shmem_get_offset_ctx(dir), dentry);
void *fs_info)
{
struct shmem_inode_info *info = SHMEM_I(inode);
+ struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
const struct xattr *xattr;
struct simple_xattr *new_xattr;
+ size_t ispace = 0;
size_t len;
+ if (sbinfo->max_inodes) {
+ for (xattr = xattr_array; xattr->name != NULL; xattr++) {
+ ispace += simple_xattr_space(xattr->name,
+ xattr->value_len + XATTR_SECURITY_PREFIX_LEN);
+ }
+ if (ispace) {
+ raw_spin_lock(&sbinfo->stat_lock);
+ if (sbinfo->free_ispace < ispace)
+ ispace = 0;
+ else
+ sbinfo->free_ispace -= ispace;
+ raw_spin_unlock(&sbinfo->stat_lock);
+ if (!ispace)
+ return -ENOSPC;
+ }
+ }
+
for (xattr = xattr_array; xattr->name != NULL; xattr++) {
new_xattr = simple_xattr_alloc(xattr->value, xattr->value_len);
if (!new_xattr)
- return -ENOMEM;
+ break;
len = strlen(xattr->name) + 1;
new_xattr->name = kmalloc(XATTR_SECURITY_PREFIX_LEN + len,
GFP_KERNEL);
if (!new_xattr->name) {
kvfree(new_xattr);
- return -ENOMEM;
+ break;
}
memcpy(new_xattr->name, XATTR_SECURITY_PREFIX,
simple_xattr_add(&info->xattrs, new_xattr);
}
+ if (xattr->name != NULL) {
+ if (ispace) {
+ raw_spin_lock(&sbinfo->stat_lock);
+ sbinfo->free_ispace += ispace;
+ raw_spin_unlock(&sbinfo->stat_lock);
+ }
+ simple_xattrs_free(&info->xattrs, NULL);
+ return -ENOMEM;
+ }
+
return 0;
}
size_t size, int flags)
{
struct shmem_inode_info *info = SHMEM_I(inode);
+ struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
struct simple_xattr *old_xattr;
+ size_t ispace = 0;
name = xattr_full_name(handler, name);
+ if (value && sbinfo->max_inodes) {
+ ispace = simple_xattr_space(name, size);
+ raw_spin_lock(&sbinfo->stat_lock);
+ if (sbinfo->free_ispace < ispace)
+ ispace = 0;
+ else
+ sbinfo->free_ispace -= ispace;
+ raw_spin_unlock(&sbinfo->stat_lock);
+ if (!ispace)
+ return -ENOSPC;
+ }
+
old_xattr = simple_xattr_set(&info->xattrs, name, value, size, flags);
if (!IS_ERR(old_xattr)) {
+ ispace = 0;
+ if (old_xattr && sbinfo->max_inodes)
+ ispace = simple_xattr_space(old_xattr->name,
+ old_xattr->size);
simple_xattr_free(old_xattr);
old_xattr = NULL;
inode->i_ctime = current_time(inode);
inode_inc_iversion(inode);
}
+ if (ispace) {
+ raw_spin_lock(&sbinfo->stat_lock);
+ sbinfo->free_ispace += ispace;
+ raw_spin_unlock(&sbinfo->stat_lock);
+ }
return PTR_ERR(old_xattr);
}
.set = shmem_xattr_handler_set,
};
+static const struct xattr_handler shmem_user_xattr_handler = {
+ .prefix = XATTR_USER_PREFIX,
+ .get = shmem_xattr_handler_get,
+ .set = shmem_xattr_handler_set,
+};
+
static const struct xattr_handler *shmem_xattr_handlers[] = {
&shmem_security_xattr_handler,
&shmem_trusted_xattr_handler,
+ &shmem_user_xattr_handler,
NULL
};