tmpfs,xattr: enable limited user extended attributes
Enable "user." extended attributes on tmpfs, limiting them by tracking the space they occupy, and deducting that space from the limited ispace (unless tmpfs mounted with nr_inodes=0 to leave that ispace unlimited). tmpfs inodes and simple xattrs are both unswappable, and have to be in lowmem on a 32-bit highmem kernel: so the ispace limit is appropriate for xattrs, without any need for a further mount option. Add simple_xattr_space() to give approximate but deterministic estimate of the space taken up by each xattr: with simple_xattrs_free() outputting the space freed if required (but kernfs and even some tmpfs usages do not require that, so don't waste time on strlen'ing if not needed). Security and trusted xattrs were already supported: for consistency and simplicity, account them from the same pool; though there's a small risk that a tmpfs with enough space before would now be considered too small. When extended attributes are used, "df -i" does show more IUsed and less IFree than can be explained by the inodes: document that (manpage later). xfstests tests/generic which were not run on tmpfs before but now pass: 020 037 062 070 077 097 103 117 337 377 454 486 523 533 611 618 728 with no new failures. Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Message-Id: <2e63b26e-df46-5baa-c7d6-f9a8dd3282c5@google.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
parent
e07c469e97
commit
2daf18a788
|
@ -21,8 +21,8 @@ explained further below, some of which can be reconfigured dynamically on the
|
||||||
fly using a remount ('mount -o remount ...') of the filesystem. A tmpfs
|
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
|
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
|
usage. tmpfs also supports POSIX ACLs, and extended attributes for the
|
||||||
trusted.* and security.* namespaces. ramfs does not use swap and you cannot
|
trusted.*, security.* and user.* namespaces. ramfs does not use swap and you
|
||||||
modify any parameter for a ramfs filesystem. The size limit of a ramfs
|
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
|
filesystem is how much memory you have available, and so care must be taken if
|
||||||
used so to not run out of memory.
|
used so to not run out of memory.
|
||||||
|
|
||||||
|
@ -97,6 +97,9 @@ mount with such options, since it allows any user with write access to
|
||||||
use up all the memory on the machine; but enhances the scalability of
|
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.
|
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 blocks may be swapped out, when there is a shortage of memory.
|
||||||
tmpfs has a mount option to disable its use of swap:
|
tmpfs has a mount option to disable its use of swap:
|
||||||
|
|
||||||
|
|
|
@ -205,8 +205,8 @@ config TMPFS_XATTR
|
||||||
Extended attributes are name:value pairs associated with inodes by
|
Extended attributes are name:value pairs associated with inodes by
|
||||||
the kernel or by users (see the attr(5) manual page for details).
|
the kernel or by users (see the attr(5) manual page for details).
|
||||||
|
|
||||||
Currently this enables support for the trusted.* and
|
This enables support for the trusted.*, security.* and user.*
|
||||||
security.* namespaces.
|
namespaces.
|
||||||
|
|
||||||
You need this for POSIX ACL support on tmpfs.
|
You need this for POSIX ACL support on tmpfs.
|
||||||
|
|
||||||
|
|
|
@ -556,7 +556,7 @@ void kernfs_put(struct kernfs_node *kn)
|
||||||
kfree_const(kn->name);
|
kfree_const(kn->name);
|
||||||
|
|
||||||
if (kn->iattr) {
|
if (kn->iattr) {
|
||||||
simple_xattrs_free(&kn->iattr->xattrs);
|
simple_xattrs_free(&kn->iattr->xattrs, NULL);
|
||||||
kmem_cache_free(kernfs_iattrs_cache, kn->iattr);
|
kmem_cache_free(kernfs_iattrs_cache, kn->iattr);
|
||||||
}
|
}
|
||||||
spin_lock(&kernfs_idr_lock);
|
spin_lock(&kernfs_idr_lock);
|
||||||
|
|
28
fs/xattr.c
28
fs/xattr.c
|
@ -1039,6 +1039,26 @@ const char *xattr_full_name(const struct xattr_handler *handler,
|
||||||
}
|
}
|
||||||
EXPORT_SYMBOL(xattr_full_name);
|
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
|
* simple_xattr_free - free an xattr object
|
||||||
* @xattr: the xattr object
|
* @xattr: the xattr object
|
||||||
|
@ -1363,14 +1383,17 @@ void simple_xattrs_init(struct simple_xattrs *xattrs)
|
||||||
/**
|
/**
|
||||||
* simple_xattrs_free - free xattrs
|
* simple_xattrs_free - free xattrs
|
||||||
* @xattrs: xattr header whose xattrs to destroy
|
* @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
|
* Destroy all xattrs in @xattr. When this is called no one can hold a
|
||||||
* reference to any of the xattrs anymore.
|
* 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;
|
struct rb_node *rbp;
|
||||||
|
|
||||||
|
if (freed_space)
|
||||||
|
*freed_space = 0;
|
||||||
rbp = rb_first(&xattrs->rb_root);
|
rbp = rb_first(&xattrs->rb_root);
|
||||||
while (rbp) {
|
while (rbp) {
|
||||||
struct simple_xattr *xattr;
|
struct simple_xattr *xattr;
|
||||||
|
@ -1379,6 +1402,9 @@ void simple_xattrs_free(struct simple_xattrs *xattrs)
|
||||||
rbp_next = rb_next(rbp);
|
rbp_next = rb_next(rbp);
|
||||||
xattr = rb_entry(rbp, struct simple_xattr, rb_node);
|
xattr = rb_entry(rbp, struct simple_xattr, rb_node);
|
||||||
rb_erase(&xattr->rb_node, &xattrs->rb_root);
|
rb_erase(&xattr->rb_node, &xattrs->rb_root);
|
||||||
|
if (freed_space)
|
||||||
|
*freed_space += simple_xattr_space(xattr->name,
|
||||||
|
xattr->size);
|
||||||
simple_xattr_free(xattr);
|
simple_xattr_free(xattr);
|
||||||
rbp = rbp_next;
|
rbp = rbp_next;
|
||||||
}
|
}
|
||||||
|
|
|
@ -114,7 +114,8 @@ struct simple_xattr {
|
||||||
};
|
};
|
||||||
|
|
||||||
void simple_xattrs_init(struct simple_xattrs *xattrs);
|
void simple_xattrs_init(struct simple_xattrs *xattrs);
|
||||||
void simple_xattrs_free(struct simple_xattrs *xattrs);
|
void simple_xattrs_free(struct simple_xattrs *xattrs, size_t *freed_space);
|
||||||
|
size_t simple_xattr_space(const char *name, size_t size);
|
||||||
struct simple_xattr *simple_xattr_alloc(const void *value, size_t size);
|
struct simple_xattr *simple_xattr_alloc(const void *value, size_t size);
|
||||||
void simple_xattr_free(struct simple_xattr *xattr);
|
void simple_xattr_free(struct simple_xattr *xattr);
|
||||||
int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
|
int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
|
||||||
|
|
78
mm/shmem.c
78
mm/shmem.c
|
@ -393,12 +393,12 @@ static int shmem_reserve_inode(struct super_block *sb, ino_t *inop)
|
||||||
return 0;
|
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);
|
struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
|
||||||
if (sbinfo->max_inodes) {
|
if (sbinfo->max_inodes) {
|
||||||
raw_spin_lock(&sbinfo->stat_lock);
|
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);
|
raw_spin_unlock(&sbinfo->stat_lock);
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
@ -1232,6 +1232,7 @@ static void shmem_evict_inode(struct inode *inode)
|
||||||
{
|
{
|
||||||
struct shmem_inode_info *info = SHMEM_I(inode);
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
||||||
struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
|
struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
|
||||||
|
size_t freed = 0;
|
||||||
|
|
||||||
if (shmem_mapping(inode->i_mapping)) {
|
if (shmem_mapping(inode->i_mapping)) {
|
||||||
shmem_unacct_size(info->flags, inode->i_size);
|
shmem_unacct_size(info->flags, inode->i_size);
|
||||||
|
@ -1258,9 +1259,9 @@ static void shmem_evict_inode(struct inode *inode)
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
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);
|
WARN_ON(inode->i_blocks);
|
||||||
shmem_free_inode(inode->i_sb);
|
|
||||||
clear_inode(inode);
|
clear_inode(inode);
|
||||||
#ifdef CONFIG_TMPFS_QUOTA
|
#ifdef CONFIG_TMPFS_QUOTA
|
||||||
dquot_free_inode(inode);
|
dquot_free_inode(inode);
|
||||||
|
@ -2440,7 +2441,7 @@ static struct inode *__shmem_get_inode(struct mnt_idmap *idmap,
|
||||||
inode = new_inode(sb);
|
inode = new_inode(sb);
|
||||||
|
|
||||||
if (!inode) {
|
if (!inode) {
|
||||||
shmem_free_inode(sb);
|
shmem_free_inode(sb, 0);
|
||||||
return ERR_PTR(-ENOSPC);
|
return ERR_PTR(-ENOSPC);
|
||||||
}
|
}
|
||||||
|
|
||||||
|
@ -3284,7 +3285,7 @@ static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentr
|
||||||
ret = simple_offset_add(shmem_get_offset_ctx(dir), dentry);
|
ret = simple_offset_add(shmem_get_offset_ctx(dir), dentry);
|
||||||
if (ret) {
|
if (ret) {
|
||||||
if (inode->i_nlink)
|
if (inode->i_nlink)
|
||||||
shmem_free_inode(inode->i_sb);
|
shmem_free_inode(inode->i_sb, 0);
|
||||||
goto out;
|
goto out;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
@ -3304,7 +3305,7 @@ static int shmem_unlink(struct inode *dir, struct dentry *dentry)
|
||||||
struct inode *inode = d_inode(dentry);
|
struct inode *inode = d_inode(dentry);
|
||||||
|
|
||||||
if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode))
|
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);
|
simple_offset_remove(shmem_get_offset_ctx(dir), dentry);
|
||||||
|
|
||||||
|
@ -3557,21 +3558,40 @@ static int shmem_initxattrs(struct inode *inode,
|
||||||
void *fs_info)
|
void *fs_info)
|
||||||
{
|
{
|
||||||
struct shmem_inode_info *info = SHMEM_I(inode);
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
||||||
|
struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
|
||||||
const struct xattr *xattr;
|
const struct xattr *xattr;
|
||||||
struct simple_xattr *new_xattr;
|
struct simple_xattr *new_xattr;
|
||||||
|
size_t ispace = 0;
|
||||||
size_t len;
|
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++) {
|
for (xattr = xattr_array; xattr->name != NULL; xattr++) {
|
||||||
new_xattr = simple_xattr_alloc(xattr->value, xattr->value_len);
|
new_xattr = simple_xattr_alloc(xattr->value, xattr->value_len);
|
||||||
if (!new_xattr)
|
if (!new_xattr)
|
||||||
return -ENOMEM;
|
break;
|
||||||
|
|
||||||
len = strlen(xattr->name) + 1;
|
len = strlen(xattr->name) + 1;
|
||||||
new_xattr->name = kmalloc(XATTR_SECURITY_PREFIX_LEN + len,
|
new_xattr->name = kmalloc(XATTR_SECURITY_PREFIX_LEN + len,
|
||||||
GFP_KERNEL);
|
GFP_KERNEL);
|
||||||
if (!new_xattr->name) {
|
if (!new_xattr->name) {
|
||||||
kvfree(new_xattr);
|
kvfree(new_xattr);
|
||||||
return -ENOMEM;
|
break;
|
||||||
}
|
}
|
||||||
|
|
||||||
memcpy(new_xattr->name, XATTR_SECURITY_PREFIX,
|
memcpy(new_xattr->name, XATTR_SECURITY_PREFIX,
|
||||||
|
@ -3582,6 +3602,16 @@ static int shmem_initxattrs(struct inode *inode,
|
||||||
simple_xattr_add(&info->xattrs, new_xattr);
|
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;
|
return 0;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
@ -3602,16 +3632,39 @@ static int shmem_xattr_handler_set(const struct xattr_handler *handler,
|
||||||
size_t size, int flags)
|
size_t size, int flags)
|
||||||
{
|
{
|
||||||
struct shmem_inode_info *info = SHMEM_I(inode);
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
||||||
|
struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
|
||||||
struct simple_xattr *old_xattr;
|
struct simple_xattr *old_xattr;
|
||||||
|
size_t ispace = 0;
|
||||||
|
|
||||||
name = xattr_full_name(handler, name);
|
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);
|
old_xattr = simple_xattr_set(&info->xattrs, name, value, size, flags);
|
||||||
if (!IS_ERR(old_xattr)) {
|
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);
|
simple_xattr_free(old_xattr);
|
||||||
old_xattr = NULL;
|
old_xattr = NULL;
|
||||||
inode->i_ctime = current_time(inode);
|
inode->i_ctime = current_time(inode);
|
||||||
inode_inc_iversion(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);
|
return PTR_ERR(old_xattr);
|
||||||
}
|
}
|
||||||
|
|
||||||
|
@ -3627,9 +3680,16 @@ static const struct xattr_handler shmem_trusted_xattr_handler = {
|
||||||
.set = shmem_xattr_handler_set,
|
.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[] = {
|
static const struct xattr_handler *shmem_xattr_handlers[] = {
|
||||||
&shmem_security_xattr_handler,
|
&shmem_security_xattr_handler,
|
||||||
&shmem_trusted_xattr_handler,
|
&shmem_trusted_xattr_handler,
|
||||||
|
&shmem_user_xattr_handler,
|
||||||
NULL
|
NULL
|
||||||
};
|
};
|
||||||
|
|
||||||
|
|
Loading…
Reference in New Issue