diff options
| -rw-r--r-- | Documentation/filesystems/tmpfs.rst | 7 | ||||
| -rw-r--r-- | fs/Kconfig | 4 | ||||
| -rw-r--r-- | fs/kernfs/dir.c | 2 | ||||
| -rw-r--r-- | fs/xattr.c | 28 | ||||
| -rw-r--r-- | include/linux/xattr.h | 3 | ||||
| -rw-r--r-- | mm/shmem.c | 78 |
6 files changed, 106 insertions, 16 deletions
diff --git a/Documentation/filesystems/tmpfs.rst b/Documentation/filesystems/tmpfs.rst index 67422ee10e03..56a26c843dbe 100644 --- a/Documentation/filesystems/tmpfs.rst +++ b/Documentation/filesystems/tmpfs.rst @@ -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 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. @@ -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 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: diff --git a/fs/Kconfig b/fs/Kconfig index 8218a71933f9..7da21f563192 100644 --- a/fs/Kconfig +++ b/fs/Kconfig @@ -205,8 +205,8 @@ config TMPFS_XATTR Extended attributes are name:value pairs associated with inodes by the kernel or by users (see the attr(5) manual page for details). - Currently this enables support for the trusted.* and - security.* namespaces. + This enables support for the trusted.*, security.* and user.* + namespaces. You need this for POSIX ACL support on tmpfs. diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index 5a1a4af9d3d2..660995856a04 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -556,7 +556,7 @@ void kernfs_put(struct kernfs_node *kn) kfree_const(kn->name); if (kn->iattr) { - simple_xattrs_free(&kn->iattr->xattrs); + simple_xattrs_free(&kn->iattr->xattrs, NULL); kmem_cache_free(kernfs_iattrs_cache, kn->iattr); } spin_lock(&kernfs_idr_lock); diff --git a/fs/xattr.c b/fs/xattr.c index ba37a8f5cfd1..2d607542281b 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -1040,6 +1040,26 @@ const char *xattr_full_name(const struct xattr_handler *handler, 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 * @@ -1363,14 +1383,17 @@ void simple_xattrs_init(struct simple_xattrs *xattrs) /** * 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; @@ -1379,6 +1402,9 @@ void simple_xattrs_free(struct simple_xattrs *xattrs) 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; } diff --git a/include/linux/xattr.h b/include/linux/xattr.h index e37fe667ae04..d20051865800 100644 --- a/include/linux/xattr.h +++ b/include/linux/xattr.h @@ -114,7 +114,8 @@ struct simple_xattr { }; 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); void simple_xattr_free(struct simple_xattr *xattr); int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, diff --git a/mm/shmem.c b/mm/shmem.c index 8c8f0b1b700c..ca43fb256b8e 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -393,12 +393,12 @@ static int shmem_reserve_inode(struct super_block *sb, ino_t *inop) 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); } } @@ -1232,6 +1232,7 @@ static void shmem_evict_inode(struct inode *inode) { 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); @@ -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); - shmem_free_inode(inode->i_sb); clear_inode(inode); #ifdef CONFIG_TMPFS_QUOTA dquot_free_inode(inode); @@ -2440,7 +2441,7 @@ static struct inode *__shmem_get_inode(struct mnt_idmap *idmap, inode = new_inode(sb); if (!inode) { - shmem_free_inode(sb); + shmem_free_inode(sb, 0); 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); if (ret) { if (inode->i_nlink) - shmem_free_inode(inode->i_sb); + shmem_free_inode(inode->i_sb, 0); goto out; } @@ -3304,7 +3305,7 @@ static int shmem_unlink(struct inode *dir, struct dentry *dentry) 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); @@ -3557,21 +3558,40 @@ static int shmem_initxattrs(struct inode *inode, 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, @@ -3582,6 +3602,16 @@ static int shmem_initxattrs(struct inode *inode, 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; } @@ -3602,16 +3632,39 @@ static int shmem_xattr_handler_set(const struct xattr_handler *handler, 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); } @@ -3627,9 +3680,16 @@ static const struct xattr_handler shmem_trusted_xattr_handler = { .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 }; |