From 38f38657444d15e1a8574eae80ed3de9f501737a Mon Sep 17 00:00:00 2001 From: Aristeu Rozanski Date: Thu, 23 Aug 2012 16:53:28 -0400 Subject: xattr: extract simple_xattr code from tmpfs Extract in-memory xattr APIs from tmpfs. Will be used by cgroup. $ size vmlinux.o text data bss dec hex filename 4658782 880729 5195032 10734543 a3cbcf vmlinux.o $ size vmlinux.o text data bss dec hex filename 4658957 880729 5195032 10734718 a3cc7e vmlinux.o v7: - checkpatch warnings fixed - Implement the changes requested by Hugh Dickins: - make simple_xattrs_init and simple_xattrs_free inline - get rid of locking and list reinitialization in simple_xattrs_free, they're not needed v6: - no changes v5: - no changes v4: - move simple_xattrs_free() to fs/xattr.c v3: - in kmem_xattrs_free(), reinitialize the list - use simple_xattr_* prefix - introduce simple_xattr_add() to prevent direct list usage Original-patch-by: Li Zefan Cc: Li Zefan Cc: Hillf Danton Cc: Lennart Poettering Acked-by: Hugh Dickins Signed-off-by: Li Zefan Signed-off-by: Aristeu Rozanski Signed-off-by: Tejun Heo --- mm/shmem.c | 171 +++++-------------------------------------------------------- 1 file changed, 13 insertions(+), 158 deletions(-) (limited to 'mm/shmem.c') diff --git a/mm/shmem.c b/mm/shmem.c index d4e184e2a38e..d3752110c8c7 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -77,13 +77,6 @@ static struct vfsmount *shm_mnt; /* Symlink up to this size is kmalloc'ed instead of using a swappable page */ #define SHORT_SYMLINK_LEN 128 -struct shmem_xattr { - struct list_head list; /* anchored by shmem_inode_info->xattr_list */ - char *name; /* xattr name */ - size_t size; - char value[0]; -}; - /* * shmem_fallocate and shmem_writepage communicate via inode->i_private * (with i_mutex making sure that it has only one user at a time): @@ -636,7 +629,6 @@ static int shmem_setattr(struct dentry *dentry, struct iattr *attr) static void shmem_evict_inode(struct inode *inode) { struct shmem_inode_info *info = SHMEM_I(inode); - struct shmem_xattr *xattr, *nxattr; if (inode->i_mapping->a_ops == &shmem_aops) { shmem_unacct_size(info->flags, inode->i_size); @@ -650,10 +642,7 @@ static void shmem_evict_inode(struct inode *inode) } else kfree(info->symlink); - list_for_each_entry_safe(xattr, nxattr, &info->xattr_list, list) { - kfree(xattr->name); - kfree(xattr); - } + simple_xattrs_free(&info->xattrs); BUG_ON(inode->i_blocks); shmem_free_inode(inode->i_sb); clear_inode(inode); @@ -1377,7 +1366,7 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode spin_lock_init(&info->lock); info->flags = flags & VM_NORESERVE; INIT_LIST_HEAD(&info->swaplist); - INIT_LIST_HEAD(&info->xattr_list); + simple_xattrs_init(&info->xattrs); cache_no_acl(inode); switch (mode & S_IFMT) { @@ -2059,28 +2048,6 @@ static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *co * filesystem level, though. */ -/* - * Allocate new xattr and copy in the value; but leave the name to callers. - */ -static struct shmem_xattr *shmem_xattr_alloc(const void *value, size_t size) -{ - struct shmem_xattr *new_xattr; - size_t len; - - /* wrap around? */ - len = sizeof(*new_xattr) + size; - if (len <= sizeof(*new_xattr)) - return NULL; - - new_xattr = kmalloc(len, GFP_KERNEL); - if (!new_xattr) - return NULL; - - new_xattr->size = size; - memcpy(new_xattr->value, value, size); - return new_xattr; -} - /* * Callback for security_inode_init_security() for acquiring xattrs. */ @@ -2090,11 +2057,11 @@ static int shmem_initxattrs(struct inode *inode, { struct shmem_inode_info *info = SHMEM_I(inode); const struct xattr *xattr; - struct shmem_xattr *new_xattr; + struct simple_xattr *new_xattr; size_t len; for (xattr = xattr_array; xattr->name != NULL; xattr++) { - new_xattr = shmem_xattr_alloc(xattr->value, xattr->value_len); + new_xattr = simple_xattr_alloc(xattr->value, xattr->value_len); if (!new_xattr) return -ENOMEM; @@ -2111,91 +2078,12 @@ static int shmem_initxattrs(struct inode *inode, memcpy(new_xattr->name + XATTR_SECURITY_PREFIX_LEN, xattr->name, len); - spin_lock(&info->lock); - list_add(&new_xattr->list, &info->xattr_list); - spin_unlock(&info->lock); + simple_xattr_list_add(&info->xattrs, new_xattr); } return 0; } -static int shmem_xattr_get(struct dentry *dentry, const char *name, - void *buffer, size_t size) -{ - struct shmem_inode_info *info; - struct shmem_xattr *xattr; - int ret = -ENODATA; - - info = SHMEM_I(dentry->d_inode); - - spin_lock(&info->lock); - list_for_each_entry(xattr, &info->xattr_list, list) { - if (strcmp(name, xattr->name)) - continue; - - ret = xattr->size; - if (buffer) { - if (size < xattr->size) - ret = -ERANGE; - else - memcpy(buffer, xattr->value, xattr->size); - } - break; - } - spin_unlock(&info->lock); - return ret; -} - -static int shmem_xattr_set(struct inode *inode, const char *name, - const void *value, size_t size, int flags) -{ - struct shmem_inode_info *info = SHMEM_I(inode); - struct shmem_xattr *xattr; - struct shmem_xattr *new_xattr = NULL; - int err = 0; - - /* value == NULL means remove */ - if (value) { - new_xattr = shmem_xattr_alloc(value, size); - if (!new_xattr) - return -ENOMEM; - - new_xattr->name = kstrdup(name, GFP_KERNEL); - if (!new_xattr->name) { - kfree(new_xattr); - return -ENOMEM; - } - } - - spin_lock(&info->lock); - list_for_each_entry(xattr, &info->xattr_list, list) { - if (!strcmp(name, xattr->name)) { - if (flags & XATTR_CREATE) { - xattr = new_xattr; - err = -EEXIST; - } else if (new_xattr) { - list_replace(&xattr->list, &new_xattr->list); - } else { - list_del(&xattr->list); - } - goto out; - } - } - if (flags & XATTR_REPLACE) { - xattr = new_xattr; - err = -ENODATA; - } else { - list_add(&new_xattr->list, &info->xattr_list); - xattr = NULL; - } -out: - spin_unlock(&info->lock); - if (xattr) - kfree(xattr->name); - kfree(xattr); - return err; -} - static const struct xattr_handler *shmem_xattr_handlers[] = { #ifdef CONFIG_TMPFS_POSIX_ACL &generic_acl_access_handler, @@ -2226,6 +2114,7 @@ static int shmem_xattr_validate(const char *name) static ssize_t shmem_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size) { + struct shmem_inode_info *info = SHMEM_I(dentry->d_inode); int err; /* @@ -2240,12 +2129,13 @@ static ssize_t shmem_getxattr(struct dentry *dentry, const char *name, if (err) return err; - return shmem_xattr_get(dentry, name, buffer, size); + return simple_xattr_get(&info->xattrs, name, buffer, size); } static int shmem_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) { + struct shmem_inode_info *info = SHMEM_I(dentry->d_inode); int err; /* @@ -2260,15 +2150,12 @@ static int shmem_setxattr(struct dentry *dentry, const char *name, if (err) return err; - if (size == 0) - value = ""; /* empty EA, do not remove */ - - return shmem_xattr_set(dentry->d_inode, name, value, size, flags); - + return simple_xattr_set(&info->xattrs, name, value, size, flags); } static int shmem_removexattr(struct dentry *dentry, const char *name) { + struct shmem_inode_info *info = SHMEM_I(dentry->d_inode); int err; /* @@ -2283,45 +2170,13 @@ static int shmem_removexattr(struct dentry *dentry, const char *name) if (err) return err; - return shmem_xattr_set(dentry->d_inode, name, NULL, 0, XATTR_REPLACE); -} - -static bool xattr_is_trusted(const char *name) -{ - return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); + return simple_xattr_remove(&info->xattrs, name); } static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size) { - bool trusted = capable(CAP_SYS_ADMIN); - struct shmem_xattr *xattr; - struct shmem_inode_info *info; - size_t used = 0; - - info = SHMEM_I(dentry->d_inode); - - spin_lock(&info->lock); - list_for_each_entry(xattr, &info->xattr_list, list) { - size_t len; - - /* skip "trusted." attributes for unprivileged callers */ - if (!trusted && xattr_is_trusted(xattr->name)) - continue; - - len = strlen(xattr->name) + 1; - used += len; - if (buffer) { - if (size < used) { - used = -ERANGE; - break; - } - memcpy(buffer, xattr->name, len); - buffer += len; - } - } - spin_unlock(&info->lock); - - return used; + struct shmem_inode_info *info = SHMEM_I(dentry->d_inode); + return simple_xattr_list(&info->xattrs, buffer, size); } #endif /* CONFIG_TMPFS_XATTR */ -- cgit v1.2.3