diff options
Diffstat (limited to 'fs/aufs/xattr.c')
| -rw-r--r-- | fs/aufs/xattr.c | 344 |
1 files changed, 344 insertions, 0 deletions
diff --git a/fs/aufs/xattr.c b/fs/aufs/xattr.c new file mode 100644 index 000000000..b7e13ca3e --- /dev/null +++ b/fs/aufs/xattr.c @@ -0,0 +1,344 @@ +/* + * Copyright (C) 2014-2015 Junjiro R. Okajima + * + * This program, aufs is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +/* + * handling xattr functions + */ + +#include <linux/xattr.h> +#include "aufs.h" + +static int au_xattr_ignore(int err, char *name, unsigned int ignore_flags) +{ + if (!ignore_flags) + goto out; + switch (err) { + case -ENOMEM: + case -EDQUOT: + goto out; + } + + if ((ignore_flags & AuBrAttr_ICEX) == AuBrAttr_ICEX) { + err = 0; + goto out; + } + +#define cmp(brattr, prefix) do { \ + if (!strncmp(name, XATTR_##prefix##_PREFIX, \ + XATTR_##prefix##_PREFIX_LEN)) { \ + if (ignore_flags & AuBrAttr_ICEX_##brattr) \ + err = 0; \ + goto out; \ + } \ + } while (0) + + cmp(SEC, SECURITY); + cmp(SYS, SYSTEM); + cmp(TR, TRUSTED); + cmp(USR, USER); +#undef cmp + + if (ignore_flags & AuBrAttr_ICEX_OTH) + err = 0; + +out: + return err; +} + +static const int au_xattr_out_of_list = AuBrAttr_ICEX_OTH << 1; + +static int au_do_cpup_xattr(struct dentry *h_dst, struct dentry *h_src, + char *name, char **buf, unsigned int ignore_flags, + unsigned int verbose) +{ + int err; + ssize_t ssz; + struct inode *h_idst; + + ssz = vfs_getxattr_alloc(h_src, name, buf, 0, GFP_NOFS); + err = ssz; + if (unlikely(err <= 0)) { + if (err == -ENODATA + || (err == -EOPNOTSUPP + && ((ignore_flags & au_xattr_out_of_list) + || (au_test_nfs_noacl(d_inode(h_src)) + && (!strcmp(name, XATTR_NAME_POSIX_ACL_ACCESS) + || !strcmp(name, + XATTR_NAME_POSIX_ACL_DEFAULT)))) + )) + err = 0; + if (err && (verbose || au_debug_test())) + pr_err("%s, err %d\n", name, err); + goto out; + } + + /* unlock it temporary */ + h_idst = d_inode(h_dst); + mutex_unlock(&h_idst->i_mutex); + err = vfsub_setxattr(h_dst, name, *buf, ssz, /*flags*/0); + mutex_lock_nested(&h_idst->i_mutex, AuLsc_I_CHILD2); + if (unlikely(err)) { + if (verbose || au_debug_test()) + pr_err("%s, err %d\n", name, err); + err = au_xattr_ignore(err, name, ignore_flags); + } + +out: + return err; +} + +int au_cpup_xattr(struct dentry *h_dst, struct dentry *h_src, int ignore_flags, + unsigned int verbose) +{ + int err, unlocked, acl_access, acl_default; + ssize_t ssz; + struct inode *h_isrc, *h_idst; + char *value, *p, *o, *e; + + /* try stopping to update the source inode while we are referencing */ + /* there should not be the parent-child relationship between them */ + h_isrc = d_inode(h_src); + h_idst = d_inode(h_dst); + mutex_unlock(&h_idst->i_mutex); + mutex_lock_nested(&h_isrc->i_mutex, AuLsc_I_CHILD); + mutex_lock_nested(&h_idst->i_mutex, AuLsc_I_CHILD2); + unlocked = 0; + + /* some filesystems don't list POSIX ACL, for example tmpfs */ + ssz = vfs_listxattr(h_src, NULL, 0); + err = ssz; + if (unlikely(err < 0)) { + AuTraceErr(err); + if (err == -ENODATA + || err == -EOPNOTSUPP) + err = 0; /* ignore */ + goto out; + } + + err = 0; + p = NULL; + o = NULL; + if (ssz) { + err = -ENOMEM; + p = kmalloc(ssz, GFP_NOFS); + o = p; + if (unlikely(!p)) + goto out; + err = vfs_listxattr(h_src, p, ssz); + } + mutex_unlock(&h_isrc->i_mutex); + unlocked = 1; + AuDbg("err %d, ssz %zd\n", err, ssz); + if (unlikely(err < 0)) + goto out_free; + + err = 0; + e = p + ssz; + value = NULL; + acl_access = 0; + acl_default = 0; + while (!err && p < e) { + acl_access |= !strncmp(p, XATTR_NAME_POSIX_ACL_ACCESS, + sizeof(XATTR_NAME_POSIX_ACL_ACCESS) - 1); + acl_default |= !strncmp(p, XATTR_NAME_POSIX_ACL_DEFAULT, + sizeof(XATTR_NAME_POSIX_ACL_DEFAULT) + - 1); + err = au_do_cpup_xattr(h_dst, h_src, p, &value, ignore_flags, + verbose); + p += strlen(p) + 1; + } + AuTraceErr(err); + ignore_flags |= au_xattr_out_of_list; + if (!err && !acl_access) { + err = au_do_cpup_xattr(h_dst, h_src, + XATTR_NAME_POSIX_ACL_ACCESS, &value, + ignore_flags, verbose); + AuTraceErr(err); + } + if (!err && !acl_default) { + err = au_do_cpup_xattr(h_dst, h_src, + XATTR_NAME_POSIX_ACL_DEFAULT, &value, + ignore_flags, verbose); + AuTraceErr(err); + } + + kfree(value); + +out_free: + kfree(o); +out: + if (!unlocked) + mutex_unlock(&h_isrc->i_mutex); + AuTraceErr(err); + return err; +} + +/* ---------------------------------------------------------------------- */ + +enum { + AU_XATTR_LIST, + AU_XATTR_GET +}; + +struct au_lgxattr { + int type; + union { + struct { + char *list; + size_t size; + } list; + struct { + const char *name; + void *value; + size_t size; + } get; + } u; +}; + +static ssize_t au_lgxattr(struct dentry *dentry, struct au_lgxattr *arg) +{ + ssize_t err; + struct path h_path; + struct super_block *sb; + + sb = dentry->d_sb; + err = si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLM); + if (unlikely(err)) + goto out; + err = au_h_path_getattr(dentry, /*force*/1, &h_path); + if (unlikely(err)) + goto out_si; + if (unlikely(!h_path.dentry)) + /* illegally overlapped or something */ + goto out_di; /* pretending success */ + + /* always topmost entry only */ + switch (arg->type) { + case AU_XATTR_LIST: + err = vfs_listxattr(h_path.dentry, + arg->u.list.list, arg->u.list.size); + break; + case AU_XATTR_GET: + err = vfs_getxattr(h_path.dentry, + arg->u.get.name, arg->u.get.value, + arg->u.get.size); + break; + } + +out_di: + di_read_unlock(dentry, AuLock_IR); +out_si: + si_read_unlock(sb); +out: + AuTraceErr(err); + return err; +} + +ssize_t aufs_listxattr(struct dentry *dentry, char *list, size_t size) +{ + struct au_lgxattr arg = { + .type = AU_XATTR_LIST, + .u.list = { + .list = list, + .size = size + }, + }; + + return au_lgxattr(dentry, &arg); +} + +ssize_t aufs_getxattr(struct dentry *dentry, const char *name, void *value, + size_t size) +{ + struct au_lgxattr arg = { + .type = AU_XATTR_GET, + .u.get = { + .name = name, + .value = value, + .size = size + }, + }; + + return au_lgxattr(dentry, &arg); +} + +int aufs_setxattr(struct dentry *dentry, const char *name, const void *value, + size_t size, int flags) +{ + struct au_srxattr arg = { + .type = AU_XATTR_SET, + .u.set = { + .name = name, + .value = value, + .size = size, + .flags = flags + }, + }; + + return au_srxattr(dentry, &arg); +} + +int aufs_removexattr(struct dentry *dentry, const char *name) +{ + struct au_srxattr arg = { + .type = AU_XATTR_REMOVE, + .u.remove = { + .name = name + }, + }; + + return au_srxattr(dentry, &arg); +} + +/* ---------------------------------------------------------------------- */ + +#if 0 +static size_t au_xattr_list(struct dentry *dentry, char *list, size_t list_size, + const char *name, size_t name_len, int type) +{ + return aufs_listxattr(dentry, list, list_size); +} + +static int au_xattr_get(struct dentry *dentry, const char *name, void *buffer, + size_t size, int type) +{ + return aufs_getxattr(dentry, name, buffer, size); +} + +static int au_xattr_set(struct dentry *dentry, const char *name, + const void *value, size_t size, int flags, int type) +{ + return aufs_setxattr(dentry, name, value, size, flags); +} + +static const struct xattr_handler au_xattr_handler = { + /* no prefix, no flags */ + .list = au_xattr_list, + .get = au_xattr_get, + .set = au_xattr_set + /* why no remove? */ +}; + +static const struct xattr_handler *au_xattr_handlers[] = { + &au_xattr_handler +}; + +void au_xattr_init(struct super_block *sb) +{ + /* sb->s_xattr = au_xattr_handlers; */ +} +#endif |