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author | David S. Miller <davem@davemloft.net> | 2009-06-15 03:02:23 -0700 |
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committer | David S. Miller <davem@davemloft.net> | 2009-06-15 03:02:23 -0700 |
commit | 9cbc1cb8cd46ce1f7645b9de249b2ce8460129bb (patch) | |
tree | 8d104ec2a459346b99413b0b77421ca7b9936c1a /fs/xfs/linux-2.6/xfs_acl.c | |
parent | ca44d6e60f9de26281fda203f58b570e1748c015 (diff) | |
parent | 45e3e1935e2857c54783291107d33323b3ef33c8 (diff) | |
download | op-kernel-dev-9cbc1cb8cd46ce1f7645b9de249b2ce8460129bb.zip op-kernel-dev-9cbc1cb8cd46ce1f7645b9de249b2ce8460129bb.tar.gz |
Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6
Conflicts:
Documentation/feature-removal-schedule.txt
drivers/scsi/fcoe/fcoe.c
net/core/drop_monitor.c
net/core/net-traces.c
Diffstat (limited to 'fs/xfs/linux-2.6/xfs_acl.c')
-rw-r--r-- | fs/xfs/linux-2.6/xfs_acl.c | 523 |
1 files changed, 523 insertions, 0 deletions
diff --git a/fs/xfs/linux-2.6/xfs_acl.c b/fs/xfs/linux-2.6/xfs_acl.c new file mode 100644 index 0000000..1e9d124 --- /dev/null +++ b/fs/xfs/linux-2.6/xfs_acl.c @@ -0,0 +1,523 @@ +/* + * Copyright (c) 2008, Christoph Hellwig + * All Rights Reserved. + * + * This program 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. + * + * This program is distributed in the hope that it would 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, write the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ +#include "xfs.h" +#include "xfs_acl.h" +#include "xfs_attr.h" +#include "xfs_bmap_btree.h" +#include "xfs_inode.h" +#include "xfs_vnodeops.h" +#include <linux/xattr.h> +#include <linux/posix_acl_xattr.h> + + +#define XFS_ACL_NOT_CACHED ((void *)-1) + +/* + * Locking scheme: + * - all ACL updates are protected by inode->i_mutex, which is taken before + * calling into this file. + * - access and updates to the ip->i_acl and ip->i_default_acl pointers are + * protected by inode->i_lock. + */ + +STATIC struct posix_acl * +xfs_acl_from_disk(struct xfs_acl *aclp) +{ + struct posix_acl_entry *acl_e; + struct posix_acl *acl; + struct xfs_acl_entry *ace; + int count, i; + + count = be32_to_cpu(aclp->acl_cnt); + + acl = posix_acl_alloc(count, GFP_KERNEL); + if (!acl) + return ERR_PTR(-ENOMEM); + + for (i = 0; i < count; i++) { + acl_e = &acl->a_entries[i]; + ace = &aclp->acl_entry[i]; + + /* + * The tag is 32 bits on disk and 16 bits in core. + * + * Because every access to it goes through the core + * format first this is not a problem. + */ + acl_e->e_tag = be32_to_cpu(ace->ae_tag); + acl_e->e_perm = be16_to_cpu(ace->ae_perm); + + switch (acl_e->e_tag) { + case ACL_USER: + case ACL_GROUP: + acl_e->e_id = be32_to_cpu(ace->ae_id); + break; + case ACL_USER_OBJ: + case ACL_GROUP_OBJ: + case ACL_MASK: + case ACL_OTHER: + acl_e->e_id = ACL_UNDEFINED_ID; + break; + default: + goto fail; + } + } + return acl; + +fail: + posix_acl_release(acl); + return ERR_PTR(-EINVAL); +} + +STATIC void +xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl) +{ + const struct posix_acl_entry *acl_e; + struct xfs_acl_entry *ace; + int i; + + aclp->acl_cnt = cpu_to_be32(acl->a_count); + for (i = 0; i < acl->a_count; i++) { + ace = &aclp->acl_entry[i]; + acl_e = &acl->a_entries[i]; + + ace->ae_tag = cpu_to_be32(acl_e->e_tag); + ace->ae_id = cpu_to_be32(acl_e->e_id); + ace->ae_perm = cpu_to_be16(acl_e->e_perm); + } +} + +/* + * Update the cached ACL pointer in the inode. + * + * Because we don't hold any locks while reading/writing the attribute + * from/to disk another thread could have raced and updated the cached + * ACL value before us. In that case we release the previous cached value + * and update it with our new value. + */ +STATIC void +xfs_update_cached_acl(struct inode *inode, struct posix_acl **p_acl, + struct posix_acl *acl) +{ + spin_lock(&inode->i_lock); + if (*p_acl && *p_acl != XFS_ACL_NOT_CACHED) + posix_acl_release(*p_acl); + *p_acl = posix_acl_dup(acl); + spin_unlock(&inode->i_lock); +} + +struct posix_acl * +xfs_get_acl(struct inode *inode, int type) +{ + struct xfs_inode *ip = XFS_I(inode); + struct posix_acl *acl = NULL, **p_acl; + struct xfs_acl *xfs_acl; + int len = sizeof(struct xfs_acl); + char *ea_name; + int error; + + switch (type) { + case ACL_TYPE_ACCESS: + ea_name = SGI_ACL_FILE; + p_acl = &ip->i_acl; + break; + case ACL_TYPE_DEFAULT: + ea_name = SGI_ACL_DEFAULT; + p_acl = &ip->i_default_acl; + break; + default: + return ERR_PTR(-EINVAL); + } + + spin_lock(&inode->i_lock); + if (*p_acl != XFS_ACL_NOT_CACHED) + acl = posix_acl_dup(*p_acl); + spin_unlock(&inode->i_lock); + + /* + * If we have a cached ACLs value just return it, not need to + * go out to the disk. + */ + if (acl) + return acl; + + xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL); + if (!xfs_acl) + return ERR_PTR(-ENOMEM); + + error = -xfs_attr_get(ip, ea_name, (char *)xfs_acl, &len, ATTR_ROOT); + if (error) { + /* + * If the attribute doesn't exist make sure we have a negative + * cache entry, for any other error assume it is transient and + * leave the cache entry as XFS_ACL_NOT_CACHED. + */ + if (error == -ENOATTR) { + acl = NULL; + goto out_update_cache; + } + goto out; + } + + acl = xfs_acl_from_disk(xfs_acl); + if (IS_ERR(acl)) + goto out; + + out_update_cache: + xfs_update_cached_acl(inode, p_acl, acl); + out: + kfree(xfs_acl); + return acl; +} + +STATIC int +xfs_set_acl(struct inode *inode, int type, struct posix_acl *acl) +{ + struct xfs_inode *ip = XFS_I(inode); + struct posix_acl **p_acl; + char *ea_name; + int error; + + if (S_ISLNK(inode->i_mode)) + return -EOPNOTSUPP; + + switch (type) { + case ACL_TYPE_ACCESS: + ea_name = SGI_ACL_FILE; + p_acl = &ip->i_acl; + break; + case ACL_TYPE_DEFAULT: + if (!S_ISDIR(inode->i_mode)) + return acl ? -EACCES : 0; + ea_name = SGI_ACL_DEFAULT; + p_acl = &ip->i_default_acl; + break; + default: + return -EINVAL; + } + + if (acl) { + struct xfs_acl *xfs_acl; + int len; + + xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL); + if (!xfs_acl) + return -ENOMEM; + + xfs_acl_to_disk(xfs_acl, acl); + len = sizeof(struct xfs_acl) - + (sizeof(struct xfs_acl_entry) * + (XFS_ACL_MAX_ENTRIES - acl->a_count)); + + error = -xfs_attr_set(ip, ea_name, (char *)xfs_acl, + len, ATTR_ROOT); + + kfree(xfs_acl); + } else { + /* + * A NULL ACL argument means we want to remove the ACL. + */ + error = -xfs_attr_remove(ip, ea_name, ATTR_ROOT); + + /* + * If the attribute didn't exist to start with that's fine. + */ + if (error == -ENOATTR) + error = 0; + } + + if (!error) + xfs_update_cached_acl(inode, p_acl, acl); + return error; +} + +int +xfs_check_acl(struct inode *inode, int mask) +{ + struct xfs_inode *ip = XFS_I(inode); + struct posix_acl *acl; + int error = -EAGAIN; + + xfs_itrace_entry(ip); + + /* + * If there is no attribute fork no ACL exists on this inode and + * we can skip the whole exercise. + */ + if (!XFS_IFORK_Q(ip)) + return -EAGAIN; + + acl = xfs_get_acl(inode, ACL_TYPE_ACCESS); + if (IS_ERR(acl)) + return PTR_ERR(acl); + if (acl) { + error = posix_acl_permission(inode, acl, mask); + posix_acl_release(acl); + } + + return error; +} + +static int +xfs_set_mode(struct inode *inode, mode_t mode) +{ + int error = 0; + + if (mode != inode->i_mode) { + struct iattr iattr; + + iattr.ia_valid = ATTR_MODE; + iattr.ia_mode = mode; + + error = -xfs_setattr(XFS_I(inode), &iattr, XFS_ATTR_NOACL); + } + + return error; +} + +static int +xfs_acl_exists(struct inode *inode, char *name) +{ + int len = sizeof(struct xfs_acl); + + return (xfs_attr_get(XFS_I(inode), name, NULL, &len, + ATTR_ROOT|ATTR_KERNOVAL) == 0); +} + +int +posix_acl_access_exists(struct inode *inode) +{ + return xfs_acl_exists(inode, SGI_ACL_FILE); +} + +int +posix_acl_default_exists(struct inode *inode) +{ + if (!S_ISDIR(inode->i_mode)) + return 0; + return xfs_acl_exists(inode, SGI_ACL_DEFAULT); +} + +/* + * No need for i_mutex because the inode is not yet exposed to the VFS. + */ +int +xfs_inherit_acl(struct inode *inode, struct posix_acl *default_acl) +{ + struct posix_acl *clone; + mode_t mode; + int error = 0, inherit = 0; + + if (S_ISDIR(inode->i_mode)) { + error = xfs_set_acl(inode, ACL_TYPE_DEFAULT, default_acl); + if (error) + return error; + } + + clone = posix_acl_clone(default_acl, GFP_KERNEL); + if (!clone) + return -ENOMEM; + + mode = inode->i_mode; + error = posix_acl_create_masq(clone, &mode); + if (error < 0) + goto out_release_clone; + + /* + * If posix_acl_create_masq returns a positive value we need to + * inherit a permission that can't be represented using the Unix + * mode bits and we actually need to set an ACL. + */ + if (error > 0) + inherit = 1; + + error = xfs_set_mode(inode, mode); + if (error) + goto out_release_clone; + + if (inherit) + error = xfs_set_acl(inode, ACL_TYPE_ACCESS, clone); + + out_release_clone: + posix_acl_release(clone); + return error; +} + +int +xfs_acl_chmod(struct inode *inode) +{ + struct posix_acl *acl, *clone; + int error; + + if (S_ISLNK(inode->i_mode)) + return -EOPNOTSUPP; + + acl = xfs_get_acl(inode, ACL_TYPE_ACCESS); + if (IS_ERR(acl) || !acl) + return PTR_ERR(acl); + + clone = posix_acl_clone(acl, GFP_KERNEL); + posix_acl_release(acl); + if (!clone) + return -ENOMEM; + + error = posix_acl_chmod_masq(clone, inode->i_mode); + if (!error) + error = xfs_set_acl(inode, ACL_TYPE_ACCESS, clone); + + posix_acl_release(clone); + return error; +} + +void +xfs_inode_init_acls(struct xfs_inode *ip) +{ + /* + * No need for locking, inode is not live yet. + */ + ip->i_acl = XFS_ACL_NOT_CACHED; + ip->i_default_acl = XFS_ACL_NOT_CACHED; +} + +void +xfs_inode_clear_acls(struct xfs_inode *ip) +{ + /* + * No need for locking here, the inode is not live anymore + * and just about to be freed. + */ + if (ip->i_acl != XFS_ACL_NOT_CACHED) + posix_acl_release(ip->i_acl); + if (ip->i_default_acl != XFS_ACL_NOT_CACHED) + posix_acl_release(ip->i_default_acl); +} + + +/* + * System xattr handlers. + * + * Currently Posix ACLs are the only system namespace extended attribute + * handlers supported by XFS, so we just implement the handlers here. + * If we ever support other system extended attributes this will need + * some refactoring. + */ + +static int +xfs_decode_acl(const char *name) +{ + if (strcmp(name, "posix_acl_access") == 0) + return ACL_TYPE_ACCESS; + else if (strcmp(name, "posix_acl_default") == 0) + return ACL_TYPE_DEFAULT; + return -EINVAL; +} + +static int +xfs_xattr_system_get(struct inode *inode, const char *name, + void *value, size_t size) +{ + struct posix_acl *acl; + int type, error; + + type = xfs_decode_acl(name); + if (type < 0) + return type; + + acl = xfs_get_acl(inode, type); + if (IS_ERR(acl)) + return PTR_ERR(acl); + if (acl == NULL) + return -ENODATA; + + error = posix_acl_to_xattr(acl, value, size); + posix_acl_release(acl); + + return error; +} + +static int +xfs_xattr_system_set(struct inode *inode, const char *name, + const void *value, size_t size, int flags) +{ + struct posix_acl *acl = NULL; + int error = 0, type; + + type = xfs_decode_acl(name); + if (type < 0) + return type; + if (flags & XATTR_CREATE) + return -EINVAL; + if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) + return value ? -EACCES : 0; + if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER)) + return -EPERM; + + if (!value) + goto set_acl; + + acl = posix_acl_from_xattr(value, size); + if (!acl) { + /* + * acl_set_file(3) may request that we set default ACLs with + * zero length -- defend (gracefully) against that here. + */ + goto out; + } + if (IS_ERR(acl)) { + error = PTR_ERR(acl); + goto out; + } + + error = posix_acl_valid(acl); + if (error) + goto out_release; + + error = -EINVAL; + if (acl->a_count > XFS_ACL_MAX_ENTRIES) + goto out_release; + + if (type == ACL_TYPE_ACCESS) { + mode_t mode = inode->i_mode; + error = posix_acl_equiv_mode(acl, &mode); + + if (error <= 0) { + posix_acl_release(acl); + acl = NULL; + + if (error < 0) + return error; + } + + error = xfs_set_mode(inode, mode); + if (error) + goto out_release; + } + + set_acl: + error = xfs_set_acl(inode, type, acl); + out_release: + posix_acl_release(acl); + out: + return error; +} + +struct xattr_handler xfs_xattr_system_handler = { + .prefix = XATTR_SYSTEM_PREFIX, + .get = xfs_xattr_system_get, + .set = xfs_xattr_system_set, +}; |