diff options
Diffstat (limited to 'fs/aufs/i_op.c')
| -rw-r--r-- | fs/aufs/i_op.c | 1447 |
1 files changed, 1447 insertions, 0 deletions
diff --git a/fs/aufs/i_op.c b/fs/aufs/i_op.c new file mode 100644 index 000000000..17364e4f1 --- /dev/null +++ b/fs/aufs/i_op.c @@ -0,0 +1,1447 @@ +/* + * Copyright (C) 2005-2015 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/>. + */ + +/* + * inode operations (except add/del/rename) + */ + +#include <linux/device_cgroup.h> +#include <linux/fs_stack.h> +#include <linux/mm.h> +#include <linux/namei.h> +#include <linux/security.h> +#include "aufs.h" + +static int h_permission(struct inode *h_inode, int mask, + struct vfsmount *h_mnt, int brperm) +{ + int err; + const unsigned char write_mask = !!(mask & (MAY_WRITE | MAY_APPEND)); + + err = -EACCES; + if ((write_mask && IS_IMMUTABLE(h_inode)) + || ((mask & MAY_EXEC) + && S_ISREG(h_inode->i_mode) + && ((h_mnt->mnt_flags & MNT_NOEXEC) + || !(h_inode->i_mode & S_IXUGO)))) + goto out; + + /* + * - skip the lower fs test in the case of write to ro branch. + * - nfs dir permission write check is optimized, but a policy for + * link/rename requires a real check. + * - nfs always sets MS_POSIXACL regardless its mount option 'noacl.' + * in this case, generic_permission() returns -EOPNOTSUPP. + */ + if ((write_mask && !au_br_writable(brperm)) + || (au_test_nfs(h_inode->i_sb) && S_ISDIR(h_inode->i_mode) + && write_mask && !(mask & MAY_READ)) + || !h_inode->i_op->permission) { + /* AuLabel(generic_permission); */ + /* AuDbg("get_acl %pf\n", h_inode->i_op->get_acl); */ + err = generic_permission(h_inode, mask); + if (err == -EOPNOTSUPP && au_test_nfs_noacl(h_inode)) + err = h_inode->i_op->permission(h_inode, mask); + AuTraceErr(err); + } else { + /* AuLabel(h_inode->permission); */ + err = h_inode->i_op->permission(h_inode, mask); + AuTraceErr(err); + } + + if (!err) + err = devcgroup_inode_permission(h_inode, mask); + if (!err) + err = security_inode_permission(h_inode, mask); + +#if 0 + if (!err) { + /* todo: do we need to call ima_path_check()? */ + struct path h_path = { + .dentry = + .mnt = h_mnt + }; + err = ima_path_check(&h_path, + mask & (MAY_READ | MAY_WRITE | MAY_EXEC), + IMA_COUNT_LEAVE); + } +#endif + +out: + return err; +} + +static int aufs_permission(struct inode *inode, int mask) +{ + int err; + aufs_bindex_t bindex, bend; + const unsigned char isdir = !!S_ISDIR(inode->i_mode), + write_mask = !!(mask & (MAY_WRITE | MAY_APPEND)); + struct inode *h_inode; + struct super_block *sb; + struct au_branch *br; + + /* todo: support rcu-walk? */ + if (mask & MAY_NOT_BLOCK) + return -ECHILD; + + sb = inode->i_sb; + si_read_lock(sb, AuLock_FLUSH); + ii_read_lock_child(inode); +#if 0 + err = au_iigen_test(inode, au_sigen(sb)); + if (unlikely(err)) + goto out; +#endif + + if (!isdir + || write_mask + || au_opt_test(au_mntflags(sb), DIRPERM1)) { + err = au_busy_or_stale(); + h_inode = au_h_iptr(inode, au_ibstart(inode)); + if (unlikely(!h_inode + || (h_inode->i_mode & S_IFMT) + != (inode->i_mode & S_IFMT))) + goto out; + + err = 0; + bindex = au_ibstart(inode); + br = au_sbr(sb, bindex); + err = h_permission(h_inode, mask, au_br_mnt(br), br->br_perm); + if (write_mask + && !err + && !special_file(h_inode->i_mode)) { + /* test whether the upper writable branch exists */ + err = -EROFS; + for (; bindex >= 0; bindex--) + if (!au_br_rdonly(au_sbr(sb, bindex))) { + err = 0; + break; + } + } + goto out; + } + + /* non-write to dir */ + err = 0; + bend = au_ibend(inode); + for (bindex = au_ibstart(inode); !err && bindex <= bend; bindex++) { + h_inode = au_h_iptr(inode, bindex); + if (h_inode) { + err = au_busy_or_stale(); + if (unlikely(!S_ISDIR(h_inode->i_mode))) + break; + + br = au_sbr(sb, bindex); + err = h_permission(h_inode, mask, au_br_mnt(br), + br->br_perm); + } + } + +out: + ii_read_unlock(inode); + si_read_unlock(sb); + return err; +} + +/* ---------------------------------------------------------------------- */ + +static struct dentry *aufs_lookup(struct inode *dir, struct dentry *dentry, + unsigned int flags) +{ + struct dentry *ret, *parent; + struct inode *inode; + struct super_block *sb; + int err, npositive; + + IMustLock(dir); + + /* todo: support rcu-walk? */ + ret = ERR_PTR(-ECHILD); + if (flags & LOOKUP_RCU) + goto out; + + ret = ERR_PTR(-ENAMETOOLONG); + if (unlikely(dentry->d_name.len > AUFS_MAX_NAMELEN)) + goto out; + + sb = dir->i_sb; + err = si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLM); + ret = ERR_PTR(err); + if (unlikely(err)) + goto out; + + err = au_di_init(dentry); + ret = ERR_PTR(err); + if (unlikely(err)) + goto out_si; + + inode = NULL; + npositive = 0; /* suppress a warning */ + parent = dentry->d_parent; /* dir inode is locked */ + di_read_lock_parent(parent, AuLock_IR); + err = au_alive_dir(parent); + if (!err) + err = au_digen_test(parent, au_sigen(sb)); + if (!err) { + npositive = au_lkup_dentry(dentry, au_dbstart(parent), + /*type*/0); + err = npositive; + } + di_read_unlock(parent, AuLock_IR); + ret = ERR_PTR(err); + if (unlikely(err < 0)) + goto out_unlock; + + if (npositive) { + inode = au_new_inode(dentry, /*must_new*/0); + if (IS_ERR(inode)) { + ret = (void *)inode; + inode = NULL; + goto out_unlock; + } + } + + if (inode) + atomic_inc(&inode->i_count); + ret = d_splice_alias(inode, dentry); +#if 0 + if (unlikely(d_need_lookup(dentry))) { + spin_lock(&dentry->d_lock); + dentry->d_flags &= ~DCACHE_NEED_LOOKUP; + spin_unlock(&dentry->d_lock); + } else +#endif + if (inode) { + if (!IS_ERR(ret)) { + iput(inode); + if (ret && ret != dentry) + ii_write_unlock(inode); + } else { + ii_write_unlock(inode); + iput(inode); + inode = NULL; + } + } + +out_unlock: + di_write_unlock(dentry); + if (inode) { + /* verbose coding for lock class name */ + if (unlikely(S_ISLNK(inode->i_mode))) + au_rw_class(&au_di(dentry)->di_rwsem, + au_lc_key + AuLcSymlink_DIINFO); + else if (unlikely(S_ISDIR(inode->i_mode))) + au_rw_class(&au_di(dentry)->di_rwsem, + au_lc_key + AuLcDir_DIINFO); + else /* likely */ + au_rw_class(&au_di(dentry)->di_rwsem, + au_lc_key + AuLcNonDir_DIINFO); + } +out_si: + si_read_unlock(sb); +out: + return ret; +} + +/* ---------------------------------------------------------------------- */ + +struct aopen_node { + struct hlist_node hlist; + struct file *file, *h_file; +}; + +static int au_do_aopen(struct inode *inode, struct file *file) +{ + struct au_sphlhead *aopen; + struct aopen_node *node; + struct au_do_open_args args = { + .no_lock = 1, + .open = au_do_open_nondir + }; + + aopen = &au_sbi(inode->i_sb)->si_aopen; + spin_lock(&aopen->spin); + hlist_for_each_entry(node, &aopen->head, hlist) + if (node->file == file) { + args.h_file = node->h_file; + break; + } + spin_unlock(&aopen->spin); + /* AuDebugOn(!args.h_file); */ + + return au_do_open(file, &args); +} + +static int aufs_atomic_open(struct inode *dir, struct dentry *dentry, + struct file *file, unsigned int open_flag, + umode_t create_mode, int *opened) +{ + int err, h_opened = *opened; + struct dentry *parent; + struct dentry *d; + struct au_sphlhead *aopen; + struct vfsub_aopen_args args = { + .open_flag = open_flag, + .create_mode = create_mode, + .opened = &h_opened + }; + struct aopen_node aopen_node = { + .file = file + }; + + IMustLock(dir); + AuDbg("open_flag 0x%x\n", open_flag); + AuDbgDentry(dentry); + + err = 0; + if (!au_di(dentry)) { + d = aufs_lookup(dir, dentry, /*flags*/0); + if (IS_ERR(d)) { + err = PTR_ERR(d); + goto out; + } else if (d) { + /* + * obsoleted dentry found. + * another error will be returned later. + */ + d_drop(d); + dput(d); + AuDbgDentry(d); + } + AuDbgDentry(dentry); + } + + if (d_is_positive(dentry) + || d_unhashed(dentry) + || d_unlinked(dentry) + || !(open_flag & O_CREAT)) + goto out_no_open; + + err = aufs_read_lock(dentry, AuLock_DW | AuLock_FLUSH | AuLock_GEN); + if (unlikely(err)) + goto out; + + parent = dentry->d_parent; /* dir is locked */ + di_write_lock_parent(parent); + err = au_lkup_dentry(dentry, /*bstart*/0, /*type*/0); + if (unlikely(err)) + goto out_unlock; + + AuDbgDentry(dentry); + if (d_is_positive(dentry)) + goto out_unlock; + + args.file = get_empty_filp(); + err = PTR_ERR(args.file); + if (IS_ERR(args.file)) + goto out_unlock; + + args.file->f_flags = file->f_flags; + err = au_aopen_or_create(dir, dentry, &args); + AuTraceErr(err); + AuDbgFile(args.file); + if (unlikely(err < 0)) { + if (h_opened & FILE_OPENED) + fput(args.file); + else + put_filp(args.file); + goto out_unlock; + } + + /* some filesystems don't set FILE_CREATED while succeeded? */ + *opened |= FILE_CREATED; + if (h_opened & FILE_OPENED) + aopen_node.h_file = args.file; + else { + put_filp(args.file); + args.file = NULL; + } + aopen = &au_sbi(dir->i_sb)->si_aopen; + au_sphl_add(&aopen_node.hlist, aopen); + err = finish_open(file, dentry, au_do_aopen, opened); + au_sphl_del(&aopen_node.hlist, aopen); + AuTraceErr(err); + AuDbgFile(file); + if (aopen_node.h_file) + fput(aopen_node.h_file); + +out_unlock: + di_write_unlock(parent); + aufs_read_unlock(dentry, AuLock_DW); + AuDbgDentry(dentry); + if (unlikely(err)) + goto out; +out_no_open: + if (!err && !(*opened & FILE_CREATED)) { + AuLabel(out_no_open); + dget(dentry); + err = finish_no_open(file, dentry); + } +out: + AuDbg("%pd%s%s\n", dentry, + (*opened & FILE_CREATED) ? " created" : "", + (*opened & FILE_OPENED) ? " opened" : ""); + AuTraceErr(err); + return err; +} + + +/* ---------------------------------------------------------------------- */ + +static int au_wr_dir_cpup(struct dentry *dentry, struct dentry *parent, + const unsigned char add_entry, aufs_bindex_t bcpup, + aufs_bindex_t bstart) +{ + int err; + struct dentry *h_parent; + struct inode *h_dir; + + if (add_entry) + IMustLock(d_inode(parent)); + else + di_write_lock_parent(parent); + + err = 0; + if (!au_h_dptr(parent, bcpup)) { + if (bstart > bcpup) + err = au_cpup_dirs(dentry, bcpup); + else if (bstart < bcpup) + err = au_cpdown_dirs(dentry, bcpup); + else + BUG(); + } + if (!err && add_entry && !au_ftest_wrdir(add_entry, TMPFILE)) { + h_parent = au_h_dptr(parent, bcpup); + h_dir = d_inode(h_parent); + mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_PARENT); + err = au_lkup_neg(dentry, bcpup, /*wh*/0); + /* todo: no unlock here */ + mutex_unlock(&h_dir->i_mutex); + + AuDbg("bcpup %d\n", bcpup); + if (!err) { + if (d_really_is_negative(dentry)) + au_set_h_dptr(dentry, bstart, NULL); + au_update_dbrange(dentry, /*do_put_zero*/0); + } + } + + if (!add_entry) + di_write_unlock(parent); + if (!err) + err = bcpup; /* success */ + + AuTraceErr(err); + return err; +} + +/* + * decide the branch and the parent dir where we will create a new entry. + * returns new bindex or an error. + * copyup the parent dir if needed. + */ +int au_wr_dir(struct dentry *dentry, struct dentry *src_dentry, + struct au_wr_dir_args *args) +{ + int err; + unsigned int flags; + aufs_bindex_t bcpup, bstart, src_bstart; + const unsigned char add_entry + = au_ftest_wrdir(args->flags, ADD_ENTRY) + | au_ftest_wrdir(args->flags, TMPFILE); + struct super_block *sb; + struct dentry *parent; + struct au_sbinfo *sbinfo; + + sb = dentry->d_sb; + sbinfo = au_sbi(sb); + parent = dget_parent(dentry); + bstart = au_dbstart(dentry); + bcpup = bstart; + if (args->force_btgt < 0) { + if (src_dentry) { + src_bstart = au_dbstart(src_dentry); + if (src_bstart < bstart) + bcpup = src_bstart; + } else if (add_entry) { + flags = 0; + if (au_ftest_wrdir(args->flags, ISDIR)) + au_fset_wbr(flags, DIR); + err = AuWbrCreate(sbinfo, dentry, flags); + bcpup = err; + } + + if (bcpup < 0 || au_test_ro(sb, bcpup, d_inode(dentry))) { + if (add_entry) + err = AuWbrCopyup(sbinfo, dentry); + else { + if (!IS_ROOT(dentry)) { + di_read_lock_parent(parent, !AuLock_IR); + err = AuWbrCopyup(sbinfo, dentry); + di_read_unlock(parent, !AuLock_IR); + } else + err = AuWbrCopyup(sbinfo, dentry); + } + bcpup = err; + if (unlikely(err < 0)) + goto out; + } + } else { + bcpup = args->force_btgt; + AuDebugOn(au_test_ro(sb, bcpup, d_inode(dentry))); + } + + AuDbg("bstart %d, bcpup %d\n", bstart, bcpup); + err = bcpup; + if (bcpup == bstart) + goto out; /* success */ + + /* copyup the new parent into the branch we process */ + err = au_wr_dir_cpup(dentry, parent, add_entry, bcpup, bstart); + if (err >= 0) { + if (d_really_is_negative(dentry)) { + au_set_h_dptr(dentry, bstart, NULL); + au_set_dbstart(dentry, bcpup); + au_set_dbend(dentry, bcpup); + } + AuDebugOn(add_entry + && !au_ftest_wrdir(args->flags, TMPFILE) + && !au_h_dptr(dentry, bcpup)); + } + +out: + dput(parent); + return err; +} + +/* ---------------------------------------------------------------------- */ + +void au_pin_hdir_unlock(struct au_pin *p) +{ + if (p->hdir) + au_hn_imtx_unlock(p->hdir); +} + +int au_pin_hdir_lock(struct au_pin *p) +{ + int err; + + err = 0; + if (!p->hdir) + goto out; + + /* even if an error happens later, keep this lock */ + au_hn_imtx_lock_nested(p->hdir, p->lsc_hi); + + err = -EBUSY; + if (unlikely(p->hdir->hi_inode != d_inode(p->h_parent))) + goto out; + + err = 0; + if (p->h_dentry) + err = au_h_verify(p->h_dentry, p->udba, p->hdir->hi_inode, + p->h_parent, p->br); + +out: + return err; +} + +int au_pin_hdir_relock(struct au_pin *p) +{ + int err, i; + struct inode *h_i; + struct dentry *h_d[] = { + p->h_dentry, + p->h_parent + }; + + err = au_pin_hdir_lock(p); + if (unlikely(err)) + goto out; + + for (i = 0; !err && i < sizeof(h_d)/sizeof(*h_d); i++) { + if (!h_d[i]) + continue; + if (d_is_positive(h_d[i])) { + h_i = d_inode(h_d[i]); + err = !h_i->i_nlink; + } + } + +out: + return err; +} + +void au_pin_hdir_set_owner(struct au_pin *p, struct task_struct *task) +{ +#if defined(CONFIG_DEBUG_MUTEXES) || defined(CONFIG_SMP) + p->hdir->hi_inode->i_mutex.owner = task; +#endif +} + +void au_pin_hdir_acquire_nest(struct au_pin *p) +{ + if (p->hdir) { + mutex_acquire_nest(&p->hdir->hi_inode->i_mutex.dep_map, + p->lsc_hi, 0, NULL, _RET_IP_); + au_pin_hdir_set_owner(p, current); + } +} + +void au_pin_hdir_release(struct au_pin *p) +{ + if (p->hdir) { + au_pin_hdir_set_owner(p, p->task); + mutex_release(&p->hdir->hi_inode->i_mutex.dep_map, 1, _RET_IP_); + } +} + +struct dentry *au_pinned_h_parent(struct au_pin *pin) +{ + if (pin && pin->parent) + return au_h_dptr(pin->parent, pin->bindex); + return NULL; +} + +void au_unpin(struct au_pin *p) +{ + if (p->hdir) + au_pin_hdir_unlock(p); + if (p->h_mnt && au_ftest_pin(p->flags, MNT_WRITE)) + vfsub_mnt_drop_write(p->h_mnt); + if (!p->hdir) + return; + + if (!au_ftest_pin(p->flags, DI_LOCKED)) + di_read_unlock(p->parent, AuLock_IR); + iput(p->hdir->hi_inode); + dput(p->parent); + p->parent = NULL; + p->hdir = NULL; + p->h_mnt = NULL; + /* do not clear p->task */ +} + +int au_do_pin(struct au_pin *p) +{ + int err; + struct super_block *sb; + struct inode *h_dir; + + err = 0; + sb = p->dentry->d_sb; + p->br = au_sbr(sb, p->bindex); + if (IS_ROOT(p->dentry)) { + if (au_ftest_pin(p->flags, MNT_WRITE)) { + p->h_mnt = au_br_mnt(p->br); + err = vfsub_mnt_want_write(p->h_mnt); + if (unlikely(err)) { + au_fclr_pin(p->flags, MNT_WRITE); + goto out_err; + } + } + goto out; + } + + p->h_dentry = NULL; + if (p->bindex <= au_dbend(p->dentry)) + p->h_dentry = au_h_dptr(p->dentry, p->bindex); + + p->parent = dget_parent(p->dentry); + if (!au_ftest_pin(p->flags, DI_LOCKED)) + di_read_lock(p->parent, AuLock_IR, p->lsc_di); + + h_dir = NULL; + p->h_parent = au_h_dptr(p->parent, p->bindex); + p->hdir = au_hi(d_inode(p->parent), p->bindex); + if (p->hdir) + h_dir = p->hdir->hi_inode; + + /* + * udba case, or + * if DI_LOCKED is not set, then p->parent may be different + * and h_parent can be NULL. + */ + if (unlikely(!p->hdir || !h_dir || !p->h_parent)) { + err = -EBUSY; + if (!au_ftest_pin(p->flags, DI_LOCKED)) + di_read_unlock(p->parent, AuLock_IR); + dput(p->parent); + p->parent = NULL; + goto out_err; + } + + if (au_ftest_pin(p->flags, MNT_WRITE)) { + p->h_mnt = au_br_mnt(p->br); + err = vfsub_mnt_want_write(p->h_mnt); + if (unlikely(err)) { + au_fclr_pin(p->flags, MNT_WRITE); + if (!au_ftest_pin(p->flags, DI_LOCKED)) + di_read_unlock(p->parent, AuLock_IR); + dput(p->parent); + p->parent = NULL; + goto out_err; + } + } + + au_igrab(h_dir); + err = au_pin_hdir_lock(p); + if (!err) + goto out; /* success */ + + au_unpin(p); + +out_err: + pr_err("err %d\n", err); + err = au_busy_or_stale(); +out: + return err; +} + +void au_pin_init(struct au_pin *p, struct dentry *dentry, + aufs_bindex_t bindex, int lsc_di, int lsc_hi, + unsigned int udba, unsigned char flags) +{ + p->dentry = dentry; + p->udba = udba; + p->lsc_di = lsc_di; + p->lsc_hi = lsc_hi; + p->flags = flags; + p->bindex = bindex; + + p->parent = NULL; + p->hdir = NULL; + p->h_mnt = NULL; + + p->h_dentry = NULL; + p->h_parent = NULL; + p->br = NULL; + p->task = current; +} + +int au_pin(struct au_pin *pin, struct dentry *dentry, aufs_bindex_t bindex, + unsigned int udba, unsigned char flags) +{ + au_pin_init(pin, dentry, bindex, AuLsc_DI_PARENT, AuLsc_I_PARENT2, + udba, flags); + return au_do_pin(pin); +} + +/* ---------------------------------------------------------------------- */ + +/* + * ->setattr() and ->getattr() are called in various cases. + * chmod, stat: dentry is revalidated. + * fchmod, fstat: file and dentry are not revalidated, additionally they may be + * unhashed. + * for ->setattr(), ia->ia_file is passed from ftruncate only. + */ +/* todo: consolidate with do_refresh() and simple_reval_dpath() */ +int au_reval_for_attr(struct dentry *dentry, unsigned int sigen) +{ + int err; + struct dentry *parent; + + err = 0; + if (au_digen_test(dentry, sigen)) { + parent = dget_parent(dentry); + di_read_lock_parent(parent, AuLock_IR); + err = au_refresh_dentry(dentry, parent); + di_read_unlock(parent, AuLock_IR); + dput(parent); + } + + AuTraceErr(err); + return err; +} + +int au_pin_and_icpup(struct dentry *dentry, struct iattr *ia, + struct au_icpup_args *a) +{ + int err; + loff_t sz; + aufs_bindex_t bstart, ibstart; + struct dentry *hi_wh, *parent; + struct inode *inode; + struct au_wr_dir_args wr_dir_args = { + .force_btgt = -1, + .flags = 0 + }; + + if (d_is_dir(dentry)) + au_fset_wrdir(wr_dir_args.flags, ISDIR); + /* plink or hi_wh() case */ + bstart = au_dbstart(dentry); + inode = d_inode(dentry); + ibstart = au_ibstart(inode); + if (bstart != ibstart && !au_test_ro(inode->i_sb, ibstart, inode)) + wr_dir_args.force_btgt = ibstart; + err = au_wr_dir(dentry, /*src_dentry*/NULL, &wr_dir_args); + if (unlikely(err < 0)) + goto out; + a->btgt = err; + if (err != bstart) + au_fset_icpup(a->flags, DID_CPUP); + + err = 0; + a->pin_flags = AuPin_MNT_WRITE; + parent = NULL; + if (!IS_ROOT(dentry)) { + au_fset_pin(a->pin_flags, DI_LOCKED); + parent = dget_parent(dentry); + di_write_lock_parent(parent); + } + + err = au_pin(&a->pin, dentry, a->btgt, a->udba, a->pin_flags); + if (unlikely(err)) + goto out_parent; + + a->h_path.dentry = au_h_dptr(dentry, bstart); + sz = -1; + a->h_inode = d_inode(a->h_path.dentry); + if (ia && (ia->ia_valid & ATTR_SIZE)) { + mutex_lock_nested(&a->h_inode->i_mutex, AuLsc_I_CHILD); + if (ia->ia_size < i_size_read(a->h_inode)) + sz = ia->ia_size; + mutex_unlock(&a->h_inode->i_mutex); + } + + hi_wh = NULL; + if (au_ftest_icpup(a->flags, DID_CPUP) && d_unlinked(dentry)) { + hi_wh = au_hi_wh(inode, a->btgt); + if (!hi_wh) { + struct au_cp_generic cpg = { + .dentry = dentry, + .bdst = a->btgt, + .bsrc = -1, + .len = sz, + .pin = &a->pin + }; + err = au_sio_cpup_wh(&cpg, /*file*/NULL); + if (unlikely(err)) + goto out_unlock; + hi_wh = au_hi_wh(inode, a->btgt); + /* todo: revalidate hi_wh? */ + } + } + + if (parent) { + au_pin_set_parent_lflag(&a->pin, /*lflag*/0); + di_downgrade_lock(parent, AuLock_IR); + dput(parent); + parent = NULL; + } + if (!au_ftest_icpup(a->flags, DID_CPUP)) + goto out; /* success */ + + if (!d_unhashed(dentry)) { + struct au_cp_generic cpg = { + .dentry = dentry, + .bdst = a->btgt, + .bsrc = bstart, + .len = sz, + .pin = &a->pin, + .flags = AuCpup_DTIME | AuCpup_HOPEN + }; + err = au_sio_cpup_simple(&cpg); + if (!err) + a->h_path.dentry = au_h_dptr(dentry, a->btgt); + } else if (!hi_wh) + a->h_path.dentry = au_h_dptr(dentry, a->btgt); + else + a->h_path.dentry = hi_wh; /* do not dget here */ + +out_unlock: + a->h_inode = d_inode(a->h_path.dentry); + if (!err) + goto out; /* success */ + au_unpin(&a->pin); +out_parent: + if (parent) { + di_write_unlock(parent); + dput(parent); + } +out: + if (!err) + mutex_lock_nested(&a->h_inode->i_mutex, AuLsc_I_CHILD); + return err; +} + +static int aufs_setattr(struct dentry *dentry, struct iattr *ia) +{ + int err; + struct inode *inode, *delegated; + struct super_block *sb; + struct file *file; + struct au_icpup_args *a; + + inode = d_inode(dentry); + IMustLock(inode); + + err = -ENOMEM; + a = kzalloc(sizeof(*a), GFP_NOFS); + if (unlikely(!a)) + goto out; + + if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID)) + ia->ia_valid &= ~ATTR_MODE; + + file = NULL; + sb = dentry->d_sb; + err = si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLM); + if (unlikely(err)) + goto out_kfree; + + if (ia->ia_valid & ATTR_FILE) { + /* currently ftruncate(2) only */ + AuDebugOn(!d_is_reg(dentry)); + file = ia->ia_file; + err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1); + if (unlikely(err)) + goto out_si; + ia->ia_file = au_hf_top(file); + a->udba = AuOpt_UDBA_NONE; + } else { + /* fchmod() doesn't pass ia_file */ + a->udba = au_opt_udba(sb); + di_write_lock_child(dentry); + /* no d_unlinked(), to set UDBA_NONE for root */ + if (d_unhashed(dentry)) + a->udba = AuOpt_UDBA_NONE; + if (a->udba != AuOpt_UDBA_NONE) { + AuDebugOn(IS_ROOT(dentry)); + err = au_reval_for_attr(dentry, au_sigen(sb)); + if (unlikely(err)) + goto out_dentry; + } + } + + err = au_pin_and_icpup(dentry, ia, a); + if (unlikely(err < 0)) + goto out_dentry; + if (au_ftest_icpup(a->flags, DID_CPUP)) { + ia->ia_file = NULL; + ia->ia_valid &= ~ATTR_FILE; + } + + a->h_path.mnt = au_sbr_mnt(sb, a->btgt); + if ((ia->ia_valid & (ATTR_MODE | ATTR_CTIME)) + == (ATTR_MODE | ATTR_CTIME)) { + err = security_path_chmod(&a->h_path, ia->ia_mode); + if (unlikely(err)) + goto out_unlock; + } else if ((ia->ia_valid & (ATTR_UID | ATTR_GID)) + && (ia->ia_valid & ATTR_CTIME)) { + err = security_path_chown(&a->h_path, ia->ia_uid, ia->ia_gid); + if (unlikely(err)) + goto out_unlock; + } + + if (ia->ia_valid & ATTR_SIZE) { + struct file *f; + + if (ia->ia_size < i_size_read(inode)) + /* unmap only */ + truncate_setsize(inode, ia->ia_size); + + f = NULL; + if (ia->ia_valid & ATTR_FILE) + f = ia->ia_file; + mutex_unlock(&a->h_inode->i_mutex); + err = vfsub_trunc(&a->h_path, ia->ia_size, ia->ia_valid, f); + mutex_lock_nested(&a->h_inode->i_mutex, AuLsc_I_CHILD); + } else { + delegated = NULL; + while (1) { + err = vfsub_notify_change(&a->h_path, ia, &delegated); + if (delegated) { + err = break_deleg_wait(&delegated); + if (!err) + continue; + } + break; + } + } + if (!err) + au_cpup_attr_changeable(inode); + +out_unlock: + mutex_unlock(&a->h_inode->i_mutex); + au_unpin(&a->pin); + if (unlikely(err)) + au_update_dbstart(dentry); +out_dentry: + di_write_unlock(dentry); + if (file) { + fi_write_unlock(file); + ia->ia_file = file; + ia->ia_valid |= ATTR_FILE; + } +out_si: + si_read_unlock(sb); +out_kfree: + kfree(a); +out: + AuTraceErr(err); + return err; +} + +#if IS_ENABLED(CONFIG_AUFS_XATTR) || IS_ENABLED(CONFIG_FS_POSIX_ACL) +static int au_h_path_to_set_attr(struct dentry *dentry, + struct au_icpup_args *a, struct path *h_path) +{ + int err; + struct super_block *sb; + + sb = dentry->d_sb; + a->udba = au_opt_udba(sb); + /* no d_unlinked(), to set UDBA_NONE for root */ + if (d_unhashed(dentry)) + a->udba = AuOpt_UDBA_NONE; + if (a->udba != AuOpt_UDBA_NONE) { + AuDebugOn(IS_ROOT(dentry)); + err = au_reval_for_attr(dentry, au_sigen(sb)); + if (unlikely(err)) + goto out; + } + err = au_pin_and_icpup(dentry, /*ia*/NULL, a); + if (unlikely(err < 0)) + goto out; + + h_path->dentry = a->h_path.dentry; + h_path->mnt = au_sbr_mnt(sb, a->btgt); + +out: + return err; +} + +ssize_t au_srxattr(struct dentry *dentry, struct au_srxattr *arg) +{ + int err; + struct path h_path; + struct super_block *sb; + struct au_icpup_args *a; + struct inode *inode, *h_inode; + + inode = d_inode(dentry); + IMustLock(inode); + + err = -ENOMEM; + a = kzalloc(sizeof(*a), GFP_NOFS); + if (unlikely(!a)) + goto out; + + sb = dentry->d_sb; + err = si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLM); + if (unlikely(err)) + goto out_kfree; + + h_path.dentry = NULL; /* silence gcc */ + di_write_lock_child(dentry); + err = au_h_path_to_set_attr(dentry, a, &h_path); + if (unlikely(err)) + goto out_di; + + mutex_unlock(&a->h_inode->i_mutex); + switch (arg->type) { + case AU_XATTR_SET: + err = vfsub_setxattr(h_path.dentry, + arg->u.set.name, arg->u.set.value, + arg->u.set.size, arg->u.set.flags); + break; + case AU_XATTR_REMOVE: + err = vfsub_removexattr(h_path.dentry, arg->u.remove.name); + break; + case AU_ACL_SET: + err = -EOPNOTSUPP; + h_inode = d_inode(h_path.dentry); + if (h_inode->i_op->set_acl) + err = h_inode->i_op->set_acl(h_inode, + arg->u.acl_set.acl, + arg->u.acl_set.type); + break; + } + if (!err) + au_cpup_attr_timesizes(inode); + + au_unpin(&a->pin); + if (unlikely(err)) + au_update_dbstart(dentry); + +out_di: + di_write_unlock(dentry); + si_read_unlock(sb); +out_kfree: + kfree(a); +out: + AuTraceErr(err); + return err; +} +#endif + +static void au_refresh_iattr(struct inode *inode, struct kstat *st, + unsigned int nlink) +{ + unsigned int n; + + inode->i_mode = st->mode; + /* don't i_[ug]id_write() here */ + inode->i_uid = st->uid; + inode->i_gid = st->gid; + inode->i_atime = st->atime; + inode->i_mtime = st->mtime; + inode->i_ctime = st->ctime; + + au_cpup_attr_nlink(inode, /*force*/0); + if (S_ISDIR(inode->i_mode)) { + n = inode->i_nlink; + n -= nlink; + n += st->nlink; + smp_mb(); /* for i_nlink */ + /* 0 can happen */ + set_nlink(inode, n); + } + + spin_lock(&inode->i_lock); + inode->i_blocks = st->blocks; + i_size_write(inode, st->size); + spin_unlock(&inode->i_lock); +} + +/* + * common routine for aufs_getattr() and aufs_getxattr(). + * returns zero or negative (an error). + * @dentry will be read-locked in success. + */ +int au_h_path_getattr(struct dentry *dentry, int force, struct path *h_path) +{ + int err; + unsigned int mnt_flags, sigen; + unsigned char udba_none; + aufs_bindex_t bindex; + struct super_block *sb, *h_sb; + struct inode *inode; + + h_path->mnt = NULL; + h_path->dentry = NULL; + + err = 0; + sb = dentry->d_sb; + mnt_flags = au_mntflags(sb); + udba_none = !!au_opt_test(mnt_flags, UDBA_NONE); + + /* support fstat(2) */ + if (!d_unlinked(dentry) && !udba_none) { + sigen = au_sigen(sb); + err = au_digen_test(dentry, sigen); + if (!err) { + di_read_lock_child(dentry, AuLock_IR); + err = au_dbrange_test(dentry); + if (unlikely(err)) { + di_read_unlock(dentry, AuLock_IR); + goto out; + } + } else { + AuDebugOn(IS_ROOT(dentry)); + di_write_lock_child(dentry); + err = au_dbrange_test(dentry); + if (!err) + err = au_reval_for_attr(dentry, sigen); + if (!err) + di_downgrade_lock(dentry, AuLock_IR); + else { + di_write_unlock(dentry); + goto out; + } + } + } else + di_read_lock_child(dentry, AuLock_IR); + + inode = d_inode(dentry); + bindex = au_ibstart(inode); + h_path->mnt = au_sbr_mnt(sb, bindex); + h_sb = h_path->mnt->mnt_sb; + if (!force + && !au_test_fs_bad_iattr(h_sb) + && udba_none) + goto out; /* success */ + + if (au_dbstart(dentry) == bindex) + h_path->dentry = au_h_dptr(dentry, bindex); + else if (au_opt_test(mnt_flags, PLINK) && au_plink_test(inode)) { + h_path->dentry = au_plink_lkup(inode, bindex); + if (IS_ERR(h_path->dentry)) + /* pretending success */ + h_path->dentry = NULL; + else + dput(h_path->dentry); + } + +out: + return err; +} + +static int aufs_getattr(struct vfsmount *mnt __maybe_unused, + struct dentry *dentry, struct kstat *st) +{ + int err; + unsigned char positive; + struct path h_path; + struct inode *inode; + struct super_block *sb; + + inode = d_inode(dentry); + 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*/0, &h_path); + if (unlikely(err)) + goto out_si; + if (unlikely(!h_path.dentry)) + /* illegally overlapped or something */ + goto out_fill; /* pretending success */ + + positive = d_is_positive(h_path.dentry); + if (positive) + err = vfs_getattr(&h_path, st); + if (!err) { + if (positive) + au_refresh_iattr(inode, st, + d_inode(h_path.dentry)->i_nlink); + goto out_fill; /* success */ + } + AuTraceErr(err); + goto out_di; + +out_fill: + generic_fillattr(inode, st); +out_di: + di_read_unlock(dentry, AuLock_IR); +out_si: + si_read_unlock(sb); +out: + AuTraceErr(err); + return err; +} + +/* ---------------------------------------------------------------------- */ + +static int h_readlink(struct dentry *dentry, int bindex, char __user *buf, + int bufsiz) +{ + int err; + struct super_block *sb; + struct dentry *h_dentry; + struct inode *inode, *h_inode; + + err = -EINVAL; + h_dentry = au_h_dptr(dentry, bindex); + h_inode = d_inode(h_dentry); + if (unlikely(!h_inode->i_op->readlink)) + goto out; + + err = security_inode_readlink(h_dentry); + if (unlikely(err)) + goto out; + + sb = dentry->d_sb; + inode = d_inode(dentry); + if (!au_test_ro(sb, bindex, inode)) { + vfsub_touch_atime(au_sbr_mnt(sb, bindex), h_dentry); + fsstack_copy_attr_atime(inode, h_inode); + } + err = h_inode->i_op->readlink(h_dentry, buf, bufsiz); + +out: + return err; +} + +static int aufs_readlink(struct dentry *dentry, char __user *buf, int bufsiz) +{ + int err; + + err = aufs_read_lock(dentry, AuLock_IR | AuLock_GEN); + if (unlikely(err)) + goto out; + err = au_d_hashed_positive(dentry); + if (!err) + err = h_readlink(dentry, au_dbstart(dentry), buf, bufsiz); + aufs_read_unlock(dentry, AuLock_IR); + +out: + return err; +} + +static void *aufs_follow_link(struct dentry *dentry, struct nameidata *nd) +{ + int err; + mm_segment_t old_fs; + union { + char *k; + char __user *u; + } buf; + + err = -ENOMEM; + buf.k = (void *)__get_free_page(GFP_NOFS); + if (unlikely(!buf.k)) + goto out; + + err = aufs_read_lock(dentry, AuLock_IR | AuLock_GEN); + if (unlikely(err)) + goto out_name; + + err = au_d_hashed_positive(dentry); + if (!err) { + old_fs = get_fs(); + set_fs(KERNEL_DS); + err = h_readlink(dentry, au_dbstart(dentry), buf.u, PATH_MAX); + set_fs(old_fs); + } + aufs_read_unlock(dentry, AuLock_IR); + + if (err >= 0) { + buf.k[err] = 0; + /* will be freed by put_link */ + nd_set_link(nd, buf.k); + return NULL; /* success */ + } + +out_name: + free_page((unsigned long)buf.k); +out: + AuTraceErr(err); + return ERR_PTR(err); +} + +static void aufs_put_link(struct dentry *dentry __maybe_unused, + struct nameidata *nd, void *cookie __maybe_unused) +{ + char *p; + + p = nd_get_link(nd); + if (!IS_ERR_OR_NULL(p)) + free_page((unsigned long)p); +} + +/* ---------------------------------------------------------------------- */ + +static int aufs_update_time(struct inode *inode, struct timespec *ts, int flags) +{ + int err; + struct super_block *sb; + struct inode *h_inode; + + sb = inode->i_sb; + /* mmap_sem might be acquired already, cf. aufs_mmap() */ + lockdep_off(); + si_read_lock(sb, AuLock_FLUSH); + ii_write_lock_child(inode); + lockdep_on(); + h_inode = au_h_iptr(inode, au_ibstart(inode)); + err = vfsub_update_time(h_inode, ts, flags); + lockdep_off(); + if (!err) + au_cpup_attr_timesizes(inode); + ii_write_unlock(inode); + si_read_unlock(sb); + lockdep_on(); + + if (!err && (flags & S_VERSION)) + inode_inc_iversion(inode); + + return err; +} + +/* ---------------------------------------------------------------------- */ + +struct inode_operations aufs_symlink_iop = { + .permission = aufs_permission, +#ifdef CONFIG_FS_POSIX_ACL + .get_acl = aufs_get_acl, + .set_acl = aufs_set_acl, /* unsupport for symlink? */ +#endif + + .setattr = aufs_setattr, + .getattr = aufs_getattr, + +#ifdef CONFIG_AUFS_XATTR + .setxattr = aufs_setxattr, + .getxattr = aufs_getxattr, + .listxattr = aufs_listxattr, + .removexattr = aufs_removexattr, +#endif + + .readlink = aufs_readlink, + .follow_link = aufs_follow_link, + .put_link = aufs_put_link, + + /* .update_time = aufs_update_time */ +}; + +struct inode_operations aufs_dir_iop = { + .create = aufs_create, + .lookup = aufs_lookup, + .link = aufs_link, + .unlink = aufs_unlink, + .symlink = aufs_symlink, + .mkdir = aufs_mkdir, + .rmdir = aufs_rmdir, + .mknod = aufs_mknod, + .rename = aufs_rename, + + .permission = aufs_permission, +#ifdef CONFIG_FS_POSIX_ACL + .get_acl = aufs_get_acl, + .set_acl = aufs_set_acl, +#endif + + .setattr = aufs_setattr, + .getattr = aufs_getattr, + +#ifdef CONFIG_AUFS_XATTR + .setxattr = aufs_setxattr, + .getxattr = aufs_getxattr, + .listxattr = aufs_listxattr, + .removexattr = aufs_removexattr, +#endif + + .update_time = aufs_update_time, + .atomic_open = aufs_atomic_open, + .tmpfile = aufs_tmpfile +}; + +struct inode_operations aufs_iop = { + .permission = aufs_permission, +#ifdef CONFIG_FS_POSIX_ACL + .get_acl = aufs_get_acl, + .set_acl = aufs_set_acl, +#endif + + .setattr = aufs_setattr, + .getattr = aufs_getattr, + +#ifdef CONFIG_AUFS_XATTR + .setxattr = aufs_setxattr, + .getxattr = aufs_getxattr, + .listxattr = aufs_listxattr, + .removexattr = aufs_removexattr, +#endif + + .update_time = aufs_update_time +}; 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