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cac2f8b8d8
The current way of setting and getting posix acls through the generic xattr interface is error prone and type unsafe. The vfs needs to interpret and fixup posix acls before storing or reporting it to userspace. Various hacks exist to make this work. The code is hard to understand and difficult to maintain in it's current form. Instead of making this work by hacking posix acls through xattr handlers we are building a dedicated posix acl api around the get and set inode operations. This removes a lot of hackiness and makes the codepaths easier to maintain. A lot of background can be found in [1]. The current inode operation for getting posix acls takes an inode argument but various filesystems (e.g., 9p, cifs, overlayfs) need access to the dentry. In contrast to the ->set_acl() inode operation we cannot simply extend ->get_acl() to take a dentry argument. The ->get_acl() inode operation is called from: acl_permission_check() -> check_acl() -> get_acl() which is part of generic_permission() which in turn is part of inode_permission(). Both generic_permission() and inode_permission() are called in the ->permission() handler of various filesystems (e.g., overlayfs). So simply passing a dentry argument to ->get_acl() would amount to also having to pass a dentry argument to ->permission(). We should avoid this unnecessary change. So instead of extending the existing inode operation rename it from ->get_acl() to ->get_inode_acl() and add a ->get_acl() method later that passes a dentry argument and which filesystems that need access to the dentry can implement instead of ->get_inode_acl(). Filesystems like cifs which allow setting and getting posix acls but not using them for permission checking during lookup can simply not implement ->get_inode_acl(). This is intended to be a non-functional change. Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org [1] Suggested-by/Inspired-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
153 lines
3.8 KiB
C
153 lines
3.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (C) International Business Machines Corp., 2000-2002
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* Portions Copyright (C) Christoph Hellwig, 2001-2002
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*/
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#include <linux/mm.h>
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#include <linux/fs.h>
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#include <linux/posix_acl.h>
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#include <linux/quotaops.h>
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#include "jfs_incore.h"
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#include "jfs_inode.h"
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#include "jfs_dmap.h"
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#include "jfs_txnmgr.h"
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#include "jfs_xattr.h"
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#include "jfs_acl.h"
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#include "jfs_debug.h"
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int jfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
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{
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struct inode *inode = file->f_mapping->host;
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int rc = 0;
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rc = file_write_and_wait_range(file, start, end);
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if (rc)
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return rc;
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inode_lock(inode);
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if (!(inode->i_state & I_DIRTY_ALL) ||
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(datasync && !(inode->i_state & I_DIRTY_DATASYNC))) {
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/* Make sure committed changes hit the disk */
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jfs_flush_journal(JFS_SBI(inode->i_sb)->log, 1);
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inode_unlock(inode);
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return rc;
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}
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rc |= jfs_commit_inode(inode, 1);
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inode_unlock(inode);
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return rc ? -EIO : 0;
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}
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static int jfs_open(struct inode *inode, struct file *file)
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{
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int rc;
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if ((rc = dquot_file_open(inode, file)))
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return rc;
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/*
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* We attempt to allow only one "active" file open per aggregate
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* group. Otherwise, appending to files in parallel can cause
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* fragmentation within the files.
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*
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* If the file is empty, it was probably just created and going
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* to be written to. If it has a size, we'll hold off until the
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* file is actually grown.
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*/
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if (S_ISREG(inode->i_mode) && file->f_mode & FMODE_WRITE &&
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(inode->i_size == 0)) {
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struct jfs_inode_info *ji = JFS_IP(inode);
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spin_lock_irq(&ji->ag_lock);
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if (ji->active_ag == -1) {
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struct jfs_sb_info *jfs_sb = JFS_SBI(inode->i_sb);
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ji->active_ag = BLKTOAG(addressPXD(&ji->ixpxd), jfs_sb);
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atomic_inc(&jfs_sb->bmap->db_active[ji->active_ag]);
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}
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spin_unlock_irq(&ji->ag_lock);
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}
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return 0;
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}
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static int jfs_release(struct inode *inode, struct file *file)
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{
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struct jfs_inode_info *ji = JFS_IP(inode);
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spin_lock_irq(&ji->ag_lock);
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if (ji->active_ag != -1) {
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struct bmap *bmap = JFS_SBI(inode->i_sb)->bmap;
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atomic_dec(&bmap->db_active[ji->active_ag]);
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ji->active_ag = -1;
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}
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spin_unlock_irq(&ji->ag_lock);
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return 0;
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}
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int jfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
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struct iattr *iattr)
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{
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struct inode *inode = d_inode(dentry);
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int rc;
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rc = setattr_prepare(&init_user_ns, dentry, iattr);
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if (rc)
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return rc;
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if (is_quota_modification(mnt_userns, inode, iattr)) {
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rc = dquot_initialize(inode);
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if (rc)
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return rc;
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}
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if ((iattr->ia_valid & ATTR_UID && !uid_eq(iattr->ia_uid, inode->i_uid)) ||
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(iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid))) {
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rc = dquot_transfer(mnt_userns, inode, iattr);
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if (rc)
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return rc;
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}
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if ((iattr->ia_valid & ATTR_SIZE) &&
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iattr->ia_size != i_size_read(inode)) {
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inode_dio_wait(inode);
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rc = inode_newsize_ok(inode, iattr->ia_size);
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if (rc)
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return rc;
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truncate_setsize(inode, iattr->ia_size);
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jfs_truncate(inode);
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}
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setattr_copy(&init_user_ns, inode, iattr);
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mark_inode_dirty(inode);
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if (iattr->ia_valid & ATTR_MODE)
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rc = posix_acl_chmod(&init_user_ns, dentry, inode->i_mode);
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return rc;
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}
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const struct inode_operations jfs_file_inode_operations = {
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.listxattr = jfs_listxattr,
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.setattr = jfs_setattr,
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.fileattr_get = jfs_fileattr_get,
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.fileattr_set = jfs_fileattr_set,
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#ifdef CONFIG_JFS_POSIX_ACL
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.get_inode_acl = jfs_get_acl,
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.set_acl = jfs_set_acl,
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#endif
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};
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const struct file_operations jfs_file_operations = {
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.open = jfs_open,
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.llseek = generic_file_llseek,
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.read_iter = generic_file_read_iter,
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.write_iter = generic_file_write_iter,
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.mmap = generic_file_mmap,
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.splice_read = generic_file_splice_read,
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.splice_write = iter_file_splice_write,
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.fsync = jfs_fsync,
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.release = jfs_release,
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.unlocked_ioctl = jfs_ioctl,
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.compat_ioctl = compat_ptr_ioctl,
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};
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