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mirror_zfs/module/os/linux/zfs/zpl_ctldir.c
Rob Norris e64d4718a7 Linux 6.15: mkdir now returns struct dentry * 
The intent is that the filesystem may have a reference to an "old"
version of the new directory, eg if it was keeping it alive because a
remote NFS client still had it open.

We don't need anything like that, so this really just changes things so
we return error codes encoded in pointers.

Sponsored-by: https://despairlabs.com/sponsor/
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Pavel Snajdr <snajpa@snajpa.net>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Closes #17229
(cherry picked from commit bb740d66de)
2025-05-28 16:00:28 -07:00

627 lines
16 KiB
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// SPDX-License-Identifier: CDDL-1.0
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or https://opensource.org/licenses/CDDL-1.0.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (C) 2011 Lawrence Livermore National Security, LLC.
* Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
* LLNL-CODE-403049.
* Rewritten for Linux by:
* Rohan Puri <rohan.puri15@gmail.com>
* Brian Behlendorf <behlendorf1@llnl.gov>
*/
#include <sys/zfs_znode.h>
#include <sys/zfs_vfsops.h>
#include <sys/zfs_vnops.h>
#include <sys/zfs_ctldir.h>
#include <sys/zpl.h>
#include <sys/dmu.h>
#include <sys/dsl_dataset.h>
#include <sys/zap.h>
/*
* Common open routine. Disallow any write access.
*/
static int
zpl_common_open(struct inode *ip, struct file *filp)
{
if (blk_mode_is_open_write(filp->f_mode))
return (-EACCES);
return (generic_file_open(ip, filp));
}
/*
* Get root directory contents.
*/
static int
zpl_root_iterate(struct file *filp, struct dir_context *ctx)
{
zfsvfs_t *zfsvfs = ITOZSB(file_inode(filp));
int error = 0;
if (zfsvfs->z_show_ctldir == ZFS_SNAPDIR_DISABLED) {
return (SET_ERROR(ENOENT));
}
if ((error = zpl_enter(zfsvfs, FTAG)) != 0)
return (error);
if (!dir_emit_dots(filp, ctx))
goto out;
if (ctx->pos == 2) {
if (!dir_emit(ctx, ZFS_SNAPDIR_NAME,
strlen(ZFS_SNAPDIR_NAME), ZFSCTL_INO_SNAPDIR, DT_DIR))
goto out;
ctx->pos++;
}
if (ctx->pos == 3) {
if (!dir_emit(ctx, ZFS_SHAREDIR_NAME,
strlen(ZFS_SHAREDIR_NAME), ZFSCTL_INO_SHARES, DT_DIR))
goto out;
ctx->pos++;
}
out:
zpl_exit(zfsvfs, FTAG);
return (error);
}
/*
* Get root directory attributes.
*/
static int
#ifdef HAVE_IDMAP_IOPS_GETATTR
zpl_root_getattr_impl(struct mnt_idmap *user_ns,
const struct path *path, struct kstat *stat, u32 request_mask,
unsigned int query_flags)
#elif defined(HAVE_USERNS_IOPS_GETATTR)
zpl_root_getattr_impl(struct user_namespace *user_ns,
const struct path *path, struct kstat *stat, u32 request_mask,
unsigned int query_flags)
#else
zpl_root_getattr_impl(const struct path *path, struct kstat *stat,
u32 request_mask, unsigned int query_flags)
#endif
{
(void) request_mask, (void) query_flags;
struct inode *ip = path->dentry->d_inode;
#if (defined(HAVE_USERNS_IOPS_GETATTR) || defined(HAVE_IDMAP_IOPS_GETATTR))
#ifdef HAVE_GENERIC_FILLATTR_USERNS
generic_fillattr(user_ns, ip, stat);
#elif defined(HAVE_GENERIC_FILLATTR_IDMAP)
generic_fillattr(user_ns, ip, stat);
#elif defined(HAVE_GENERIC_FILLATTR_IDMAP_REQMASK)
generic_fillattr(user_ns, request_mask, ip, stat);
#else
(void) user_ns;
#endif
#else
generic_fillattr(ip, stat);
#endif
stat->atime = current_time(ip);
return (0);
}
ZPL_GETATTR_WRAPPER(zpl_root_getattr);
static struct dentry *
zpl_root_lookup(struct inode *dip, struct dentry *dentry, unsigned int flags)
{
cred_t *cr = CRED();
struct inode *ip;
int error;
crhold(cr);
error = -zfsctl_root_lookup(dip, dname(dentry), &ip, 0, cr, NULL, NULL);
ASSERT3S(error, <=, 0);
crfree(cr);
if (error) {
if (error == -ENOENT)
return (d_splice_alias(NULL, dentry));
else
return (ERR_PTR(error));
}
return (d_splice_alias(ip, dentry));
}
/*
* The '.zfs' control directory file and inode operations.
*/
const struct file_operations zpl_fops_root = {
.open = zpl_common_open,
.llseek = generic_file_llseek,
.read = generic_read_dir,
.iterate_shared = zpl_root_iterate,
};
const struct inode_operations zpl_ops_root = {
.lookup = zpl_root_lookup,
.getattr = zpl_root_getattr,
};
static struct vfsmount *
zpl_snapdir_automount(struct path *path)
{
int error;
error = -zfsctl_snapshot_mount(path, 0);
if (error)
return (ERR_PTR(error));
/*
* Rather than returning the new vfsmount for the snapshot we must
* return NULL to indicate a mount collision. This is done because
* the user space mount calls do_add_mount() which adds the vfsmount
* to the name space. If we returned the new mount here it would be
* added again to the vfsmount list resulting in list corruption.
*/
return (NULL);
}
/*
* Negative dentries must always be revalidated so newly created snapshots
* can be detected and automounted. Normal dentries should be kept because
* as of the 3.18 kernel revaliding the mountpoint dentry will result in
* the snapshot being immediately unmounted.
*/
#ifdef HAVE_D_REVALIDATE_4ARGS
static int
zpl_snapdir_revalidate(struct inode *dir, const struct qstr *name,
struct dentry *dentry, unsigned int flags)
#else
static int
zpl_snapdir_revalidate(struct dentry *dentry, unsigned int flags)
#endif
{
return (!!dentry->d_inode);
}
static dentry_operations_t zpl_dops_snapdirs = {
/*
* Auto mounting of snapshots is only supported for 2.6.37 and
* newer kernels. Prior to this kernel the ops->follow_link()
* callback was used as a hack to trigger the mount. The
* resulting vfsmount was then explicitly grafted in to the
* name space. While it might be possible to add compatibility
* code to accomplish this it would require considerable care.
*/
.d_automount = zpl_snapdir_automount,
.d_revalidate = zpl_snapdir_revalidate,
};
static struct dentry *
zpl_snapdir_lookup(struct inode *dip, struct dentry *dentry,
unsigned int flags)
{
fstrans_cookie_t cookie;
cred_t *cr = CRED();
struct inode *ip = NULL;
int error;
crhold(cr);
cookie = spl_fstrans_mark();
error = -zfsctl_snapdir_lookup(dip, dname(dentry), &ip,
0, cr, NULL, NULL);
ASSERT3S(error, <=, 0);
spl_fstrans_unmark(cookie);
crfree(cr);
if (error && error != -ENOENT)
return (ERR_PTR(error));
ASSERT(error == 0 || ip == NULL);
d_clear_d_op(dentry);
d_set_d_op(dentry, &zpl_dops_snapdirs);
dentry->d_flags |= DCACHE_NEED_AUTOMOUNT;
return (d_splice_alias(ip, dentry));
}
static int
zpl_snapdir_iterate(struct file *filp, struct dir_context *ctx)
{
zfsvfs_t *zfsvfs = ITOZSB(file_inode(filp));
fstrans_cookie_t cookie;
char snapname[MAXNAMELEN];
boolean_t case_conflict;
uint64_t id, pos;
int error = 0;
if ((error = zpl_enter(zfsvfs, FTAG)) != 0)
return (error);
cookie = spl_fstrans_mark();
if (!dir_emit_dots(filp, ctx))
goto out;
/* Start the position at 0 if it already emitted . and .. */
pos = (ctx->pos == 2 ? 0 : ctx->pos);
while (error == 0) {
dsl_pool_config_enter(dmu_objset_pool(zfsvfs->z_os), FTAG);
error = -dmu_snapshot_list_next(zfsvfs->z_os, MAXNAMELEN,
snapname, &id, &pos, &case_conflict);
dsl_pool_config_exit(dmu_objset_pool(zfsvfs->z_os), FTAG);
if (error)
goto out;
if (!dir_emit(ctx, snapname, strlen(snapname),
ZFSCTL_INO_SHARES - id, DT_DIR))
goto out;
ctx->pos = pos;
}
out:
spl_fstrans_unmark(cookie);
zpl_exit(zfsvfs, FTAG);
if (error == -ENOENT)
return (0);
return (error);
}
static int
#ifdef HAVE_IOPS_RENAME_USERNS
zpl_snapdir_rename2(struct user_namespace *user_ns, struct inode *sdip,
struct dentry *sdentry, struct inode *tdip, struct dentry *tdentry,
unsigned int flags)
#elif defined(HAVE_IOPS_RENAME_IDMAP)
zpl_snapdir_rename2(struct mnt_idmap *user_ns, struct inode *sdip,
struct dentry *sdentry, struct inode *tdip, struct dentry *tdentry,
unsigned int flags)
#else
zpl_snapdir_rename2(struct inode *sdip, struct dentry *sdentry,
struct inode *tdip, struct dentry *tdentry, unsigned int flags)
#endif
{
cred_t *cr = CRED();
int error;
/* We probably don't want to support renameat2(2) in ctldir */
if (flags)
return (-EINVAL);
crhold(cr);
error = -zfsctl_snapdir_rename(sdip, dname(sdentry),
tdip, dname(tdentry), cr, 0);
ASSERT3S(error, <=, 0);
crfree(cr);
return (error);
}
#if (!defined(HAVE_RENAME_WANTS_FLAGS) && \
!defined(HAVE_IOPS_RENAME_USERNS) && \
!defined(HAVE_IOPS_RENAME_IDMAP))
static int
zpl_snapdir_rename(struct inode *sdip, struct dentry *sdentry,
struct inode *tdip, struct dentry *tdentry)
{
return (zpl_snapdir_rename2(sdip, sdentry, tdip, tdentry, 0));
}
#endif
static int
zpl_snapdir_rmdir(struct inode *dip, struct dentry *dentry)
{
cred_t *cr = CRED();
int error;
crhold(cr);
error = -zfsctl_snapdir_remove(dip, dname(dentry), cr, 0);
ASSERT3S(error, <=, 0);
crfree(cr);
return (error);
}
#if defined(HAVE_IOPS_MKDIR_USERNS)
static int
zpl_snapdir_mkdir(struct user_namespace *user_ns, struct inode *dip,
struct dentry *dentry, umode_t mode)
#elif defined(HAVE_IOPS_MKDIR_IDMAP)
static int
zpl_snapdir_mkdir(struct mnt_idmap *user_ns, struct inode *dip,
struct dentry *dentry, umode_t mode)
#elif defined(HAVE_IOPS_MKDIR_DENTRY)
static struct dentry *
zpl_snapdir_mkdir(struct mnt_idmap *user_ns, struct inode *dip,
struct dentry *dentry, umode_t mode)
#else
static int
zpl_snapdir_mkdir(struct inode *dip, struct dentry *dentry, umode_t mode)
#endif
{
cred_t *cr = CRED();
vattr_t *vap;
struct inode *ip;
int error;
crhold(cr);
vap = kmem_zalloc(sizeof (vattr_t), KM_SLEEP);
#if (defined(HAVE_IOPS_MKDIR_USERNS) || defined(HAVE_IOPS_MKDIR_IDMAP))
zpl_vap_init(vap, dip, mode | S_IFDIR, cr, user_ns);
#else
zpl_vap_init(vap, dip, mode | S_IFDIR, cr, zfs_init_idmap);
#endif
error = -zfsctl_snapdir_mkdir(dip, dname(dentry), vap, &ip, cr, 0);
if (error == 0) {
d_clear_d_op(dentry);
d_set_d_op(dentry, &zpl_dops_snapdirs);
d_instantiate(dentry, ip);
}
kmem_free(vap, sizeof (vattr_t));
ASSERT3S(error, <=, 0);
crfree(cr);
#if defined(HAVE_IOPS_MKDIR_DENTRY)
return (ERR_PTR(error));
#else
return (error);
#endif
}
/*
* Get snapshot directory attributes.
*/
static int
#ifdef HAVE_IDMAP_IOPS_GETATTR
zpl_snapdir_getattr_impl(struct mnt_idmap *user_ns,
const struct path *path, struct kstat *stat, u32 request_mask,
unsigned int query_flags)
#elif defined(HAVE_USERNS_IOPS_GETATTR)
zpl_snapdir_getattr_impl(struct user_namespace *user_ns,
const struct path *path, struct kstat *stat, u32 request_mask,
unsigned int query_flags)
#else
zpl_snapdir_getattr_impl(const struct path *path, struct kstat *stat,
u32 request_mask, unsigned int query_flags)
#endif
{
(void) request_mask, (void) query_flags;
struct inode *ip = path->dentry->d_inode;
zfsvfs_t *zfsvfs = ITOZSB(ip);
int error;
if ((error = zpl_enter(zfsvfs, FTAG)) != 0)
return (error);
#if (defined(HAVE_USERNS_IOPS_GETATTR) || defined(HAVE_IDMAP_IOPS_GETATTR))
#ifdef HAVE_GENERIC_FILLATTR_USERNS
generic_fillattr(user_ns, ip, stat);
#elif defined(HAVE_GENERIC_FILLATTR_IDMAP)
generic_fillattr(user_ns, ip, stat);
#elif defined(HAVE_GENERIC_FILLATTR_IDMAP_REQMASK)
generic_fillattr(user_ns, request_mask, ip, stat);
#else
(void) user_ns;
#endif
#else
generic_fillattr(ip, stat);
#endif
stat->nlink = stat->size = 2;
dsl_dataset_t *ds = dmu_objset_ds(zfsvfs->z_os);
if (dsl_dataset_phys(ds)->ds_snapnames_zapobj != 0) {
uint64_t snap_count;
int err = zap_count(
dmu_objset_pool(ds->ds_objset)->dp_meta_objset,
dsl_dataset_phys(ds)->ds_snapnames_zapobj, &snap_count);
if (err != 0) {
zpl_exit(zfsvfs, FTAG);
return (-err);
}
stat->nlink += snap_count;
}
stat->ctime = stat->mtime = dmu_objset_snap_cmtime(zfsvfs->z_os);
stat->atime = current_time(ip);
zpl_exit(zfsvfs, FTAG);
return (0);
}
ZPL_GETATTR_WRAPPER(zpl_snapdir_getattr);
/*
* The '.zfs/snapshot' directory file operations. These mainly control
* generating the list of available snapshots when doing an 'ls' in the
* directory. See zpl_snapdir_readdir().
*/
const struct file_operations zpl_fops_snapdir = {
.open = zpl_common_open,
.llseek = generic_file_llseek,
.read = generic_read_dir,
.iterate_shared = zpl_snapdir_iterate,
};
/*
* The '.zfs/snapshot' directory inode operations. These mainly control
* creating an inode for a snapshot directory and initializing the needed
* infrastructure to automount the snapshot. See zpl_snapdir_lookup().
*/
const struct inode_operations zpl_ops_snapdir = {
.lookup = zpl_snapdir_lookup,
.getattr = zpl_snapdir_getattr,
#if (defined(HAVE_RENAME_WANTS_FLAGS) || \
defined(HAVE_IOPS_RENAME_USERNS) || \
defined(HAVE_IOPS_RENAME_IDMAP))
.rename = zpl_snapdir_rename2,
#else
.rename = zpl_snapdir_rename,
#endif
.rmdir = zpl_snapdir_rmdir,
.mkdir = zpl_snapdir_mkdir,
};
static struct dentry *
zpl_shares_lookup(struct inode *dip, struct dentry *dentry,
unsigned int flags)
{
fstrans_cookie_t cookie;
cred_t *cr = CRED();
struct inode *ip = NULL;
int error;
crhold(cr);
cookie = spl_fstrans_mark();
error = -zfsctl_shares_lookup(dip, dname(dentry), &ip,
0, cr, NULL, NULL);
ASSERT3S(error, <=, 0);
spl_fstrans_unmark(cookie);
crfree(cr);
if (error) {
if (error == -ENOENT)
return (d_splice_alias(NULL, dentry));
else
return (ERR_PTR(error));
}
return (d_splice_alias(ip, dentry));
}
static int
zpl_shares_iterate(struct file *filp, struct dir_context *ctx)
{
fstrans_cookie_t cookie;
cred_t *cr = CRED();
zfsvfs_t *zfsvfs = ITOZSB(file_inode(filp));
znode_t *dzp;
int error = 0;
if ((error = zpl_enter(zfsvfs, FTAG)) != 0)
return (error);
cookie = spl_fstrans_mark();
if (zfsvfs->z_shares_dir == 0) {
dir_emit_dots(filp, ctx);
goto out;
}
error = -zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp);
if (error)
goto out;
crhold(cr);
error = -zfs_readdir(ZTOI(dzp), ctx, cr);
crfree(cr);
iput(ZTOI(dzp));
out:
spl_fstrans_unmark(cookie);
zpl_exit(zfsvfs, FTAG);
ASSERT3S(error, <=, 0);
return (error);
}
static int
#ifdef HAVE_USERNS_IOPS_GETATTR
zpl_shares_getattr_impl(struct user_namespace *user_ns,
const struct path *path, struct kstat *stat, u32 request_mask,
unsigned int query_flags)
#elif defined(HAVE_IDMAP_IOPS_GETATTR)
zpl_shares_getattr_impl(struct mnt_idmap *user_ns,
const struct path *path, struct kstat *stat, u32 request_mask,
unsigned int query_flags)
#else
zpl_shares_getattr_impl(const struct path *path, struct kstat *stat,
u32 request_mask, unsigned int query_flags)
#endif
{
(void) request_mask, (void) query_flags;
struct inode *ip = path->dentry->d_inode;
zfsvfs_t *zfsvfs = ITOZSB(ip);
znode_t *dzp;
int error;
if ((error = zpl_enter(zfsvfs, FTAG)) != 0)
return (error);
if (zfsvfs->z_shares_dir == 0) {
#if (defined(HAVE_USERNS_IOPS_GETATTR) || defined(HAVE_IDMAP_IOPS_GETATTR))
#ifdef HAVE_GENERIC_FILLATTR_USERNS
generic_fillattr(user_ns, path->dentry->d_inode, stat);
#elif defined(HAVE_GENERIC_FILLATTR_IDMAP)
generic_fillattr(user_ns, path->dentry->d_inode, stat);
#elif defined(HAVE_GENERIC_FILLATTR_IDMAP_REQMASK)
generic_fillattr(user_ns, request_mask, ip, stat);
#else
(void) user_ns;
#endif
#else
generic_fillattr(path->dentry->d_inode, stat);
#endif
stat->nlink = stat->size = 2;
stat->atime = current_time(ip);
zpl_exit(zfsvfs, FTAG);
return (0);
}
error = -zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp);
if (error == 0) {
#ifdef HAVE_GENERIC_FILLATTR_IDMAP_REQMASK
error = -zfs_getattr_fast(user_ns, request_mask, ZTOI(dzp),
stat);
#elif (defined(HAVE_USERNS_IOPS_GETATTR) || defined(HAVE_IDMAP_IOPS_GETATTR))
error = -zfs_getattr_fast(user_ns, ZTOI(dzp), stat);
#else
error = -zfs_getattr_fast(kcred->user_ns, ZTOI(dzp), stat);
#endif
iput(ZTOI(dzp));
}
zpl_exit(zfsvfs, FTAG);
ASSERT3S(error, <=, 0);
return (error);
}
ZPL_GETATTR_WRAPPER(zpl_shares_getattr);
/*
* The '.zfs/shares' directory file operations.
*/
const struct file_operations zpl_fops_shares = {
.open = zpl_common_open,
.llseek = generic_file_llseek,
.read = generic_read_dir,
.iterate_shared = zpl_shares_iterate,
};
/*
* The '.zfs/shares' directory inode operations.
*/
const struct inode_operations zpl_ops_shares = {
.lookup = zpl_shares_lookup,
.getattr = zpl_shares_getattr,
};
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