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Remove zpl_revalidate: fix snapshot rollback 

Open files, which aren't present in the snapshot, which is being
roll-backed to, need to disappear from the visible VFS image of
the dataset.

Kernel provides d_drop function to drop invalid entry from
the dcache, but inode can be referenced by dentry multiple dentries.

The introduced zpl_d_drop_aliases function walks and invalidates
all aliases of an inode.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Pavel Snajdr <snajpa@snajpa.net>
Closes #9600
Closes #14070
This commit is contained in:
Pavel Snajdr 2019-12-05 01:52:27 +01:00 committed by Brian Behlendorf
parent e09fdda977
commit 86db35c447
10 changed files with 59 additions and 56 deletions
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30
config/kernel-dentry-alias.m4 Normal file
View File

@ -0,0 +1,30 @@
dnl #
dnl # 3.18 API change
dnl # Dentry aliases are in d_u struct dentry member
dnl #
AC_DEFUN([ZFS_AC_KERNEL_SRC_DENTRY_ALIAS_D_U], [
ZFS_LINUX_TEST_SRC([dentry_alias_d_u], [
#include <linux/fs.h>
#include <linux/dcache.h>
#include <linux/list.h>
], [
struct inode *inode __attribute__ ((unused)) = NULL;
struct dentry *dentry __attribute__ ((unused)) = NULL;
hlist_for_each_entry(dentry, &inode->i_dentry,
d_u.d_alias) {
d_drop(dentry);
}
])
])
AC_DEFUN([ZFS_AC_KERNEL_DENTRY_ALIAS_D_U], [
AC_MSG_CHECKING([whether dentry aliases are in d_u member])
ZFS_LINUX_TEST_RESULT([dentry_alias_d_u], [
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_DENTRY_D_U_ALIASES, 1,
[dentry aliases are in d_u member])
],[
AC_MSG_RESULT(no)
])
])

2
config/kernel.m4
View File

@ -96,6 +96,7 @@ AC_DEFUN([ZFS_AC_KERNEL_TEST_SRC], [
ZFS_AC_KERNEL_SRC_SETATTR_PREPARE
ZFS_AC_KERNEL_SRC_INSERT_INODE_LOCKED
ZFS_AC_KERNEL_SRC_DENTRY
ZFS_AC_KERNEL_SRC_DENTRY_ALIAS_D_U
ZFS_AC_KERNEL_SRC_TRUNCATE_SETSIZE
ZFS_AC_KERNEL_SRC_SECURITY_INODE
ZFS_AC_KERNEL_SRC_FST_MOUNT
@ -217,6 +218,7 @@ AC_DEFUN([ZFS_AC_KERNEL_TEST_RESULT], [
ZFS_AC_KERNEL_SETATTR_PREPARE
ZFS_AC_KERNEL_INSERT_INODE_LOCKED
ZFS_AC_KERNEL_DENTRY
ZFS_AC_KERNEL_DENTRY_ALIAS_D_U
ZFS_AC_KERNEL_TRUNCATE_SETSIZE
ZFS_AC_KERNEL_SECURITY_INODE
ZFS_AC_KERNEL_FST_MOUNT

21
include/os/linux/kernel/linux/dcache_compat.h
View File

@ -61,4 +61,25 @@ d_clear_d_op(struct dentry *dentry)
DCACHE_OP_REVALIDATE | DCACHE_OP_DELETE);
}
/*
* Walk and invalidate all dentry aliases of an inode
* unless it's a mountpoint
*/
static inline void
zpl_d_drop_aliases(struct inode *inode)
{
struct dentry *dentry;
spin_lock(&inode->i_lock);
#ifdef HAVE_DENTRY_D_U_ALIASES
hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
#else
hlist_for_each_entry(dentry, &inode->i_dentry, d_alias) {
#endif
if (!IS_ROOT(dentry) && !d_mountpoint(dentry) &&
(dentry->d_inode == inode)) {
d_drop(dentry);
}
}
spin_unlock(&inode->i_lock);
}
#endif /* _ZFS_DCACHE_H */

9
include/os/linux/zfs/sys/trace_acl.h
View File

@ -64,7 +64,6 @@ DECLARE_EVENT_CLASS(zfs_ace_class,
__field(boolean_t, z_is_sa)
__field(boolean_t, z_is_mapped)
__field(boolean_t, z_is_ctldir)
__field(boolean_t, z_is_stale)
__field(uint32_t, i_uid)
__field(uint32_t, i_gid)
@ -99,7 +98,6 @@ DECLARE_EVENT_CLASS(zfs_ace_class,
__entry->z_is_sa = zn->z_is_sa;
__entry->z_is_mapped = zn->z_is_mapped;
__entry->z_is_ctldir = zn->z_is_ctldir;
__entry->z_is_stale = zn->z_is_stale;
__entry->i_uid = KUID_TO_SUID(ZTOI(zn)->i_uid);
__entry->i_gid = KGID_TO_SGID(ZTOI(zn)->i_gid);
@ -121,9 +119,8 @@ DECLARE_EVENT_CLASS(zfs_ace_class,
"zn_prefetch %u blksz %u seq %u "
"mapcnt %llu size %llu pflags %llu "
"sync_cnt %u sync_writes_cnt %u async_writes_cnt %u "
"mode 0x%x is_sa %d is_mapped %d "
"is_ctldir %d is_stale %d inode { "
"uid %u gid %u ino %lu nlink %u size %lli "
"mode 0x%x is_sa %d is_mapped %d is_ctldir %d "
"inode { uid %u gid %u ino %lu nlink %u size %lli "
"blkbits %u bytes %u mode 0x%x generation %x } } "
"ace { type %u flags %u access_mask %u } mask_matched %u",
__entry->z_id, __entry->z_unlinked, __entry->z_atime_dirty,
@ -132,7 +129,7 @@ DECLARE_EVENT_CLASS(zfs_ace_class,
__entry->z_pflags, __entry->z_sync_cnt,
__entry->z_sync_writes_cnt, __entry->z_async_writes_cnt,
__entry->z_mode, __entry->z_is_sa, __entry->z_is_mapped,
__entry->z_is_ctldir, __entry->z_is_stale, __entry->i_uid,
__entry->z_is_ctldir, __entry->i_uid,
__entry->i_gid, __entry->i_ino, __entry->i_nlink,
__entry->i_size, __entry->i_blkbits,
__entry->i_bytes, __entry->i_mode, __entry->i_generation,

3
include/os/linux/zfs/sys/zpl.h
View File

@ -45,7 +45,8 @@ extern const struct inode_operations zpl_inode_operations;
extern const struct inode_operations zpl_dir_inode_operations;
extern const struct inode_operations zpl_symlink_inode_operations;
extern const struct inode_operations zpl_special_inode_operations;
extern dentry_operations_t zpl_dentry_operations;
/* zpl_file.c */
extern const struct address_space_operations zpl_address_space_operations;
extern const struct file_operations zpl_file_operations;
extern const struct file_operations zpl_dir_file_operations;

1
include/sys/zfs_znode.h
View File

@ -190,7 +190,6 @@ typedef struct znode {
boolean_t z_is_sa; /* are we native sa? */
boolean_t z_is_mapped; /* are we mmap'ed */
boolean_t z_is_ctldir; /* are we .zfs entry */
boolean_t z_is_stale; /* are we stale due to rollback? */
boolean_t z_suspended; /* extra ref from a suspend? */
uint_t z_blksz; /* block size in bytes */
uint_t z_seq; /* modification sequence number */

1
module/os/linux/zfs/zfs_ctldir.c
View File

@ -487,7 +487,6 @@ zfsctl_inode_alloc(zfsvfs_t *zfsvfs, uint64_t id,
zp->z_is_sa = B_FALSE;
zp->z_is_mapped = B_FALSE;
zp->z_is_ctldir = B_TRUE;
zp->z_is_stale = B_FALSE;
zp->z_sa_hdl = NULL;
zp->z_blksz = 0;
zp->z_seq = 0;

3
module/os/linux/zfs/zfs_vfsops.c
View File

@ -1522,7 +1522,6 @@ zfs_domount(struct super_block *sb, zfs_mnt_t *zm, int silent)
sb->s_op = &zpl_super_operations;
sb->s_xattr = zpl_xattr_handlers;
sb->s_export_op = &zpl_export_operations;
sb->s_d_op = &zpl_dentry_operations;
/* Set features for file system. */
zfs_set_fuid_feature(zfsvfs);
@ -1881,8 +1880,8 @@ zfs_resume_fs(zfsvfs_t *zfsvfs, dsl_dataset_t *ds)
zp = list_next(&zfsvfs->z_all_znodes, zp)) {
err2 = zfs_rezget(zp);
if (err2) {
zpl_d_drop_aliases(ZTOI(zp));
remove_inode_hash(ZTOI(zp));
zp->z_is_stale = B_TRUE;
}
/* see comment in zfs_suspend_fs() */

1
module/os/linux/zfs/zfs_znode.c
View File

@ -552,7 +552,6 @@ zfs_znode_alloc(zfsvfs_t *zfsvfs, dmu_buf_t *db, int blksz,
zp->z_atime_dirty = B_FALSE;
zp->z_is_mapped = B_FALSE;
zp->z_is_ctldir = B_FALSE;
zp->z_is_stale = B_FALSE;
zp->z_suspended = B_FALSE;
zp->z_sa_hdl = NULL;
zp->z_mapcnt = 0;

44
module/os/linux/zfs/zpl_inode.c
View File

@ -728,46 +728,6 @@ out:
return (error);
}
static int
#ifdef HAVE_D_REVALIDATE_NAMEIDATA
zpl_revalidate(struct dentry *dentry, struct nameidata *nd)
{
unsigned int flags = (nd ? nd->flags : 0);
#else
zpl_revalidate(struct dentry *dentry, unsigned int flags)
{
#endif /* HAVE_D_REVALIDATE_NAMEIDATA */
/* CSTYLED */
zfsvfs_t *zfsvfs = dentry->d_sb->s_fs_info;
int error;
if (flags & LOOKUP_RCU)
return (-ECHILD);
/*
* After a rollback negative dentries created before the rollback
* time must be invalidated. Otherwise they can obscure files which
* are only present in the rolled back dataset.
*/
if (dentry->d_inode == NULL) {
spin_lock(&dentry->d_lock);
error = time_before(dentry->d_time, zfsvfs->z_rollback_time);
spin_unlock(&dentry->d_lock);
if (error)
return (0);
}
/*
* The dentry may reference a stale inode if a mounted file system
* was rolled back to a point in time where the object didn't exist.
*/
if (dentry->d_inode && ITOZ(dentry->d_inode)->z_is_stale)
return (0);
return (1);
}
const struct inode_operations zpl_inode_operations = {
.setattr = zpl_setattr,
.getattr = zpl_getattr,
@ -856,7 +816,3 @@ const struct inode_operations zpl_special_inode_operations = {
.get_acl = zpl_get_acl,
#endif /* CONFIG_FS_POSIX_ACL */
};
dentry_operations_t zpl_dentry_operations = {
.d_revalidate = zpl_revalidate,
};