7b3e34ba5a
Rolling back a mounted filesystem with open file handles and cached dentries+inodes never worked properly in ZoL. The major issue was that Linux provides no easy mechanism for modules to invalidate the inode cache for a file system. Because of this it was possible that an inode from the previous filesystem would not get properly dropped from the cache during rolling back. Then a new inode with the same inode number would be create and collide with the existing cached inode. Ideally this would trigger an VERIFY() but in practice the error wasn't handled and it would just NULL reference. Luckily, this issue can be resolved by sprucing up the existing Solaris zfs_rezget() functionality for the Linux VFS. The way it works now is that when a file system is rolled back all the cached inodes will be traversed and refetched from disk. If a version of the cached inode exists on disk the in-core copy will be updated accordingly. If there is no match for that object on disk it will be unhashed from the inode cache and marked as stale. This will effectively make the inode unfindable for lookups allowing the inode number to be immediately recycled. The inode will then only be accessible from the cached dentries. Subsequent dentry lookups which reference a stale inode will result in the dentry being invalidated. Once invalidated the dentry will drop its reference on the inode allowing it to be safely pruned from the cache. Special care is taken for negative dentries since they do not reference any inode. These dentires will be invalidate based on when they were added to the dentry cache. Entries added before the last rollback will be invalidate to prevent them from masking real files in the dataset. Two nice side effects of this fix are: * Removes the dependency on spl_invalidate_inodes(), it can now be safely removed from the SPL when we choose to do so. * zfs_znode_alloc() no longer requires a dentry to be passed. This effectively reverts this portition of the code to its upstream counterpart. The dentry is not instantiated more correctly in the Linux ZPL layer. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Ned Bass <bass6@llnl.gov> Closes #795
195 lines
7.5 KiB
C
195 lines
7.5 KiB
C
/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License (the "License").
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* You may not use this file except in compliance with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or http://www.opensolaris.org/os/licensing.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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/*
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* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
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*/
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#ifndef _SYS_FS_ZFS_VFSOPS_H
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#define _SYS_FS_ZFS_VFSOPS_H
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#include <sys/isa_defs.h>
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#include <sys/types32.h>
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#include <sys/list.h>
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#include <sys/vfs.h>
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#include <sys/zil.h>
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#include <sys/sa.h>
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#include <sys/rrwlock.h>
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#include <sys/zfs_ioctl.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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struct zfs_sb;
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struct znode;
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typedef struct zfs_sb {
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struct super_block *z_sb; /* generic super_block */
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struct backing_dev_info z_bdi; /* generic backing dev info */
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struct zfs_sb *z_parent; /* parent fs */
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objset_t *z_os; /* objset reference */
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uint64_t z_flags; /* super_block flags */
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uint64_t z_root; /* id of root znode */
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uint64_t z_unlinkedobj; /* id of unlinked zapobj */
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uint64_t z_max_blksz; /* maximum block size for files */
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uint64_t z_fuid_obj; /* fuid table object number */
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uint64_t z_fuid_size; /* fuid table size */
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avl_tree_t z_fuid_idx; /* fuid tree keyed by index */
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avl_tree_t z_fuid_domain; /* fuid tree keyed by domain */
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krwlock_t z_fuid_lock; /* fuid lock */
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boolean_t z_fuid_loaded; /* fuid tables are loaded */
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boolean_t z_fuid_dirty; /* need to sync fuid table ? */
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struct zfs_fuid_info *z_fuid_replay; /* fuid info for replay */
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zilog_t *z_log; /* intent log pointer */
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uint_t z_acl_inherit; /* acl inheritance behavior */
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zfs_case_t z_case; /* case-sense */
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boolean_t z_utf8; /* utf8-only */
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int z_norm; /* normalization flags */
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boolean_t z_atime; /* enable atimes mount option */
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boolean_t z_unmounted; /* unmounted */
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rrwlock_t z_teardown_lock;
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krwlock_t z_teardown_inactive_lock;
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list_t z_all_znodes; /* all znodes in the fs */
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uint64_t z_nr_znodes; /* number of znodes in the fs */
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unsigned long z_rollback_time;/* last online rollback time */
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kmutex_t z_znodes_lock; /* lock for z_all_znodes */
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struct inode *z_ctldir; /* .zfs directory inode */
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avl_tree_t z_ctldir_snaps; /* .zfs/snapshot entries */
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kmutex_t z_ctldir_lock; /* .zfs ctldir lock */
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boolean_t z_show_ctldir; /* expose .zfs in the root dir */
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boolean_t z_issnap; /* true if this is a snapshot */
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boolean_t z_vscan; /* virus scan on/off */
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boolean_t z_use_fuids; /* version allows fuids */
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boolean_t z_replay; /* set during ZIL replay */
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boolean_t z_use_sa; /* version allow system attributes */
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boolean_t z_xattr_sa; /* allow xattrs to be stores as SA */
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uint64_t z_version; /* ZPL version */
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uint64_t z_shares_dir; /* hidden shares dir */
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kmutex_t z_lock;
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uint64_t z_userquota_obj;
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uint64_t z_groupquota_obj;
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uint64_t z_replay_eof; /* New end of file - replay only */
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sa_attr_type_t *z_attr_table; /* SA attr mapping->id */
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#define ZFS_OBJ_MTX_SZ 256
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kmutex_t z_hold_mtx[ZFS_OBJ_MTX_SZ]; /* znode hold locks */
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} zfs_sb_t;
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#define ZFS_SUPER_MAGIC 0x2fc12fc1
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#define ZSB_XATTR 0x0001 /* Enable user xattrs */
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/*
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* Allow a maximum number of links. While ZFS does not internally limit
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* this the inode->i_nlink member is defined as an unsigned int. To be
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* safe we use 2^31-1 as the limit.
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*/
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#define ZFS_LINK_MAX ((1U << 31) - 1U)
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/*
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* Normal filesystems (those not under .zfs/snapshot) have a total
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* file ID size limited to 12 bytes (including the length field) due to
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* NFSv2 protocol's limitation of 32 bytes for a filehandle. For historical
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* reasons, this same limit is being imposed by the Solaris NFSv3 implementation
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* (although the NFSv3 protocol actually permits a maximum of 64 bytes). It
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* is not possible to expand beyond 12 bytes without abandoning support
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* of NFSv2.
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*
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* For normal filesystems, we partition up the available space as follows:
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* 2 bytes fid length (required)
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* 6 bytes object number (48 bits)
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* 4 bytes generation number (32 bits)
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*
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* We reserve only 48 bits for the object number, as this is the limit
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* currently defined and imposed by the DMU.
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*/
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typedef struct zfid_short {
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uint16_t zf_len;
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uint8_t zf_object[6]; /* obj[i] = obj >> (8 * i) */
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uint8_t zf_gen[4]; /* gen[i] = gen >> (8 * i) */
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} zfid_short_t;
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/*
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* Filesystems under .zfs/snapshot have a total file ID size of 22 bytes
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* (including the length field). This makes files under .zfs/snapshot
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* accessible by NFSv3 and NFSv4, but not NFSv2.
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*
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* For files under .zfs/snapshot, we partition up the available space
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* as follows:
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* 2 bytes fid length (required)
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* 6 bytes object number (48 bits)
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* 4 bytes generation number (32 bits)
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* 6 bytes objset id (48 bits)
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* 4 bytes currently just zero (32 bits)
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*
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* We reserve only 48 bits for the object number and objset id, as these are
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* the limits currently defined and imposed by the DMU.
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*/
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typedef struct zfid_long {
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zfid_short_t z_fid;
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uint8_t zf_setid[6]; /* obj[i] = obj >> (8 * i) */
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uint8_t zf_setgen[4]; /* gen[i] = gen >> (8 * i) */
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} zfid_long_t;
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#define SHORT_FID_LEN (sizeof (zfid_short_t) - sizeof (uint16_t))
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#define LONG_FID_LEN (sizeof (zfid_long_t) - sizeof (uint16_t))
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extern uint_t zfs_fsyncer_key;
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extern int zfs_suspend_fs(zfs_sb_t *zsb);
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extern int zfs_resume_fs(zfs_sb_t *zsb, const char *osname);
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extern int zfs_userspace_one(zfs_sb_t *zsb, zfs_userquota_prop_t type,
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const char *domain, uint64_t rid, uint64_t *valuep);
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extern int zfs_userspace_many(zfs_sb_t *zsb, zfs_userquota_prop_t type,
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uint64_t *cookiep, void *vbuf, uint64_t *bufsizep);
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extern int zfs_set_userquota(zfs_sb_t *zsb, zfs_userquota_prop_t type,
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const char *domain, uint64_t rid, uint64_t quota);
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extern boolean_t zfs_owner_overquota(zfs_sb_t *zsb, struct znode *,
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boolean_t isgroup);
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extern boolean_t zfs_fuid_overquota(zfs_sb_t *zsb, boolean_t isgroup,
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uint64_t fuid);
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extern int zfs_set_version(zfs_sb_t *zsb, uint64_t newvers);
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extern int zfs_get_zplprop(objset_t *os, zfs_prop_t prop,
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uint64_t *value);
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extern int zfs_sb_create(const char *name, zfs_sb_t **zsbp);
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extern int zfs_sb_setup(zfs_sb_t *zsb, boolean_t mounting);
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extern void zfs_sb_free(zfs_sb_t *zsb);
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extern int zfs_sb_prune(struct super_block *sb, unsigned long nr_to_scan,
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int *objects);
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extern int zfs_sb_teardown(zfs_sb_t *zsb, boolean_t unmounting);
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extern int zfs_check_global_label(const char *dsname, const char *hexsl);
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extern boolean_t zfs_is_readonly(zfs_sb_t *zsb);
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extern int zfs_register_callbacks(zfs_sb_t *zsb);
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extern void zfs_unregister_callbacks(zfs_sb_t *zsb);
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extern int zfs_domount(struct super_block *sb, void *data, int silent);
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extern void zfs_preumount(struct super_block *sb);
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extern int zfs_umount(struct super_block *sb);
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extern int zfs_remount(struct super_block *sb, int *flags, char *data);
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extern int zfs_root(zfs_sb_t *zsb, struct inode **ipp);
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extern int zfs_statvfs(struct dentry *dentry, struct kstatfs *statp);
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extern int zfs_vget(struct super_block *sb, struct inode **ipp, fid_t *fidp);
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#ifdef __cplusplus
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}
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#endif
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#endif /* _SYS_FS_ZFS_VFSOPS_H */
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