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
93 lines
3.2 KiB
C
93 lines
3.2 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) 2011, Lawrence Livermore National Security, LLC.
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*/
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#ifndef _SYS_ZPL_H
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#define _SYS_ZPL_H
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#include <sys/vfs.h>
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#include <linux/vfs_compat.h>
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#include <linux/xattr_compat.h>
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#include <linux/dcache_compat.h>
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#include <linux/exportfs.h>
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#include <linux/writeback.h>
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#include <linux/falloc.h>
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/* zpl_inode.c */
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extern void zpl_vap_init(vattr_t *vap, struct inode *dir,
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zpl_umode_t mode, cred_t *cr);
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extern const struct inode_operations zpl_inode_operations;
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extern const struct inode_operations zpl_dir_inode_operations;
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extern const struct inode_operations zpl_symlink_inode_operations;
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extern const struct inode_operations zpl_special_inode_operations;
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extern dentry_operations_t zpl_dentry_operations;
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/* zpl_file.c */
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extern ssize_t zpl_read_common(struct inode *ip, const char *buf,
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size_t len, loff_t pos, uio_seg_t segment, int flags, cred_t *cr);
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extern ssize_t zpl_write_common(struct inode *ip, const char *buf,
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size_t len, loff_t pos, uio_seg_t segment, int flags, cred_t *cr);
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extern long zpl_fallocate_common(struct inode *ip, int mode,
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loff_t offset, loff_t len);
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extern const struct address_space_operations zpl_address_space_operations;
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extern const struct file_operations zpl_file_operations;
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extern const struct file_operations zpl_dir_file_operations;
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/* zpl_super.c */
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extern void zpl_prune_sbs(int64_t bytes_to_scan, void *private);
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typedef struct zpl_mount_data {
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const char *z_osname; /* Dataset name */
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void *z_data; /* Mount options string */
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} zpl_mount_data_t;
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extern const struct super_operations zpl_super_operations;
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extern const struct export_operations zpl_export_operations;
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extern struct file_system_type zpl_fs_type;
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/* zpl_xattr.c */
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extern ssize_t zpl_xattr_list(struct dentry *dentry, char *buf, size_t size);
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extern int zpl_xattr_security_init(struct inode *ip, struct inode *dip,
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const struct qstr *qstr);
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extern xattr_handler_t *zpl_xattr_handlers[];
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/* zpl_ctldir.c */
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extern const struct file_operations zpl_fops_root;
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extern const struct inode_operations zpl_ops_root;
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extern const struct file_operations zpl_fops_snapdir;
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extern const struct inode_operations zpl_ops_snapdir;
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#ifdef HAVE_AUTOMOUNT
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extern const struct dentry_operations zpl_dops_snapdirs;
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#else
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extern const struct inode_operations zpl_ops_snapdirs;
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#endif /* HAVE_AUTOMOUNT */
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extern const struct file_operations zpl_fops_shares;
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extern const struct inode_operations zpl_ops_shares;
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#endif /* _SYS_ZPL_H */
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