![Theodore Ts'o](/assets/img/avatar_default.png)
Add a new mount option which enables a new "lazytime" mode. This mode causes atime, mtime, and ctime updates to only be made to the in-memory version of the inode. The on-disk times will only get updated when (a) if the inode needs to be updated for some non-time related change, (b) if userspace calls fsync(), syncfs() or sync(), or (c) just before an undeleted inode is evicted from memory. This is OK according to POSIX because there are no guarantees after a crash unless userspace explicitly requests via a fsync(2) call. For workloads which feature a large number of random write to a preallocated file, the lazytime mount option significantly reduces writes to the inode table. The repeated 4k writes to a single block will result in undesirable stress on flash devices and SMR disk drives. Even on conventional HDD's, the repeated writes to the inode table block will trigger Adjacent Track Interference (ATI) remediation latencies, which very negatively impact long tail latencies --- which is a very big deal for web serving tiers (for example). Google-Bug-Id: 18297052 Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
168 lines
4.5 KiB
C
168 lines
4.5 KiB
C
/*
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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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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
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* the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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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 = filemap_write_and_wait_range(inode->i_mapping, start, end);
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if (rc)
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return rc;
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mutex_lock(&inode->i_mutex);
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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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mutex_unlock(&inode->i_mutex);
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return rc;
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}
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rc |= jfs_commit_inode(inode, 1);
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mutex_unlock(&inode->i_mutex);
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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 dentry *dentry, struct iattr *iattr)
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{
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struct inode *inode = dentry->d_inode;
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int rc;
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rc = inode_change_ok(inode, iattr);
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if (rc)
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return rc;
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if (is_quota_modification(inode, iattr))
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dquot_initialize(inode);
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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(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(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(inode, 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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.setxattr = jfs_setxattr,
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.getxattr = jfs_getxattr,
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.listxattr = jfs_listxattr,
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.removexattr = jfs_removexattr,
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.setattr = jfs_setattr,
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#ifdef CONFIG_JFS_POSIX_ACL
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.get_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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.write = new_sync_write,
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.read = new_sync_read,
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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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#ifdef CONFIG_COMPAT
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.compat_ioctl = jfs_compat_ioctl,
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#endif
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};
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