fa0d7e3de6
RCU free the struct inode. This will allow: - Subsequent store-free path walking patch. The inode must be consulted for permissions when walking, so an RCU inode reference is a must. - sb_inode_list_lock to be moved inside i_lock because sb list walkers who want to take i_lock no longer need to take sb_inode_list_lock to walk the list in the first place. This will simplify and optimize locking. - Could remove some nested trylock loops in dcache code - Could potentially simplify things a bit in VM land. Do not need to take the page lock to follow page->mapping. The downsides of this is the performance cost of using RCU. In a simple creat/unlink microbenchmark, performance drops by about 10% due to inability to reuse cache-hot slab objects. As iterations increase and RCU freeing starts kicking over, this increases to about 20%. In cases where inode lifetimes are longer (ie. many inodes may be allocated during the average life span of a single inode), a lot of this cache reuse is not applicable, so the regression caused by this patch is smaller. The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU, however this adds some complexity to list walking and store-free path walking, so I prefer to implement this at a later date, if it is shown to be a win in real situations. I haven't found a regression in any non-micro benchmark so I doubt it will be a problem. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
362 lines
9.0 KiB
C
362 lines
9.0 KiB
C
/*
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* Copyright (c) 2000-2001 Christoph Hellwig.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions, and the following disclaimer,
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* without modification.
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* 2. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* Alternatively, this software may be distributed under the terms of the
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* GNU General Public License ("GPL").
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* Veritas filesystem driver - inode routines.
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*/
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#include <linux/fs.h>
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#include <linux/buffer_head.h>
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#include <linux/pagemap.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include "vxfs.h"
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#include "vxfs_inode.h"
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#include "vxfs_extern.h"
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struct kmem_cache *vxfs_inode_cachep;
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#ifdef DIAGNOSTIC
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/*
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* Dump inode contents (partially).
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*/
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void
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vxfs_dumpi(struct vxfs_inode_info *vip, ino_t ino)
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{
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printk(KERN_DEBUG "\n\n");
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if (ino)
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printk(KERN_DEBUG "dumping vxfs inode %ld\n", ino);
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else
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printk(KERN_DEBUG "dumping unknown vxfs inode\n");
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printk(KERN_DEBUG "---------------------------\n");
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printk(KERN_DEBUG "mode is %x\n", vip->vii_mode);
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printk(KERN_DEBUG "nlink:%u, uid:%u, gid:%u\n",
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vip->vii_nlink, vip->vii_uid, vip->vii_gid);
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printk(KERN_DEBUG "size:%Lx, blocks:%u\n",
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vip->vii_size, vip->vii_blocks);
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printk(KERN_DEBUG "orgtype:%u\n", vip->vii_orgtype);
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}
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#endif
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/**
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* vxfs_blkiget - find inode based on extent #
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* @sbp: superblock of the filesystem we search in
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* @extent: number of the extent to search
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* @ino: inode number to search
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*
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* Description:
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* vxfs_blkiget searches inode @ino in the filesystem described by
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* @sbp in the extent @extent.
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* Returns the matching VxFS inode on success, else a NULL pointer.
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*
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* NOTE:
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* While __vxfs_iget uses the pagecache vxfs_blkiget uses the
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* buffercache. This function should not be used outside the
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* read_super() method, otherwise the data may be incoherent.
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*/
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struct vxfs_inode_info *
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vxfs_blkiget(struct super_block *sbp, u_long extent, ino_t ino)
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{
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struct buffer_head *bp;
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u_long block, offset;
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block = extent + ((ino * VXFS_ISIZE) / sbp->s_blocksize);
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offset = ((ino % (sbp->s_blocksize / VXFS_ISIZE)) * VXFS_ISIZE);
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bp = sb_bread(sbp, block);
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if (bp && buffer_mapped(bp)) {
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struct vxfs_inode_info *vip;
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struct vxfs_dinode *dip;
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if (!(vip = kmem_cache_alloc(vxfs_inode_cachep, GFP_KERNEL)))
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goto fail;
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dip = (struct vxfs_dinode *)(bp->b_data + offset);
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memcpy(vip, dip, sizeof(*vip));
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#ifdef DIAGNOSTIC
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vxfs_dumpi(vip, ino);
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#endif
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brelse(bp);
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return (vip);
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}
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fail:
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printk(KERN_WARNING "vxfs: unable to read block %ld\n", block);
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brelse(bp);
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return NULL;
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}
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/**
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* __vxfs_iget - generic find inode facility
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* @sbp: VFS superblock
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* @ino: inode number
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* @ilistp: inode list
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*
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* Description:
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* Search the for inode number @ino in the filesystem
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* described by @sbp. Use the specified inode table (@ilistp).
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* Returns the matching VxFS inode on success, else an error code.
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*/
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static struct vxfs_inode_info *
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__vxfs_iget(ino_t ino, struct inode *ilistp)
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{
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struct page *pp;
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u_long offset;
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offset = (ino % (PAGE_SIZE / VXFS_ISIZE)) * VXFS_ISIZE;
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pp = vxfs_get_page(ilistp->i_mapping, ino * VXFS_ISIZE / PAGE_SIZE);
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if (!IS_ERR(pp)) {
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struct vxfs_inode_info *vip;
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struct vxfs_dinode *dip;
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caddr_t kaddr = (char *)page_address(pp);
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if (!(vip = kmem_cache_alloc(vxfs_inode_cachep, GFP_KERNEL)))
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goto fail;
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dip = (struct vxfs_dinode *)(kaddr + offset);
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memcpy(vip, dip, sizeof(*vip));
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#ifdef DIAGNOSTIC
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vxfs_dumpi(vip, ino);
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#endif
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vxfs_put_page(pp);
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return (vip);
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}
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printk(KERN_WARNING "vxfs: error on page %p\n", pp);
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return ERR_CAST(pp);
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fail:
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printk(KERN_WARNING "vxfs: unable to read inode %ld\n", (unsigned long)ino);
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vxfs_put_page(pp);
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return ERR_PTR(-ENOMEM);
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}
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/**
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* vxfs_stiget - find inode using the structural inode list
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* @sbp: VFS superblock
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* @ino: inode #
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*
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* Description:
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* Find inode @ino in the filesystem described by @sbp using
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* the structural inode list.
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* Returns the matching VxFS inode on success, else a NULL pointer.
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*/
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struct vxfs_inode_info *
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vxfs_stiget(struct super_block *sbp, ino_t ino)
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{
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struct vxfs_inode_info *vip;
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vip = __vxfs_iget(ino, VXFS_SBI(sbp)->vsi_stilist);
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return IS_ERR(vip) ? NULL : vip;
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}
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/**
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* vxfs_transmod - mode for a VxFS inode
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* @vip: VxFS inode
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*
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* Description:
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* vxfs_transmod returns a Linux mode_t for a given
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* VxFS inode structure.
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*/
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static __inline__ mode_t
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vxfs_transmod(struct vxfs_inode_info *vip)
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{
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mode_t ret = vip->vii_mode & ~VXFS_TYPE_MASK;
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if (VXFS_ISFIFO(vip))
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ret |= S_IFIFO;
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if (VXFS_ISCHR(vip))
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ret |= S_IFCHR;
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if (VXFS_ISDIR(vip))
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ret |= S_IFDIR;
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if (VXFS_ISBLK(vip))
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ret |= S_IFBLK;
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if (VXFS_ISLNK(vip))
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ret |= S_IFLNK;
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if (VXFS_ISREG(vip))
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ret |= S_IFREG;
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if (VXFS_ISSOC(vip))
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ret |= S_IFSOCK;
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return (ret);
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}
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/**
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* vxfs_iinit- helper to fill inode fields
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* @ip: VFS inode
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* @vip: VxFS inode
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*
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* Description:
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* vxfs_instino is a helper function to fill in all relevant
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* fields in @ip from @vip.
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*/
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static void
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vxfs_iinit(struct inode *ip, struct vxfs_inode_info *vip)
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{
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ip->i_mode = vxfs_transmod(vip);
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ip->i_uid = (uid_t)vip->vii_uid;
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ip->i_gid = (gid_t)vip->vii_gid;
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ip->i_nlink = vip->vii_nlink;
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ip->i_size = vip->vii_size;
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ip->i_atime.tv_sec = vip->vii_atime;
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ip->i_ctime.tv_sec = vip->vii_ctime;
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ip->i_mtime.tv_sec = vip->vii_mtime;
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ip->i_atime.tv_nsec = 0;
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ip->i_ctime.tv_nsec = 0;
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ip->i_mtime.tv_nsec = 0;
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ip->i_blocks = vip->vii_blocks;
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ip->i_generation = vip->vii_gen;
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ip->i_private = vip;
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}
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/**
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* vxfs_get_fake_inode - get fake inode structure
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* @sbp: filesystem superblock
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* @vip: fspriv inode
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*
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* Description:
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* vxfs_fake_inode gets a fake inode (not in the inode hash) for a
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* superblock, vxfs_inode pair.
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* Returns the filled VFS inode.
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*/
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struct inode *
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vxfs_get_fake_inode(struct super_block *sbp, struct vxfs_inode_info *vip)
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{
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struct inode *ip = NULL;
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if ((ip = new_inode(sbp))) {
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ip->i_ino = get_next_ino();
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vxfs_iinit(ip, vip);
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ip->i_mapping->a_ops = &vxfs_aops;
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}
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return (ip);
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}
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/**
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* vxfs_put_fake_inode - free faked inode
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* *ip: VFS inode
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*
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* Description:
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* vxfs_put_fake_inode frees all data asssociated with @ip.
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*/
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void
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vxfs_put_fake_inode(struct inode *ip)
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{
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iput(ip);
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}
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/**
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* vxfs_iget - get an inode
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* @sbp: the superblock to get the inode for
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* @ino: the number of the inode to get
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*
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* Description:
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* vxfs_read_inode creates an inode, reads the disk inode for @ino and fills
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* in all relevant fields in the new inode.
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*/
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struct inode *
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vxfs_iget(struct super_block *sbp, ino_t ino)
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{
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struct vxfs_inode_info *vip;
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const struct address_space_operations *aops;
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struct inode *ip;
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ip = iget_locked(sbp, ino);
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if (!ip)
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return ERR_PTR(-ENOMEM);
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if (!(ip->i_state & I_NEW))
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return ip;
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vip = __vxfs_iget(ino, VXFS_SBI(sbp)->vsi_ilist);
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if (IS_ERR(vip)) {
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iget_failed(ip);
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return ERR_CAST(vip);
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}
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vxfs_iinit(ip, vip);
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if (VXFS_ISIMMED(vip))
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aops = &vxfs_immed_aops;
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else
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aops = &vxfs_aops;
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if (S_ISREG(ip->i_mode)) {
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ip->i_fop = &generic_ro_fops;
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ip->i_mapping->a_ops = aops;
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} else if (S_ISDIR(ip->i_mode)) {
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ip->i_op = &vxfs_dir_inode_ops;
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ip->i_fop = &vxfs_dir_operations;
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ip->i_mapping->a_ops = aops;
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} else if (S_ISLNK(ip->i_mode)) {
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if (!VXFS_ISIMMED(vip)) {
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ip->i_op = &page_symlink_inode_operations;
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ip->i_mapping->a_ops = &vxfs_aops;
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} else {
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ip->i_op = &vxfs_immed_symlink_iops;
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vip->vii_immed.vi_immed[ip->i_size] = '\0';
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}
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} else
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init_special_inode(ip, ip->i_mode, old_decode_dev(vip->vii_rdev));
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unlock_new_inode(ip);
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return ip;
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}
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static void vxfs_i_callback(struct rcu_head *head)
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{
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struct inode *inode = container_of(head, struct inode, i_rcu);
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INIT_LIST_HEAD(&inode->i_dentry);
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kmem_cache_free(vxfs_inode_cachep, inode->i_private);
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}
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/**
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* vxfs_evict_inode - remove inode from main memory
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* @ip: inode to discard.
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*
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* Description:
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* vxfs_evict_inode() is called on the final iput and frees the private
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* inode area.
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*/
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void
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vxfs_evict_inode(struct inode *ip)
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{
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truncate_inode_pages(&ip->i_data, 0);
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end_writeback(ip);
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call_rcu(&ip->i_rcu, vxfs_i_callback);
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}
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