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![Nick Piggin](/assets/img/avatar_default.png)
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>
496 lines
12 KiB
C
496 lines
12 KiB
C
/*
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* fs/bfs/inode.c
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* BFS superblock and inode operations.
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* Copyright (C) 1999-2006 Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
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* From fs/minix, Copyright (C) 1991, 1992 Linus Torvalds.
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*
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* Made endianness-clean by Andrew Stribblehill <ads@wompom.org>, 2005.
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*/
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/buffer_head.h>
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#include <linux/vfs.h>
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#include <linux/writeback.h>
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#include <asm/uaccess.h>
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#include "bfs.h"
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MODULE_AUTHOR("Tigran Aivazian <tigran@aivazian.fsnet.co.uk>");
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MODULE_DESCRIPTION("SCO UnixWare BFS filesystem for Linux");
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MODULE_LICENSE("GPL");
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#undef DEBUG
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#ifdef DEBUG
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#define dprintf(x...) printf(x)
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#else
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#define dprintf(x...)
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#endif
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void dump_imap(const char *prefix, struct super_block *s);
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struct inode *bfs_iget(struct super_block *sb, unsigned long ino)
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{
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struct bfs_inode *di;
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struct inode *inode;
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struct buffer_head *bh;
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int block, off;
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inode = iget_locked(sb, ino);
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if (IS_ERR(inode))
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return ERR_PTR(-ENOMEM);
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if (!(inode->i_state & I_NEW))
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return inode;
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if ((ino < BFS_ROOT_INO) || (ino > BFS_SB(inode->i_sb)->si_lasti)) {
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printf("Bad inode number %s:%08lx\n", inode->i_sb->s_id, ino);
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goto error;
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}
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block = (ino - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
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bh = sb_bread(inode->i_sb, block);
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if (!bh) {
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printf("Unable to read inode %s:%08lx\n", inode->i_sb->s_id,
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ino);
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goto error;
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}
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off = (ino - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
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di = (struct bfs_inode *)bh->b_data + off;
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inode->i_mode = 0x0000FFFF & le32_to_cpu(di->i_mode);
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if (le32_to_cpu(di->i_vtype) == BFS_VDIR) {
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inode->i_mode |= S_IFDIR;
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inode->i_op = &bfs_dir_inops;
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inode->i_fop = &bfs_dir_operations;
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} else if (le32_to_cpu(di->i_vtype) == BFS_VREG) {
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inode->i_mode |= S_IFREG;
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inode->i_op = &bfs_file_inops;
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inode->i_fop = &bfs_file_operations;
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inode->i_mapping->a_ops = &bfs_aops;
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}
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BFS_I(inode)->i_sblock = le32_to_cpu(di->i_sblock);
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BFS_I(inode)->i_eblock = le32_to_cpu(di->i_eblock);
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BFS_I(inode)->i_dsk_ino = le16_to_cpu(di->i_ino);
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inode->i_uid = le32_to_cpu(di->i_uid);
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inode->i_gid = le32_to_cpu(di->i_gid);
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inode->i_nlink = le32_to_cpu(di->i_nlink);
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inode->i_size = BFS_FILESIZE(di);
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inode->i_blocks = BFS_FILEBLOCKS(di);
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inode->i_atime.tv_sec = le32_to_cpu(di->i_atime);
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inode->i_mtime.tv_sec = le32_to_cpu(di->i_mtime);
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inode->i_ctime.tv_sec = le32_to_cpu(di->i_ctime);
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inode->i_atime.tv_nsec = 0;
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inode->i_mtime.tv_nsec = 0;
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inode->i_ctime.tv_nsec = 0;
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brelse(bh);
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unlock_new_inode(inode);
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return inode;
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error:
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iget_failed(inode);
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return ERR_PTR(-EIO);
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}
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static struct bfs_inode *find_inode(struct super_block *sb, u16 ino, struct buffer_head **p)
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{
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if ((ino < BFS_ROOT_INO) || (ino > BFS_SB(sb)->si_lasti)) {
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printf("Bad inode number %s:%08x\n", sb->s_id, ino);
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return ERR_PTR(-EIO);
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}
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ino -= BFS_ROOT_INO;
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*p = sb_bread(sb, 1 + ino / BFS_INODES_PER_BLOCK);
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if (!*p) {
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printf("Unable to read inode %s:%08x\n", sb->s_id, ino);
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return ERR_PTR(-EIO);
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}
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return (struct bfs_inode *)(*p)->b_data + ino % BFS_INODES_PER_BLOCK;
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}
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static int bfs_write_inode(struct inode *inode, struct writeback_control *wbc)
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{
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struct bfs_sb_info *info = BFS_SB(inode->i_sb);
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unsigned int ino = (u16)inode->i_ino;
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unsigned long i_sblock;
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struct bfs_inode *di;
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struct buffer_head *bh;
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int err = 0;
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dprintf("ino=%08x\n", ino);
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di = find_inode(inode->i_sb, ino, &bh);
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if (IS_ERR(di))
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return PTR_ERR(di);
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mutex_lock(&info->bfs_lock);
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if (ino == BFS_ROOT_INO)
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di->i_vtype = cpu_to_le32(BFS_VDIR);
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else
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di->i_vtype = cpu_to_le32(BFS_VREG);
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di->i_ino = cpu_to_le16(ino);
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di->i_mode = cpu_to_le32(inode->i_mode);
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di->i_uid = cpu_to_le32(inode->i_uid);
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di->i_gid = cpu_to_le32(inode->i_gid);
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di->i_nlink = cpu_to_le32(inode->i_nlink);
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di->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
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di->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
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di->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
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i_sblock = BFS_I(inode)->i_sblock;
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di->i_sblock = cpu_to_le32(i_sblock);
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di->i_eblock = cpu_to_le32(BFS_I(inode)->i_eblock);
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di->i_eoffset = cpu_to_le32(i_sblock * BFS_BSIZE + inode->i_size - 1);
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mark_buffer_dirty(bh);
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if (wbc->sync_mode == WB_SYNC_ALL) {
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sync_dirty_buffer(bh);
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if (buffer_req(bh) && !buffer_uptodate(bh))
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err = -EIO;
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}
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brelse(bh);
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mutex_unlock(&info->bfs_lock);
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return err;
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}
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static void bfs_evict_inode(struct inode *inode)
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{
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unsigned long ino = inode->i_ino;
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struct bfs_inode *di;
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struct buffer_head *bh;
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struct super_block *s = inode->i_sb;
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struct bfs_sb_info *info = BFS_SB(s);
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struct bfs_inode_info *bi = BFS_I(inode);
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dprintf("ino=%08lx\n", ino);
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truncate_inode_pages(&inode->i_data, 0);
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invalidate_inode_buffers(inode);
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end_writeback(inode);
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if (inode->i_nlink)
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return;
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di = find_inode(s, inode->i_ino, &bh);
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if (IS_ERR(di))
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return;
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mutex_lock(&info->bfs_lock);
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/* clear on-disk inode */
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memset(di, 0, sizeof(struct bfs_inode));
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mark_buffer_dirty(bh);
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brelse(bh);
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if (bi->i_dsk_ino) {
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if (bi->i_sblock)
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info->si_freeb += bi->i_eblock + 1 - bi->i_sblock;
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info->si_freei++;
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clear_bit(ino, info->si_imap);
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dump_imap("delete_inode", s);
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}
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/*
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* If this was the last file, make the previous block
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* "last block of the last file" even if there is no
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* real file there, saves us 1 gap.
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*/
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if (info->si_lf_eblk == bi->i_eblock)
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info->si_lf_eblk = bi->i_sblock - 1;
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mutex_unlock(&info->bfs_lock);
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}
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static void bfs_put_super(struct super_block *s)
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{
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struct bfs_sb_info *info = BFS_SB(s);
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if (!info)
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return;
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mutex_destroy(&info->bfs_lock);
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kfree(info->si_imap);
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kfree(info);
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s->s_fs_info = NULL;
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}
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static int bfs_statfs(struct dentry *dentry, struct kstatfs *buf)
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{
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struct super_block *s = dentry->d_sb;
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struct bfs_sb_info *info = BFS_SB(s);
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u64 id = huge_encode_dev(s->s_bdev->bd_dev);
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buf->f_type = BFS_MAGIC;
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buf->f_bsize = s->s_blocksize;
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buf->f_blocks = info->si_blocks;
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buf->f_bfree = buf->f_bavail = info->si_freeb;
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buf->f_files = info->si_lasti + 1 - BFS_ROOT_INO;
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buf->f_ffree = info->si_freei;
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buf->f_fsid.val[0] = (u32)id;
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buf->f_fsid.val[1] = (u32)(id >> 32);
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buf->f_namelen = BFS_NAMELEN;
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return 0;
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}
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static struct kmem_cache *bfs_inode_cachep;
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static struct inode *bfs_alloc_inode(struct super_block *sb)
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{
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struct bfs_inode_info *bi;
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bi = kmem_cache_alloc(bfs_inode_cachep, GFP_KERNEL);
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if (!bi)
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return NULL;
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return &bi->vfs_inode;
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}
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static void bfs_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(bfs_inode_cachep, BFS_I(inode));
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}
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static void bfs_destroy_inode(struct inode *inode)
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{
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call_rcu(&inode->i_rcu, bfs_i_callback);
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}
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static void init_once(void *foo)
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{
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struct bfs_inode_info *bi = foo;
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inode_init_once(&bi->vfs_inode);
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}
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static int init_inodecache(void)
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{
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bfs_inode_cachep = kmem_cache_create("bfs_inode_cache",
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sizeof(struct bfs_inode_info),
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0, (SLAB_RECLAIM_ACCOUNT|
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SLAB_MEM_SPREAD),
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init_once);
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if (bfs_inode_cachep == NULL)
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return -ENOMEM;
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return 0;
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}
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static void destroy_inodecache(void)
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{
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kmem_cache_destroy(bfs_inode_cachep);
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}
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static const struct super_operations bfs_sops = {
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.alloc_inode = bfs_alloc_inode,
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.destroy_inode = bfs_destroy_inode,
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.write_inode = bfs_write_inode,
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.evict_inode = bfs_evict_inode,
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.put_super = bfs_put_super,
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.statfs = bfs_statfs,
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};
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void dump_imap(const char *prefix, struct super_block *s)
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{
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#ifdef DEBUG
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int i;
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char *tmpbuf = (char *)get_zeroed_page(GFP_KERNEL);
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if (!tmpbuf)
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return;
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for (i = BFS_SB(s)->si_lasti; i >= 0; i--) {
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if (i > PAGE_SIZE - 100) break;
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if (test_bit(i, BFS_SB(s)->si_imap))
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strcat(tmpbuf, "1");
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else
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strcat(tmpbuf, "0");
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}
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printf("BFS-fs: %s: lasti=%08lx <%s>\n",
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prefix, BFS_SB(s)->si_lasti, tmpbuf);
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free_page((unsigned long)tmpbuf);
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#endif
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}
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static int bfs_fill_super(struct super_block *s, void *data, int silent)
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{
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struct buffer_head *bh, *sbh;
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struct bfs_super_block *bfs_sb;
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struct inode *inode;
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unsigned i, imap_len;
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struct bfs_sb_info *info;
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int ret = -EINVAL;
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unsigned long i_sblock, i_eblock, i_eoff, s_size;
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info = kzalloc(sizeof(*info), GFP_KERNEL);
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if (!info)
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return -ENOMEM;
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mutex_init(&info->bfs_lock);
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s->s_fs_info = info;
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sb_set_blocksize(s, BFS_BSIZE);
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sbh = sb_bread(s, 0);
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if (!sbh)
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goto out;
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bfs_sb = (struct bfs_super_block *)sbh->b_data;
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if (le32_to_cpu(bfs_sb->s_magic) != BFS_MAGIC) {
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if (!silent)
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printf("No BFS filesystem on %s (magic=%08x)\n",
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s->s_id, le32_to_cpu(bfs_sb->s_magic));
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goto out1;
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}
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if (BFS_UNCLEAN(bfs_sb, s) && !silent)
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printf("%s is unclean, continuing\n", s->s_id);
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s->s_magic = BFS_MAGIC;
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if (le32_to_cpu(bfs_sb->s_start) > le32_to_cpu(bfs_sb->s_end)) {
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printf("Superblock is corrupted\n");
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goto out1;
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}
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info->si_lasti = (le32_to_cpu(bfs_sb->s_start) - BFS_BSIZE) /
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sizeof(struct bfs_inode)
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+ BFS_ROOT_INO - 1;
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imap_len = (info->si_lasti / 8) + 1;
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info->si_imap = kzalloc(imap_len, GFP_KERNEL);
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if (!info->si_imap)
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goto out1;
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for (i = 0; i < BFS_ROOT_INO; i++)
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set_bit(i, info->si_imap);
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s->s_op = &bfs_sops;
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inode = bfs_iget(s, BFS_ROOT_INO);
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if (IS_ERR(inode)) {
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ret = PTR_ERR(inode);
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goto out2;
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}
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s->s_root = d_alloc_root(inode);
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if (!s->s_root) {
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iput(inode);
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ret = -ENOMEM;
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goto out2;
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}
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info->si_blocks = (le32_to_cpu(bfs_sb->s_end) + 1) >> BFS_BSIZE_BITS;
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info->si_freeb = (le32_to_cpu(bfs_sb->s_end) + 1
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- le32_to_cpu(bfs_sb->s_start)) >> BFS_BSIZE_BITS;
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info->si_freei = 0;
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info->si_lf_eblk = 0;
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/* can we read the last block? */
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bh = sb_bread(s, info->si_blocks - 1);
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if (!bh) {
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printf("Last block not available: %lu\n", info->si_blocks - 1);
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ret = -EIO;
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goto out3;
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}
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brelse(bh);
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bh = NULL;
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for (i = BFS_ROOT_INO; i <= info->si_lasti; i++) {
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struct bfs_inode *di;
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int block = (i - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
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int off = (i - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
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unsigned long eblock;
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if (!off) {
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brelse(bh);
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bh = sb_bread(s, block);
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}
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if (!bh)
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continue;
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di = (struct bfs_inode *)bh->b_data + off;
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/* test if filesystem is not corrupted */
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i_eoff = le32_to_cpu(di->i_eoffset);
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i_sblock = le32_to_cpu(di->i_sblock);
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i_eblock = le32_to_cpu(di->i_eblock);
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s_size = le32_to_cpu(bfs_sb->s_end);
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if (i_sblock > info->si_blocks ||
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i_eblock > info->si_blocks ||
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i_sblock > i_eblock ||
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i_eoff > s_size ||
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i_sblock * BFS_BSIZE > i_eoff) {
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printf("Inode 0x%08x corrupted\n", i);
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brelse(bh);
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ret = -EIO;
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goto out3;
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}
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if (!di->i_ino) {
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info->si_freei++;
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continue;
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}
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set_bit(i, info->si_imap);
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info->si_freeb -= BFS_FILEBLOCKS(di);
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eblock = le32_to_cpu(di->i_eblock);
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if (eblock > info->si_lf_eblk)
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info->si_lf_eblk = eblock;
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}
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brelse(bh);
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brelse(sbh);
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dump_imap("read_super", s);
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return 0;
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out3:
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dput(s->s_root);
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s->s_root = NULL;
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out2:
|
|
kfree(info->si_imap);
|
|
out1:
|
|
brelse(sbh);
|
|
out:
|
|
mutex_destroy(&info->bfs_lock);
|
|
kfree(info);
|
|
s->s_fs_info = NULL;
|
|
return ret;
|
|
}
|
|
|
|
static struct dentry *bfs_mount(struct file_system_type *fs_type,
|
|
int flags, const char *dev_name, void *data)
|
|
{
|
|
return mount_bdev(fs_type, flags, dev_name, data, bfs_fill_super);
|
|
}
|
|
|
|
static struct file_system_type bfs_fs_type = {
|
|
.owner = THIS_MODULE,
|
|
.name = "bfs",
|
|
.mount = bfs_mount,
|
|
.kill_sb = kill_block_super,
|
|
.fs_flags = FS_REQUIRES_DEV,
|
|
};
|
|
|
|
static int __init init_bfs_fs(void)
|
|
{
|
|
int err = init_inodecache();
|
|
if (err)
|
|
goto out1;
|
|
err = register_filesystem(&bfs_fs_type);
|
|
if (err)
|
|
goto out;
|
|
return 0;
|
|
out:
|
|
destroy_inodecache();
|
|
out1:
|
|
return err;
|
|
}
|
|
|
|
static void __exit exit_bfs_fs(void)
|
|
{
|
|
unregister_filesystem(&bfs_fs_type);
|
|
destroy_inodecache();
|
|
}
|
|
|
|
module_init(init_bfs_fs)
|
|
module_exit(exit_bfs_fs)
|