forked from Minki/linux
02b9984d64
Previously, the no-op "mount -o mount /dev/xxx" operation when the file system is already mounted read-write causes an implied, unconditional syncfs(). This seems pretty stupid, and it's certainly documented or guaraunteed to do this, nor is it particularly useful, except in the case where the file system was mounted rw and is getting remounted read-only. However, it's possible that there might be some file systems that are actually depending on this behavior. In most file systems, it's probably fine to only call sync_filesystem() when transitioning from read-write to read-only, and there are some file systems where this is not needed at all (for example, for a pseudo-filesystem or something like romfs). Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: linux-fsdevel@vger.kernel.org Cc: Christoph Hellwig <hch@infradead.org> Cc: Artem Bityutskiy <dedekind1@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Evgeniy Dushistov <dushistov@mail.ru> Cc: Jan Kara <jack@suse.cz> Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: Anders Larsen <al@alarsen.net> Cc: Phillip Lougher <phillip@squashfs.org.uk> Cc: Kees Cook <keescook@chromium.org> Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> Cc: Petr Vandrovec <petr@vandrovec.name> Cc: xfs@oss.sgi.com Cc: linux-btrfs@vger.kernel.org Cc: linux-cifs@vger.kernel.org Cc: samba-technical@lists.samba.org Cc: codalist@coda.cs.cmu.edu Cc: linux-ext4@vger.kernel.org Cc: linux-f2fs-devel@lists.sourceforge.net Cc: fuse-devel@lists.sourceforge.net Cc: cluster-devel@redhat.com Cc: linux-mtd@lists.infradead.org Cc: jfs-discussion@lists.sourceforge.net Cc: linux-nfs@vger.kernel.org Cc: linux-nilfs@vger.kernel.org Cc: linux-ntfs-dev@lists.sourceforge.net Cc: ocfs2-devel@oss.oracle.com Cc: reiserfs-devel@vger.kernel.org
371 lines
9.5 KiB
C
371 lines
9.5 KiB
C
/*
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* linux/fs/sysv/inode.c
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*
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* minix/inode.c
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* xenix/inode.c
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* Copyright (C) 1992 Doug Evans
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*
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* coh/inode.c
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* Copyright (C) 1993 Pascal Haible, Bruno Haible
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*
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* sysv/inode.c
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* Copyright (C) 1993 Paul B. Monday
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*
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* sysv/inode.c
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* Copyright (C) 1993 Bruno Haible
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* Copyright (C) 1997, 1998 Krzysztof G. Baranowski
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*
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* This file contains code for allocating/freeing inodes and for read/writing
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* the superblock.
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*/
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#include <linux/highuid.h>
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#include <linux/slab.h>
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#include <linux/init.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 <linux/namei.h>
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#include <asm/byteorder.h>
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#include "sysv.h"
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static int sysv_sync_fs(struct super_block *sb, int wait)
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{
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struct sysv_sb_info *sbi = SYSV_SB(sb);
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unsigned long time = get_seconds(), old_time;
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mutex_lock(&sbi->s_lock);
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/*
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* If we are going to write out the super block,
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* then attach current time stamp.
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* But if the filesystem was marked clean, keep it clean.
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*/
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old_time = fs32_to_cpu(sbi, *sbi->s_sb_time);
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if (sbi->s_type == FSTYPE_SYSV4) {
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if (*sbi->s_sb_state == cpu_to_fs32(sbi, 0x7c269d38 - old_time))
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*sbi->s_sb_state = cpu_to_fs32(sbi, 0x7c269d38 - time);
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*sbi->s_sb_time = cpu_to_fs32(sbi, time);
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mark_buffer_dirty(sbi->s_bh2);
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}
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mutex_unlock(&sbi->s_lock);
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return 0;
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}
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static int sysv_remount(struct super_block *sb, int *flags, char *data)
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{
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struct sysv_sb_info *sbi = SYSV_SB(sb);
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sync_filesystem(sb);
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if (sbi->s_forced_ro)
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*flags |= MS_RDONLY;
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return 0;
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}
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static void sysv_put_super(struct super_block *sb)
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{
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struct sysv_sb_info *sbi = SYSV_SB(sb);
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if (!(sb->s_flags & MS_RDONLY)) {
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/* XXX ext2 also updates the state here */
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mark_buffer_dirty(sbi->s_bh1);
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if (sbi->s_bh1 != sbi->s_bh2)
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mark_buffer_dirty(sbi->s_bh2);
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}
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brelse(sbi->s_bh1);
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if (sbi->s_bh1 != sbi->s_bh2)
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brelse(sbi->s_bh2);
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kfree(sbi);
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}
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static int sysv_statfs(struct dentry *dentry, struct kstatfs *buf)
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{
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struct super_block *sb = dentry->d_sb;
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struct sysv_sb_info *sbi = SYSV_SB(sb);
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u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
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buf->f_type = sb->s_magic;
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buf->f_bsize = sb->s_blocksize;
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buf->f_blocks = sbi->s_ndatazones;
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buf->f_bavail = buf->f_bfree = sysv_count_free_blocks(sb);
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buf->f_files = sbi->s_ninodes;
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buf->f_ffree = sysv_count_free_inodes(sb);
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buf->f_namelen = SYSV_NAMELEN;
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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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return 0;
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}
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/*
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* NXI <-> N0XI for PDP, XIN <-> XIN0 for le32, NIX <-> 0NIX for be32
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*/
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static inline void read3byte(struct sysv_sb_info *sbi,
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unsigned char * from, unsigned char * to)
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{
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if (sbi->s_bytesex == BYTESEX_PDP) {
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to[0] = from[0];
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to[1] = 0;
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to[2] = from[1];
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to[3] = from[2];
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} else if (sbi->s_bytesex == BYTESEX_LE) {
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to[0] = from[0];
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to[1] = from[1];
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to[2] = from[2];
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to[3] = 0;
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} else {
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to[0] = 0;
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to[1] = from[0];
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to[2] = from[1];
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to[3] = from[2];
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}
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}
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static inline void write3byte(struct sysv_sb_info *sbi,
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unsigned char * from, unsigned char * to)
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{
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if (sbi->s_bytesex == BYTESEX_PDP) {
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to[0] = from[0];
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to[1] = from[2];
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to[2] = from[3];
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} else if (sbi->s_bytesex == BYTESEX_LE) {
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to[0] = from[0];
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to[1] = from[1];
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to[2] = from[2];
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} else {
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to[0] = from[1];
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to[1] = from[2];
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to[2] = from[3];
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}
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}
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static const struct inode_operations sysv_symlink_inode_operations = {
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.readlink = generic_readlink,
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.follow_link = page_follow_link_light,
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.put_link = page_put_link,
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.getattr = sysv_getattr,
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};
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void sysv_set_inode(struct inode *inode, dev_t rdev)
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{
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if (S_ISREG(inode->i_mode)) {
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inode->i_op = &sysv_file_inode_operations;
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inode->i_fop = &sysv_file_operations;
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inode->i_mapping->a_ops = &sysv_aops;
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} else if (S_ISDIR(inode->i_mode)) {
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inode->i_op = &sysv_dir_inode_operations;
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inode->i_fop = &sysv_dir_operations;
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inode->i_mapping->a_ops = &sysv_aops;
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} else if (S_ISLNK(inode->i_mode)) {
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if (inode->i_blocks) {
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inode->i_op = &sysv_symlink_inode_operations;
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inode->i_mapping->a_ops = &sysv_aops;
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} else {
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inode->i_op = &sysv_fast_symlink_inode_operations;
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nd_terminate_link(SYSV_I(inode)->i_data, inode->i_size,
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sizeof(SYSV_I(inode)->i_data) - 1);
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}
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} else
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init_special_inode(inode, inode->i_mode, rdev);
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}
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struct inode *sysv_iget(struct super_block *sb, unsigned int ino)
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{
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struct sysv_sb_info * sbi = SYSV_SB(sb);
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struct buffer_head * bh;
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struct sysv_inode * raw_inode;
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struct sysv_inode_info * si;
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struct inode *inode;
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unsigned int block;
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if (!ino || ino > sbi->s_ninodes) {
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printk("Bad inode number on dev %s: %d is out of range\n",
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sb->s_id, ino);
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return ERR_PTR(-EIO);
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}
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inode = iget_locked(sb, ino);
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if (!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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raw_inode = sysv_raw_inode(sb, ino, &bh);
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if (!raw_inode) {
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printk("Major problem: unable to read inode from dev %s\n",
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inode->i_sb->s_id);
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goto bad_inode;
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}
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/* SystemV FS: kludge permissions if ino==SYSV_ROOT_INO ?? */
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inode->i_mode = fs16_to_cpu(sbi, raw_inode->i_mode);
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i_uid_write(inode, (uid_t)fs16_to_cpu(sbi, raw_inode->i_uid));
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i_gid_write(inode, (gid_t)fs16_to_cpu(sbi, raw_inode->i_gid));
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set_nlink(inode, fs16_to_cpu(sbi, raw_inode->i_nlink));
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inode->i_size = fs32_to_cpu(sbi, raw_inode->i_size);
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inode->i_atime.tv_sec = fs32_to_cpu(sbi, raw_inode->i_atime);
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inode->i_mtime.tv_sec = fs32_to_cpu(sbi, raw_inode->i_mtime);
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inode->i_ctime.tv_sec = fs32_to_cpu(sbi, raw_inode->i_ctime);
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inode->i_ctime.tv_nsec = 0;
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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_blocks = 0;
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si = SYSV_I(inode);
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for (block = 0; block < 10+1+1+1; block++)
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read3byte(sbi, &raw_inode->i_data[3*block],
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(u8 *)&si->i_data[block]);
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brelse(bh);
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si->i_dir_start_lookup = 0;
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if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
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sysv_set_inode(inode,
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old_decode_dev(fs32_to_cpu(sbi, si->i_data[0])));
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else
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sysv_set_inode(inode, 0);
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unlock_new_inode(inode);
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return inode;
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bad_inode:
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iget_failed(inode);
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return ERR_PTR(-EIO);
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}
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static int __sysv_write_inode(struct inode *inode, int wait)
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{
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struct super_block * sb = inode->i_sb;
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struct sysv_sb_info * sbi = SYSV_SB(sb);
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struct buffer_head * bh;
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struct sysv_inode * raw_inode;
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struct sysv_inode_info * si;
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unsigned int ino, block;
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int err = 0;
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ino = inode->i_ino;
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if (!ino || ino > sbi->s_ninodes) {
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printk("Bad inode number on dev %s: %d is out of range\n",
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inode->i_sb->s_id, ino);
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return -EIO;
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}
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raw_inode = sysv_raw_inode(sb, ino, &bh);
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if (!raw_inode) {
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printk("unable to read i-node block\n");
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return -EIO;
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}
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raw_inode->i_mode = cpu_to_fs16(sbi, inode->i_mode);
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raw_inode->i_uid = cpu_to_fs16(sbi, fs_high2lowuid(i_uid_read(inode)));
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raw_inode->i_gid = cpu_to_fs16(sbi, fs_high2lowgid(i_gid_read(inode)));
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raw_inode->i_nlink = cpu_to_fs16(sbi, inode->i_nlink);
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raw_inode->i_size = cpu_to_fs32(sbi, inode->i_size);
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raw_inode->i_atime = cpu_to_fs32(sbi, inode->i_atime.tv_sec);
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raw_inode->i_mtime = cpu_to_fs32(sbi, inode->i_mtime.tv_sec);
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raw_inode->i_ctime = cpu_to_fs32(sbi, inode->i_ctime.tv_sec);
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si = SYSV_I(inode);
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if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
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si->i_data[0] = cpu_to_fs32(sbi, old_encode_dev(inode->i_rdev));
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for (block = 0; block < 10+1+1+1; block++)
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write3byte(sbi, (u8 *)&si->i_data[block],
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&raw_inode->i_data[3*block]);
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mark_buffer_dirty(bh);
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if (wait) {
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sync_dirty_buffer(bh);
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if (buffer_req(bh) && !buffer_uptodate(bh)) {
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printk ("IO error syncing sysv inode [%s:%08x]\n",
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sb->s_id, ino);
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err = -EIO;
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}
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}
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brelse(bh);
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return 0;
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}
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int sysv_write_inode(struct inode *inode, struct writeback_control *wbc)
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{
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return __sysv_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
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}
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int sysv_sync_inode(struct inode *inode)
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{
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return __sysv_write_inode(inode, 1);
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}
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static void sysv_evict_inode(struct inode *inode)
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{
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truncate_inode_pages(&inode->i_data, 0);
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if (!inode->i_nlink) {
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inode->i_size = 0;
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sysv_truncate(inode);
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}
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invalidate_inode_buffers(inode);
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clear_inode(inode);
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if (!inode->i_nlink)
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sysv_free_inode(inode);
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}
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static struct kmem_cache *sysv_inode_cachep;
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static struct inode *sysv_alloc_inode(struct super_block *sb)
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{
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struct sysv_inode_info *si;
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si = kmem_cache_alloc(sysv_inode_cachep, GFP_KERNEL);
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if (!si)
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return NULL;
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return &si->vfs_inode;
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}
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static void sysv_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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kmem_cache_free(sysv_inode_cachep, SYSV_I(inode));
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}
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static void sysv_destroy_inode(struct inode *inode)
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{
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call_rcu(&inode->i_rcu, sysv_i_callback);
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}
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static void init_once(void *p)
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{
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struct sysv_inode_info *si = (struct sysv_inode_info *)p;
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inode_init_once(&si->vfs_inode);
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}
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const struct super_operations sysv_sops = {
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.alloc_inode = sysv_alloc_inode,
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.destroy_inode = sysv_destroy_inode,
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.write_inode = sysv_write_inode,
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.evict_inode = sysv_evict_inode,
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.put_super = sysv_put_super,
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.sync_fs = sysv_sync_fs,
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.remount_fs = sysv_remount,
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.statfs = sysv_statfs,
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};
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int __init sysv_init_icache(void)
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{
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sysv_inode_cachep = kmem_cache_create("sysv_inode_cache",
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sizeof(struct sysv_inode_info), 0,
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SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
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init_once);
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if (!sysv_inode_cachep)
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return -ENOMEM;
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return 0;
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}
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void sysv_destroy_icache(void)
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{
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/*
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* Make sure all delayed rcu free inodes are flushed before we
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* destroy cache.
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*/
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rcu_barrier();
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kmem_cache_destroy(sysv_inode_cachep);
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}
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