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![Arjan van de Ven](/assets/img/avatar_default.png)
Many struct inode_operations in the kernel can be "const". Marking them const moves these to the .rodata section, which avoids false sharing with potential dirty data. In addition it'll catch accidental writes at compile time to these shared resources. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
155 lines
3.7 KiB
C
155 lines
3.7 KiB
C
/*
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* linux/fs/affs/dir.c
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*
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* (c) 1996 Hans-Joachim Widmaier - Rewritten
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*
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* (C) 1993 Ray Burr - Modified for Amiga FFS filesystem.
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*
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* (C) 1992 Eric Youngdale Modified for ISO 9660 filesystem.
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*
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* (C) 1991 Linus Torvalds - minix filesystem
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*
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* affs directory handling functions
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*
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*/
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#include "affs.h"
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static int affs_readdir(struct file *, void *, filldir_t);
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const struct file_operations affs_dir_operations = {
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.read = generic_read_dir,
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.readdir = affs_readdir,
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.fsync = file_fsync,
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};
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/*
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* directories can handle most operations...
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*/
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const struct inode_operations affs_dir_inode_operations = {
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.create = affs_create,
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.lookup = affs_lookup,
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.link = affs_link,
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.unlink = affs_unlink,
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.symlink = affs_symlink,
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.mkdir = affs_mkdir,
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.rmdir = affs_rmdir,
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.rename = affs_rename,
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.setattr = affs_notify_change,
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};
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static int
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affs_readdir(struct file *filp, void *dirent, filldir_t filldir)
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{
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struct inode *inode = filp->f_path.dentry->d_inode;
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struct super_block *sb = inode->i_sb;
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struct buffer_head *dir_bh;
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struct buffer_head *fh_bh;
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unsigned char *name;
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int namelen;
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u32 i;
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int hash_pos;
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int chain_pos;
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u32 f_pos;
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u32 ino;
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int stored;
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int res;
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pr_debug("AFFS: readdir(ino=%lu,f_pos=%lx)\n",inode->i_ino,(unsigned long)filp->f_pos);
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stored = 0;
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res = -EIO;
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dir_bh = NULL;
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fh_bh = NULL;
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f_pos = filp->f_pos;
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if (f_pos == 0) {
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filp->private_data = (void *)0;
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if (filldir(dirent, ".", 1, f_pos, inode->i_ino, DT_DIR) < 0)
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return 0;
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filp->f_pos = f_pos = 1;
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stored++;
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}
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if (f_pos == 1) {
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if (filldir(dirent, "..", 2, f_pos, parent_ino(filp->f_path.dentry), DT_DIR) < 0)
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return stored;
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filp->f_pos = f_pos = 2;
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stored++;
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}
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affs_lock_dir(inode);
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chain_pos = (f_pos - 2) & 0xffff;
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hash_pos = (f_pos - 2) >> 16;
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if (chain_pos == 0xffff) {
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affs_warning(sb, "readdir", "More than 65535 entries in chain");
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chain_pos = 0;
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hash_pos++;
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filp->f_pos = ((hash_pos << 16) | chain_pos) + 2;
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}
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dir_bh = affs_bread(sb, inode->i_ino);
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if (!dir_bh)
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goto readdir_out;
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/* If the directory hasn't changed since the last call to readdir(),
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* we can jump directly to where we left off.
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*/
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ino = (u32)(long)filp->private_data;
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if (ino && filp->f_version == inode->i_version) {
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pr_debug("AFFS: readdir() left off=%d\n", ino);
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goto inside;
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}
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ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]);
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for (i = 0; ino && i < chain_pos; i++) {
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fh_bh = affs_bread(sb, ino);
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if (!fh_bh) {
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affs_error(sb, "readdir","Cannot read block %d", i);
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goto readdir_out;
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}
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ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain);
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affs_brelse(fh_bh);
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fh_bh = NULL;
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}
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if (ino)
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goto inside;
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hash_pos++;
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for (; hash_pos < AFFS_SB(sb)->s_hashsize; hash_pos++) {
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ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]);
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if (!ino)
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continue;
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f_pos = (hash_pos << 16) + 2;
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inside:
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do {
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fh_bh = affs_bread(sb, ino);
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if (!fh_bh) {
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affs_error(sb, "readdir","Cannot read block %d", ino);
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goto readdir_done;
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}
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namelen = min(AFFS_TAIL(sb, fh_bh)->name[0], (u8)30);
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name = AFFS_TAIL(sb, fh_bh)->name + 1;
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pr_debug("AFFS: readdir(): filldir(\"%.*s\", ino=%u), hash=%d, f_pos=%x\n",
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namelen, name, ino, hash_pos, f_pos);
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if (filldir(dirent, name, namelen, f_pos, ino, DT_UNKNOWN) < 0)
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goto readdir_done;
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stored++;
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f_pos++;
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ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain);
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affs_brelse(fh_bh);
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fh_bh = NULL;
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} while (ino);
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}
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readdir_done:
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filp->f_pos = f_pos;
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filp->f_version = inode->i_version;
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filp->private_data = (void *)(long)ino;
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res = stored;
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readdir_out:
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affs_brelse(dir_bh);
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affs_brelse(fh_bh);
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affs_unlock_dir(inode);
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pr_debug("AFFS: readdir()=%d\n", stored);
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return res;
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}
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