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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>
405 lines
9.1 KiB
C
405 lines
9.1 KiB
C
/*
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* linux/fs/ext2/namei.c
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*
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* Rewrite to pagecache. Almost all code had been changed, so blame me
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* if the things go wrong. Please, send bug reports to
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* viro@parcelfarce.linux.theplanet.co.uk
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*
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* Stuff here is basically a glue between the VFS and generic UNIXish
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* filesystem that keeps everything in pagecache. All knowledge of the
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* directory layout is in fs/ext2/dir.c - it turned out to be easily separatable
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* and it's easier to debug that way. In principle we might want to
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* generalize that a bit and turn it into a library. Or not.
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*
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* The only non-static object here is ext2_dir_inode_operations.
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*
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* TODO: get rid of kmap() use, add readahead.
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*
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* Copyright (C) 1992, 1993, 1994, 1995
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* Remy Card (card@masi.ibp.fr)
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* Laboratoire MASI - Institut Blaise Pascal
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* Universite Pierre et Marie Curie (Paris VI)
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*
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* from
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*
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* linux/fs/minix/namei.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* Big-endian to little-endian byte-swapping/bitmaps by
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* David S. Miller (davem@caip.rutgers.edu), 1995
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*/
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#include <linux/pagemap.h>
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#include "ext2.h"
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#include "xattr.h"
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#include "acl.h"
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#include "xip.h"
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static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
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{
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int err = ext2_add_link(dentry, inode);
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if (!err) {
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d_instantiate(dentry, inode);
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return 0;
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}
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inode_dec_link_count(inode);
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iput(inode);
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return err;
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}
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/*
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* Methods themselves.
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*/
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static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd)
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{
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struct inode * inode;
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ino_t ino;
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if (dentry->d_name.len > EXT2_NAME_LEN)
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return ERR_PTR(-ENAMETOOLONG);
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ino = ext2_inode_by_name(dir, dentry);
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inode = NULL;
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if (ino) {
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inode = iget(dir->i_sb, ino);
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if (!inode)
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return ERR_PTR(-EACCES);
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}
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return d_splice_alias(inode, dentry);
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}
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struct dentry *ext2_get_parent(struct dentry *child)
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{
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unsigned long ino;
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struct dentry *parent;
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struct inode *inode;
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struct dentry dotdot;
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dotdot.d_name.name = "..";
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dotdot.d_name.len = 2;
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ino = ext2_inode_by_name(child->d_inode, &dotdot);
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if (!ino)
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return ERR_PTR(-ENOENT);
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inode = iget(child->d_inode->i_sb, ino);
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if (!inode)
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return ERR_PTR(-EACCES);
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parent = d_alloc_anon(inode);
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if (!parent) {
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iput(inode);
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parent = ERR_PTR(-ENOMEM);
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}
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return parent;
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}
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/*
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* By the time this is called, we already have created
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* the directory cache entry for the new file, but it
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* is so far negative - it has no inode.
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*
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* If the create succeeds, we fill in the inode information
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* with d_instantiate().
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*/
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static int ext2_create (struct inode * dir, struct dentry * dentry, int mode, struct nameidata *nd)
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{
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struct inode * inode = ext2_new_inode (dir, mode);
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int err = PTR_ERR(inode);
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if (!IS_ERR(inode)) {
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inode->i_op = &ext2_file_inode_operations;
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if (ext2_use_xip(inode->i_sb)) {
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inode->i_mapping->a_ops = &ext2_aops_xip;
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inode->i_fop = &ext2_xip_file_operations;
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} else if (test_opt(inode->i_sb, NOBH)) {
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inode->i_mapping->a_ops = &ext2_nobh_aops;
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inode->i_fop = &ext2_file_operations;
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} else {
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inode->i_mapping->a_ops = &ext2_aops;
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inode->i_fop = &ext2_file_operations;
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}
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mark_inode_dirty(inode);
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err = ext2_add_nondir(dentry, inode);
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}
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return err;
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}
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static int ext2_mknod (struct inode * dir, struct dentry *dentry, int mode, dev_t rdev)
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{
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struct inode * inode;
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int err;
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if (!new_valid_dev(rdev))
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return -EINVAL;
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inode = ext2_new_inode (dir, mode);
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err = PTR_ERR(inode);
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if (!IS_ERR(inode)) {
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init_special_inode(inode, inode->i_mode, rdev);
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#ifdef CONFIG_EXT2_FS_XATTR
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inode->i_op = &ext2_special_inode_operations;
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#endif
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mark_inode_dirty(inode);
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err = ext2_add_nondir(dentry, inode);
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}
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return err;
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}
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static int ext2_symlink (struct inode * dir, struct dentry * dentry,
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const char * symname)
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{
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struct super_block * sb = dir->i_sb;
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int err = -ENAMETOOLONG;
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unsigned l = strlen(symname)+1;
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struct inode * inode;
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if (l > sb->s_blocksize)
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goto out;
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inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO);
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err = PTR_ERR(inode);
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if (IS_ERR(inode))
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goto out;
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if (l > sizeof (EXT2_I(inode)->i_data)) {
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/* slow symlink */
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inode->i_op = &ext2_symlink_inode_operations;
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if (test_opt(inode->i_sb, NOBH))
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inode->i_mapping->a_ops = &ext2_nobh_aops;
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else
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inode->i_mapping->a_ops = &ext2_aops;
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err = page_symlink(inode, symname, l);
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if (err)
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goto out_fail;
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} else {
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/* fast symlink */
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inode->i_op = &ext2_fast_symlink_inode_operations;
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memcpy((char*)(EXT2_I(inode)->i_data),symname,l);
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inode->i_size = l-1;
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}
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mark_inode_dirty(inode);
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err = ext2_add_nondir(dentry, inode);
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out:
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return err;
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out_fail:
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inode_dec_link_count(inode);
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iput (inode);
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goto out;
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}
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static int ext2_link (struct dentry * old_dentry, struct inode * dir,
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struct dentry *dentry)
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{
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struct inode *inode = old_dentry->d_inode;
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if (inode->i_nlink >= EXT2_LINK_MAX)
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return -EMLINK;
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inode->i_ctime = CURRENT_TIME_SEC;
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inode_inc_link_count(inode);
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atomic_inc(&inode->i_count);
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return ext2_add_nondir(dentry, inode);
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}
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static int ext2_mkdir(struct inode * dir, struct dentry * dentry, int mode)
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{
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struct inode * inode;
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int err = -EMLINK;
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if (dir->i_nlink >= EXT2_LINK_MAX)
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goto out;
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inode_inc_link_count(dir);
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inode = ext2_new_inode (dir, S_IFDIR | mode);
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err = PTR_ERR(inode);
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if (IS_ERR(inode))
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goto out_dir;
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inode->i_op = &ext2_dir_inode_operations;
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inode->i_fop = &ext2_dir_operations;
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if (test_opt(inode->i_sb, NOBH))
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inode->i_mapping->a_ops = &ext2_nobh_aops;
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else
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inode->i_mapping->a_ops = &ext2_aops;
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inode_inc_link_count(inode);
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err = ext2_make_empty(inode, dir);
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if (err)
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goto out_fail;
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err = ext2_add_link(dentry, inode);
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if (err)
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goto out_fail;
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d_instantiate(dentry, inode);
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out:
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return err;
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out_fail:
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inode_dec_link_count(inode);
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inode_dec_link_count(inode);
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iput(inode);
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out_dir:
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inode_dec_link_count(dir);
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goto out;
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}
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static int ext2_unlink(struct inode * dir, struct dentry *dentry)
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{
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struct inode * inode = dentry->d_inode;
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struct ext2_dir_entry_2 * de;
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struct page * page;
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int err = -ENOENT;
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de = ext2_find_entry (dir, dentry, &page);
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if (!de)
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goto out;
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err = ext2_delete_entry (de, page);
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if (err)
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goto out;
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inode->i_ctime = dir->i_ctime;
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inode_dec_link_count(inode);
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err = 0;
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out:
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return err;
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}
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static int ext2_rmdir (struct inode * dir, struct dentry *dentry)
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{
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struct inode * inode = dentry->d_inode;
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int err = -ENOTEMPTY;
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if (ext2_empty_dir(inode)) {
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err = ext2_unlink(dir, dentry);
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if (!err) {
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inode->i_size = 0;
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inode_dec_link_count(inode);
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inode_dec_link_count(dir);
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}
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}
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return err;
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}
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static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
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struct inode * new_dir, struct dentry * new_dentry )
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{
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struct inode * old_inode = old_dentry->d_inode;
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struct inode * new_inode = new_dentry->d_inode;
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struct page * dir_page = NULL;
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struct ext2_dir_entry_2 * dir_de = NULL;
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struct page * old_page;
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struct ext2_dir_entry_2 * old_de;
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int err = -ENOENT;
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old_de = ext2_find_entry (old_dir, old_dentry, &old_page);
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if (!old_de)
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goto out;
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if (S_ISDIR(old_inode->i_mode)) {
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err = -EIO;
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dir_de = ext2_dotdot(old_inode, &dir_page);
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if (!dir_de)
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goto out_old;
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}
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if (new_inode) {
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struct page *new_page;
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struct ext2_dir_entry_2 *new_de;
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err = -ENOTEMPTY;
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if (dir_de && !ext2_empty_dir (new_inode))
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goto out_dir;
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err = -ENOENT;
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new_de = ext2_find_entry (new_dir, new_dentry, &new_page);
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if (!new_de)
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goto out_dir;
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inode_inc_link_count(old_inode);
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ext2_set_link(new_dir, new_de, new_page, old_inode);
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new_inode->i_ctime = CURRENT_TIME_SEC;
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if (dir_de)
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drop_nlink(new_inode);
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inode_dec_link_count(new_inode);
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} else {
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if (dir_de) {
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err = -EMLINK;
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if (new_dir->i_nlink >= EXT2_LINK_MAX)
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goto out_dir;
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}
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inode_inc_link_count(old_inode);
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err = ext2_add_link(new_dentry, old_inode);
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if (err) {
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inode_dec_link_count(old_inode);
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goto out_dir;
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}
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if (dir_de)
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inode_inc_link_count(new_dir);
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}
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/*
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* Like most other Unix systems, set the ctime for inodes on a
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* rename.
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* inode_dec_link_count() will mark the inode dirty.
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*/
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old_inode->i_ctime = CURRENT_TIME_SEC;
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ext2_delete_entry (old_de, old_page);
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inode_dec_link_count(old_inode);
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if (dir_de) {
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ext2_set_link(old_inode, dir_de, dir_page, new_dir);
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inode_dec_link_count(old_dir);
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}
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return 0;
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out_dir:
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if (dir_de) {
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kunmap(dir_page);
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page_cache_release(dir_page);
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}
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out_old:
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kunmap(old_page);
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page_cache_release(old_page);
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out:
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return err;
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}
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const struct inode_operations ext2_dir_inode_operations = {
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.create = ext2_create,
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.lookup = ext2_lookup,
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.link = ext2_link,
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.unlink = ext2_unlink,
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.symlink = ext2_symlink,
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.mkdir = ext2_mkdir,
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.rmdir = ext2_rmdir,
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.mknod = ext2_mknod,
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.rename = ext2_rename,
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#ifdef CONFIG_EXT2_FS_XATTR
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.setxattr = generic_setxattr,
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.getxattr = generic_getxattr,
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.listxattr = ext2_listxattr,
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.removexattr = generic_removexattr,
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#endif
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.setattr = ext2_setattr,
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.permission = ext2_permission,
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};
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const struct inode_operations ext2_special_inode_operations = {
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#ifdef CONFIG_EXT2_FS_XATTR
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.setxattr = generic_setxattr,
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.getxattr = generic_getxattr,
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.listxattr = ext2_listxattr,
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.removexattr = generic_removexattr,
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#endif
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.setattr = ext2_setattr,
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.permission = ext2_permission,
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};
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