linux/fs/ufs/dir.c
Arjan van de Ven 4b6f5d20b0 [PATCH] Make most file operations structs in fs/ const
This is a conversion to make the various file_operations structs in fs/
const.  Basically a regexp job, with a few manual fixups

The goal is both to increase correctness (harder to accidentally write to
shared datastructures) and reducing the false sharing of cachelines with
things that get dirty in .data (while .rodata is nicely read only and thus
cache clean)

Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28 09:16:06 -08:00

627 lines
17 KiB
C

/*
* linux/fs/ufs/ufs_dir.c
*
* Copyright (C) 1996
* Adrian Rodriguez (adrian@franklins-tower.rutgers.edu)
* Laboratory for Computer Science Research Computing Facility
* Rutgers, The State University of New Jersey
*
* swab support by Francois-Rene Rideau <fare@tunes.org> 19970406
*
* 4.4BSD (FreeBSD) support added on February 1st 1998 by
* Niels Kristian Bech Jensen <nkbj@image.dk> partially based
* on code by Martin von Loewis <martin@mira.isdn.cs.tu-berlin.de>.
*/
#include <linux/time.h>
#include <linux/fs.h>
#include <linux/ufs_fs.h>
#include <linux/smp_lock.h>
#include <linux/buffer_head.h>
#include <linux/sched.h>
#include "swab.h"
#include "util.h"
#undef UFS_DIR_DEBUG
#ifdef UFS_DIR_DEBUG
#define UFSD(x) printk("(%s, %d), %s: ", __FILE__, __LINE__, __FUNCTION__); printk x;
#else
#define UFSD(x)
#endif
static int
ufs_check_dir_entry (const char *, struct inode *, struct ufs_dir_entry *,
struct buffer_head *, unsigned long);
/*
* NOTE! unlike strncmp, ufs_match returns 1 for success, 0 for failure.
*
* len <= UFS_MAXNAMLEN and de != NULL are guaranteed by caller.
*/
static inline int ufs_match(struct super_block *sb, int len,
const char * const name, struct ufs_dir_entry * de)
{
if (len != ufs_get_de_namlen(sb, de))
return 0;
if (!de->d_ino)
return 0;
return !memcmp(name, de->d_name, len);
}
/*
* This is blatantly stolen from ext2fs
*/
static int
ufs_readdir (struct file * filp, void * dirent, filldir_t filldir)
{
struct inode *inode = filp->f_dentry->d_inode;
int error = 0;
unsigned long offset, lblk;
int i, stored;
struct buffer_head * bh;
struct ufs_dir_entry * de;
struct super_block * sb;
int de_reclen;
unsigned flags;
u64 blk= 0L;
lock_kernel();
sb = inode->i_sb;
flags = UFS_SB(sb)->s_flags;
UFSD(("ENTER, ino %lu f_pos %lu\n", inode->i_ino, (unsigned long) filp->f_pos))
stored = 0;
bh = NULL;
offset = filp->f_pos & (sb->s_blocksize - 1);
while (!error && !stored && filp->f_pos < inode->i_size) {
lblk = (filp->f_pos) >> sb->s_blocksize_bits;
blk = ufs_frag_map(inode, lblk);
if (!blk || !(bh = sb_bread(sb, blk))) {
/* XXX - error - skip to the next block */
printk("ufs_readdir: "
"dir inode %lu has a hole at offset %lu\n",
inode->i_ino, (unsigned long int)filp->f_pos);
filp->f_pos += sb->s_blocksize - offset;
continue;
}
revalidate:
/* If the dir block has changed since the last call to
* readdir(2), then we might be pointing to an invalid
* dirent right now. Scan from the start of the block
* to make sure. */
if (filp->f_version != inode->i_version) {
for (i = 0; i < sb->s_blocksize && i < offset; ) {
de = (struct ufs_dir_entry *)(bh->b_data + i);
/* It's too expensive to do a full
* dirent test each time round this
* loop, but we do have to test at
* least that it is non-zero. A
* failure will be detected in the
* dirent test below. */
de_reclen = fs16_to_cpu(sb, de->d_reclen);
if (de_reclen < 1)
break;
i += de_reclen;
}
offset = i;
filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
| offset;
filp->f_version = inode->i_version;
}
while (!error && filp->f_pos < inode->i_size
&& offset < sb->s_blocksize) {
de = (struct ufs_dir_entry *) (bh->b_data + offset);
/* XXX - put in a real ufs_check_dir_entry() */
if ((de->d_reclen == 0) || (ufs_get_de_namlen(sb, de) == 0)) {
filp->f_pos = (filp->f_pos &
(sb->s_blocksize - 1)) +
sb->s_blocksize;
brelse(bh);
unlock_kernel();
return stored;
}
if (!ufs_check_dir_entry ("ufs_readdir", inode, de,
bh, offset)) {
/* On error, skip the f_pos to the
next block. */
filp->f_pos = (filp->f_pos |
(sb->s_blocksize - 1)) +
1;
brelse (bh);
unlock_kernel();
return stored;
}
offset += fs16_to_cpu(sb, de->d_reclen);
if (de->d_ino) {
/* We might block in the next section
* if the data destination is
* currently swapped out. So, use a
* version stamp to detect whether or
* not the directory has been modified
* during the copy operation. */
unsigned long version = filp->f_version;
unsigned char d_type = DT_UNKNOWN;
UFSD(("filldir(%s,%u)\n", de->d_name,
fs32_to_cpu(sb, de->d_ino)))
UFSD(("namlen %u\n", ufs_get_de_namlen(sb, de)))
if ((flags & UFS_DE_MASK) == UFS_DE_44BSD)
d_type = de->d_u.d_44.d_type;
error = filldir(dirent, de->d_name,
ufs_get_de_namlen(sb, de), filp->f_pos,
fs32_to_cpu(sb, de->d_ino), d_type);
if (error)
break;
if (version != filp->f_version)
goto revalidate;
stored ++;
}
filp->f_pos += fs16_to_cpu(sb, de->d_reclen);
}
offset = 0;
brelse (bh);
}
unlock_kernel();
return 0;
}
/*
* define how far ahead to read directories while searching them.
*/
#define NAMEI_RA_CHUNKS 2
#define NAMEI_RA_BLOCKS 4
#define NAMEI_RA_SIZE (NAMEI_RA_CHUNKS * NAMEI_RA_BLOCKS)
#define NAMEI_RA_INDEX(c,b) (((c) * NAMEI_RA_BLOCKS) + (b))
/*
* ufs_find_entry()
*
* finds an entry in the specified directory with the wanted name. It
* returns the cache buffer in which the entry was found, and the entry
* itself (as a parameter - res_bh). It does NOT read the inode of the
* entry - you'll have to do that yourself if you want to.
*/
struct ufs_dir_entry * ufs_find_entry (struct dentry *dentry,
struct buffer_head ** res_bh)
{
struct super_block * sb;
struct buffer_head * bh_use[NAMEI_RA_SIZE];
struct buffer_head * bh_read[NAMEI_RA_SIZE];
unsigned long offset;
int block, toread, i, err;
struct inode *dir = dentry->d_parent->d_inode;
const char *name = dentry->d_name.name;
int namelen = dentry->d_name.len;
UFSD(("ENTER, dir_ino %lu, name %s, namlen %u\n", dir->i_ino, name, namelen))
*res_bh = NULL;
sb = dir->i_sb;
if (namelen > UFS_MAXNAMLEN)
return NULL;
memset (bh_use, 0, sizeof (bh_use));
toread = 0;
for (block = 0; block < NAMEI_RA_SIZE; ++block) {
struct buffer_head * bh;
if ((block << sb->s_blocksize_bits) >= dir->i_size)
break;
bh = ufs_getfrag (dir, block, 0, &err);
bh_use[block] = bh;
if (bh && !buffer_uptodate(bh))
bh_read[toread++] = bh;
}
for (block = 0, offset = 0; offset < dir->i_size; block++) {
struct buffer_head * bh;
struct ufs_dir_entry * de;
char * dlimit;
if ((block % NAMEI_RA_BLOCKS) == 0 && toread) {
ll_rw_block (READ, toread, bh_read);
toread = 0;
}
bh = bh_use[block % NAMEI_RA_SIZE];
if (!bh) {
ufs_error (sb, "ufs_find_entry",
"directory #%lu contains a hole at offset %lu",
dir->i_ino, offset);
offset += sb->s_blocksize;
continue;
}
wait_on_buffer (bh);
if (!buffer_uptodate(bh)) {
/*
* read error: all bets are off
*/
break;
}
de = (struct ufs_dir_entry *) bh->b_data;
dlimit = bh->b_data + sb->s_blocksize;
while ((char *) de < dlimit && offset < dir->i_size) {
/* this code is executed quadratically often */
/* do minimal checking by hand */
int de_len;
if ((char *) de + namelen <= dlimit &&
ufs_match(sb, namelen, name, de)) {
/* found a match -
just to be sure, do a full check */
if (!ufs_check_dir_entry("ufs_find_entry",
dir, de, bh, offset))
goto failed;
for (i = 0; i < NAMEI_RA_SIZE; ++i) {
if (bh_use[i] != bh)
brelse (bh_use[i]);
}
*res_bh = bh;
return de;
}
/* prevent looping on a bad block */
de_len = fs16_to_cpu(sb, de->d_reclen);
if (de_len <= 0)
goto failed;
offset += de_len;
de = (struct ufs_dir_entry *) ((char *) de + de_len);
}
brelse (bh);
if (((block + NAMEI_RA_SIZE) << sb->s_blocksize_bits ) >=
dir->i_size)
bh = NULL;
else
bh = ufs_getfrag (dir, block + NAMEI_RA_SIZE, 0, &err);
bh_use[block % NAMEI_RA_SIZE] = bh;
if (bh && !buffer_uptodate(bh))
bh_read[toread++] = bh;
}
failed:
for (i = 0; i < NAMEI_RA_SIZE; ++i) brelse (bh_use[i]);
UFSD(("EXIT\n"))
return NULL;
}
static int
ufs_check_dir_entry (const char *function, struct inode *dir,
struct ufs_dir_entry *de, struct buffer_head *bh,
unsigned long offset)
{
struct super_block *sb = dir->i_sb;
const char *error_msg = NULL;
int rlen = fs16_to_cpu(sb, de->d_reclen);
if (rlen < UFS_DIR_REC_LEN(1))
error_msg = "reclen is smaller than minimal";
else if (rlen % 4 != 0)
error_msg = "reclen % 4 != 0";
else if (rlen < UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de)))
error_msg = "reclen is too small for namlen";
else if (((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize)
error_msg = "directory entry across blocks";
else if (fs32_to_cpu(sb, de->d_ino) > (UFS_SB(sb)->s_uspi->s_ipg *
UFS_SB(sb)->s_uspi->s_ncg))
error_msg = "inode out of bounds";
if (error_msg != NULL)
ufs_error (sb, function, "bad entry in directory #%lu, size %Lu: %s - "
"offset=%lu, inode=%lu, reclen=%d, namlen=%d",
dir->i_ino, dir->i_size, error_msg, offset,
(unsigned long)fs32_to_cpu(sb, de->d_ino),
rlen, ufs_get_de_namlen(sb, de));
return (error_msg == NULL ? 1 : 0);
}
struct ufs_dir_entry *ufs_dotdot(struct inode *dir, struct buffer_head **p)
{
int err;
struct buffer_head *bh = ufs_bread (dir, 0, 0, &err);
struct ufs_dir_entry *res = NULL;
if (bh) {
res = (struct ufs_dir_entry *) bh->b_data;
res = (struct ufs_dir_entry *)((char *)res +
fs16_to_cpu(dir->i_sb, res->d_reclen));
}
*p = bh;
return res;
}
ino_t ufs_inode_by_name(struct inode * dir, struct dentry *dentry)
{
ino_t res = 0;
struct ufs_dir_entry * de;
struct buffer_head *bh;
de = ufs_find_entry (dentry, &bh);
if (de) {
res = fs32_to_cpu(dir->i_sb, de->d_ino);
brelse(bh);
}
return res;
}
void ufs_set_link(struct inode *dir, struct ufs_dir_entry *de,
struct buffer_head *bh, struct inode *inode)
{
dir->i_version++;
de->d_ino = cpu_to_fs32(dir->i_sb, inode->i_ino);
mark_buffer_dirty(bh);
if (IS_DIRSYNC(dir))
sync_dirty_buffer(bh);
brelse (bh);
}
/*
* ufs_add_entry()
*
* adds a file entry to the specified directory, using the same
* semantics as ufs_find_entry(). It returns NULL if it failed.
*/
int ufs_add_link(struct dentry *dentry, struct inode *inode)
{
struct super_block * sb;
struct ufs_sb_private_info * uspi;
unsigned long offset;
unsigned fragoff;
unsigned short rec_len;
struct buffer_head * bh;
struct ufs_dir_entry * de, * de1;
struct inode *dir = dentry->d_parent->d_inode;
const char *name = dentry->d_name.name;
int namelen = dentry->d_name.len;
int err;
UFSD(("ENTER, name %s, namelen %u\n", name, namelen))
sb = dir->i_sb;
uspi = UFS_SB(sb)->s_uspi;
if (!namelen)
return -EINVAL;
bh = ufs_bread (dir, 0, 0, &err);
if (!bh)
return err;
rec_len = UFS_DIR_REC_LEN(namelen);
offset = 0;
de = (struct ufs_dir_entry *) bh->b_data;
while (1) {
if ((char *)de >= UFS_SECTOR_SIZE + bh->b_data) {
fragoff = offset & ~uspi->s_fmask;
if (fragoff != 0 && fragoff != UFS_SECTOR_SIZE)
ufs_error (sb, "ufs_add_entry", "internal error"
" fragoff %u", fragoff);
if (!fragoff) {
brelse (bh);
bh = ufs_bread (dir, offset >> sb->s_blocksize_bits, 1, &err);
if (!bh)
return err;
}
if (dir->i_size <= offset) {
if (dir->i_size == 0) {
brelse(bh);
return -ENOENT;
}
de = (struct ufs_dir_entry *) (bh->b_data + fragoff);
de->d_ino = 0;
de->d_reclen = cpu_to_fs16(sb, UFS_SECTOR_SIZE);
ufs_set_de_namlen(sb, de, 0);
dir->i_size = offset + UFS_SECTOR_SIZE;
mark_inode_dirty(dir);
} else {
de = (struct ufs_dir_entry *) bh->b_data;
}
}
if (!ufs_check_dir_entry ("ufs_add_entry", dir, de, bh, offset)) {
brelse (bh);
return -ENOENT;
}
if (ufs_match(sb, namelen, name, de)) {
brelse (bh);
return -EEXIST;
}
if (de->d_ino == 0 && fs16_to_cpu(sb, de->d_reclen) >= rec_len)
break;
if (fs16_to_cpu(sb, de->d_reclen) >=
UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de)) + rec_len)
break;
offset += fs16_to_cpu(sb, de->d_reclen);
de = (struct ufs_dir_entry *) ((char *) de + fs16_to_cpu(sb, de->d_reclen));
}
if (de->d_ino) {
de1 = (struct ufs_dir_entry *) ((char *) de +
UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de)));
de1->d_reclen =
cpu_to_fs16(sb, fs16_to_cpu(sb, de->d_reclen) -
UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de)));
de->d_reclen =
cpu_to_fs16(sb, UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de)));
de = de1;
}
de->d_ino = 0;
ufs_set_de_namlen(sb, de, namelen);
memcpy (de->d_name, name, namelen + 1);
de->d_ino = cpu_to_fs32(sb, inode->i_ino);
ufs_set_de_type(sb, de, inode->i_mode);
mark_buffer_dirty(bh);
if (IS_DIRSYNC(dir))
sync_dirty_buffer(bh);
brelse (bh);
dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
dir->i_version++;
mark_inode_dirty(dir);
UFSD(("EXIT\n"))
return 0;
}
/*
* ufs_delete_entry deletes a directory entry by merging it with the
* previous entry.
*/
int ufs_delete_entry (struct inode * inode, struct ufs_dir_entry * dir,
struct buffer_head * bh )
{
struct super_block * sb;
struct ufs_dir_entry * de, * pde;
unsigned i;
UFSD(("ENTER\n"))
sb = inode->i_sb;
i = 0;
pde = NULL;
de = (struct ufs_dir_entry *) bh->b_data;
UFSD(("ino %u, reclen %u, namlen %u, name %s\n",
fs32_to_cpu(sb, de->d_ino),
fs16_to_cpu(sb, de->d_reclen),
ufs_get_de_namlen(sb, de), de->d_name))
while (i < bh->b_size) {
if (!ufs_check_dir_entry ("ufs_delete_entry", inode, de, bh, i)) {
brelse(bh);
return -EIO;
}
if (de == dir) {
if (pde)
fs16_add(sb, &pde->d_reclen,
fs16_to_cpu(sb, dir->d_reclen));
dir->d_ino = 0;
inode->i_version++;
inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
mark_inode_dirty(inode);
mark_buffer_dirty(bh);
if (IS_DIRSYNC(inode))
sync_dirty_buffer(bh);
brelse(bh);
UFSD(("EXIT\n"))
return 0;
}
i += fs16_to_cpu(sb, de->d_reclen);
if (i == UFS_SECTOR_SIZE) pde = NULL;
else pde = de;
de = (struct ufs_dir_entry *)
((char *) de + fs16_to_cpu(sb, de->d_reclen));
if (i == UFS_SECTOR_SIZE && de->d_reclen == 0)
break;
}
UFSD(("EXIT\n"))
brelse(bh);
return -ENOENT;
}
int ufs_make_empty(struct inode * inode, struct inode *dir)
{
struct super_block * sb = dir->i_sb;
struct buffer_head * dir_block;
struct ufs_dir_entry * de;
int err;
dir_block = ufs_bread (inode, 0, 1, &err);
if (!dir_block)
return err;
inode->i_blocks = sb->s_blocksize / UFS_SECTOR_SIZE;
de = (struct ufs_dir_entry *) dir_block->b_data;
de->d_ino = cpu_to_fs32(sb, inode->i_ino);
ufs_set_de_type(sb, de, inode->i_mode);
ufs_set_de_namlen(sb, de, 1);
de->d_reclen = cpu_to_fs16(sb, UFS_DIR_REC_LEN(1));
strcpy (de->d_name, ".");
de = (struct ufs_dir_entry *)
((char *)de + fs16_to_cpu(sb, de->d_reclen));
de->d_ino = cpu_to_fs32(sb, dir->i_ino);
ufs_set_de_type(sb, de, dir->i_mode);
de->d_reclen = cpu_to_fs16(sb, UFS_SECTOR_SIZE - UFS_DIR_REC_LEN(1));
ufs_set_de_namlen(sb, de, 2);
strcpy (de->d_name, "..");
mark_buffer_dirty(dir_block);
brelse (dir_block);
mark_inode_dirty(inode);
return 0;
}
/*
* routine to check that the specified directory is empty (for rmdir)
*/
int ufs_empty_dir (struct inode * inode)
{
struct super_block * sb;
unsigned long offset;
struct buffer_head * bh;
struct ufs_dir_entry * de, * de1;
int err;
sb = inode->i_sb;
if (inode->i_size < UFS_DIR_REC_LEN(1) + UFS_DIR_REC_LEN(2) ||
!(bh = ufs_bread (inode, 0, 0, &err))) {
ufs_warning (inode->i_sb, "empty_dir",
"bad directory (dir #%lu) - no data block",
inode->i_ino);
return 1;
}
de = (struct ufs_dir_entry *) bh->b_data;
de1 = (struct ufs_dir_entry *)
((char *)de + fs16_to_cpu(sb, de->d_reclen));
if (fs32_to_cpu(sb, de->d_ino) != inode->i_ino || de1->d_ino == 0 ||
strcmp (".", de->d_name) || strcmp ("..", de1->d_name)) {
ufs_warning (inode->i_sb, "empty_dir",
"bad directory (dir #%lu) - no `.' or `..'",
inode->i_ino);
return 1;
}
offset = fs16_to_cpu(sb, de->d_reclen) + fs16_to_cpu(sb, de1->d_reclen);
de = (struct ufs_dir_entry *)
((char *)de1 + fs16_to_cpu(sb, de1->d_reclen));
while (offset < inode->i_size ) {
if (!bh || (void *) de >= (void *) (bh->b_data + sb->s_blocksize)) {
brelse (bh);
bh = ufs_bread (inode, offset >> sb->s_blocksize_bits, 1, &err);
if (!bh) {
ufs_error (sb, "empty_dir",
"directory #%lu contains a hole at offset %lu",
inode->i_ino, offset);
offset += sb->s_blocksize;
continue;
}
de = (struct ufs_dir_entry *) bh->b_data;
}
if (!ufs_check_dir_entry ("empty_dir", inode, de, bh, offset)) {
brelse (bh);
return 1;
}
if (de->d_ino) {
brelse (bh);
return 0;
}
offset += fs16_to_cpu(sb, de->d_reclen);
de = (struct ufs_dir_entry *)
((char *)de + fs16_to_cpu(sb, de->d_reclen));
}
brelse (bh);
return 1;
}
const struct file_operations ufs_dir_operations = {
.read = generic_read_dir,
.readdir = ufs_readdir,
.fsync = file_fsync,
};