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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/fs/ufs/dir.c

628 строки
17 KiB
C
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/*
* 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,
};
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