forked from Minki/linux
ca572727db
Do not use the fallback default_llseek() if the readdir operation of the filesystem still uses the big kernel lock. Since llseek() modifies file->f_pos of the directory directly it may need locking to not confuse readdir which usually uses file->f_pos directly as well Since the special characteristics of the BKL (unlocked on schedule) are not necessary in this case, the inode mutex can be used for locking as provided by generic_file_llseek(). This is only possible since all filesystems, except reiserfs, either use a directory as a flat file or with disk address offsets. Reiserfs on the other hand uses a 32bit hash off the filename as the offset so generic_file_llseek() can get used as well since the hash is always smaller than sb->s_maxbytes (= (512 << 32) - blocksize). Signed-off-by: Jan Blunck <jblunck@suse.de> Acked-by: Jan Kara <jack@suse.cz> Acked-by: Anders Larsen <al@alarsen.net> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
90 lines
2.3 KiB
C
90 lines
2.3 KiB
C
/*
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* QNX4 file system, Linux implementation.
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*
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* Version : 0.2.1
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*
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* Using parts of the xiafs filesystem.
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*
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* History :
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*
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* 28-05-1998 by Richard Frowijn : first release.
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* 20-06-1998 by Frank Denis : Linux 2.1.99+ & dcache support.
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*/
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#include <linux/smp_lock.h>
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#include <linux/buffer_head.h>
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#include "qnx4.h"
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static int qnx4_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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unsigned int offset;
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struct buffer_head *bh;
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struct qnx4_inode_entry *de;
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struct qnx4_link_info *le;
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unsigned long blknum;
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int ix, ino;
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int size;
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QNX4DEBUG((KERN_INFO "qnx4_readdir:i_size = %ld\n", (long) inode->i_size));
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QNX4DEBUG((KERN_INFO "filp->f_pos = %ld\n", (long) filp->f_pos));
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lock_kernel();
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while (filp->f_pos < inode->i_size) {
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blknum = qnx4_block_map( inode, filp->f_pos >> QNX4_BLOCK_SIZE_BITS );
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bh = sb_bread(inode->i_sb, blknum);
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if(bh==NULL) {
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printk(KERN_ERR "qnx4_readdir: bread failed (%ld)\n", blknum);
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break;
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}
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ix = (int)(filp->f_pos >> QNX4_DIR_ENTRY_SIZE_BITS) % QNX4_INODES_PER_BLOCK;
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while (ix < QNX4_INODES_PER_BLOCK) {
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offset = ix * QNX4_DIR_ENTRY_SIZE;
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de = (struct qnx4_inode_entry *) (bh->b_data + offset);
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size = strlen(de->di_fname);
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if (size) {
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if ( !( de->di_status & QNX4_FILE_LINK ) && size > QNX4_SHORT_NAME_MAX )
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size = QNX4_SHORT_NAME_MAX;
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else if ( size > QNX4_NAME_MAX )
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size = QNX4_NAME_MAX;
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if ( ( de->di_status & (QNX4_FILE_USED|QNX4_FILE_LINK) ) != 0 ) {
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QNX4DEBUG((KERN_INFO "qnx4_readdir:%.*s\n", size, de->di_fname));
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if ( ( de->di_status & QNX4_FILE_LINK ) == 0 )
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ino = blknum * QNX4_INODES_PER_BLOCK + ix - 1;
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else {
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le = (struct qnx4_link_info*)de;
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ino = ( le32_to_cpu(le->dl_inode_blk) - 1 ) *
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QNX4_INODES_PER_BLOCK +
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le->dl_inode_ndx;
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}
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if (filldir(dirent, de->di_fname, size, filp->f_pos, ino, DT_UNKNOWN) < 0) {
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brelse(bh);
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goto out;
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}
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}
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}
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ix++;
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filp->f_pos += QNX4_DIR_ENTRY_SIZE;
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}
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brelse(bh);
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}
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out:
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unlock_kernel();
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return 0;
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}
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const struct file_operations qnx4_dir_operations =
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{
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.llseek = generic_file_llseek,
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.read = generic_read_dir,
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.readdir = qnx4_readdir,
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.fsync = simple_fsync,
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};
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const struct inode_operations qnx4_dir_inode_operations =
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{
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.lookup = qnx4_lookup,
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};
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