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[/] [or1k/] [tags/] [LINUX_2_4_26_OR32/] [linux/] [linux-2.4/] [fs/] [ext3/] [dir.c] - Rev 1279
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/* * linux/fs/ext3/dir.c * * Copyright (C) 1992, 1993, 1994, 1995 * Remy Card (card@masi.ibp.fr) * Laboratoire MASI - Institut Blaise Pascal * Universite Pierre et Marie Curie (Paris VI) * * from * * linux/fs/minix/dir.c * * Copyright (C) 1991, 1992 Linus Torvalds * * ext3 directory handling functions * * Big-endian to little-endian byte-swapping/bitmaps by * David S. Miller (davem@caip.rutgers.edu), 1995 */ #include <linux/fs.h> #include <linux/jbd.h> #include <linux/ext3_fs.h> static unsigned char ext3_filetype_table[] = { DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK }; static int ext3_readdir(struct file *, void *, filldir_t); struct file_operations ext3_dir_operations = { read: generic_read_dir, readdir: ext3_readdir, /* BKL held */ ioctl: ext3_ioctl, /* BKL held */ fsync: ext3_sync_file, /* BKL held */ }; int ext3_check_dir_entry (const char * function, struct inode * dir, struct ext3_dir_entry_2 * de, struct buffer_head * bh, unsigned long offset) { const char * error_msg = NULL; const int rlen = le16_to_cpu(de->rec_len); if (rlen < EXT3_DIR_REC_LEN(1)) error_msg = "rec_len is smaller than minimal"; else if (rlen % 4 != 0) error_msg = "rec_len % 4 != 0"; else if (rlen < EXT3_DIR_REC_LEN(de->name_len)) error_msg = "rec_len is too small for name_len"; else if (((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize) error_msg = "directory entry across blocks"; else if (le32_to_cpu(de->inode) > le32_to_cpu(dir->i_sb->u.ext3_sb.s_es->s_inodes_count)) error_msg = "inode out of bounds"; if (error_msg != NULL) ext3_error (dir->i_sb, function, "bad entry in directory #%lu: %s - " "offset=%lu, inode=%lu, rec_len=%d, name_len=%d", dir->i_ino, error_msg, offset, (unsigned long) le32_to_cpu(de->inode), rlen, de->name_len); return error_msg == NULL ? 1 : 0; } static int ext3_readdir(struct file * filp, void * dirent, filldir_t filldir) { int error = 0; unsigned long offset, blk; int i, num, stored; struct buffer_head * bh, * tmp, * bha[16]; struct ext3_dir_entry_2 * de; struct super_block * sb; int err; struct inode *inode = filp->f_dentry->d_inode; sb = inode->i_sb; stored = 0; bh = NULL; offset = filp->f_pos & (sb->s_blocksize - 1); while (!error && !stored && filp->f_pos < inode->i_size) { blk = (filp->f_pos) >> EXT3_BLOCK_SIZE_BITS(sb); bh = ext3_bread (0, inode, blk, 0, &err); if (!bh) { ext3_error (sb, "ext3_readdir", "directory #%lu contains a hole at offset %lu", inode->i_ino, (unsigned long)filp->f_pos); filp->f_pos += sb->s_blocksize - offset; continue; } /* * Do the readahead */ if (!offset) { for (i = 16 >> (EXT3_BLOCK_SIZE_BITS(sb) - 9), num = 0; i > 0; i--) { tmp = ext3_getblk (NULL, inode, ++blk, 0, &err); if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp)) bha[num++] = tmp; else brelse (tmp); } if (num) { ll_rw_block (READA, num, bha); for (i = 0; i < num; i++) brelse (bha[i]); } } 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 ext3_dir_entry_2 *) (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. */ if (le16_to_cpu(de->rec_len) < EXT3_DIR_REC_LEN(1)) break; i += le16_to_cpu(de->rec_len); } 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 ext3_dir_entry_2 *) (bh->b_data + offset); if (!ext3_check_dir_entry ("ext3_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); return stored; } offset += le16_to_cpu(de->rec_len); if (le32_to_cpu(de->inode)) { /* 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; if (EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_FILETYPE) && de->file_type < EXT3_FT_MAX) d_type = ext3_filetype_table[de->file_type]; error = filldir(dirent, de->name, de->name_len, filp->f_pos, le32_to_cpu(de->inode), d_type); if (error) break; if (version != filp->f_version) goto revalidate; stored ++; } filp->f_pos += le16_to_cpu(de->rec_len); } offset = 0; brelse (bh); } UPDATE_ATIME(inode); return 0; }
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