fs/jffs2/readinode.c

Source file repositories/reference/linux-study-clean/fs/jffs2/readinode.c

File Facts

System
Linux kernel
Corpus path
fs/jffs2/readinode.c
Extension
.c
Size
44273 bytes
Lines
1448
Domain
Core OS
Bucket
VFS And Filesystem Core
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

if (adj >= tn->csize) {
			dbg_readinode("no need to check node at %#08x, data length %u, data starts at %#08x - it has already been checked.\n",
				      ref_offset(ref), tn->csize, ofs);
			goto adj_acc;
		}

		ofs += adj;
		len -= adj;
	}

	dbg_readinode("check node at %#08x, data length %u, partial CRC %#08x, correct CRC %#08x, data starts at %#08x, start checking from %#08x - %u bytes.\n",
		ref_offset(ref), tn->csize, tn->partial_crc, tn->data_crc, ofs - len, ofs, len);

#ifndef __ECOS
	/* TODO: instead, incapsulate point() stuff to jffs2_flash_read(),
	 * adding and jffs2_flash_read_end() interface. */
	err = mtd_point(c->mtd, ofs, len, &retlen, (void **)&buffer, NULL);
	if (!err && retlen < len) {
		JFFS2_WARNING("MTD point returned len too short: %zu instead of %u.\n", retlen, tn->csize);
		mtd_unpoint(c->mtd, ofs, retlen);
	} else if (err) {
		if (err != -EOPNOTSUPP)
			JFFS2_WARNING("MTD point failed: error code %d.\n", err);
	} else
		pointed = 1; /* successfully pointed to device */
#endif

	if (!pointed) {
		buffer = kmalloc(len, GFP_KERNEL);
		if (unlikely(!buffer))
			return -ENOMEM;

		/* TODO: this is very frequent pattern, make it a separate
		 * routine */
		err = jffs2_flash_read(c, ofs, len, &retlen, buffer);
		if (err) {
			JFFS2_ERROR("can not read %d bytes from 0x%08x, error code: %d.\n", len, ofs, err);
			goto free_out;
		}

		if (retlen != len) {
			JFFS2_ERROR("short read at %#08x: %zd instead of %d.\n", ofs, retlen, len);
			err = -EIO;
			goto free_out;
		}
	}

	/* Continue calculating CRC */
	crc = crc32(tn->partial_crc, buffer, len);
	if(!pointed)
		kfree(buffer);
#ifndef __ECOS
	else
		mtd_unpoint(c->mtd, ofs, len);
#endif

	if (crc != tn->data_crc) {
		JFFS2_NOTICE("wrong data CRC in data node at 0x%08x: read %#08x, calculated %#08x.\n",
			     ref_offset(ref), tn->data_crc, crc);
		return 1;
	}

adj_acc:
	jeb = &c->blocks[ref->flash_offset / c->sector_size];
	len = ref_totlen(c, jeb, ref);
	/* If it should be REF_NORMAL, it'll get marked as such when
	   we build the fragtree, shortly. No need to worry about GC
	   moving it while it's marked REF_PRISTINE -- GC won't happen
	   till we've finished checking every inode anyway. */
	ref->flash_offset |= REF_PRISTINE;
	/*
	 * Mark the node as having been checked and fix the
	 * accounting accordingly.
	 */
	spin_lock(&c->erase_completion_lock);
	jeb->used_size += len;
	jeb->unchecked_size -= len;
	c->used_size += len;
	c->unchecked_size -= len;
	jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
	spin_unlock(&c->erase_completion_lock);

	return 0;

free_out:
	if(!pointed)
		kfree(buffer);
#ifndef __ECOS
	else
		mtd_unpoint(c->mtd, ofs, len);

Annotation

Implementation Notes