fs/jffs2/xattr.c

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

File Facts

System
Linux kernel
Corpus path
fs/jffs2/xattr.c
Extension
.c
Size
39232 bytes
Lines
1354
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 (ref_flags(raw) == REF_UNCHECKED) {
			rc = 1;
			break;
		}
	}
	spin_unlock(&c->erase_completion_lock);
	return rc;
}

static void unload_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd)
{
	/* must be called under down_write(xattr_sem) */
	D1(dbg_xattr("%s: xid=%u, version=%u\n", __func__, xd->xid, xd->version));
	if (xd->xname) {
		c->xdatum_mem_usage -= (xd->name_len + 1 + xd->value_len);
		kfree(xd->xname);
	}

	list_del_init(&xd->xindex);
	xd->hashkey = 0;
	xd->xname = NULL;
	xd->xvalue = NULL;
}

static void reclaim_xattr_datum(struct jffs2_sb_info *c)
{
	/* must be called under down_write(xattr_sem) */
	struct jffs2_xattr_datum *xd, *_xd;
	uint32_t target, before;
	static int index = 0;
	int count;

	if (c->xdatum_mem_threshold > c->xdatum_mem_usage)
		return;

	before = c->xdatum_mem_usage;
	target = c->xdatum_mem_usage * 4 / 5; /* 20% reduction */
	for (count = 0; count < XATTRINDEX_HASHSIZE; count++) {
		list_for_each_entry_safe(xd, _xd, &c->xattrindex[index], xindex) {
			if (xd->flags & JFFS2_XFLAGS_HOT) {
				xd->flags &= ~JFFS2_XFLAGS_HOT;
			} else if (!(xd->flags & JFFS2_XFLAGS_BIND)) {
				unload_xattr_datum(c, xd);
			}
			if (c->xdatum_mem_usage <= target)
				goto out;
		}
		index = (index+1) % XATTRINDEX_HASHSIZE;
	}
 out:
	JFFS2_NOTICE("xdatum_mem_usage from %u byte to %u byte (%u byte reclaimed)\n",
		     before, c->xdatum_mem_usage, before - c->xdatum_mem_usage);
}

static int do_verify_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd)
{
	/* must be called under down_write(xattr_sem) */
	struct jffs2_eraseblock *jeb;
	struct jffs2_raw_node_ref *raw;
	struct jffs2_raw_xattr rx;
	size_t readlen;
	uint32_t crc, offset, totlen;
	int rc;

	spin_lock(&c->erase_completion_lock);
	offset = ref_offset(xd->node);
	if (ref_flags(xd->node) == REF_PRISTINE)
		goto complete;
	spin_unlock(&c->erase_completion_lock);

	rc = jffs2_flash_read(c, offset, sizeof(rx), &readlen, (char *)&rx);
	if (rc || readlen != sizeof(rx)) {
		JFFS2_WARNING("jffs2_flash_read()=%d, req=%zu, read=%zu at %#08x\n",
			      rc, sizeof(rx), readlen, offset);
		return rc ? rc : -EIO;
	}
	crc = crc32(0, &rx, sizeof(rx) - 4);
	if (crc != je32_to_cpu(rx.node_crc)) {
		JFFS2_ERROR("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
			    offset, je32_to_cpu(rx.hdr_crc), crc);
		xd->flags |= JFFS2_XFLAGS_INVALID;
		return JFFS2_XATTR_IS_CORRUPTED;
	}
	totlen = PAD(sizeof(rx) + rx.name_len + 1 + je16_to_cpu(rx.value_len));
	if (je16_to_cpu(rx.magic) != JFFS2_MAGIC_BITMASK
	    || je16_to_cpu(rx.nodetype) != JFFS2_NODETYPE_XATTR
	    || je32_to_cpu(rx.totlen) != totlen
	    || je32_to_cpu(rx.xid) != xd->xid
	    || je32_to_cpu(rx.version) != xd->version) {
		JFFS2_ERROR("inconsistent xdatum at %#08x, magic=%#04x/%#04x, "

Annotation

Implementation Notes