1 files changed, 341 insertions, 0 deletions
diff --git a/fs/jffs2/file.c b/fs/jffs2/file.c
new file mode 100644
index 000000000..0479096b9
--- /dev/null
+++ b/fs/jffs2/file.c
@@ -0,0 +1,341 @@
+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * Copyright © 2001-2007 Red Hat, Inc.
+ * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
+ *
+ * Created by David Woodhouse <dwmw2@infradead.org>
+ *
+ * For licensing information, see the file 'LICENCE' in this directory.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/time.h>
+#include <linux/pagemap.h>
+#include <linux/highmem.h>
+#include <linux/crc32.h>
+#include <linux/jffs2.h>
+#include "nodelist.h"
+
+static int jffs2_write_end(struct file *filp, struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned copied,
+			struct page *pg, void *fsdata);
+static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
+			loff_t pos, unsigned len,
+			struct page **pagep, void **fsdata);
+static int jffs2_read_folio(struct file *filp, struct folio *folio);
+
+int jffs2_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
+{
+	struct inode *inode = filp->f_mapping->host;
+	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
+	int ret;
+
+	ret = file_write_and_wait_range(filp, start, end);
+	if (ret)
+		return ret;
+
+	inode_lock(inode);
+	/* Trigger GC to flush any pending writes for this inode */
+	jffs2_flush_wbuf_gc(c, inode->i_ino);
+	inode_unlock(inode);
+
+	return 0;
+}
+
+const struct file_operations jffs2_file_operations =
+{
+	.llseek =	generic_file_llseek,
+	.open =		generic_file_open,
+ 	.read_iter =	generic_file_read_iter,
+ 	.write_iter =	generic_file_write_iter,
+	.unlocked_ioctl=jffs2_ioctl,
+	.mmap =		generic_file_readonly_mmap,
+	.fsync =	jffs2_fsync,
+	.splice_read =	generic_file_splice_read,
+	.splice_write = iter_file_splice_write,
+};
+
+/* jffs2_file_inode_operations */
+
+const struct inode_operations jffs2_file_inode_operations =
+{
+	.get_acl =	jffs2_get_acl,
+	.set_acl =	jffs2_set_acl,
+	.setattr =	jffs2_setattr,
+	.listxattr =	jffs2_listxattr,
+};
+
+const struct address_space_operations jffs2_file_address_operations =
+{
+	.read_folio =	jffs2_read_folio,
+	.write_begin =	jffs2_write_begin,
+	.write_end =	jffs2_write_end,
+};
+
+static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
+{
+	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
+	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
+	unsigned char *pg_buf;
+	int ret;
+
+	jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n",
+		  __func__, inode->i_ino, pg->index << PAGE_SHIFT);
+
+	BUG_ON(!PageLocked(pg));
+
+	pg_buf = kmap(pg);
+	/* FIXME: Can kmap fail? */
+
+	ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_SHIFT,
+				     PAGE_SIZE);
+
+	if (ret) {
+		ClearPageUptodate(pg);
+		SetPageError(pg);
+	} else {
+		SetPageUptodate(pg);
+		ClearPageError(pg);
+	}
+
+	flush_dcache_page(pg);
+	kunmap(pg);
+
+	jffs2_dbg(2, "readpage finished\n");
+	return ret;
+}
+
+int __jffs2_read_folio(struct file *file, struct folio *folio)
+{
+	int ret = jffs2_do_readpage_nolock(folio->mapping->host, &folio->page);
+	folio_unlock(folio);
+	return ret;
+}
+
+static int jffs2_read_folio(struct file *file, struct folio *folio)
+{
+	struct jffs2_inode_info *f = JFFS2_INODE_INFO(folio->mapping->host);
+	int ret;
+
+	mutex_lock(&f->sem);
+	ret = __jffs2_read_folio(file, folio);
+	mutex_unlock(&f->sem);
+	return ret;
+}
+
+static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
+			loff_t pos, unsigned len,
+			struct page **pagep, void **fsdata)
+{
+	struct page *pg;
+	struct inode *inode = mapping->host;
+	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
+	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
+	pgoff_t index = pos >> PAGE_SHIFT;
+	int ret = 0;
+
+	jffs2_dbg(1, "%s()\n", __func__);
+
+	if (pos > inode->i_size) {
+		/* Make new hole frag from old EOF to new position */
+		struct jffs2_raw_inode ri;
+		struct jffs2_full_dnode *fn;
+		uint32_t alloc_len;
+
+		jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new position\n",
+			  (unsigned int)inode->i_size, (uint32_t)pos);
+
+		ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
+					  ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
+		if (ret)
+			goto out_err;
+
+		mutex_lock(&f->sem);
+		memset(&ri, 0, sizeof(ri));
+
+		ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
+		ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
+		ri.totlen = cpu_to_je32(sizeof(ri));
+		ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
+
+		ri.ino = cpu_to_je32(f->inocache->ino);
+		ri.version = cpu_to_je32(++f->highest_version);
+		ri.mode = cpu_to_jemode(inode->i_mode);
+		ri.uid = cpu_to_je16(i_uid_read(inode));
+		ri.gid = cpu_to_je16(i_gid_read(inode));
+		ri.isize = cpu_to_je32((uint32_t)pos);
+		ri.atime = ri.ctime = ri.mtime = cpu_to_je32(JFFS2_NOW());
+		ri.offset = cpu_to_je32(inode->i_size);
+		ri.dsize = cpu_to_je32((uint32_t)pos - inode->i_size);
+		ri.csize = cpu_to_je32(0);
+		ri.compr = JFFS2_COMPR_ZERO;
+		ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
+		ri.data_crc = cpu_to_je32(0);
+
+		fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
+
+		if (IS_ERR(fn)) {
+			ret = PTR_ERR(fn);
+			jffs2_complete_reservation(c);
+			mutex_unlock(&f->sem);
+			goto out_err;
+		}
+		ret = jffs2_add_full_dnode_to_inode(c, f, fn);
+		if (f->metadata) {
+			jffs2_mark_node_obsolete(c, f->metadata->raw);
+			jffs2_free_full_dnode(f->metadata);
+			f->metadata = NULL;
+		}
+		if (ret) {
+			jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n",
+				  ret);
+			jffs2_mark_node_obsolete(c, fn->raw);
+			jffs2_free_full_dnode(fn);
+			jffs2_complete_reservation(c);
+			mutex_unlock(&f->sem);
+			goto out_err;
+		}
+		jffs2_complete_reservation(c);
+		inode->i_size = pos;
+		mutex_unlock(&f->sem);
+	}
+
+	/*
+	 * While getting a page and reading data in, lock c->alloc_sem until
+	 * the page is Uptodate. Otherwise GC task may attempt to read the same
+	 * page in read_cache_page(), which causes a deadlock.
+	 */
+	mutex_lock(&c->alloc_sem);
+	pg = grab_cache_page_write_begin(mapping, index);
+	if (!pg) {
+		ret = -ENOMEM;
+		goto release_sem;
+	}
+	*pagep = pg;
+
+	/*
+	 * Read in the page if it wasn't already present. Cannot optimize away
+	 * the whole page write case until jffs2_write_end can handle the
+	 * case of a short-copy.
+	 */
+	if (!PageUptodate(pg)) {
+		mutex_lock(&f->sem);
+		ret = jffs2_do_readpage_nolock(inode, pg);
+		mutex_unlock(&f->sem);
+		if (ret) {
+			unlock_page(pg);
+			put_page(pg);
+			goto release_sem;
+		}
+	}
+	jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags);
+
+release_sem:
+	mutex_unlock(&c->alloc_sem);
+out_err:
+	return ret;
+}
+
+static int jffs2_write_end(struct file *filp, struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned copied,
+			struct page *pg, void *fsdata)
+{
+	/* Actually commit the write from the page cache page we're looking at.
+	 * For now, we write the full page out each time. It sucks, but it's simple
+	 */
+	struct inode *inode = mapping->host;
+	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
+	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
+	struct jffs2_raw_inode *ri;
+	unsigned start = pos & (PAGE_SIZE - 1);
+	unsigned end = start + copied;
+	unsigned aligned_start = start & ~3;
+	int ret = 0;
+	uint32_t writtenlen = 0;
+
+	jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
+		  __func__, inode->i_ino, pg->index << PAGE_SHIFT,
+		  start, end, pg->flags);
+
+	/* We need to avoid deadlock with page_cache_read() in
+	   jffs2_garbage_collect_pass(). So the page must be
+	   up to date to prevent page_cache_read() from trying
+	   to re-lock it. */
+	BUG_ON(!PageUptodate(pg));
+
+	if (end == PAGE_SIZE) {
+		/* When writing out the end of a page, write out the
+		   _whole_ page. This helps to reduce the number of
+		   nodes in files which have many short writes, like
+		   syslog files. */
+		aligned_start = 0;
+	}
+
+	ri = jffs2_alloc_raw_inode();
+
+	if (!ri) {
+		jffs2_dbg(1, "%s(): Allocation of raw inode failed\n",
+			  __func__);
+		unlock_page(pg);
+		put_page(pg);
+		return -ENOMEM;
+	}
+
+	/* Set the fields that the generic jffs2_write_inode_range() code can't find */
+	ri->ino = cpu_to_je32(inode->i_ino);
+	ri->mode = cpu_to_jemode(inode->i_mode);
+	ri->uid = cpu_to_je16(i_uid_read(inode));
+	ri->gid = cpu_to_je16(i_gid_read(inode));
+	ri->isize = cpu_to_je32((uint32_t)inode->i_size);
+	ri->atime = ri->ctime = ri->mtime = cpu_to_je32(JFFS2_NOW());
+
+	/* In 2.4, it was already kmapped by generic_file_write(). Doesn't
+	   hurt to do it again. The alternative is ifdefs, which are ugly. */
+	kmap(pg);
+
+	ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
+				      (pg->index << PAGE_SHIFT) + aligned_start,
+				      end - aligned_start, &writtenlen);
+
+	kunmap(pg);
+
+	if (ret) {
+		/* There was an error writing. */
+		SetPageError(pg);
+	}
+
+	/* Adjust writtenlen for the padding we did, so we don't confuse our caller */
+	writtenlen -= min(writtenlen, (start - aligned_start));
+
+	if (writtenlen) {
+		if (inode->i_size < pos + writtenlen) {
+			inode->i_size = pos + writtenlen;
+			inode->i_blocks = (inode->i_size + 511) >> 9;
+
+			inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
+		}
+	}
+
+	jffs2_free_raw_inode(ri);
+
+	if (start+writtenlen < end) {
+		/* generic_file_write has written more to the page cache than we've
+		   actually written to the medium. Mark the page !Uptodate so that
+		   it gets reread */
+		jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n",
+			__func__);
+		SetPageError(pg);
+		ClearPageUptodate(pg);
+	}
+
+	jffs2_dbg(1, "%s() returning %d\n",
+		  __func__, writtenlen > 0 ? writtenlen : ret);
+	unlock_page(pg);
+	put_page(pg);
+	return writtenlen > 0 ? writtenlen : ret;
+}