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Commit bd39597c authored by Eric Sandeen's avatar Eric Sandeen Committed by Linus Torvalds
Browse files

ext2: avoid printk floods in the face of directory corruption 



A very large directory with many read failures (either due to storage
problems, or due to invalid size & blocks from corruption) will generate a
printk storm as the filesystem continues to try to read all the blocks.
This flood of messages can tie up the box until it is complete - which may
be a very long time, especially for very large corrupted values.

This is fixed by only reporting the corruption once each time we try to
read the directory.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: default avatarEric Sandeen <sandeen@redhat.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
Cc: Eugene Teo <eugeneteo@kernel.sg>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d707d31c

fs/ext2/dir.c

+35 −25
Original line number Diff line number Diff line
@@ -103,7 +103,7 @@ static int ext2_commit_chunk(struct page *page, loff_t pos, unsigned len) 
	return err;

}



static void ext2_check_page(struct page *page)

static void ext2_check_page(struct page *page, int quiet)

{

	struct inode *dir = page->mapping->host;

	struct super_block *sb = dir->i_sb;
@@ -146,10 +146,10 @@ static void ext2_check_page(struct page *page) 
	/* Too bad, we had an error */



Ebadsize:

	ext2_error(sb, "ext2_check_page",

		"size of directory #%lu is not a multiple of chunk size",

		dir->i_ino

	);

	if (!quiet)

		ext2_error(sb, __func__,

			"size of directory #%lu is not a multiple "

			"of chunk size", dir->i_ino);

	goto fail;

Eshort:

	error = "rec_len is smaller than minimal";
@@ -166,32 +166,36 @@ static void ext2_check_page(struct page *page) 
Einumber:

	error = "inode out of bounds";

bad_entry:

	ext2_error (sb, "ext2_check_page", "bad entry in directory #%lu: %s - "

	if (!quiet)

		ext2_error(sb, __func__, "bad entry in directory #%lu: : %s - "

			"offset=%lu, inode=%lu, rec_len=%d, name_len=%d",

			dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,

			(unsigned long) le32_to_cpu(p->inode),

			rec_len, p->name_len);

	goto fail;

Eend:

	if (!quiet) {

		p = (ext2_dirent *)(kaddr + offs);

		ext2_error(sb, "ext2_check_page",

			"entry in directory #%lu spans the page boundary"

			"offset=%lu, inode=%lu",

			dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs,

			(unsigned long) le32_to_cpu(p->inode));

	}

fail:

	SetPageChecked(page);

	SetPageError(page);

}



static struct page * ext2_get_page(struct inode *dir, unsigned long n)

static struct page * ext2_get_page(struct inode *dir, unsigned long n,

				   int quiet)

{

	struct address_space *mapping = dir->i_mapping;

	struct page *page = read_mapping_page(mapping, n, NULL);

	if (!IS_ERR(page)) {

		kmap(page);

		if (!PageChecked(page))

			ext2_check_page(page);

			ext2_check_page(page, quiet);

		if (PageError(page))

			goto fail;

	}
@@ -292,7 +296,7 @@ ext2_readdir (struct file * filp, void * dirent, filldir_t filldir) 
	for ( ; n < npages; n++, offset = 0) {

		char *kaddr, *limit;

		ext2_dirent *de;

		struct page *page = ext2_get_page(inode, n);

		struct page *page = ext2_get_page(inode, n, 0);



		if (IS_ERR(page)) {

			ext2_error(sb, __func__,
@@ -361,6 +365,7 @@ struct ext2_dir_entry_2 * ext2_find_entry (struct inode * dir, 
	struct page *page = NULL;

	struct ext2_inode_info *ei = EXT2_I(dir);

	ext2_dirent * de;

	int dir_has_error = 0;



	if (npages == 0)

		goto out;
@@ -374,7 +379,7 @@ struct ext2_dir_entry_2 * ext2_find_entry (struct inode * dir, 
	n = start;

	do {

		char *kaddr;

		page = ext2_get_page(dir, n);

		page = ext2_get_page(dir, n, dir_has_error);

		if (!IS_ERR(page)) {

			kaddr = page_address(page);

			de = (ext2_dirent *) kaddr;
@@ -391,7 +396,9 @@ struct ext2_dir_entry_2 * ext2_find_entry (struct inode * dir, 
				de = ext2_next_entry(de);

			}

			ext2_put_page(page);

		}

		} else

			dir_has_error = 1;



		if (++n >= npages)

			n = 0;

		/* next page is past the blocks we've got */
@@ -414,7 +421,7 @@ struct ext2_dir_entry_2 * ext2_find_entry (struct inode * dir, 


struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p)

{

	struct page *page = ext2_get_page(dir, 0);

	struct page *page = ext2_get_page(dir, 0, 0);

	ext2_dirent *de = NULL;



	if (!IS_ERR(page)) {
@@ -487,7 +494,7 @@ int ext2_add_link (struct dentry *dentry, struct inode *inode) 
	for (n = 0; n <= npages; n++) {

		char *dir_end;



		page = ext2_get_page(dir, n);

		page = ext2_get_page(dir, n, 0);

		err = PTR_ERR(page);

		if (IS_ERR(page))

			goto out;
@@ -655,14 +662,17 @@ int ext2_empty_dir (struct inode * inode) 
{

	struct page *page = NULL;

	unsigned long i, npages = dir_pages(inode);

	int dir_has_error = 0;



	for (i = 0; i < npages; i++) {

		char *kaddr;

		ext2_dirent * de;

		page = ext2_get_page(inode, i);

		page = ext2_get_page(inode, i, dir_has_error);



		if (IS_ERR(page))

		if (IS_ERR(page)) {

			dir_has_error = 1;

			continue;

		}



		kaddr = page_address(page);

		de = (ext2_dirent *)kaddr;