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: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Eugene Teo <eugeneteo@kernel.sg>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c
index a78c6b4..11a49ce 100644 (file)
--- a/fs/ext2/dir.c
+++ b/fs/ext2/dir.c
@@ -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 @@ out:
        /* 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 @@ Espan:
 Einumber:
        error = "inode out of bounds";
 bad_entry:
-       ext2_error (sb, "ext2_check_page", "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);
+       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:
-       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));
+       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 @@ found:
 
 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;