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-rw-r--r--fs/ext4/dir.c19
-rw-r--r--fs/ext4/namei.c45
2 files changed, 46 insertions, 18 deletions
diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index 770a1e6d4672..3a77b7affd09 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -112,7 +112,6 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)
struct inode *inode = file_inode(file);
struct super_block *sb = inode->i_sb;
struct buffer_head *bh = NULL;
- int dir_has_error = 0;
struct fscrypt_str fstr = FSTR_INIT(NULL, 0);
if (IS_ENCRYPTED(inode)) {
@@ -148,8 +147,6 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)
return err;
}
- offset = ctx->pos & (sb->s_blocksize - 1);
-
while (ctx->pos < inode->i_size) {
struct ext4_map_blocks map;
@@ -158,9 +155,18 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)
goto errout;
}
cond_resched();
+ offset = ctx->pos & (sb->s_blocksize - 1);
map.m_lblk = ctx->pos >> EXT4_BLOCK_SIZE_BITS(sb);
map.m_len = 1;
err = ext4_map_blocks(NULL, inode, &map, 0);
+ if (err == 0) {
+ /* m_len should never be zero but let's avoid
+ * an infinite loop if it somehow is */
+ if (map.m_len == 0)
+ map.m_len = 1;
+ ctx->pos += map.m_len * sb->s_blocksize;
+ continue;
+ }
if (err > 0) {
pgoff_t index = map.m_pblk >>
(PAGE_SHIFT - inode->i_blkbits);
@@ -179,13 +185,6 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)
}
if (!bh) {
- if (!dir_has_error) {
- EXT4_ERROR_FILE(file, 0,
- "directory contains a "
- "hole at offset %llu",
- (unsigned long long) ctx->pos);
- dir_has_error = 1;
- }
/* corrupt size? Maybe no more blocks to read */
if (ctx->pos > inode->i_blocks << 9)
break;
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 4909ced4e672..0cda080f3fd5 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -82,8 +82,18 @@ static struct buffer_head *ext4_append(handle_t *handle,
static int ext4_dx_csum_verify(struct inode *inode,
struct ext4_dir_entry *dirent);
+/*
+ * Hints to ext4_read_dirblock regarding whether we expect a directory
+ * block being read to be an index block, or a block containing
+ * directory entries (and if the latter, whether it was found via a
+ * logical block in an htree index block). This is used to control
+ * what sort of sanity checkinig ext4_read_dirblock() will do on the
+ * directory block read from the storage device. EITHER will means
+ * the caller doesn't know what kind of directory block will be read,
+ * so no specific verification will be done.
+ */
typedef enum {
- EITHER, INDEX, DIRENT
+ EITHER, INDEX, DIRENT, DIRENT_HTREE
} dirblock_type_t;
#define ext4_read_dirblock(inode, block, type) \
@@ -109,11 +119,14 @@ static struct buffer_head *__ext4_read_dirblock(struct inode *inode,
return bh;
}
- if (!bh) {
+ if (!bh && (type == INDEX || type == DIRENT_HTREE)) {
ext4_error_inode(inode, func, line, block,
- "Directory hole found");
+ "Directory hole found for htree %s block",
+ (type == INDEX) ? "index" : "leaf");
return ERR_PTR(-EFSCORRUPTED);
}
+ if (!bh)
+ return NULL;
dirent = (struct ext4_dir_entry *) bh->b_data;
/* Determine whether or not we have an index block */
if (is_dx(inode)) {
@@ -980,7 +993,7 @@ static int htree_dirblock_to_tree(struct file *dir_file,
dxtrace(printk(KERN_INFO "In htree dirblock_to_tree: block %lu\n",
(unsigned long)block));
- bh = ext4_read_dirblock(dir, block, DIRENT);
+ bh = ext4_read_dirblock(dir, block, DIRENT_HTREE);
if (IS_ERR(bh))
return PTR_ERR(bh);
@@ -1619,7 +1632,7 @@ static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
return (struct buffer_head *) frame;
do {
block = dx_get_block(frame->at);
- bh = ext4_read_dirblock(dir, block, DIRENT);
+ bh = ext4_read_dirblock(dir, block, DIRENT_HTREE);
if (IS_ERR(bh))
goto errout;
@@ -2203,6 +2216,11 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
blocks = dir->i_size >> sb->s_blocksize_bits;
for (block = 0; block < blocks; block++) {
bh = ext4_read_dirblock(dir, block, DIRENT);
+ if (bh == NULL) {
+ bh = ext4_bread(handle, dir, block,
+ EXT4_GET_BLOCKS_CREATE);
+ goto add_to_new_block;
+ }
if (IS_ERR(bh)) {
retval = PTR_ERR(bh);
bh = NULL;
@@ -2223,6 +2241,7 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
brelse(bh);
}
bh = ext4_append(handle, dir, &block);
+add_to_new_block:
if (IS_ERR(bh)) {
retval = PTR_ERR(bh);
bh = NULL;
@@ -2267,7 +2286,7 @@ again:
return PTR_ERR(frame);
entries = frame->entries;
at = frame->at;
- bh = ext4_read_dirblock(dir, dx_get_block(frame->at), DIRENT);
+ bh = ext4_read_dirblock(dir, dx_get_block(frame->at), DIRENT_HTREE);
if (IS_ERR(bh)) {
err = PTR_ERR(bh);
bh = NULL;
@@ -2815,7 +2834,10 @@ bool ext4_empty_dir(struct inode *inode)
EXT4_ERROR_INODE(inode, "invalid size");
return true;
}
- bh = ext4_read_dirblock(inode, 0, EITHER);
+ /* The first directory block must not be a hole,
+ * so treat it as DIRENT_HTREE
+ */
+ bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE);
if (IS_ERR(bh))
return true;
@@ -2837,6 +2859,10 @@ bool ext4_empty_dir(struct inode *inode)
brelse(bh);
lblock = offset >> EXT4_BLOCK_SIZE_BITS(sb);
bh = ext4_read_dirblock(inode, lblock, EITHER);
+ if (bh == NULL) {
+ offset += sb->s_blocksize;
+ continue;
+ }
if (IS_ERR(bh))
return true;
de = (struct ext4_dir_entry_2 *) bh->b_data;
@@ -3402,7 +3428,10 @@ static struct buffer_head *ext4_get_first_dir_block(handle_t *handle,
struct buffer_head *bh;
if (!ext4_has_inline_data(inode)) {
- bh = ext4_read_dirblock(inode, 0, EITHER);
+ /* The first directory block must not be a hole, so
+ * treat it as DIRENT_HTREE
+ */
+ bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE);
if (IS_ERR(bh)) {
*retval = PTR_ERR(bh);
return NULL;
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.