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Date: Fri, 21 Jun 2019 00:10:39 -0400
From: "Theodore Ts'o" <tytso@....edu>
To: Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc: "Theodore Ts'o" <tytso@....edu>, stable@...nel.org
Subject: [PATCH] ext4: allow directory holes
The largedir feature was intended to allow ext4 directories to have
unmapped directory blocks (e.g., directory holes). And so the
released e2fsprogs no longer enforces this for largedir file systems;
however, the corresponding change to the kernel-side code was not made.
This commit fixes this oversight.
Signed-off-by: Theodore Ts'o <tytso@....edu>
Cc: stable@...nel.org
---
fs/ext4/dir.c | 8 --------
fs/ext4/namei.c | 35 +++++++++++++++++++++++++++--------
2 files changed, 27 insertions(+), 16 deletions(-)
diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index 770a1e6d4672..935dc52380fc 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)) {
@@ -179,13 +178,6 @@ 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..f3140ff330c6 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -83,7 +83,7 @@ static int ext4_dx_csum_verify(struct inode *inode,
struct ext4_dir_entry *dirent);
typedef enum {
- EITHER, INDEX, DIRENT
+ EITHER, INDEX, DIRENT, DIRENT_HTREE
} dirblock_type_t;
#define ext4_read_dirblock(inode, block, type) \
@@ -109,11 +109,14 @@ 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 +983,7 @@ 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 +1622,7 @@ 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 +2206,11 @@ 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 +2231,7 @@ 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 +2276,7 @@ static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
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 +2824,10 @@ 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 +2849,10 @@ 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 +3418,10 @@ 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;
--
2.22.0
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