ext4: convert file system to meta_bg if needed during resizing
If we have run out of reserved gdt blocks, then clear the resize_inode
feature and enable the meta_bg feature, so that we can continue
resizing the file system seamlessly.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index a5be589..5932ab5 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1756,6 +1756,99 @@
return err;
} /* ext4_group_extend */
+
+static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
+{
+ return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
+}
+
+/*
+ * Release the resize inode and drop the resize_inode feature if there
+ * are no more reserved gdt blocks, and then convert the file system
+ * to enable meta_bg
+ */
+static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
+{
+ handle_t *handle;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct ext4_super_block *es = sbi->s_es;
+ struct ext4_inode_info *ei = 0;
+ ext4_fsblk_t nr;
+ int i, ret, err = 0;
+ int credits = 1;
+
+ ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
+ if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_RESIZE_INODE)) {
+ if (es->s_reserved_gdt_blocks) {
+ ext4_error(sb, "Unexpected non-zero "
+ "s_reserved_gdt_blocks");
+ return -EPERM;
+ }
+ if (!inode) {
+ ext4_error(sb, "Unexpected NULL resize_inode");
+ return -EPERM;
+ }
+ ei = EXT4_I(inode);
+
+ /* Do a quick sanity check of the resize inode */
+ if (inode->i_blocks != 1 << (inode->i_blkbits - 9))
+ goto invalid_resize_inode;
+ for (i = 0; i < EXT4_N_BLOCKS; i++) {
+ if (i == EXT4_DIND_BLOCK) {
+ if (ei->i_data[i])
+ continue;
+ else
+ goto invalid_resize_inode;
+ }
+ if (ei->i_data[i])
+ goto invalid_resize_inode;
+ }
+ credits += 3; /* block bitmap, bg descriptor, resize inode */
+ }
+
+ handle = ext4_journal_start_sb(sb, credits);
+ if (IS_ERR(handle))
+ return PTR_ERR(handle);
+
+ err = ext4_journal_get_write_access(handle, sbi->s_sbh);
+ if (err)
+ goto errout;
+
+ EXT4_CLEAR_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_RESIZE_INODE);
+ EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG);
+ sbi->s_es->s_first_meta_bg =
+ cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
+
+ err = ext4_handle_dirty_super(handle, sb);
+ if (err) {
+ ext4_std_error(sb, err);
+ goto errout;
+ }
+
+ if (inode) {
+ nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
+ ext4_free_blocks(handle, inode, NULL, nr, 1,
+ EXT4_FREE_BLOCKS_METADATA |
+ EXT4_FREE_BLOCKS_FORGET);
+ ei->i_data[EXT4_DIND_BLOCK] = 0;
+ inode->i_blocks = 0;
+
+ err = ext4_mark_inode_dirty(handle, inode);
+ if (err)
+ ext4_std_error(sb, err);
+ }
+
+errout:
+ ret = ext4_journal_stop(handle);
+ if (!err)
+ err = ret;
+ return ret;
+
+invalid_resize_inode:
+ ext4_error(sb, "corrupted/inconsistent resize inode");
+ return -EINVAL;
+}
+
/*
* ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
*
@@ -1772,13 +1865,14 @@
ext4_grpblk_t add, offset;
unsigned long n_desc_blocks;
unsigned long o_desc_blocks;
- unsigned long desc_blocks;
ext4_group_t o_group;
ext4_group_t n_group;
ext4_fsblk_t o_blocks_count;
+ ext4_fsblk_t n_blocks_count_retry = 0;
int err = 0, flexbg_size = 1 << sbi->s_log_groups_per_flex;
int meta_bg;
+retry:
o_blocks_count = ext4_blocks_count(es);
if (test_opt(sb, DEBUG))
@@ -1798,11 +1892,8 @@
ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &offset);
ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
- n_desc_blocks = (n_group + EXT4_DESC_PER_BLOCK(sb)) /
- EXT4_DESC_PER_BLOCK(sb);
- o_desc_blocks = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
- EXT4_DESC_PER_BLOCK(sb);
- desc_blocks = n_desc_blocks - o_desc_blocks;
+ n_desc_blocks = num_desc_blocks(sb, n_group + 1);
+ o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
meta_bg = EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG);
@@ -1812,20 +1903,37 @@
"simultaneously");
return -EINVAL;
}
- if (le16_to_cpu(es->s_reserved_gdt_blocks) < desc_blocks) {
- ext4_warning(sb,
- "No reserved GDT blocks, can't resize");
- return -EPERM;
+ if (n_desc_blocks > o_desc_blocks +
+ le16_to_cpu(es->s_reserved_gdt_blocks)) {
+ n_blocks_count_retry = n_blocks_count;
+ n_desc_blocks = o_desc_blocks +
+ le16_to_cpu(es->s_reserved_gdt_blocks);
+ n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
+ n_blocks_count = n_group * EXT4_BLOCKS_PER_GROUP(sb);
+ n_group--; /* set to last group number */
}
- resize_inode = ext4_iget(sb, EXT4_RESIZE_INO);
+
+ if (!resize_inode)
+ resize_inode = ext4_iget(sb, EXT4_RESIZE_INO);
if (IS_ERR(resize_inode)) {
ext4_warning(sb, "Error opening resize inode");
return PTR_ERR(resize_inode);
}
- } else if (!meta_bg) {
- ext4_warning(sb, "File system features do not permit "
- "online resize");
- return -EPERM;
+ }
+
+ if ((!resize_inode && !meta_bg) || n_group == o_group) {
+ err = ext4_convert_meta_bg(sb, resize_inode);
+ if (err)
+ goto out;
+ if (resize_inode) {
+ iput(resize_inode);
+ resize_inode = NULL;
+ }
+ if (n_blocks_count_retry) {
+ n_blocks_count = n_blocks_count_retry;
+ n_blocks_count_retry = 0;
+ goto retry;
+ }
}
/* See if the device is actually as big as what was requested */
@@ -1876,13 +1984,21 @@
break;
}
+ if (!err && n_blocks_count_retry) {
+ n_blocks_count = n_blocks_count_retry;
+ n_blocks_count_retry = 0;
+ free_flex_gd(flex_gd);
+ flex_gd = NULL;
+ goto retry;
+ }
+
out:
if (flex_gd)
free_flex_gd(flex_gd);
if (resize_inode != NULL)
iput(resize_inode);
if (test_opt(sb, DEBUG))
- ext4_msg(sb, KERN_DEBUG, "resized filesystem from %llu "
- "upto %llu blocks", o_blocks_count, n_blocks_count);
+ ext4_msg(sb, KERN_DEBUG, "resized filesystem to %llu",
+ n_blocks_count);
return err;
}