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ext4: convert file system to meta_bg if needed during resizing

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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>
This commit is contained in:
Theodore Ts'o 2012-09-13 10:19:24 -04:00
parent 93f9052643
commit 1c6bd7173d
1 changed files with 133 additions and 17 deletions
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148
fs/ext4/resize.c
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@ -1756,6 +1756,99 @@ int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
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 @@ int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
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 @@ int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
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 @@ int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
"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 */
}
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 @@ int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
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;
}