36a7badb2d
- Fix ext4 resize issues (#496982)
242 lines
8.7 KiB
Diff
242 lines
8.7 KiB
Diff
3 patches from the list to address resize issues (18 Apr 2009):
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When allocating a new set of block group metadata as part of growing
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the filesystem, the resize2fs code assumes that the bitmap and inode
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table blocks are in their own block group; an assumption which is
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changed by the flex_bg feature. This commit works around the problem
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by temporarily turning off flex_bg while allocating the new block
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group metadata, to avoid potentially overwriting previously allocated
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data blocks.
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Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
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---
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If we need to shrink the inode table, we need to make sure the inodes
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contained in the part of the inode table we are vacating don't get
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reused as part of the filesystem shrink operation. This wasn't a
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problem with ext3 filesystems, since the inode table was located in
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the block group that was going away, so that location was not eligible
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for reallocation.
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However with ext4 filesystems with flex_bg enabled, it's possible for
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a portion of the inode table in the last flex_bg group to be
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deallocated, but in a part of the filesystem which could be used as
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data blocks. So we must mark those blocks as reserved to prevent
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their reuse, and adjust the minimum filesystem size calculation to
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assure that we don't shrink a filesystem too small for the resize
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operation to succeed.
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Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
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---
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Due to a fencepost bug, when skipping a block group whose block bitmap
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was uninitialized (and hence could not contain any blocks eligible for
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relaocation), the block immediately following the block group wasn't
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checked as well. If it was in use and required relocation, it
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wouldn't get properly relocated, with the result that an inode using
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such a block would end up, post resize, with a pointer to a block now
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outside the bounds of the filesystem.
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This commit fixes this fencepost error.
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Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
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---
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Index: e2fsprogs-1.41.4/resize/resize2fs.c
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===================================================================
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--- e2fsprogs-1.41.4.orig/resize/resize2fs.c
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+++ e2fsprogs-1.41.4/resize/resize2fs.c
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@@ -233,20 +233,29 @@ static void fix_uninit_block_bitmaps(ext
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/*
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* If the group descriptor's bitmap and inode table blocks are valid,
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- * release them in the specified filesystem data structure
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+ * release them in the new filesystem data structure, and mark them as
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+ * reserved so the old inode table blocks don't get overwritten.
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*/
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-static void free_gdp_blocks(ext2_filsys fs, struct ext2_group_desc *gdp)
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+static void free_gdp_blocks(ext2_filsys fs,
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+ ext2fs_block_bitmap reserve_blocks,
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+ struct ext2_group_desc *gdp)
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{
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blk_t blk;
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int j;
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if (gdp->bg_block_bitmap &&
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- (gdp->bg_block_bitmap < fs->super->s_blocks_count))
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+ (gdp->bg_block_bitmap < fs->super->s_blocks_count)) {
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ext2fs_block_alloc_stats(fs, gdp->bg_block_bitmap, -1);
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+ ext2fs_mark_block_bitmap(reserve_blocks,
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+ gdp->bg_block_bitmap);
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+ }
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if (gdp->bg_inode_bitmap &&
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- (gdp->bg_inode_bitmap < fs->super->s_blocks_count))
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+ (gdp->bg_inode_bitmap < fs->super->s_blocks_count)) {
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ext2fs_block_alloc_stats(fs, gdp->bg_inode_bitmap, -1);
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+ ext2fs_mark_block_bitmap(reserve_blocks,
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+ gdp->bg_inode_bitmap);
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+ }
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if (gdp->bg_inode_table == 0 ||
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(gdp->bg_inode_table >= fs->super->s_blocks_count))
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@@ -257,14 +266,19 @@ static void free_gdp_blocks(ext2_filsys
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if (blk >= fs->super->s_blocks_count)
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break;
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ext2fs_block_alloc_stats(fs, blk, -1);
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+ ext2fs_mark_block_bitmap(reserve_blocks, blk);
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}
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}
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/*
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* This routine is shared by the online and offline resize routines.
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* All of the information which is adjusted in memory is done here.
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+ *
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+ * The reserve_blocks parameter is only needed when shrinking the
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+ * filesystem.
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*/
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-errcode_t adjust_fs_info(ext2_filsys fs, ext2_filsys old_fs, blk_t new_size)
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+errcode_t adjust_fs_info(ext2_filsys fs, ext2_filsys old_fs,
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+ ext2fs_block_bitmap reserve_blocks, blk_t new_size)
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{
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errcode_t retval;
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int overhead = 0;
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@@ -399,8 +413,8 @@ retry:
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}
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/*
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- * If we are shrinking the number block groups, we're done and
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- * can exit now.
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+ * If we are shrinking the number of block groups, we're done
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+ * and can exit now.
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*/
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if (old_fs->group_desc_count > fs->group_desc_count) {
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/*
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@@ -409,7 +423,8 @@ retry:
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*/
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for (i = fs->group_desc_count;
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i < old_fs->group_desc_count; i++) {
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- free_gdp_blocks(fs, &old_fs->group_desc[i]);
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+ free_gdp_blocks(fs, reserve_blocks,
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+ &old_fs->group_desc[i]);
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}
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retval = 0;
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goto errout;
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@@ -550,7 +565,12 @@ static errcode_t adjust_superblock(ext2_
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ext2fs_mark_bb_dirty(fs);
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ext2fs_mark_ib_dirty(fs);
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- retval = adjust_fs_info(fs, rfs->old_fs, new_size);
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+ retval = ext2fs_allocate_block_bitmap(fs, _("reserved blocks"),
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+ &rfs->reserve_blocks);
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+ if (retval)
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+ return retval;
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+
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+ retval = adjust_fs_info(fs, rfs->old_fs, rfs->reserve_blocks, new_size);
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if (retval)
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goto errout;
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@@ -746,17 +766,13 @@ static errcode_t blocks_to_move(ext2_res
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errcode_t retval;
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ext2_filsys fs, old_fs;
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ext2fs_block_bitmap meta_bmap;
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+ __u32 save_incompat_flag;
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fs = rfs->new_fs;
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old_fs = rfs->old_fs;
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if (old_fs->super->s_blocks_count > fs->super->s_blocks_count)
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fs = rfs->old_fs;
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- retval = ext2fs_allocate_block_bitmap(fs, _("reserved blocks"),
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- &rfs->reserve_blocks);
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- if (retval)
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- return retval;
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-
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retval = ext2fs_allocate_block_bitmap(fs, _("blocks to be moved"),
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&rfs->move_blocks);
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if (retval)
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@@ -788,7 +804,7 @@ static errcode_t blocks_to_move(ext2_res
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* to the next block group.
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*/
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blk = ((g+1) * fs->super->s_blocks_per_group) +
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- fs->super->s_first_data_block;
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+ fs->super->s_first_data_block - 1;
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continue;
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}
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if (ext2fs_test_block_bitmap(old_fs->block_map, blk) &&
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@@ -890,9 +906,29 @@ static errcode_t blocks_to_move(ext2_res
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/*
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* Allocate the missing data structures
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+ *
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+ * XXX We have a problem with FLEX_BG and off-line
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+ * resizing where we are growing the size of the
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+ * filesystem. ext2fs_allocate_group_table() will try
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+ * to reserve the inode table in the desired flex_bg
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+ * location. However, passing rfs->reserve_blocks
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+ * doesn't work since it only has reserved the blocks
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+ * that will be used in the new block group -- and
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+ * with flex_bg, we can and will allocate the tables
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+ * outside of the block group. And we can't pass in
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+ * the fs->block_map because it doesn't handle
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+ * overlapping inode table movements right. So for
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+ * now, we temporarily disable flex_bg to force
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+ * ext2fs_allocate_group_tables() to allocate the bg
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+ * metadata in side the block group, and the restore
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+ * it afterwards. Ugly, until we can fix this up
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+ * right later.
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*/
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+ save_incompat_flag = fs->super->s_feature_incompat;
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+ fs->super->s_feature_incompat &= ~EXT4_FEATURE_INCOMPAT_FLEX_BG;
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retval = ext2fs_allocate_group_table(fs, i,
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rfs->reserve_blocks);
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+ fs->super->s_feature_incompat = save_incompat_flag;
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if (retval)
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goto errout;
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@@ -1857,6 +1893,19 @@ blk_t calculate_minimum_resize_size(ext2
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data_needed -= SUPER_OVERHEAD(fs) * num_of_superblocks;
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data_needed -= META_OVERHEAD(fs) * fs->group_desc_count;
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+ if (fs->super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_FLEX_BG) {
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+ /*
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+ * For ext4 we need to allow for up to a flex_bg worth
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+ * of inode tables of slack space so the resize
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+ * operation can be guaranteed to finish.
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+ */
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+ int flexbg_size = 1 << fs->super->s_log_groups_per_flex;
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+ int extra_groups;
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+
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+ extra_groups = flexbg_size - (groups & (flexbg_size - 1));
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+ data_needed += META_OVERHEAD(fs) * extra_groups;
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+ }
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+
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/*
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* figure out how many data blocks we have given the number of groups
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* we need for our inodes
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Index: e2fsprogs-1.41.4/resize/online.c
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===================================================================
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--- e2fsprogs-1.41.4.orig/resize/online.c
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+++ e2fsprogs-1.41.4/resize/online.c
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@@ -104,7 +104,7 @@ errcode_t online_resize_fs(ext2_filsys f
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* but at least it allows on-line resizing to function.
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*/
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new_fs->super->s_feature_incompat &= ~EXT4_FEATURE_INCOMPAT_FLEX_BG;
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- retval = adjust_fs_info(new_fs, fs, *new_size);
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+ retval = adjust_fs_info(new_fs, fs, 0, *new_size);
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if (retval)
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return retval;
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Index: e2fsprogs-1.41.4/resize/resize2fs.h
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===================================================================
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--- e2fsprogs-1.41.4.orig/resize/resize2fs.h
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+++ e2fsprogs-1.41.4/resize/resize2fs.h
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@@ -128,6 +128,7 @@ extern errcode_t resize_fs(ext2_filsys f
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unsigned long max));
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extern errcode_t adjust_fs_info(ext2_filsys fs, ext2_filsys old_fs,
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+ ext2fs_block_bitmap reserve_blocks,
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blk_t new_size);
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extern blk_t calculate_minimum_resize_size(ext2_filsys fs);
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