Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
---
resize/main.c | 2 +-
resize/resize2fs.8.in | 4 +++-
resize/resize2fs.c | 59 +++++++++++++++++++++++++++++++++++++++++++++------
resize/resize2fs.h | 3 ++-
4 files changed, 59 insertions(+), 9 deletions(-)
diff --git a/resize/main.c b/resize/main.c
index b648a15..1394ae1 100644
--- a/resize/main.c
+++ b/resize/main.c
@@ -328,7 +328,7 @@ int main (int argc, char ** argv)
exit(1);
}
- min_size = calculate_minimum_resize_size(fs);
+ min_size = calculate_minimum_resize_size(fs, flags);
if (print_min_size) {
if (!force && ((fs->super->s_state & EXT2_ERROR_FS) ||
diff --git a/resize/resize2fs.8.in b/resize/resize2fs.8.in
index 735fc91..a1f3099 100644
--- a/resize/resize2fs.8.in
+++ b/resize/resize2fs.8.in
@@ -101,7 +101,9 @@ from the following list:
8 \-\ Debug moving the inode table
.br
16 \-\ Print timing information
-.TP
+.br
+ 32 \-\ Debug minimum filesystem size (\-M) calculation
+.TP
.B \-f
Forces resize2fs to proceed with the filesystem resize operation, overriding
some safety checks which resize2fs normally enforces.
diff --git a/resize/resize2fs.c b/resize/resize2fs.c
index 3b48206..51b85b8 100644
--- a/resize/resize2fs.c
+++ b/resize/resize2fs.c
@@ -2034,10 +2034,11 @@ static int calc_group_overhead(ext2_filsys fs, blk64_t grp,
/*
* calcluate the minimum number of blocks the given fs can be resized to
*/
-blk64_t calculate_minimum_resize_size(ext2_filsys fs)
+blk64_t calculate_minimum_resize_size(ext2_filsys fs, int flags)
{
ext2_ino_t inode_count;
- blk64_t blks_needed, groups, data_blocks;
+ dgrp_t groups;
+ blk64_t blks_needed, data_blocks;
blk64_t grp, data_needed, last_start;
blk64_t overhead = 0;
int old_desc_blocks;
@@ -2055,6 +2056,11 @@ blk64_t calculate_minimum_resize_size(ext2_filsys fs)
EXT2_BLOCKS_PER_GROUP(fs->super);
groups = ext2fs_div64_ceil(blks_needed,
EXT2_BLOCKS_PER_GROUP(fs->super));
+#ifdef RESIZE2FS_DEBUG
+ if (flags & RESIZE_DEBUG_MIN_CALC)
+ printf("fs has %d inodes, %d groups required.\n",
+ inode_count, groups);
+#endif
/*
* number of old-style block group descriptor blocks
@@ -2071,6 +2077,10 @@ blk64_t calculate_minimum_resize_size(ext2_filsys fs)
for (grp = 0; grp < fs->group_desc_count; grp++)
data_needed -= calc_group_overhead(fs, grp, old_desc_blocks);
+#ifdef RESIZE2FS_DEBUG
+ if (flags & RESIZE_DEBUG_MIN_CALC)
+ printf("fs requires %llu data blocks.\n", data_needed);
+#endif
/*
* For ext4 we need to allow for up to a flex_bg worth of
@@ -2103,6 +2113,11 @@ blk64_t calculate_minimum_resize_size(ext2_filsys fs)
data_blocks -= overhead;
}
+#ifdef RESIZE2FS_DEBUG
+ if (flags & RESIZE_DEBUG_MIN_CALC)
+ printf("With %d group(s), we have %llu blocks available.\n",
+ groups, data_blocks);
+#endif
/*
* if we need more group descriptors in order to accomodate our data
@@ -2110,7 +2125,7 @@ blk64_t calculate_minimum_resize_size(ext2_filsys fs)
*/
while (data_needed > data_blocks) {
blk64_t remainder = data_needed - data_blocks;
- blk64_t extra_grps;
+ dgrp_t extra_grps;
/* figure out how many more groups we need for the data */
extra_grps = ext2fs_div64_ceil(remainder,
@@ -2153,10 +2168,22 @@ blk64_t calculate_minimum_resize_size(ext2_filsys fs)
extra_groups);
extra_groups = groups % flexbg_size;
}
+#ifdef RESIZE2FS_DEBUG
+ if (flags & RESIZE_DEBUG_MIN_CALC)
+ printf("Added %d extra group(s), "
+ "data_needed %llu, data_blocks %llu, "
+ "last_start %llu\n",
+ extra_grps, data_needed, data_blocks,
+ last_start);
+#endif
}
/* now for the fun voodoo */
overhead = calc_group_overhead(fs, groups-1, old_desc_blocks);
+#ifdef RESIZE2FS_DEBUG
+ if (flags & RESIZE_DEBUG_MIN_CALC)
+ printf("Last group's overhead is %llu\n", overhead);
+#endif
/*
* if this is the case then the last group is going to have data in it
@@ -2165,6 +2192,11 @@ blk64_t calculate_minimum_resize_size(ext2_filsys fs)
if (last_start < data_needed) {
blk64_t remainder = data_needed - last_start;
+#ifdef RESIZE2FS_DEBUG
+ if (flags & RESIZE_DEBUG_MIN_CALC)
+ printf("Need %llu data blocks in last group\n",
+ remainder);
+#endif
/*
* 50 is a magic number that mkfs/resize uses to see if its
* even worth making/resizing the fs. basically you need to
@@ -2179,6 +2211,10 @@ blk64_t calculate_minimum_resize_size(ext2_filsys fs)
overhead += 50;
overhead += fs->super->s_first_data_block;
+#ifdef RESIZE2FS_DEBUG
+ if (flags & RESIZE_DEBUG_MIN_CALC)
+ printf("Final size of last group is %lld\n", overhead);
+#endif
/*
* since our last group doesn't have to be BLOCKS_PER_GROUP large, we
@@ -2188,6 +2224,11 @@ blk64_t calculate_minimum_resize_size(ext2_filsys fs)
blks_needed = (groups-1) * EXT2_BLOCKS_PER_GROUP(fs->super);
blks_needed += overhead;
+#ifdef RESIZE2FS_DEBUG
+ if (flags & RESIZE_DEBUG_MIN_CALC)
+ printf("Estimated blocks needed: %llu\n", blks_needed);
+#endif
+
/*
* If at this point we've already added up more "needed" than
* the current size, just return current size as minimum.
@@ -2199,9 +2240,15 @@ blk64_t calculate_minimum_resize_size(ext2_filsys fs)
* enabled, in case we need to grow the extent tree. The more
* we shrink the file system, the more space we need.
*/
- if (fs->super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_EXTENTS)
- blks_needed += (ext2fs_blocks_count(fs->super) -
- blks_needed)/500;
+ if (fs->super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_EXTENTS) {
+ blk64_t safe_margin = (ext2fs_blocks_count(fs->super) -
+ blks_needed)/500;
+#ifdef RESIZE2FS_DEBUG
+ if (flags & RESIZE_DEBUG_MIN_CALC)
+ printf("Extents safety margin: %llu\n", safe_margin);
+#endif
+ blks_needed += safe_margin;
+ }
return blks_needed;
}
diff --git a/resize/resize2fs.h b/resize/resize2fs.h
index d425491..52319b5 100644
--- a/resize/resize2fs.h
+++ b/resize/resize2fs.h
@@ -77,6 +77,7 @@ typedef struct ext2_sim_progress *ext2_sim_progmeter;
#define RESIZE_DEBUG_INODEMAP 0x0004
#define RESIZE_DEBUG_ITABLEMOVE 0x0008
#define RESIZE_DEBUG_RTRACK 0x0010
+#define RESIZE_DEBUG_MIN_CALC 0x0020
#define RESIZE_PERCENT_COMPLETE 0x0100
#define RESIZE_VERBOSE 0x0200
@@ -145,7 +146,7 @@ extern errcode_t resize_fs(ext2_filsys fs, blk64_t *new_size, int flags,
extern errcode_t adjust_fs_info(ext2_filsys fs, ext2_filsys old_fs,
ext2fs_block_bitmap reserve_blocks,
blk64_t new_size);
-extern blk64_t calculate_minimum_resize_size(ext2_filsys fs);
+extern blk64_t calculate_minimum_resize_size(ext2_filsys fs, int flags);
/* extent.c */
--
1.7.12.rc0.22.gcdd159b
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