From: Theodore Ts'o Subject: [PATCH 1/4] resize2fs: add debugging support for resize2fs -M calcuations Date: Mon, 30 Sep 2013 23:59:31 -0400 Message-ID: <1380599974-2886-1-git-send-email-tytso@mit.edu> References: <20131001015746.GF5845@thunk.org> Cc: sandeen@redhat.com, Theodore Ts'o To: Ext4 Developers List Return-path: Received: from imap.thunk.org ([74.207.234.97]:40496 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755995Ab3JAD7m (ORCPT ); Mon, 30 Sep 2013 23:59:42 -0400 In-Reply-To: <20131001015746.GF5845@thunk.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: Signed-off-by: "Theodore Ts'o" --- 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