Hi Andreas, >From: linux-ext4-owner@xxxxxxxxxxxxxxx [mailto:linux-ext4-owner@xxxxxxxxxxxxxxx] On Behalf Of >Andreas Dilger >Sent: Wednesday, July 30, 2014 5:30 PM >To: tytso@xxxxxxx >Cc: linux-ext4@xxxxxxxxxxxxxxx; Andreas Dilger; Andreas Dilger >Subject: [PATCH] mke2fs: fix flexbg check to allow small filesystems > >Fix the flexbg check added in d988201ef9c so that it allows common >small filesystem configurations to succeed instead of reporting >a cryptic error message and failing due to a bad flex_bg layout: > > mke2fs -O flex_bg -b 4096 -I 1024 -F /tmp/tt 79106 > mke2fs 1.42.11 (09-Jul-2014) > /tmp/tt: Invalid argument passed to ext2 library while setting > up superblock > >This check in ext2fs_initialize() was added to prevent the metadata >from being allocated beyond the end of the filesystem, but it is >also causing a wide range of failures for small filesystems. > >Fix this by shrinking the flex_bg factor by half repeatedly until it >would be expected to fit into the current filesystem size, rather >than return an error as previously done. Ideally it would only try >a smaller flex_bg factor if the default value was being used, and had >not been specified on the command line, but it isn't possible to see >if this is the case in ext2fs_initialize() or not. > >Signed-off-by: Andreas Dilger <andreas.dilger@xxxxxxxxx> >--- > lib/ext2fs/initialize.c | 13 +++++++------ > 1 files changed, 7 insertions(+), 6 deletions(-) > >diff --git a/lib/ext2fs/initialize.c b/lib/ext2fs/initialize.c >index de358fd..d58a664 100644 >--- a/lib/ext2fs/initialize.c >+++ b/lib/ext2fs/initialize.c >@@ -91,7 +91,7 @@ errcode_t ext2fs_initialize(const char *name, int flags, > unsigned int rem; > unsigned int overhead = 0; > unsigned int ipg; >- unsigned int flexbg_size; >+ unsigned int flexbg_factor; > dgrp_t i; > blk64_t free_blocks; > blk64_t flexbg_overhead; >@@ -428,18 +428,19 @@ ipg_retry: > * This is a simple check, so that the backup superblock and > * other feature related blocks are not considered. > */ >- flexbg_size = 1 << fs->super->s_log_groups_per_flex; >+flex_retry: >+ flexbg_factor = 1 << super->s_log_groups_per_flex; > flexbg_overhead = super->s_first_data_block + 1 + > fs->desc_blocks + super->s_reserved_gdt_blocks + >- (__u64)flexbg_size * (2 + fs->inode_blocks_per_group); >+ (__u64)flexbg_factor * (2 + fs->inode_blocks_per_group); > > /* > * Disallow creating ext4 which breaks flex_bg metadata layout > * obviously. > */ This comment is unneeded any more, But patch looks good to me, thanks. Reviewed-by: Akira Fujita <a-fujita@xxxxxxxxxxxxxxx> >- if (flexbg_overhead > ext2fs_blocks_count(fs->super)) { >- retval = EXT2_ET_INVALID_ARGUMENT; >- goto cleanup; >+ if (flexbg_overhead > ext2fs_blocks_count(super)) { >+ super->s_log_groups_per_flex -= 1; >+ goto flex_retry; > } > > /* >-- >1.7.3.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
