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Message-Id: <1325674932-26069-3-git-send-email-xiaoqiangnk@gmail.com>
Date: Wed, 4 Jan 2012 19:02:12 +0800
From: Yongqiang Yang <xiaoqiangnk@...il.com>
To: tytso@....edu
Cc: linux-ext4@...r.kernel.org, Yongqiang Yang <xiaoqiangnk@...il.com>
Subject: [PATCH 3/3] e2fsprogs: add a function computing old desc blocks without reserved ones
If first_meta_bg > desc_blocks, ext2fs_open reads more decs_blocks,
however desc buffer in memory is allocated based on desc_blocks.
Maybe there are similar problems in other places, so this patch adds a
function which computes right old_desc_blocks.
The problem can be reproduced by setting first_meta_bg.
Signed-off-by: Yongqiang Yang <xiaoqiangnk@...il.com>
---
lib/ext2fs/blknum.c | 15 +++++++++++++++
lib/ext2fs/closefs.c | 5 +----
lib/ext2fs/ext2fs.h | 1 +
lib/ext2fs/openfs.c | 18 ++++++++----------
misc/dumpe2fs.c | 10 ++--------
5 files changed, 27 insertions(+), 22 deletions(-)
diff --git a/lib/ext2fs/blknum.c b/lib/ext2fs/blknum.c
index f1d5156..6d057ed 100644
--- a/lib/ext2fs/blknum.c
+++ b/lib/ext2fs/blknum.c
@@ -112,6 +112,21 @@ blk64_t ext2fs_old_desc_blocks_count(ext2_filsys fs)
}
/*
+ * Return the old desc blocks count without reserved ones.
+ */
+blk64_t ext2fs_old_desc_blocks_count_without_rsved(ext2_filsys fs)
+{
+ blk64_t old_desc_blocks;
+
+ old_desc_blocks = fs->desc_blocks;
+ if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG &&
+ old_desc_blocks > fs->super->s_first_meta_bg)
+ old_desc_blocks = fs->super->s_first_meta_bg;
+
+ return old_desc_blocks;
+}
+
+/*
* Set the fs block count
*/
void ext2fs_blocks_count_set(struct ext2_super_block *super, blk64_t blk)
diff --git a/lib/ext2fs/closefs.c b/lib/ext2fs/closefs.c
index 0a97b69..75210c2 100644
--- a/lib/ext2fs/closefs.c
+++ b/lib/ext2fs/closefs.c
@@ -328,10 +328,7 @@ errcode_t ext2fs_flush2(ext2_filsys fs, int flags)
* superblocks and group descriptors.
*/
group_ptr = (char *) group_shadow;
- if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
- old_desc_blocks = fs->super->s_first_meta_bg;
- else
- old_desc_blocks = fs->desc_blocks;
+ old_desc_blocks = ext2fs_old_desc_blocks_count_without_rsved(fs);
ext2fs_numeric_progress_init(fs, &progress, NULL,
fs->group_desc_count);
diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index 78f0f94..aae57e3 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -806,6 +806,7 @@ extern blk64_t ext2fs_inode_i_blocks(ext2_filsys fs,
struct ext2_inode *inode);
extern blk64_t ext2fs_blocks_count(struct ext2_super_block *super);
extern blk64_t ext2fs_old_desc_blocks_count(ext2_filsys fs);
+extern blk64_t ext2fs_old_desc_blocks_count_without_rsved(ext2_filsys fs);
extern void ext2fs_blocks_count_set(struct ext2_super_block *super,
blk64_t blk);
extern void ext2fs_blocks_count_add(struct ext2_super_block *super,
diff --git a/lib/ext2fs/openfs.c b/lib/ext2fs/openfs.c
index 40a52c5..1077321 100644
--- a/lib/ext2fs/openfs.c
+++ b/lib/ext2fs/openfs.c
@@ -95,7 +95,7 @@ errcode_t ext2fs_open2(const char *name, const char *io_options,
{
ext2_filsys fs;
errcode_t retval;
- unsigned long i, first_meta_bg;
+ unsigned long i, old_desc_blocks;
__u32 features;
unsigned int groups_per_block, blocks_per_group, io_flags;
blk64_t group_block, blk;
@@ -331,25 +331,23 @@ errcode_t ext2fs_open2(const char *name, const char *io_options,
group_block = 1; /* Deal with 1024 blocksize && bigalloc */
dest = (char *) fs->group_desc;
groups_per_block = EXT2_DESC_PER_BLOCK(fs->super);
- if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
- first_meta_bg = fs->super->s_first_meta_bg;
- else
- first_meta_bg = fs->desc_blocks;
- if (first_meta_bg) {
+
+ old_desc_blocks = ext2fs_old_desc_blocks_count_without_rsved(fs);
+ if (old_desc_blocks) {
retval = io_channel_read_blk(fs->io, group_block+1,
- first_meta_bg, dest);
+ old_desc_blocks, dest);
if (retval)
goto cleanup;
#ifdef WORDS_BIGENDIAN
gdp = (struct ext2_group_desc *) dest;
- for (j=0; j < groups_per_block*first_meta_bg; j++) {
+ for (j=0; j < groups_per_block * old_desc_blocks; j++) {
gdp = ext2fs_group_desc(fs, fs->group_desc, j);
ext2fs_swap_group_desc2(fs, gdp);
}
#endif
- dest += fs->blocksize*first_meta_bg;
+ dest += fs->blocksize * old_desc_blocks;
}
- for (i=first_meta_bg ; i < fs->desc_blocks; i++) {
+ for (i = old_desc_blocks; i < fs->desc_blocks; i++) {
blk = ext2fs_descriptor_block_loc2(fs, group_block, i);
retval = io_channel_read_blk64(fs->io, blk, 1, dest);
if (retval)
diff --git a/misc/dumpe2fs.c b/misc/dumpe2fs.c
index 2f9e87b..61c32f2 100644
--- a/misc/dumpe2fs.c
+++ b/misc/dumpe2fs.c
@@ -175,10 +175,7 @@ static void list_desc (ext2_filsys fs)
reserved_gdt = fs->super->s_reserved_gdt_blocks;
fputc('\n', stdout);
first_block = fs->super->s_first_data_block;
- if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
- old_desc_blocks = fs->super->s_first_meta_bg;
- else
- old_desc_blocks = fs->desc_blocks;
+ old_desc_blocks = ext2fs_old_desc_blocks_count_without_rsved(fs);
for (i = 0; i < fs->group_desc_count; i++) {
first_block = ext2fs_group_first_block2(fs, i);
last_block = ext2fs_group_last_block2(fs, i);
@@ -495,10 +492,7 @@ void print_super_gdt_blocks_count (ext2_filsys fs) {
blk64_t old_desc_blocks;
unsigned int grp;
- if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
- old_desc_blocks = fs->super->s_first_meta_bg;
- else
- old_desc_blocks = fs->desc_blocks;
+ old_desc_blocks = ext2fs_old_desc_blocks_count_without_rsved(fs);
for (grp = 0; grp < fs->group_desc_count; grp++) {
ext2fs_super_and_bgd_loc2(fs, grp, &super_blk,
--
1.7.5.1
--
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