aufs: au_statfs_sum calculates wrong sums when different block sizes are in use
If aufs is mounted in sum mode, but the source file systems have different
block sizes, the result of statfs is the sum of all block counts which does
not make sense. This patch corrects this problem by normalizing the block
counts to the same block size and then adds them.
Signed-off-by: Daniel Alder <hac...@wolke7.net>
Index: aufs3-standalone.git/fs/aufs/super.c
===================================================================
--- a/fs/aufs/super.c
+++ b/fs/aufs/super.c
@@ -305,7 +305,18 @@ static u64 au_add_till_max(u64 a, u64 b)
old = a;
a += b;
- if (old < a)
+ if (old <= a)
+ return a;
+ return ULLONG_MAX;
+}
+
+static u64 au_mul_till_max(u64 a, long mul)
+{
+ u64 old;
+
+ old = a;
+ a *= mul;
+ if (old <= a)
return a;
return ULLONG_MAX;
}
@@ -313,25 +324,26 @@ static u64 au_add_till_max(u64 a, u64 b)
static int au_statfs_sum(struct super_block *sb, struct kstatfs *buf)
{
int err;
+ long bsize, factor;
u64 blocks, bfree, bavail, files, ffree;
aufs_bindex_t bend, bindex, i;
unsigned char shared;
struct path h_path;
struct super_block *h_sb;
+ bend = au_sbend(sb);
+
+ bsize = LONG_MAX;
+ files = 0;
+ ffree = 0;
blocks = 0;
bfree = 0;
bavail = 0;
- files = 0;
- ffree = 0;
-
- err = 0;
- bend = au_sbend(sb);
- for (bindex = bend; bindex >= 0; bindex--) {
+ for (bindex = 0; bindex <= bend; bindex++) {
h_path.mnt = au_sbr_mnt(sb, bindex);
h_sb = h_path.mnt->mnt_sb;
shared = 0;
- for (i = bindex + 1; !shared && i <= bend; i++)
+ for (i = 0; !shared && i < bindex; i++)
shared = (au_sbr_sb(sb, i) == h_sb);
if (shared)
continue;
@@ -342,18 +354,37 @@ static int au_statfs_sum(struct super_block *sb, struct
kstatfs *buf)
if (unlikely(err))
goto out;
- blocks = au_add_till_max(blocks, buf->f_blocks);
- bfree = au_add_till_max(bfree, buf->f_bfree);
- bavail = au_add_till_max(bavail, buf->f_bavail);
+ if (bsize > buf->f_bsize) {
+ /*
+ * we will reduce bsize, so we have to expand blocks
+ * etc. to match them again
+ */
+ factor = (bsize / buf->f_bsize);
+ blocks = au_mul_till_max(blocks, factor);
+ bfree = au_mul_till_max(bfree, factor);
+ bavail = au_mul_till_max(bavail, factor);
+ bsize = buf->f_bsize;
+ }
+
+ factor = (buf->f_bsize / bsize);
+ blocks = au_add_till_max(blocks,
+ au_mul_till_max(buf->f_blocks, factor));
+ bfree = au_add_till_max(bfree,
+ au_mul_till_max(buf->f_bfree, factor));
+ bavail = au_add_till_max(bavail,
+ au_mul_till_max(buf->f_bavail, factor));
+
files = au_add_till_max(files, buf->f_files);
ffree = au_add_till_max(ffree, buf->f_ffree);
}
+ buf->f_bsize = bsize;
buf->f_blocks = blocks;
buf->f_bfree = bfree;
buf->f_bavail = bavail;
buf->f_files = files;
buf->f_ffree = ffree;
+ buf->f_frsize = 0;
out:
return err;
aufs: au_statfs_sum calculates wrong sums when different block sizes are in use
If aufs is mounted in sum mode, but the source file systems have different
block sizes, the result of statfs is the sum of all block counts which does
not make sense. This patch corrects this problem by normalizing the block
counts to the same block size and then adds them.
Signed-off-by: Daniel Alder <hac...@wolke7.net>
Index: aufs3-standalone.git/fs/aufs/super.c
===================================================================
--- a/fs/aufs/super.c
+++ b/fs/aufs/super.c
@@ -305,7 +305,18 @@ static u64 au_add_till_max(u64 a, u64 b)
old = a;
a += b;
- if (old < a)
+ if (old <= a)
+ return a;
+ return ULLONG_MAX;
+}
+
+static u64 au_mul_till_max(u64 a, long mul)
+{
+ u64 old;
+
+ old = a;
+ a *= mul;
+ if (old <= a)
return a;
return ULLONG_MAX;
}
@@ -313,25 +324,26 @@ static u64 au_add_till_max(u64 a, u64 b)
static int au_statfs_sum(struct super_block *sb, struct kstatfs *buf)
{
int err;
+ long bsize, factor;
u64 blocks, bfree, bavail, files, ffree;
aufs_bindex_t bend, bindex, i;
unsigned char shared;
struct path h_path;
struct super_block *h_sb;
+ bend = au_sbend(sb);
+
+ bsize = LONG_MAX;
+ files = 0;
+ ffree = 0;
blocks = 0;
bfree = 0;
bavail = 0;
- files = 0;
- ffree = 0;
-
- err = 0;
- bend = au_sbend(sb);
- for (bindex = bend; bindex >= 0; bindex--) {
+ for (bindex = 0; bindex <= bend; bindex++) {
h_path.mnt = au_sbr_mnt(sb, bindex);
h_sb = h_path.mnt->mnt_sb;
shared = 0;
- for (i = bindex + 1; !shared && i <= bend; i++)
+ for (i = 0; !shared && i < bindex; i++)
shared = (au_sbr_sb(sb, i) == h_sb);
if (shared)
continue;
@@ -342,18 +354,37 @@ static int au_statfs_sum(struct super_block *sb, struct kstatfs *buf)
if (unlikely(err))
goto out;
- blocks = au_add_till_max(blocks, buf->f_blocks);
- bfree = au_add_till_max(bfree, buf->f_bfree);
- bavail = au_add_till_max(bavail, buf->f_bavail);
+ if (bsize > buf->f_bsize) {
+ /*
+ * we will reduce bsize, so we have to expand blocks
+ * etc. to match them again
+ */
+ factor = (bsize / buf->f_bsize);
+ blocks = au_mul_till_max(blocks, factor);
+ bfree = au_mul_till_max(bfree, factor);
+ bavail = au_mul_till_max(bavail, factor);
+ bsize = buf->f_bsize;
+ }
+
+ factor = (buf->f_bsize / bsize);
+ blocks = au_add_till_max(blocks,
+ au_mul_till_max(buf->f_blocks, factor));
+ bfree = au_add_till_max(bfree,
+ au_mul_till_max(buf->f_bfree, factor));
+ bavail = au_add_till_max(bavail,
+ au_mul_till_max(buf->f_bavail, factor));
+
files = au_add_till_max(files, buf->f_files);
ffree = au_add_till_max(ffree, buf->f_ffree);
}
+ buf->f_bsize = bsize;
buf->f_blocks = blocks;
buf->f_bfree = bfree;
buf->f_bavail = bavail;
buf->f_files = files;
buf->f_ffree = ffree;
+ buf->f_frsize = 0;
out:
return err;
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