The block mapped inode format can address only blocks within
2**32. So with file system larger than 2**32 don't allow
noextents mount option. There are multiple issues that need
to addressed in the long run.
a) When e2fsprogs support resizing an already existing ext3
file system to greater than 2**32 we need to add support to block
allocator to handle growing already existing block mapped inode
so that blocks allocated for them fall within 2**32
b) When we do that we should enable mounting larger file system
with -o noextents mount option.
Till them we fail mount of large file systems with -o noextents.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
---
fs/ext4/super.c | 15 +++++++++++++++
1 files changed, 15 insertions(+), 0 deletions(-)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 4e104dd..2bf9cdd 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1004,6 +1004,7 @@ static int parse_options (char *options, struct super_block *sb,
int qtype, qfmt;
char *qname;
#endif
+ ext4_fsblk_t last_block;
if (!options)
return 1;
@@ -1326,6 +1327,20 @@ static int parse_options (char *options, struct super_block *sb,
set_opt (sbi->s_mount_opt, EXTENTS);
break;
case Opt_noextents:
+ /*
+ * When e2fsprogs support resizing an already existing
+ * ext3 file system to greater than 2**32 we need to
+ * add support to block allocator to handle growing
+ * already existing block mapped inode so that blocks
+ * allocated for them fall within 2**32
+ */
+ last_block = ext4_blocks_count(sbi->s_es) - 1;
+ if (last_block > 0xffffffffULL) {
+ printk(KERN_ERR "EXT4-fs: Filesystem too "
+ "large to mount with "
+ "-o noextents options\n");
+ return 0;
+ }
clear_opt (sbi->s_mount_opt, EXTENTS);
break;
case Opt_i_version:
--
1.5.6.1.102.g8e69d.dirty
--
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