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ext4: Add support for 48 bit inode i_blocks.
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Use the __le16 l_i_reserved1 field of the linux2 struct of ext4_inode
to represet the higher 16 bits for i_blocks. With this change max_file
size becomes (2**48 -1 )* 512 bytes.

We add a RO_COMPAT feature to the super block to indicate that inode
have i_blocks represented as a split 48 bits. Super block with this
feature set cannot be mounted read write on a kernel with CONFIG_LSF
disabled.

Super block flag EXT4_FEATURE_RO_COMPAT_HUGE_FILE

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
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Aneesh Kumar K.V authored and Theodore Ts'o committed Jan 29, 2008
1 parent a48380f commit 0fc1b45
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Showing 3 changed files with 119 additions and 11 deletions.
58 changes: 56 additions & 2 deletions fs/ext4/inode.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2667,6 +2667,22 @@ void ext4_get_inode_flags(struct ext4_inode_info *ei)
if (flags & S_DIRSYNC)
ei->i_flags |= EXT4_DIRSYNC_FL;
}
static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
struct ext4_inode_info *ei)
{
blkcnt_t i_blocks ;
struct super_block *sb = ei->vfs_inode.i_sb;

if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
/* we are using combined 48 bit field */
i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
le32_to_cpu(raw_inode->i_blocks_lo);
return i_blocks;
} else {
return le32_to_cpu(raw_inode->i_blocks_lo);
}
}

void ext4_read_inode(struct inode * inode)
{
Expand Down Expand Up @@ -2715,8 +2731,8 @@ void ext4_read_inode(struct inode * inode)
* recovery code: that's fine, we're about to complete
* the process of deleting those. */
}
inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
ei->i_flags = le32_to_cpu(raw_inode->i_flags);
inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
cpu_to_le32(EXT4_OS_HURD)) {
Expand Down Expand Up @@ -2799,6 +2815,43 @@ void ext4_read_inode(struct inode * inode)
return;
}

static int ext4_inode_blocks_set(handle_t *handle,
struct ext4_inode *raw_inode,
struct ext4_inode_info *ei)
{
struct inode *inode = &(ei->vfs_inode);
u64 i_blocks = inode->i_blocks;
struct super_block *sb = inode->i_sb;
int err = 0;

if (i_blocks <= ~0U) {
/*
* i_blocks can be represnted in a 32 bit variable
* as multiple of 512 bytes
*/
raw_inode->i_blocks_lo = cpu_to_le32((u32)i_blocks);
raw_inode->i_blocks_high = 0;
} else if (i_blocks <= 0xffffffffffffULL) {
/*
* i_blocks can be represented in a 48 bit variable
* as multiple of 512 bytes
*/
err = ext4_update_rocompat_feature(handle, sb,
EXT4_FEATURE_RO_COMPAT_HUGE_FILE);
if (err)
goto err_out;
/* i_block is stored in the split 48 bit fields */
raw_inode->i_blocks_lo = cpu_to_le32((u32)i_blocks);
raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
} else {
ext4_error(sb, __FUNCTION__,
"Wrong inode i_blocks count %llu\n",
(unsigned long long)inode->i_blocks);
}
err_out:
return err;
}

/*
* Post the struct inode info into an on-disk inode location in the
* buffer-cache. This gobbles the caller's reference to the
Expand Down Expand Up @@ -2853,7 +2906,8 @@ static int ext4_do_update_inode(handle_t *handle,
EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);

raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
if (ext4_inode_blocks_set(handle, raw_inode, ei))
goto out_brelse;
raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
raw_inode->i_flags = cpu_to_le32(ei->i_flags);
if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
Expand Down
62 changes: 56 additions & 6 deletions fs/ext4/super.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1603,24 +1603,61 @@ static void ext4_orphan_cleanup (struct super_block * sb,

/*
* Maximal file size. There is a direct, and {,double-,triple-}indirect
* block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
* We need to be 1 filesystem block less than the 2^32 sector limit.
* block limit, and also a limit of (2^48 - 1) 512-byte sectors in i_blocks.
* We need to be 1 filesystem block less than the 2^48 sector limit.
*/
static loff_t ext4_max_size(int bits)
{
loff_t res = EXT4_NDIR_BLOCKS;
/* This constant is calculated to be the largest file size for a
* dense, 4k-blocksize file such that the total number of
int meta_blocks;
loff_t upper_limit;
/* This is calculated to be the largest file size for a
* dense, file such that the total number of
* sectors in the file, including data and all indirect blocks,
* does not exceed 2^32. */
const loff_t upper_limit = 0x1ff7fffd000LL;
* does not exceed 2^48 -1
* __u32 i_blocks_lo and _u16 i_blocks_high representing the
* total number of 512 bytes blocks of the file
*/

if (sizeof(blkcnt_t) < sizeof(u64)) {
/*
* CONFIG_LSF is not enabled implies the inode
* i_block represent total blocks in 512 bytes
* 32 == size of vfs inode i_blocks * 8
*/
upper_limit = (1LL << 32) - 1;

/* total blocks in file system block size */
upper_limit >>= (bits - 9);

} else {
/* We use 48 bit ext4_inode i_blocks */
upper_limit = (1LL << 48) - 1;

/* total blocks in file system block size */
upper_limit >>= (bits - 9);
}

/* indirect blocks */
meta_blocks = 1;
/* double indirect blocks */
meta_blocks += 1 + (1LL << (bits-2));
/* tripple indirect blocks */
meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));

upper_limit -= meta_blocks;
upper_limit <<= bits;

res += 1LL << (bits-2);
res += 1LL << (2*(bits-2));
res += 1LL << (3*(bits-2));
res <<= bits;
if (res > upper_limit)
res = upper_limit;

if (res > MAX_LFS_FILESIZE)
res = MAX_LFS_FILESIZE;

return res;
}

Expand Down Expand Up @@ -1789,6 +1826,19 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
sb->s_id, le32_to_cpu(features));
goto failed_mount;
}
if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
/*
* Large file size enabled file system can only be
* mount if kernel is build with CONFIG_LSF
*/
if (sizeof(root->i_blocks) < sizeof(u64) &&
!(sb->s_flags & MS_RDONLY)) {
printk(KERN_ERR "EXT4-fs: %s: Filesystem with huge "
"files cannot be mounted read-write "
"without CONFIG_LSF.\n", sb->s_id);
goto failed_mount;
}
}
blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);

if (blocksize < EXT4_MIN_BLOCK_SIZE ||
Expand Down
10 changes: 7 additions & 3 deletions include/linux/ext4_fs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -282,7 +282,7 @@ struct ext4_inode {
__le32 i_dtime; /* Deletion Time */
__le16 i_gid; /* Low 16 bits of Group Id */
__le16 i_links_count; /* Links count */
__le32 i_blocks; /* Blocks count */
__le32 i_blocks_lo; /* Blocks count */
__le32 i_flags; /* File flags */
union {
struct {
Expand All @@ -302,7 +302,7 @@ struct ext4_inode {
__le32 i_obso_faddr; /* Obsoleted fragment address */
union {
struct {
__le16 l_i_reserved1; /* Obsoleted fragment number/size which are removed in ext4 */
__le16 l_i_blocks_high; /* were l_i_reserved1 */
__le16 l_i_file_acl_high;
__le16 l_i_uid_high; /* these 2 fields */
__le16 l_i_gid_high; /* were reserved2[0] */
Expand Down Expand Up @@ -404,6 +404,7 @@ do { \
#if defined(__KERNEL__) || defined(__linux__)
#define i_reserved1 osd1.linux1.l_i_reserved1
#define i_file_acl_high osd2.linux2.l_i_file_acl_high
#define i_blocks_high osd2.linux2.l_i_blocks_high
#define i_uid_low i_uid
#define i_gid_low i_gid
#define i_uid_high osd2.linux2.l_i_uid_high
Expand Down Expand Up @@ -670,6 +671,7 @@ static inline int ext4_valid_inum(struct super_block *sb, unsigned long ino)
#define EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER 0x0001
#define EXT4_FEATURE_RO_COMPAT_LARGE_FILE 0x0002
#define EXT4_FEATURE_RO_COMPAT_BTREE_DIR 0x0004
#define EXT4_FEATURE_RO_COMPAT_HUGE_FILE 0x0008
#define EXT4_FEATURE_RO_COMPAT_GDT_CSUM 0x0010
#define EXT4_FEATURE_RO_COMPAT_DIR_NLINK 0x0020
#define EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE 0x0040
Expand All @@ -681,6 +683,7 @@ static inline int ext4_valid_inum(struct super_block *sb, unsigned long ino)
#define EXT4_FEATURE_INCOMPAT_META_BG 0x0010
#define EXT4_FEATURE_INCOMPAT_EXTENTS 0x0040 /* extents support */
#define EXT4_FEATURE_INCOMPAT_64BIT 0x0080
#define EXT4_FEATURE_INCOMPAT_MMP 0x0100
#define EXT4_FEATURE_INCOMPAT_FLEX_BG 0x0200

#define EXT4_FEATURE_COMPAT_SUPP EXT2_FEATURE_COMPAT_EXT_ATTR
Expand All @@ -695,7 +698,8 @@ static inline int ext4_valid_inum(struct super_block *sb, unsigned long ino)
EXT4_FEATURE_RO_COMPAT_GDT_CSUM| \
EXT4_FEATURE_RO_COMPAT_DIR_NLINK | \
EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE | \
EXT4_FEATURE_RO_COMPAT_BTREE_DIR)
EXT4_FEATURE_RO_COMPAT_BTREE_DIR |\
EXT4_FEATURE_RO_COMPAT_HUGE_FILE)

/*
* Default values for user and/or group using reserved blocks
Expand Down

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