[PATCH v3 1/6] fat: add i_disksize to represent uninitialized size

From: Namjae Jeon
Date: Wed Dec 25 2013 - 01:32:36 EST


From: Namjae Jeon <namjae.jeon@xxxxxxxxxxx>

Add i_disksize to represent uninitialized allocated size.
And mmu_private represent initialized allocated size.

Signed-off-by: Namjae Jeon <namjae.jeon@xxxxxxxxxxx>
Signed-off-by: Amit Sahrawat <a.sahrawat@xxxxxxxxxxx>
---
fs/fat/cache.c | 6 +++---
fs/fat/fat.h | 3 ++-
fs/fat/file.c | 4 +++-
fs/fat/inode.c | 4 ++++
4 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/fs/fat/cache.c b/fs/fat/cache.c
index 91ad9e1..a132666 100644
--- a/fs/fat/cache.c
+++ b/fs/fat/cache.c
@@ -329,10 +329,10 @@ int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
return 0;

/*
- * ->mmu_private can access on only allocation path.
- * (caller must hold ->i_mutex)
+ * Both ->mmu_private and ->i_disksize can access
+ * on only allocation path. (caller must hold ->i_mutex)
*/
- last_block = (MSDOS_I(inode)->mmu_private + (blocksize - 1))
+ last_block = (MSDOS_I(inode)->i_disksize + (blocksize - 1))
>> blocksize_bits;
if (sector >= last_block)
return 0;
diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index 7c31f4b..7b5851f 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -118,7 +118,8 @@ struct msdos_inode_info {
unsigned int cache_valid_id;

/* NOTE: mmu_private is 64bits, so must hold ->i_mutex to access */
- loff_t mmu_private; /* physically allocated size */
+ loff_t mmu_private; /* physically allocated size (initialized) */
+ loff_t i_disksize; /* physically allocated size (uninitialized) */

int i_start; /* first cluster or 0 */
int i_logstart; /* logical first cluster */
diff --git a/fs/fat/file.c b/fs/fat/file.c
index 9b104f5..0bf0d28 100644
--- a/fs/fat/file.c
+++ b/fs/fat/file.c
@@ -300,8 +300,10 @@ void fat_truncate_blocks(struct inode *inode, loff_t offset)
* This protects against truncating a file bigger than it was then
* trying to write into the hole.
*/
- if (MSDOS_I(inode)->mmu_private > offset)
+ if (MSDOS_I(inode)->i_disksize > offset) {
MSDOS_I(inode)->mmu_private = offset;
+ MSDOS_I(inode)->i_disksize = offset;
+ }

nr_clusters = (offset + (cluster_size - 1)) >> sbi->cluster_bits;

diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 854b578..7e5531a 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -93,6 +93,7 @@ static inline int __fat_get_block(struct inode *inode, sector_t iblock,

*max_blocks = min(mapped_blocks, *max_blocks);
MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
+ MSDOS_I(inode)->i_disksize = MSDOS_I(inode)->mmu_private;

err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
if (err)
@@ -408,6 +409,7 @@ int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
if (error < 0)
return error;
MSDOS_I(inode)->mmu_private = inode->i_size;
+ MSDOS_I(inode)->i_disksize = inode->i_size;

set_nlink(inode, fat_subdirs(inode));
} else { /* not a directory */
@@ -423,6 +425,7 @@ int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
inode->i_fop = &fat_file_operations;
inode->i_mapping->a_ops = &fat_aops;
MSDOS_I(inode)->mmu_private = inode->i_size;
+ MSDOS_I(inode)->i_disksize = inode->i_size;
}
if (de->attr & ATTR_SYS) {
if (sbi->options.sys_immutable)
@@ -1223,6 +1226,7 @@ static int fat_read_root(struct inode *inode)
& ~((loff_t)sbi->cluster_size - 1)) >> 9;
MSDOS_I(inode)->i_logstart = 0;
MSDOS_I(inode)->mmu_private = inode->i_size;
+ MSDOS_I(inode)->i_disksize = inode->i_size;

fat_save_attrs(inode, ATTR_DIR);
inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
--
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/