diff options
| author | Artem Bityutskiy <artem.bityutskiy@linux.intel.com> | 2012-05-31 16:26:12 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-05-31 17:49:27 -0700 |
| commit | 020ac5b6bef15785f9dde9de89d2734ff97da733 (patch) | |
| tree | 18724448be398af715d45dea42966bf276d2febb /include | |
| parent | 7bc1bac77a69011550ce0613f4a23712a002d7ad (diff) | |
fat: introduce special inode for managing the FSINFO block
This is patchset makes fatfs stop using the VFS '->write_super()' method
for writing out the FSINFO block.
The final goal is to get rid of the 'sync_supers()' kernel thread. This
kernel thread wakes up every 5 seconds (by default) and calls
'->write_super()' for all mounted file-systems. And the bad thing is that
this is done even if all the superblocks are clean. Moreover, some
file-systems do not even need this end they do not register the
'->write_super()' method at all (e.g., btrfs).
So 'sync_supers()' most often just generates useless wake-ups and wastes
power. I am trying to make all file-systems independent of
'->write_super()' and plan to remove 'sync_supers()' and '->write_super'
completely once there are no more users.
The '->write_supers()' method is mostly used by baroque file-systems like
hfs, udf, etc. Modern file-systems like btrfs and xfs do not use it.
This justifies removing this stuff from VFS completely and make every FS
self-manage own superblock.
Tested with xfstests.
This patch:
Preparation for further changes. It introduces a special inode
('fsinfo_inode') in FAT file-system which we'll later use for managing the
FSINFO block. Note, this there is already one special inode ('fat_inode')
which is used for managing the FAT tables.
Introduce new 'MSDOS_FSINFO_INO' constant for this special inode. It is
safe to do because FAT file-system does not store inode numbers on the
media but generates them run-time.
I've also cleaned up the comment to existing 'MSDOS_ROOT_INO' constant,
while on it.
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/msdos_fs.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/msdos_fs.h b/include/linux/msdos_fs.h index 34066e65fde..11cc2ac67e7 100644 --- a/include/linux/msdos_fs.h +++ b/include/linux/msdos_fs.h @@ -21,8 +21,9 @@ #define CT_LE_W(v) cpu_to_le16(v) #define CT_LE_L(v) cpu_to_le32(v) +#define MSDOS_ROOT_INO 1 /* The root inode number */ +#define MSDOS_FSINFO_INO 2 /* Used for managing the FSINFO block */ -#define MSDOS_ROOT_INO 1 /* == MINIX_ROOT_INO */ #define MSDOS_DIR_BITS 5 /* log2(sizeof(struct msdos_dir_entry)) */ /* directory limit */ |