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author | Artem Bityutskiy <artem.bityutskiy@linux.intel.com> | 2012-06-01 03:26:12 +0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-06-01 04:49:27 +0400 |
commit | 020ac5b6bef15785f9dde9de89d2734ff97da733 (patch) | |
tree | 18724448be398af715d45dea42966bf276d2febb /fs/fat/fat.h | |
parent | 7bc1bac77a69011550ce0613f4a23712a002d7ad (diff) | |
download | linux-020ac5b6bef15785f9dde9de89d2734ff97da733.tar.xz |
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 'fs/fat/fat.h')
-rw-r--r-- | fs/fat/fat.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/fat/fat.h b/fs/fat/fat.h index 66994f316e18..951d12b61b58 100644 --- a/fs/fat/fat.h +++ b/fs/fat/fat.h @@ -82,6 +82,7 @@ struct msdos_sb_info { int fatent_shift; struct fatent_operations *fatent_ops; struct inode *fat_inode; + struct inode *fsinfo_inode; struct ratelimit_state ratelimit; |