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author | Artem Bityutskiy <artem.bityutskiy@linux.intel.com> | 2012-05-31 16:26:13 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-05-31 17:49:28 -0700 |
commit | 78491189ddb6d84d4a4abae992ed891a236d0263 (patch) | |
tree | f451b46a2c0a505b6812b696e03604b8613b3df0 /fs/fat | |
parent | 330fe3c4c6509e0418c434b5bcf80e65cffab477 (diff) | |
download | kernel_goldelico_gta04-78491189ddb6d84d4a4abae992ed891a236d0263.zip kernel_goldelico_gta04-78491189ddb6d84d4a4abae992ed891a236d0263.tar.gz kernel_goldelico_gta04-78491189ddb6d84d4a4abae992ed891a236d0263.tar.bz2 |
fat: switch to fsinfo_inode
Currently FAT file-system maps the VFS "superblock" abstraction to the
FSINFO block. The FSINFO block contains non-essential data about the
amount of free clusters and the next free cluster. FAT file-system can
always find out this information by scanning the FAT table, but having it
in the FSINFO block may speed things up sometimes. So FAT file-system
relies on the VFS superblock write-out services to make sure the FSINFO
block is written out to the media from time to time.
The whole "superblock write-out" VFS infrastructure is served by the
'sync_supers()' kernel thread, which wakes up every 5 (by default) seconds
and writes out all dirty superblock using the '->write_super()' call-back.
But the problem with this thread is that it wastes power by waking up the
system every 5 seconds no matter what. So we want to kill it completely
and thus, we need to make file-systems to stop using the '->write_super'
VFS service, and then remove it together with the kernel thread.
This patch switches the FAT FSINFO block management from
'->write_super()'/'->s_dirt' to 'fsinfo_inode'/'->write_inode'. Now,
instead of setting the 's_dirt' flag, we just mark the special
'fsinfo_inode' inode as dirty and let VFS invoke the '->write_inode'
call-back when needed, where we write-out the FSINFO block.
This patch also makes sure we do not mark the 'fsinfo_inode' inode as
dirty if we are not FAT32 (FAT16 and FAT12 do not have the FSINFO block)
or if we are in R/O mode.
As a bonus, we can also remove the '->sync_fs()' and '->write_super()' FAT
call-back function because they become unneeded.
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')
-rw-r--r-- | fs/fat/fatent.c | 7 | ||||
-rw-r--r-- | fs/fat/inode.c | 42 |
2 files changed, 18 insertions, 31 deletions
diff --git a/fs/fat/fatent.c b/fs/fat/fatent.c index 8181548..31f08ab 100644 --- a/fs/fat/fatent.c +++ b/fs/fat/fatent.c @@ -310,7 +310,12 @@ void fat_ent_access_init(struct super_block *sb) static void mark_fsinfo_dirty(struct super_block *sb) { - sb->s_dirt = 1; + struct msdos_sb_info *sbi = MSDOS_SB(sb); + + if (sb->s_flags & MS_RDONLY || sbi->fat_bits != 32) + return; + + __mark_inode_dirty(sbi->fsinfo_inode, I_DIRTY_SYNC); } static inline int fat_ent_update_ptr(struct super_block *sb, diff --git a/fs/fat/inode.c b/fs/fat/inode.c index 84c602b..c2973ea 100644 --- a/fs/fat/inode.c +++ b/fs/fat/inode.c @@ -459,37 +459,10 @@ static void fat_evict_inode(struct inode *inode) fat_detach(inode); } -static void fat_write_super(struct super_block *sb) -{ - lock_super(sb); - sb->s_dirt = 0; - - if (!(sb->s_flags & MS_RDONLY)) - fat_clusters_flush(sb); - unlock_super(sb); -} - -static int fat_sync_fs(struct super_block *sb, int wait) -{ - int err = 0; - - if (sb->s_dirt) { - lock_super(sb); - sb->s_dirt = 0; - err = fat_clusters_flush(sb); - unlock_super(sb); - } - - return err; -} - static void fat_put_super(struct super_block *sb) { struct msdos_sb_info *sbi = MSDOS_SB(sb); - if (sb->s_dirt) - fat_write_super(sb); - iput(sbi->fsinfo_inode); iput(sbi->fat_inode); @@ -662,7 +635,18 @@ retry: static int fat_write_inode(struct inode *inode, struct writeback_control *wbc) { - return __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL); + int err; + + if (inode->i_ino == MSDOS_FSINFO_INO) { + struct super_block *sb = inode->i_sb; + + lock_super(sb); + err = fat_clusters_flush(sb); + unlock_super(sb); + } else + err = __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL); + + return err; } int fat_sync_inode(struct inode *inode) @@ -679,8 +663,6 @@ static const struct super_operations fat_sops = { .write_inode = fat_write_inode, .evict_inode = fat_evict_inode, .put_super = fat_put_super, - .write_super = fat_write_super, - .sync_fs = fat_sync_fs, .statfs = fat_statfs, .remount_fs = fat_remount, |