From: Artem Bityutskiy <[email protected]> This patch makes hfs stop using the VFS '->write_super()' method along with the 's_dirt' superblock flag, because they are on their way out.
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 superblocks 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, even if there are no diry superblocks, or there are no client file-systems which would need this (e.g., btrfs does not use '->write_super()'). 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. Tested using fsstress from the LTP project. Signed-off-by: Artem Bityutskiy <[email protected]> --- fs/hfs/extent.c | 2 +- fs/hfs/hfs_fs.h | 9 ++++++- fs/hfs/inode.c | 11 +++------ fs/hfs/super.c | 65 +++++++++++++++++++++++++++++------------------------- 4 files changed, 48 insertions(+), 39 deletions(-) diff --git a/fs/hfs/extent.c b/fs/hfs/extent.c index 2c16316..a67955a 100644 --- a/fs/hfs/extent.c +++ b/fs/hfs/extent.c @@ -432,7 +432,7 @@ out: if (inode->i_ino < HFS_FIRSTUSER_CNID) set_bit(HFS_FLG_ALT_MDB_DIRTY, &HFS_SB(sb)->flags); set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags); - sb->s_dirt = 1; + hfs_mark_mdb_dirty(sb); } return res; diff --git a/fs/hfs/hfs_fs.h b/fs/hfs/hfs_fs.h index 3515612..8275175 100644 --- a/fs/hfs/hfs_fs.h +++ b/fs/hfs/hfs_fs.h @@ -14,6 +14,7 @@ #include <linux/mutex.h> #include <linux/buffer_head.h> #include <linux/fs.h> +#include <linux/workqueue.h> #include <asm/byteorder.h> #include <asm/uaccess.h> @@ -143,6 +144,9 @@ struct hfs_sb_info { u16 blockoffset; int fs_div; struct super_block *sb; + int work_queued; /* non-zero delayed work is queued */ + struct delayed_work mdb_work; /* MDB flush delayed work */ + spinlock_t work_lock; /* protects mdb_work and work_queued */ }; #define HFS_FLG_BITMAP_DIRTY 0 @@ -222,6 +226,9 @@ extern int hfs_compare_dentry(const struct dentry *parent, extern void hfs_asc2mac(struct super_block *, struct hfs_name *, struct qstr *); extern int hfs_mac2asc(struct super_block *, char *, const struct hfs_name *); +/* super.c */ +extern void hfs_mark_mdb_dirty(struct super_block *sb); + extern struct timezone sys_tz; /* @@ -249,7 +256,7 @@ static inline const char *hfs_mdb_name(struct super_block *sb) static inline void hfs_bitmap_dirty(struct super_block *sb) { set_bit(HFS_FLG_BITMAP_DIRTY, &HFS_SB(sb)->flags); - sb->s_dirt = 1; + hfs_mark_mdb_dirty(sb); } #define sb_bread512(sb, sec, data) ({ \ diff --git a/fs/hfs/inode.c b/fs/hfs/inode.c index 629eba4..cb78138 100644 --- a/fs/hfs/inode.c +++ b/fs/hfs/inode.c @@ -220,7 +220,7 @@ struct inode *hfs_new_inode(struct inode *dir, struct qstr *name, umode_t mode) insert_inode_hash(inode); mark_inode_dirty(inode); set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags); - sb->s_dirt = 1; + hfs_mark_mdb_dirty(sb); return inode; } @@ -235,7 +235,7 @@ void hfs_delete_inode(struct inode *inode) if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID)) HFS_SB(sb)->root_dirs--; set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags); - sb->s_dirt = 1; + hfs_mark_mdb_dirty(sb); return; } HFS_SB(sb)->file_count--; @@ -248,7 +248,7 @@ void hfs_delete_inode(struct inode *inode) } } set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags); - sb->s_dirt = 1; + hfs_mark_mdb_dirty(sb); } void hfs_inode_read_fork(struct inode *inode, struct hfs_extent *ext, @@ -644,10 +644,7 @@ static int hfs_file_fsync(struct file *filp, loff_t start, loff_t end, /* sync the superblock to buffers */ sb = inode->i_sb; - if (sb->s_dirt) { - sb->s_dirt = 0; - hfs_mdb_commit(sb); - } + flush_delayed_work_sync(&HFS_SB(sb)->mdb_work); /* .. finally sync the buffers to disk */ err = sync_blockdev(sb->s_bdev); if (!ret) diff --git a/fs/hfs/super.c b/fs/hfs/super.c index 99c6239..4eb873e 100644 --- a/fs/hfs/super.c +++ b/fs/hfs/super.c @@ -29,38 +29,9 @@ static struct kmem_cache *hfs_inode_cachep; MODULE_LICENSE("GPL"); -/* - * hfs_write_super() - * - * Description: - * This function is called by the VFS only. When the filesystem - * is mounted r/w it updates the MDB on disk. - * Input Variable(s): - * struct super_block *sb: Pointer to the hfs superblock - * Output Variable(s): - * NONE - * Returns: - * void - * Preconditions: - * 'sb' points to a "valid" (struct super_block). - * Postconditions: - * The MDB is marked 'unsuccessfully unmounted' by clearing bit 8 of drAtrb - * (hfs_put_super() must set this flag!). Some MDB fields are updated - * and the MDB buffer is written to disk by calling hfs_mdb_commit(). - */ -static void hfs_write_super(struct super_block *sb) -{ - sb->s_dirt = 0; - - /* sync everything to the buffers */ - hfs_mdb_commit(sb); -} - static int hfs_sync_fs(struct super_block *sb, int wait) { hfs_mdb_commit(sb); - sb->s_dirt = 0; - return 0; } @@ -73,11 +44,44 @@ static int hfs_sync_fs(struct super_block *sb, int wait) */ static void hfs_put_super(struct super_block *sb) { + cancel_delayed_work_sync(&HFS_SB(sb)->mdb_work); hfs_mdb_close(sb); /* release the MDB's resources */ hfs_mdb_put(sb); } +static void flush_mdb(struct work_struct *work) +{ + struct hfs_sb_info *sbi; + struct super_block *sb; + + sbi = container_of(work, struct hfs_sb_info, mdb_work.work); + sb = sbi->sb; + + spin_lock(&sbi->work_lock); + sbi->work_queued = 0; + spin_unlock(&sbi->work_lock); + + hfs_mdb_commit(sb); +} + +void hfs_mark_mdb_dirty(struct super_block *sb) +{ + struct hfs_sb_info *sbi = HFS_SB(sb); + unsigned long delay; + + if (sb->s_flags & MS_RDONLY) + return; + + spin_lock(&sbi->work_lock); + if (!sbi->work_queued) { + delay = msecs_to_jiffies(dirty_writeback_interval * 10); + queue_delayed_work(system_long_wq, &sbi->mdb_work, delay); + sbi->work_queued = 1; + } + spin_unlock(&sbi->work_lock); +} + /* * hfs_statfs() * @@ -177,7 +181,6 @@ static const struct super_operations hfs_super_operations = { .write_inode = hfs_write_inode, .evict_inode = hfs_evict_inode, .put_super = hfs_put_super, - .write_super = hfs_write_super, .sync_fs = hfs_sync_fs, .statfs = hfs_statfs, .remount_fs = hfs_remount, @@ -382,6 +385,8 @@ static int hfs_fill_super(struct super_block *sb, void *data, int silent) sbi->sb = sb; sb->s_fs_info = sbi; + spin_lock_init(&sbi->work_lock); + INIT_DELAYED_WORK(&sbi->mdb_work, flush_mdb); res = -EINVAL; if (!parse_options((char *)data, sbi)) { -- 1.7.7.6 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
