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authorAndreas Rohner <andreas.rohner@gmx.net>2014-12-10 15:54:29 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-12-10 17:41:16 -0800
commit75dc857c46996e336cb2f9cf0ed1e5508fb241a7 (patch)
treeb8893865031ac34609d7991478a71483b3ce8a5f
parent6528b889955d36caa06712789746cfbd0ecf3898 (diff)
downloadlinux-75dc857c46996e336cb2f9cf0ed1e5508fb241a7.tar.bz2
nilfs2: avoid duplicate segment construction for fsync()
This patch removes filemap_write_and_wait_range() from nilfs_sync_file(), because it triggers a data segment construction by calling nilfs_writepages() with WB_SYNC_ALL. A data segment construction does not remove the inode from the i_dirty list and it does not clear the NILFS_I_DIRTY flag. Therefore nilfs_inode_dirty() still returns true, which leads to an unnecessary duplicate segment construction in nilfs_sync_file(). A call to filemap_write_and_wait_range() is not needed, because NILFS2 does not rely on the generic writeback mechanisms. Instead it implements its own mechanism to collect all dirty pages and write them into segments. It is more efficient to initiate the segment construction directly in nilfs_sync_file() without the detour over filemap_write_and_wait_range(). Additionally the lock of i_mutex is not needed, because all code blocks that are protected by i_mutex are also protected by a NILFS transaction: Function i_mutex nilfs_transaction ------------------------------------------------------ nilfs_ioctl_setflags: yes yes nilfs_fiemap: yes no nilfs_write_begin: yes yes nilfs_write_end: yes yes nilfs_lookup: yes no nilfs_create: yes yes nilfs_link: yes yes nilfs_mknod: yes yes nilfs_symlink: yes yes nilfs_mkdir: yes yes nilfs_unlink: yes yes nilfs_rmdir: yes yes nilfs_rename: yes yes nilfs_setattr: yes yes For nilfs_lookup() i_mutex is held for the parent directory, to protect it from modification. The segment construction does not modify directory inodes, so no lock is needed. nilfs_fiemap() reads the block layout on the disk, by using nilfs_bmap_lookup_contig(). This is already protected by bmap->b_sem. Signed-off-by: Andreas Rohner <andreas.rohner@gmx.net> Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/nilfs2/file.c10
1 files changed, 2 insertions, 8 deletions
diff --git a/fs/nilfs2/file.c b/fs/nilfs2/file.c
index e9e3325f29f3..3a03e0aea1fb 100644
--- a/fs/nilfs2/file.c
+++ b/fs/nilfs2/file.c
@@ -39,21 +39,15 @@ int nilfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
*/
struct the_nilfs *nilfs;
struct inode *inode = file->f_mapping->host;
- int err;
-
- err = filemap_write_and_wait_range(inode->i_mapping, start, end);
- if (err)
- return err;
- mutex_lock(&inode->i_mutex);
+ int err = 0;
if (nilfs_inode_dirty(inode)) {
if (datasync)
err = nilfs_construct_dsync_segment(inode->i_sb, inode,
- 0, LLONG_MAX);
+ start, end);
else
err = nilfs_construct_segment(inode->i_sb);
}
- mutex_unlock(&inode->i_mutex);
nilfs = inode->i_sb->s_fs_info;
if (!err)