[PATCH 2/2] updating ctime and mtime at syncing
From: Anton Salikhmetov
Date: Sat Jan 12 2008 - 23:40:57 EST
http://bugzilla.kernel.org/show_bug.cgi?id=2645
Changes for updating the ctime and mtime fields for memory-mapped files:
1) new flag triggering update of the inode data;
2) new function to update ctime and mtime for block device files;
3) new helper function to update ctime and mtime when needed;
4) updating time stamps for mapped files in sys_msync() and do_fsync();
5) implementing the feature of auto-updating ctime and mtime.
Signed-off-by: Anton Salikhmetov <salikhmetov@xxxxxxxxx>
---
fs/buffer.c | 1 +
fs/fs-writeback.c | 2 ++
fs/inode.c | 42 +++++++++++++++++++++++++++++++++++-------
fs/sync.c | 2 ++
include/linux/fs.h | 9 ++++++++-
include/linux/pagemap.h | 3 ++-
mm/msync.c | 24 ++++++++++++++++--------
mm/page-writeback.c | 1 +
8 files changed, 67 insertions(+), 17 deletions(-)
diff --git a/fs/buffer.c b/fs/buffer.c
index 7249e01..09adf7e 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -719,6 +719,7 @@ static int __set_page_dirty(struct page *page,
}
write_unlock_irq(&mapping->tree_lock);
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
+ set_bit(AS_MCTIME, &mapping->flags);
return 1;
}
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 0fca820..c25ebd5 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -243,6 +243,8 @@ __sync_single_inode(struct inode *inode, struct writeback_control *wbc)
spin_unlock(&inode_lock);
+ mapping_update_time(mapping);
+
ret = do_writepages(mapping, wbc);
/* Don't write the inode if only I_DIRTY_PAGES was set */
diff --git a/fs/inode.c b/fs/inode.c
index ed35383..c02bfab 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1243,8 +1243,8 @@ void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
EXPORT_SYMBOL(touch_atime);
/**
- * file_update_time - update mtime and ctime time
- * @file: file accessed
+ * inode_update_time - update mtime and ctime time
+ * @inode: inode accessed
*
* Update the mtime and ctime members of an inode and mark the inode
* for writeback. Note that this function is meant exclusively for
@@ -1253,10 +1253,8 @@ EXPORT_SYMBOL(touch_atime);
* S_NOCTIME inode flag, e.g. for network filesystem where these
* timestamps are handled by the server.
*/
-
-void file_update_time(struct file *file)
+void inode_update_time(struct inode *inode)
{
- struct inode *inode = file->f_path.dentry->d_inode;
struct timespec now;
int sync_it = 0;
@@ -1279,8 +1277,39 @@ void file_update_time(struct file *file)
if (sync_it)
mark_inode_dirty_sync(inode);
}
+EXPORT_SYMBOL(inode_update_time);
+
+/*
+ * Update the ctime and mtime stamps for memory-mapped block device files.
+ */
+static void bd_inode_update_time(struct inode *inode)
+{
+ struct block_device *bdev = inode->i_bdev;
+ struct list_head *p;
+
+ if (bdev == NULL)
+ return;
+
+ mutex_lock(&bdev->bd_mutex);
+ list_for_each(p, &bdev->bd_inodes) {
+ inode = list_entry(p, struct inode, i_devices);
+ inode_update_time(inode);
+ }
+ mutex_unlock(&bdev->bd_mutex);
+}
-EXPORT_SYMBOL(file_update_time);
+/*
+ * Update the ctime and mtime stamps after checking if they are to be updated.
+ */
+void mapping_update_time(struct address_space *mapping)
+{
+ if (test_and_clear_bit(AS_MCTIME, &mapping->flags)) {
+ if (S_ISBLK(mapping->host->i_mode))
+ bd_inode_update_time(mapping->host);
+ else
+ inode_update_time(mapping->host);
+ }
+}
int inode_needs_sync(struct inode *inode)
{
@@ -1290,7 +1319,6 @@ int inode_needs_sync(struct inode *inode)
return 1;
return 0;
}
-
EXPORT_SYMBOL(inode_needs_sync);
int inode_wait(void *word)
diff --git a/fs/sync.c b/fs/sync.c
index 7cd005e..5561464 100644
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -87,6 +87,8 @@ long do_fsync(struct file *file, int datasync)
goto out;
}
+ mapping_update_time(mapping);
+
ret = filemap_fdatawrite(mapping);
/*
diff --git a/include/linux/fs.h b/include/linux/fs.h
index b3ec4a4..1dccd4b 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1977,7 +1977,14 @@ extern int buffer_migrate_page(struct address_space *,
extern int inode_change_ok(struct inode *, struct iattr *);
extern int __must_check inode_setattr(struct inode *, struct iattr *);
-extern void file_update_time(struct file *file);
+extern void inode_update_time(struct inode *);
+
+static inline void file_update_time(struct file *file)
+{
+ inode_update_time(file->f_path.dentry->d_inode);
+}
+
+extern void mapping_update_time(struct address_space *);
static inline ino_t parent_ino(struct dentry *dentry)
{
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index db8a410..bf0f9e7 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -17,8 +17,9 @@
* Bits in mapping->flags. The lower __GFP_BITS_SHIFT bits are the page
* allocation mode flags.
*/
-#define AS_EIO (__GFP_BITS_SHIFT + 0) /* IO error on async write */
+#define AS_EIO (__GFP_BITS_SHIFT + 0) /* IO error on async write */
#define AS_ENOSPC (__GFP_BITS_SHIFT + 1) /* ENOSPC on async write */
+#define AS_MCTIME (__GFP_BITS_SHIFT + 2) /* mtime and ctime to update */
static inline void mapping_set_error(struct address_space *mapping, int error)
{
diff --git a/mm/msync.c b/mm/msync.c
index ff654c9..07dc8fc 100644
--- a/mm/msync.c
+++ b/mm/msync.c
@@ -5,6 +5,7 @@
* Copyright (C) 1994-1999 Linus Torvalds
*
* Substantial code cleanup.
+ * Updating the ctime and mtime stamps for memory-mapped files.
* Copyright (C) 2008 Anton Salikhmetov <salikhmetov@xxxxxxxxx>
*/
@@ -22,6 +23,10 @@
* Nor does it mark the relevant pages dirty (it used to up to 2.6.17).
* Now it doesn't do anything, since dirty pages are properly tracked.
*
+ * The msync() system call updates the ctime and mtime fields for
+ * the mapped file when called with the MS_SYNC or MS_ASYNC flags
+ * according to the POSIX standard.
+ *
* The application may now run fsync() to
* write out the dirty pages and wait on the writeout and check the result.
* Or the application may run fadvise(FADV_DONTNEED) against the fd to start
@@ -76,14 +81,17 @@ asmlinkage long sys_msync(unsigned long start, size_t len, int flags)
break;
}
file = vma->vm_file;
- if ((flags & MS_SYNC) && file && (vma->vm_flags & VM_SHARED)) {
- get_file(file);
- up_read(&mm->mmap_sem);
- error = do_fsync(file, 0);
- fput(file);
- if (error)
- return error;
- down_read(&mm->mmap_sem);
+ if (file && (vma->vm_flags & VM_SHARED)) {
+ mapping_update_time(file->f_mapping);
+ if (flags & MS_SYNC) {
+ get_file(file);
+ up_read(&mm->mmap_sem);
+ error = do_fsync(file, 0);
+ fput(file);
+ if (error)
+ return error;
+ down_read(&mm->mmap_sem);
+ }
}
start = vma->vm_end;
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index d55cfca..a85df0b 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1025,6 +1025,7 @@ int __set_page_dirty_nobuffers(struct page *page)
if (mapping->host) {
/* !PageAnon && !swapper_space */
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
+ set_bit(AS_MCTIME, &mapping->flags);
}
return 1;
}
--
1.4.4.4
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