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Commit c3b2da31 authored by Josef Bacik's avatar Josef Bacik Committed by Al Viro
Browse files

fs: introduce inode operation ->update_time 



Btrfs has to make sure we have space to allocate new blocks in order to modify
the inode, so updating time can fail.  We've gotten around this by having our
own file_update_time but this is kind of a pain, and Christoph has indicated he
would like to make xfs do something different with atime updates.  So introduce
->update_time, where we will deal with i_version an a/m/c time updates and
indicate which changes need to be made.  The normal version just does what it
has always done, updates the time and marks the inode dirty, and then
filesystems can choose to do something different.

I've gone through all of the users of file_update_time and made them check for
errors with the exception of the fault code since it's complicated and I wasn't
quite sure what to do there, also Jan is going to be pushing the file time
updates into page_mkwrite for those who have it so that should satisfy btrfs and
make it not a big deal to check the file_update_time() return code in the
generic fault path. Thanks,

Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
parent 033369d1

Documentation/filesystems/Locking

+3 −0
Original line number Diff line number Diff line
@@ -62,6 +62,7 @@ ata *); 
	int (*removexattr) (struct dentry *, const char *);

	void (*truncate_range)(struct inode *, loff_t, loff_t);

	int (*fiemap)(struct inode *, struct fiemap_extent_info *, u64 start, u64 len);

	void (*update_time)(struct inode *, struct timespec *, int);



locking rules:

	all may block
@@ -89,6 +90,8 @@ listxattr: no 
removexattr:	yes

truncate_range:	yes

fiemap:		no

update_time:	no



	Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_mutex on

victim.

	cross-directory ->rename() has (per-superblock) ->s_vfs_rename_sem.

Documentation/filesystems/vfs.txt

+4 −0
Original line number Diff line number Diff line
@@ -364,6 +364,7 @@ struct inode_operations { 
	ssize_t (*listxattr) (struct dentry *, char *, size_t);

	int (*removexattr) (struct dentry *, const char *);

	void (*truncate_range)(struct inode *, loff_t, loff_t);

	void (*update_time)(struct inode *, struct timespec *, int);

};



Again, all methods are called without any locks being held, unless
@@ -475,6 +476,9 @@ otherwise noted. 
  truncate_range: a method provided by the underlying filesystem to truncate a

  	range of blocks , i.e. punch a hole somewhere in a file.



  update_time: called by the VFS to update a specific time or the i_version of

  	an inode.  If this is not defined the VFS will update the inode itself

  	and call mark_inode_dirty_sync.



The Address Space Object

========================

fs/fuse/file.c

+3 −1
Original line number Diff line number Diff line
@@ -962,7 +962,9 @@ static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov, 
	if (err)

		goto out;



	file_update_time(file);

	err = file_update_time(file);

	if (err)

		goto out;



	if (file->f_flags & O_DIRECT) {

		written = generic_file_direct_write(iocb, iov, &nr_segs,

fs/inode.c

+40 −16
Original line number Diff line number Diff line
@@ -1487,6 +1487,27 @@ static int relatime_need_update(struct vfsmount *mnt, struct inode *inode, 
	return 0;

}



/*

 * This does the actual work of updating an inodes time or version.  Must have

 * had called mnt_want_write() before calling this.

 */

static int update_time(struct inode *inode, struct timespec *time, int flags)

{

	if (inode->i_op->update_time)

		return inode->i_op->update_time(inode, time, flags);



	if (flags & S_ATIME)

		inode->i_atime = *time;

	if (flags & S_VERSION)

		inode_inc_iversion(inode);

	if (flags & S_CTIME)

		inode->i_ctime = *time;

	if (flags & S_MTIME)

		inode->i_mtime = *time;

	mark_inode_dirty_sync(inode);

	return 0;

}



/**

 *	touch_atime	-	update the access time

 *	@path: the &struct path to update
@@ -1524,8 +1545,14 @@ void touch_atime(struct path *path) 
	if (mnt_want_write(mnt))

		return;



	inode->i_atime = now;

	mark_inode_dirty_sync(inode);

	/*

	 * File systems can error out when updating inodes if they need to

	 * allocate new space to modify an inode (such is the case for

	 * Btrfs), but since we touch atime while walking down the path we

	 * really don't care if we failed to update the atime of the file,

	 * so just ignore the return value.

	 */

	update_time(inode, &now, S_ATIME);

	mnt_drop_write(mnt);

}

EXPORT_SYMBOL(touch_atime);
@@ -1604,18 +1631,20 @@ EXPORT_SYMBOL(file_remove_suid); 
 *	usage in the file write path of filesystems, and filesystems may

 *	choose to explicitly ignore update via this function with the

 *	S_NOCMTIME inode flag, e.g. for network filesystem where these

 *	timestamps are handled by the server.

 *	timestamps are handled by the server.  This can return an error for

 *	file systems who need to allocate space in order to update an inode.

 */



void file_update_time(struct file *file)

int file_update_time(struct file *file)

{

	struct inode *inode = file->f_path.dentry->d_inode;

	struct timespec now;

	enum { S_MTIME = 1, S_CTIME = 2, S_VERSION = 4 } sync_it = 0;

	int sync_it = 0;

	int ret;



	/* First try to exhaust all avenues to not sync */

	if (IS_NOCMTIME(inode))

		return;

		return 0;



	now = current_fs_time(inode->i_sb);

	if (!timespec_equal(&inode->i_mtime, &now))
@@ -1628,21 +1657,16 @@ void file_update_time(struct file *file) 
		sync_it |= S_VERSION;



	if (!sync_it)

		return;

		return 0;



	/* Finally allowed to write? Takes lock. */

	if (mnt_want_write_file(file))

		return;

		return 0;



	/* Only change inode inside the lock region */

	if (sync_it & S_VERSION)

		inode_inc_iversion(inode);

	if (sync_it & S_CTIME)

		inode->i_ctime = now;

	if (sync_it & S_MTIME)

		inode->i_mtime = now;

	mark_inode_dirty_sync(inode);

	ret = update_time(inode, &now, sync_it);

	mnt_drop_write_file(file);



	return ret;

}

EXPORT_SYMBOL(file_update_time);

fs/ncpfs/file.c

+4 −2
Original line number Diff line number Diff line
@@ -221,6 +221,10 @@ ncp_file_write(struct file *file, const char __user *buf, size_t count, loff_t * 


	already_written = 0;



	errno = file_update_time(file);

	if (errno)

		goto outrel;



	bouncebuffer = vmalloc(bufsize);

	if (!bouncebuffer) {

		errno = -EIO;	/* -ENOMEM */
@@ -252,8 +256,6 @@ ncp_file_write(struct file *file, const char __user *buf, size_t count, loff_t * 
	}

	vfree(bouncebuffer);



	file_update_time(file);



	*ppos = pos;



	if (pos > i_size_read(inode)) {