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Commit a40dc6cc authored by Sage Weil's avatar Sage Weil
Browse files

ceph: enable/disable dentry complete flags via mount option 



Enable/disable use of the dentry dir 'complete' flag via a mount option.
This lets the admin control whether ceph uses the dcache to satisfy
negative lookups or readdir when it has the entire directory contents in
its cache.

This is purely a performance optimization; correctness is guaranteed
whether it is enabled or not.

Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarSage Weil <sage@newdream.net>
parent 46f72b34

Documentation/filesystems/ceph.txt

+13 −5
Original line number Diff line number Diff line
@@ -119,12 +119,20 @@ Mount Options 
	must rely on TCP's error correction to detect data corruption

	in the data payload.



  noasyncreaddir

	Disable client's use its local cache to satisfy	readdir

	requests.  (This does not change correctness; the client uses

  dcache

        Use the dcache contents to perform negative lookups and

        readdir when the client has the entire directory contents in

        its cache.  (This does not change correctness; the client uses

        cached metadata only when a lease or capability ensures it is

        valid.)



  nodcache

        Do not use the dcache as above.  This avoids a significant amount of

        complex code, sacrificing performance without affecting correctness,

        and is useful for tracking down bugs.



  noasyncreaddir

	Do not use the dcache as above for readdir.



More Information

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

fs/ceph/dir.c

+22 −3
Original line number Diff line number Diff line
@@ -1094,17 +1094,36 @@ static int ceph_snapdir_d_revalidate(struct dentry *dentry, 
 */

void ceph_dir_set_complete(struct inode *inode)

{

	/* not yet implemented */

	struct dentry *dentry = d_find_any_alias(inode);

	

	if (dentry && ceph_dentry(dentry) &&

	    ceph_test_mount_opt(ceph_sb_to_client(dentry->d_sb), DCACHE)) {

		dout(" marking %p (%p) complete\n", inode, dentry);

		set_bit(CEPH_D_COMPLETE, &ceph_dentry(dentry)->flags);

	}

	dput(dentry);

}



void ceph_dir_clear_complete(struct inode *inode)

{

	/* not yet implemented */

	struct dentry *dentry = d_find_any_alias(inode);



	if (dentry && ceph_dentry(dentry)) {

		dout(" marking %p (%p) complete\n", inode, dentry);

		set_bit(CEPH_D_COMPLETE, &ceph_dentry(dentry)->flags);

	}

	dput(dentry);

}



bool ceph_dir_test_complete(struct inode *inode)

{

	/* not yet implemented */

	struct dentry *dentry = d_find_any_alias(inode);



	if (dentry && ceph_dentry(dentry)) {

		dout(" marking %p (%p) NOT complete\n", inode, dentry);

		clear_bit(CEPH_D_COMPLETE, &ceph_dentry(dentry)->flags);

	}

	dput(dentry);

	return false;

}

fs/ceph/super.c

+14 −0
Original line number Diff line number Diff line
@@ -131,6 +131,8 @@ enum { 
	Opt_rbytes,

	Opt_norbytes,

	Opt_noasyncreaddir,

	Opt_dcache,

	Opt_nodcache,

	Opt_ino32,

};
@@ -152,6 +154,8 @@ static match_table_t fsopt_tokens = { 
	{Opt_rbytes, "rbytes"},

	{Opt_norbytes, "norbytes"},

	{Opt_noasyncreaddir, "noasyncreaddir"},

	{Opt_dcache, "dcache"},

	{Opt_nodcache, "nodcache"},

	{Opt_ino32, "ino32"},

	{-1, NULL}

};
@@ -231,6 +235,12 @@ static int parse_fsopt_token(char *c, void *private) 
	case Opt_noasyncreaddir:

		fsopt->flags |= CEPH_MOUNT_OPT_NOASYNCREADDIR;

		break;

	case Opt_dcache:

		fsopt->flags |= CEPH_MOUNT_OPT_DCACHE;

		break;

	case Opt_nodcache:

		fsopt->flags &= ~CEPH_MOUNT_OPT_DCACHE;

		break;

	case Opt_ino32:

		fsopt->flags |= CEPH_MOUNT_OPT_INO32;

		break;
@@ -377,6 +387,10 @@ static int ceph_show_options(struct seq_file *m, struct vfsmount *mnt) 
		seq_puts(m, ",norbytes");

	if (fsopt->flags & CEPH_MOUNT_OPT_NOASYNCREADDIR)

		seq_puts(m, ",noasyncreaddir");

	if (fsopt->flags & CEPH_MOUNT_OPT_DCACHE)

		seq_puts(m, ",dcache");

	else

		seq_puts(m, ",nodcache");



	if (fsopt->wsize)

		seq_printf(m, ",wsize=%d", fsopt->wsize);

fs/ceph/super.h

+1 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 
#define CEPH_MOUNT_OPT_RBYTES          (1<<5) /* dir st_bytes = rbytes */

#define CEPH_MOUNT_OPT_NOASYNCREADDIR  (1<<7) /* no dcache readdir */

#define CEPH_MOUNT_OPT_INO32           (1<<8) /* 32 bit inos */

#define CEPH_MOUNT_OPT_DCACHE          (1<<9) /* use dcache for readdir etc */



#define CEPH_MOUNT_OPT_DEFAULT    (CEPH_MOUNT_OPT_RBYTES)