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authorkernelOfTruth <[email protected]>2015-08-21 03:43:10 +0200
committerBrian Behlendorf <[email protected]>2016-01-26 15:26:02 -0800
commita966c5640e432f723753e63354394406a7c3dcf8 (patch)
tree85256b0cae2619ed097320ba16b51dcf97178642
parent460a021391d32b7f2e9eb05a9a01946714174e3b (diff)
Reintroduce zfs_remove() synchronous deletes
Reintroduce a slightly adapted version of the Illumos logic for synchronous unlinks. The basic idea here is that only files smaller than zfs_delete_blocks (20480) blocks should be deleted synchronously. Unlinking larger files should be handled asynchronously to minimize impact to the caller. To accomplish this iput() which is responsible for calling zfs_znode_delete() on Linux is only called in the delete_now path. Otherwise zfs_async_iput() is used which allows the last reference to be dropped by a taskq thread effectively making the removal asynchronous. Porting notes: - Add zfs_delete_blocks module option for performance analysis. The default value is DMU_MAX_DELETEBLKCNT which is the same as upstream. Reducing this value means that smaller files will be unlinked asynchronously like large files. - All occurrences of zfsvfs changes to zsb. Ported-by: KernelOfTruth [email protected] Signed-off-by: Brian Behlendorf <[email protected]>
-rw-r--r--man/man5/zfs-module-parameters.515
-rw-r--r--module/zfs/zfs_vnops.c78
2 files changed, 81 insertions, 12 deletions
diff --git a/man/man5/zfs-module-parameters.5 b/man/man5/zfs-module-parameters.5
index e0c61ec21..f801f257b 100644
--- a/man/man5/zfs-module-parameters.5
+++ b/man/man5/zfs-module-parameters.5
@@ -718,6 +718,21 @@ Default value: \fB500,000\fR.
.sp
.ne 2
.na
+\fBzfs_delete_blocks\fR (ulong)
+.ad
+.RS 12n
+This is the used to define a large file for the purposes of delete. Files
+containing more than \fBzfs_delete_blocks\fR will be deleted asynchronously
+while smaller files are deleted synchronously. Decreasing this value will
+reduce the time spent in an unlink(2) system call at the expense of a longer
+delay before the freed space is available.
+.sp
+Default value: \fB20,480\fR.
+.RE
+
+.sp
+.ne 2
+.na
\fBzfs_dirty_data_max\fR (int)
.ad
.RS 12n
diff --git a/module/zfs/zfs_vnops.c b/module/zfs/zfs_vnops.c
index 2f003de9f..f386b98a7 100644
--- a/module/zfs/zfs_vnops.c
+++ b/module/zfs/zfs_vnops.c
@@ -418,6 +418,7 @@ mappedread(struct inode *ip, int nbytes, uio_t *uio)
#endif /* _KERNEL */
unsigned long zfs_read_chunk_size = 1024 * 1024; /* Tunable */
+unsigned long zfs_delete_blocks = DMU_MAX_DELETEBLKCNT;
/*
* Read bytes from specified file into supplied buffer.
@@ -1520,13 +1521,13 @@ zfs_remove(struct inode *dip, char *name, cred_t *cr)
struct inode *ip;
zfs_sb_t *zsb = ITOZSB(dip);
zilog_t *zilog;
- uint64_t xattr_obj;
+ uint64_t acl_obj, xattr_obj;
uint64_t xattr_obj_unlinked = 0;
uint64_t obj = 0;
zfs_dirlock_t *dl;
dmu_tx_t *tx;
- boolean_t may_delete_now;
- boolean_t unlinked;
+ boolean_t may_delete_now, delete_now = FALSE;
+ boolean_t unlinked, toobig = FALSE;
uint64_t txtype;
pathname_t *realnmp = NULL;
#ifdef HAVE_PN_UTILS
@@ -1590,9 +1591,10 @@ top:
mutex_exit(&zp->z_lock);
/*
- * We never delete the znode and always place it in the unlinked
- * set. The dentry cache will always hold the last reference and
- * is responsible for safely freeing the znode.
+ * We may delete the znode now, or we may put it in the unlinked set;
+ * it depends on whether we're the last link, and on whether there are
+ * other holds on the inode. So we dmu_tx_hold() the right things to
+ * allow for either case.
*/
obj = zp->z_id;
tx = dmu_tx_create(zsb->z_os);
@@ -1600,6 +1602,12 @@ top:
dmu_tx_hold_sa(tx, zp->z_sa_hdl, B_FALSE);
zfs_sa_upgrade_txholds(tx, zp);
zfs_sa_upgrade_txholds(tx, dzp);
+ if (may_delete_now) {
+ toobig = zp->z_size > zp->z_blksz * zfs_delete_blocks;
+ /* if the file is too big, only hold_free a token amount */
+ dmu_tx_hold_free(tx, zp->z_id, 0,
+ (toobig ? DMU_MAX_ACCESS : DMU_OBJECT_END));
+ }
/* are there any extended attributes? */
error = sa_lookup(zp->z_sa_hdl, SA_ZPL_XATTR(zsb),
@@ -1611,6 +1619,11 @@ top:
dmu_tx_hold_sa(tx, xzp->z_sa_hdl, B_FALSE);
}
+ mutex_enter(&zp->z_lock);
+ if ((acl_obj = zfs_external_acl(zp)) != 0 && may_delete_now)
+ dmu_tx_hold_free(tx, acl_obj, 0, DMU_OBJECT_END);
+ mutex_exit(&zp->z_lock);
+
/* charge as an update -- would be nice not to charge at all */
dmu_tx_hold_zap(tx, zsb->z_unlinkedobj, FALSE, NULL);
@@ -1662,6 +1675,42 @@ top:
mutex_enter(&zp->z_lock);
(void) sa_lookup(zp->z_sa_hdl, SA_ZPL_XATTR(zsb),
&xattr_obj_unlinked, sizeof (xattr_obj_unlinked));
+ delete_now = may_delete_now && !toobig &&
+ atomic_read(&ip->i_count) == 1 && !(zp->z_is_mapped) &&
+ xattr_obj == xattr_obj_unlinked && zfs_external_acl(zp) ==
+ acl_obj;
+ }
+
+ if (delete_now) {
+ if (xattr_obj_unlinked) {
+ ASSERT3U(xzp->z_links, ==, 2);
+ mutex_enter(&xzp->z_lock);
+ xzp->z_unlinked = 1;
+ xzp->z_links = 0;
+ error = sa_update(xzp->z_sa_hdl, SA_ZPL_LINKS(zsb),
+ &xzp->z_links, sizeof (xzp->z_links), tx);
+ ASSERT3U(error, ==, 0);
+ mutex_exit(&xzp->z_lock);
+ zfs_unlinked_add(xzp, tx);
+
+ if (zp->z_is_sa)
+ error = sa_remove(zp->z_sa_hdl,
+ SA_ZPL_XATTR(zsb), tx);
+ else
+ error = sa_update(zp->z_sa_hdl,
+ SA_ZPL_XATTR(zsb), &null_xattr,
+ sizeof (uint64_t), tx);
+ ASSERT0(error);
+ }
+ /*
+ * Add to the unlinked set because a new reference could be
+ * taken concurrently resulting in a deferred destruction.
+ */
+ zfs_unlinked_add(zp, tx);
+ mutex_exit(&zp->z_lock);
+ zfs_inode_update(zp);
+ iput(ip);
+ } else if (unlinked) {
mutex_exit(&zp->z_lock);
zfs_unlinked_add(zp, tx);
}
@@ -1682,13 +1731,16 @@ out:
zfs_dirent_unlock(dl);
zfs_inode_update(dzp);
- zfs_inode_update(zp);
- if (xzp)
- zfs_inode_update(xzp);
- iput(ip);
- if (xzp)
- iput(ZTOI(xzp));
+ if (!delete_now) {
+ zfs_inode_update(zp);
+ zfs_iput_async(ip);
+ }
+
+ if (xzp) {
+ zfs_inode_update(xzp);
+ zfs_iput_async(ZTOI(xzp));
+ }
if (zsb->z_os->os_sync == ZFS_SYNC_ALWAYS)
zil_commit(zilog, 0);
@@ -4710,6 +4762,8 @@ zfs_retzcbuf(struct inode *ip, xuio_t *xuio, cred_t *cr)
#endif /* HAVE_UIO_ZEROCOPY */
#if defined(_KERNEL) && defined(HAVE_SPL)
+module_param(zfs_delete_blocks, ulong, 0644);
+MODULE_PARM_DESC(zfs_delete_blocks, "Delete files larger than N blocks async");
module_param(zfs_read_chunk_size, long, 0644);
MODULE_PARM_DESC(zfs_read_chunk_size, "Bytes to read per chunk");
#endif