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Add zfs_iput_async() interface 

Handle all iputs in zfs_purgedir() and zfs_inode_destroy()
asynchronously to prevent deadlocks.  When the iputs are allowed
to run synchronously in the destroy call path deadlocks between
xattr directory inodes and their parent file inodes are possible.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Closes #457
This commit is contained in:
Brian Behlendorf 2014-08-04 13:30:20 -07:00
parent 4dd18932ba
commit 0a50679ce9
4 changed files with 17 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/sys/zfs_vnops.h
View File

@ -79,6 +79,7 @@ extern int zfs_putpage(struct inode *ip, struct page *pp,
extern int zfs_dirty_inode(struct inode *ip, int flags);
extern int zfs_map(struct inode *ip, offset_t off, caddr_t *addrp,
size_t len, unsigned long vm_flags);
extern void zfs_iput_async(struct inode *ip);
#ifdef __cplusplus
}

7
module/zfs/zfs_dir.c
View File

@ -46,6 +46,7 @@
#include <sys/policy.h>
#include <sys/zfs_dir.h>
#include <sys/zfs_acl.h>
#include <sys/zfs_vnops.h>
#include <sys/fs/zfs.h>
#include "fs/fs_subr.h"
#include <sys/zap.h>
@ -528,7 +529,7 @@ zfs_purgedir(znode_t *dzp)
error = dmu_tx_assign(tx, TXG_WAIT);
if (error) {
dmu_tx_abort(tx);
iput(ZTOI(xzp));
zfs_iput_async(ZTOI(xzp));
skipped += 1;
continue;
}
@ -541,7 +542,7 @@ zfs_purgedir(znode_t *dzp)
skipped += 1;
dmu_tx_commit(tx);
iput(ZTOI(xzp));
zfs_iput_async(ZTOI(xzp));
}
zap_cursor_fini(&zc);
if (error != ENOENT)
@ -729,7 +730,7 @@ zfs_rmnode(znode_t *zp)
dmu_tx_commit(tx);
out:
if (xzp)
iput(ZTOI(xzp));
zfs_iput_async(ZTOI(xzp));
}
static uint64_t

18
module/zfs/zfs_vnops.c
View File

@ -101,7 +101,7 @@
* pushing cached pages (which acquires range locks) and syncing out
* cached atime changes. Third, zfs_zinactive() may require a new tx,
* which could deadlock the system if you were already holding one.
* If you must call iput() within a tx then use iput_ASYNC().
* If you must call iput() within a tx then use zfs_iput_async().
*
* (3) All range locks must be grabbed before calling dmu_tx_assign(),
* as they can span dmu_tx_assign() calls.
@ -927,12 +927,17 @@ zfs_write(struct inode *ip, uio_t *uio, int ioflag, cred_t *cr)
}
EXPORT_SYMBOL(zfs_write);
static void
iput_async(struct inode *ip, taskq_t *taskq)
void
zfs_iput_async(struct inode *ip)
{
objset_t *os = ITOZSB(ip)->z_os;
ASSERT(atomic_read(&ip->i_count) > 0);
ASSERT(os != NULL);
if (atomic_read(&ip->i_count) == 1)
taskq_dispatch(taskq, (task_func_t *)iput, ip, TQ_PUSHPAGE);
taskq_dispatch(dsl_pool_iput_taskq(dmu_objset_pool(os)),
(task_func_t *)iput, ip, TQ_PUSHPAGE);
else
iput(ip);
}
@ -941,7 +946,6 @@ void
zfs_get_done(zgd_t *zgd, int error)
{
znode_t *zp = zgd->zgd_private;
objset_t *os = ZTOZSB(zp)->z_os;
if (zgd->zgd_db)
dmu_buf_rele(zgd->zgd_db, zgd);
@ -952,7 +956,7 @@ zfs_get_done(zgd_t *zgd, int error)
* Release the vnode asynchronously as we currently have the
* txg stopped from syncing.
*/
iput_async(ZTOI(zp), dsl_pool_iput_taskq(dmu_objset_pool(os)));
zfs_iput_async(ZTOI(zp));
if (error == 0 && zgd->zgd_bp)
zil_add_block(zgd->zgd_zilog, zgd->zgd_bp);
@ -994,7 +998,7 @@ zfs_get_data(void *arg, lr_write_t *lr, char *buf, zio_t *zio)
* Release the vnode asynchronously as we currently have the
* txg stopped from syncing.
*/
iput_async(ZTOI(zp), dsl_pool_iput_taskq(dmu_objset_pool(os)));
zfs_iput_async(ZTOI(zp));
return (SET_ERROR(ENOENT));
}

2
module/zfs/zfs_znode.c
View File

@ -292,7 +292,7 @@ zfs_inode_destroy(struct inode *ip)
}
if (zp->z_xattr_parent) {
iput(ZTOI(zp->z_xattr_parent));
zfs_iput_async(ZTOI(zp->z_xattr_parent));
zp->z_xattr_parent = NULL;
}