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zfs_rename: pick up and finish renameat2 flags support
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Removing new txtypes in favor of compound ZIL operations, see comment in
module/zfs/zfs_log.c.

Other notable changes:

- unlock after the inodes are updated
- pass whiteout znode pointer to zfs_log_rename_whiteout
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@snajpa
snajpa committed Oct 6, 2019
1 parent 9c12922 commit 9964601
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Showing 5 changed files with 155 additions and 75 deletions.
7 changes: 7 additions & 0 deletions include/sys/zfs_znode.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -402,6 +402,13 @@ extern void zfs_log_link(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
znode_t *dzp, znode_t *zp, char *name);
extern void zfs_log_symlink(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
znode_t *dzp, znode_t *zp, char *name, char *link);
extern void zfs_log_rename_exchange(zilog_t *zilog, dmu_tx_t *tx,
uint64_t txtype, znode_t *sdzp, char *sname, znode_t *tdzp,
char *dname, znode_t *szp);
extern void zfs_log_rename_whiteout(zilog_t *zilog, dmu_tx_t *tx,
uint64_t txtype, znode_t *sdzp, char *sname, znode_t *tdzp,
char *dname, znode_t *szp, znode_t *wzp, vsecattr_t *vsecp,
zfs_fuid_info_t *fuidp, vattr_t *vap);
extern void zfs_log_rename(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
znode_t *sdzp, char *sname, znode_t *tdzp, char *dname, znode_t *szp);
extern void zfs_log_write(zilog_t *zilog, dmu_tx_t *tx, int txtype,
Expand Down
4 changes: 1 addition & 3 deletions include/sys/zil.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -162,9 +162,7 @@ typedef enum zil_create {
#define TX_MKDIR_ATTR 18 /* mkdir with attr */
#define TX_MKDIR_ACL_ATTR 19 /* mkdir with ACL + attrs */
#define TX_WRITE2 20 /* dmu_sync EALREADY write */
#define TX_EXCHANGE 21 /* Exchange two paths */
#define TX_WHITEOUT 22 /* Rename a file, leaving a whiteout */
#define TX_MAX_TYPE 23 /* Max transaction type */
#define TX_MAX_TYPE 21 /* Max transaction type */

/*
* The transactions for mkdir, symlink, remove, rmdir, link, and rename
Expand Down
104 changes: 56 additions & 48 deletions module/os/linux/zfs/zfs_vnops.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3671,24 +3671,18 @@ zfs_rename(struct inode *sdip, char *snm, struct inode *tdip, char *tnm,
int error = 0;
int zflg = 0;
boolean_t waited = B_FALSE;
uint64_t txtype;
/* Needed for whiteout inode creation. */
vattr_t wo_vap;
uint64_t wo_projid;
boolean_t fuid_dirtied;
zfs_acl_ids_t acl_ids;
boolean_t have_acl = B_FALSE;
znode_t *wzp = NULL;


if (snm == NULL || tnm == NULL)
return (SET_ERROR(EINVAL));

if (flags & RENAME_EXCHANGE)
txtype = TX_EXCHANGE;
else if (flags & RENAME_WHITEOUT)
txtype = TX_WHITEOUT;
else
txtype = TX_RENAME;

ZFS_ENTER(zfsvfs);
zilog = zfsvfs->z_log;

Expand Down Expand Up @@ -3887,7 +3881,7 @@ zfs_rename(struct inode *sdip, char *snm, struct inode *tdip, char *tnm,
/*
* Source and target must be the same type (unless exchanging).
*/
if (txtype != TX_EXCHANGE) {
if (!(flags & RENAME_EXCHANGE)) {
boolean_t s_is_dir = S_ISDIR(ZTOI(szp)->i_mode) != 0;
boolean_t t_is_dir = S_ISDIR(ZTOI(tzp)->i_mode) != 0;

Expand All @@ -3905,15 +3899,14 @@ zfs_rename(struct inode *sdip, char *snm, struct inode *tdip, char *tnm,
error = 0;
goto out;
}
}
/* Target must exist for RENAME_EXCHANGE. */
if (!tzp && txtype == TX_EXCHANGE) {
} else if (flags & RENAME_EXCHANGE) {
/* Target must exist for RENAME_EXCHANGE. */
error = SET_ERROR(ENOENT);
goto out;
}

/* Set up inode creation for RENAME_WHITEOUT. */
if (txtype == TX_WHITEOUT) {
if (flags & RENAME_WHITEOUT) {
error = zfs_zaccess(sdzp, ACE_ADD_FILE, 0, B_FALSE, cr);
if (error)
goto out;
Expand All @@ -3937,7 +3930,7 @@ zfs_rename(struct inode *sdip, char *snm, struct inode *tdip, char *tnm,
tx = dmu_tx_create(zfsvfs->z_os);
dmu_tx_hold_sa(tx, szp->z_sa_hdl, B_FALSE);
dmu_tx_hold_sa(tx, sdzp->z_sa_hdl, B_FALSE);
dmu_tx_hold_zap(tx, sdzp->z_id, txtype == TX_EXCHANGE, snm);
dmu_tx_hold_zap(tx, sdzp->z_id, !!(flags & RENAME_EXCHANGE), snm);
dmu_tx_hold_zap(tx, tdzp->z_id, TRUE, tnm);
if (sdzp != tdzp) {
dmu_tx_hold_sa(tx, tdzp->z_sa_hdl, B_FALSE);
Expand All @@ -3947,7 +3940,7 @@ zfs_rename(struct inode *sdip, char *snm, struct inode *tdip, char *tnm,
dmu_tx_hold_sa(tx, tzp->z_sa_hdl, B_FALSE);
zfs_sa_upgrade_txholds(tx, tzp);
}
if (txtype == TX_WHITEOUT) {
if (flags & RENAME_WHITEOUT) {
dmu_tx_hold_sa_create(tx, acl_ids.z_aclp->z_acl_bytes +
ZFS_SA_BASE_ATTR_SIZE);

Expand Down Expand Up @@ -4012,7 +4005,7 @@ zfs_rename(struct inode *sdip, char *snm, struct inode *tdip, char *tnm,
if (tzp) {
int tzflg = zflg;

if (txtype == TX_EXCHANGE) {
if (flags & RENAME_EXCHANGE) {
/* This inode will be re-linked soon. */
tzflg |= ZRENAMING;

Expand Down Expand Up @@ -4046,51 +4039,56 @@ zfs_rename(struct inode *sdip, char *snm, struct inode *tdip, char *tnm,
goto commit_link_tzp;
}

switch (txtype) {
case TX_EXCHANGE:
error = zfs_link_create(sdl, tzp, tx, ZRENAMING);
/*
* The same argument as zfs_link_create() failing for
* szp applies here, since the source directory must
* have had an entry we are replacing.
*/
ASSERT3U(error, ==, 0);
if (error)
goto commit_unlink_td_szp;
break;
case TX_WHITEOUT: {
znode_t *wzp;

zfs_mknode(sdzp, &wo_vap, tx, cr, 0, &wzp, &acl_ids);
error = zfs_link_create(sdl, wzp, tx, ZNEW);
if (error) {
zfs_znode_delete(wzp, tx);
remove_inode_hash(ZTOI(wzp));
goto commit_unlink_td_szp;
}
/* No need to zfs_log_create_txtype here. */
if (flags & RENAME_EXCHANGE) {
error = zfs_link_create(sdl, tzp, tx, ZRENAMING);
/*
* The same argument as zfs_link_create() failing for
* szp applies here, since the source directory must
* have had an entry we are replacing.
*/
ASSERT3U(error, ==, 0);
if (error)
goto commit_unlink_td_szp;
} else if (flags & RENAME_WHITEOUT) {
zfs_mknode(sdzp, &wo_vap, tx, cr, 0, &wzp, &acl_ids);
error = zfs_link_create(sdl, wzp, tx, ZNEW);
if (error) {
zfs_znode_delete(wzp, tx);
remove_inode_hash(ZTOI(wzp));
goto commit_unlink_td_szp;
}
/* No need to zfs_log_create_txtype here. */
}

if (fuid_dirtied)
zfs_fuid_sync(zfsvfs, tx);

zfs_log_rename(zilog, tx, txtype |
(flags & FIGNORECASE ? TX_CI : 0), sdzp,
sdl->dl_name, tdzp, tdl->dl_name, szp);
if (flags & RENAME_EXCHANGE) {
zfs_log_rename_exchange(zilog, tx,
(flags & FIGNORECASE ? TX_CI : 0), sdzp,
sdl->dl_name, tdzp, tdl->dl_name, szp);
} else if (flags & RENAME_WHITEOUT) {
vsecattr_t vsecp;

vsecp.vsa_mask |= VSA_ACE_ALLTYPES;
error = zfs_getacl(szp, &vsecp, B_TRUE, cr);

zfs_log_rename_whiteout(zilog, tx,
(flags & FIGNORECASE ? TX_CI : 0), sdzp,
sdl->dl_name, tdzp, tdl->dl_name, szp, wzp,
&vsecp, acl_ids.z_fuidp, &wo_vap);
} else {
zfs_log_rename(zilog, tx,
(flags & FIGNORECASE ? TX_CI : 0), sdzp,
sdl->dl_name, tdzp, tdl->dl_name, szp);
}

commit:
dmu_tx_commit(tx);
out:
if (have_acl)
zfs_acl_ids_free(&acl_ids);

if (zl != NULL)
zfs_rename_unlock(&zl);

zfs_dirent_unlock(sdl);
zfs_dirent_unlock(tdl);

zfs_inode_update(sdzp);
if (sdzp == tdzp)
rw_exit(&sdzp->z_name_lock);
Expand All @@ -4100,11 +4098,21 @@ zfs_rename(struct inode *sdip, char *snm, struct inode *tdip, char *tnm,

zfs_inode_update(szp);
iput(ZTOI(szp));
if (wzp) {
zfs_inode_update(wzp);
iput(ZTOI(wzp));
}
if (tzp) {
zfs_inode_update(tzp);
iput(ZTOI(tzp));
}

if (zl != NULL)
zfs_rename_unlock(&zl);

zfs_dirent_unlock(sdl);
zfs_dirent_unlock(tdl);

if (zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS)
zil_commit(zilog, 0);

Expand Down
92 changes: 89 additions & 3 deletions module/zfs/zfs_log.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -474,9 +474,7 @@ zfs_log_symlink(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
}

/*
* Handles TX_{RENAME,EXCHANGE,WHITEOUT} transactions. They all have the same
* underyling structure (lr_rename_t) but have different txtypes to indicate
* different renameat2(2) flags.
* Handles TX_RENAME transactions.
*/
void
zfs_log_rename(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
Expand All @@ -490,6 +488,7 @@ zfs_log_rename(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
if (zil_replaying(zilog, tx))
return;

txtype |= TX_RENAME;
itx = zil_itx_create(txtype, sizeof (*lr) + snamesize + dnamesize);
lr = (lr_rename_t *)&itx->itx_lr;
lr->lr_sdoid = sdzp->z_id;
Expand All @@ -501,6 +500,93 @@ zfs_log_rename(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
zil_itx_assign(zilog, itx, tx);
}

/*
* At the moment, only Linux supports renameat2 variant of renameat, which
* adds three new flags of interest for us:
* RENAME_NOREPLACE: if the target name at the moment of the call exists,
* don't rewrite it and return error
* RENAME_EXCHANGE: atomically swap the two names on the filesystem
* RENAME_WHITEOUT: creates a whiteout inode in place of renamed file as
* an atomic operation
*
* Ideally, these operations should be represented as new ZFS Intent Log record
* types, which should mandate a new ZFS feature flag due to the on-disk format
* change. One would use spa_feature_incr/decr functions to indicate that we're
* actually actively using the new on-disk txtypes - but these functions are
* only supposed to be called from the txg syncing context.
* This means that would need to force out in-progress txg to disk and start
* a new one before writing any ZIL records, just so we can be sure that ZIL
* replaying ZFS gets told it should expect potentially incompatible ZIL
* txtypes. Doing this would hurt performance.
* Alternatively, we could just activate the feature on a pool when these
* renameat2 flags get first used and leave it at that - which would render the
* pool importable read-only on implementations without the new feature flag,
* even when no new txtypes IL records would be present on-disk - which on most
* setups could be 'almost' all the time, so it'd be a shame to have them all
* read-only on non-Linux platforms.
* As a third option, at least until more platforms implement renameat2, we
* choose to rely on the fact that the ZIL is replayed in single-threaded mode
* before the dataset is mounted. This way, we can represent the otherwise
* atomic operations as a series of plain good old txtypes known to all current
* OpenZFS implementations. To do that, we use these hacky functions:
*
* zfs_log_rename_exchange
* zfs_log_rename_whiteout
*
* To represent atomic rename with old non-atomic operations, we need
* a temporary new name; so we try picking a name until we succeed, then
* we get a dirent lock for that temp name until the final itx gets queued
*/

void
zfs_log_rename_exchange(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
znode_t *sdzp, char *sname, znode_t *tdzp, char *dname, znode_t *szp)
{
zfs_dirlock_t *tmpdl;
znode_t *tmpzp = NULL;
char rndname[16];
char *tmpname;
int retries = 0;
int error;

tmpname = kmem_alloc(MAXPATHLEN, KM_SLEEP);
ASSERT3P(tmpname, !=, NULL);

for (int i = 0; i < 16; i++) {
int r = 0xFF;
while (r > 127 || r == 0 || r == '/')
random_get_pseudo_bytes((void *)&r, 1);
rndname[i] = (char)r;
}

do {
retries++;
(void) snprintf(tmpname, MAXPATHLEN,
"%s.zfs_renameat2_emul_%s%4d",
dname, rndname, retries);
error = zfs_dirent_lock(&tmpdl, tdzp, tmpname,
&tmpzp, ZNEW, NULL, NULL);
} while (error != 0 && retries != INT_MAX);
ASSERT3U(retries, !=, INT_MAX);

zfs_log_rename(zilog, tx, txtype, sdzp, sname, tdzp, tmpname, szp);
zfs_log_rename(zilog, tx, txtype, tdzp, tmpname, tdzp, dname, szp);

zfs_dirent_unlock(tmpdl);
kmem_free(tmpname, MAXPATHLEN);
}

/* See comment above zfs_log_rename_exchange */
void
zfs_log_rename_whiteout(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
znode_t *sdzp, char *sname, znode_t *tdzp, char *dname, znode_t *szp,
znode_t *wzp, vsecattr_t *vsecp, zfs_fuid_info_t *fuidp, vattr_t *vap)
{
zfs_log_rename(zilog, tx, txtype, sdzp, sname, tdzp, dname, szp);
txtype |= TX_CREATE_ATTR;
zfs_log_create(zilog, tx, txtype, sdzp, wzp, sname, vsecp, fuidp, vap);
}

/*
* zfs_log_write() handles TX_WRITE transactions. The specified callback is
* called as soon as the write is on stable storage (be it via a DMU sync or a
Expand Down
23 changes: 2 additions & 21 deletions module/zfs/zfs_replay.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -625,14 +625,15 @@ zfs_replay_link(void *arg1, void *arg2, boolean_t byteswap)
}

static int
_zfs_replay_renameat2(void *arg1, void *arg2, boolean_t byteswap, int vflg)
zfs_replay_rename(void *arg1, void *arg2, boolean_t byteswap)
{
zfsvfs_t *zfsvfs = arg1;
lr_rename_t *lr = arg2;
char *sname = (char *)(lr + 1); /* sname and tname follow lr_rename_t */
char *tname = sname + strlen(sname) + 1;
znode_t *sdzp, *tdzp;
int error;
int vflg = 0;

if (byteswap)
byteswap_uint64_array(lr, sizeof (*lr));
Expand All @@ -656,24 +657,6 @@ _zfs_replay_renameat2(void *arg1, void *arg2, boolean_t byteswap, int vflg)
return (error);
}

static int
zfs_replay_rename(void *arg1, void *arg2, boolean_t byteswap)
{
return (_zfs_replay_renameat2(arg1, arg2, byteswap, 0));
}

static int
zfs_replay_exchange(void *arg1, void *arg2, boolean_t byteswap)
{
return (_zfs_replay_renameat2(arg1, arg2, byteswap, RENAME_EXCHANGE));
}

static int
zfs_replay_whiteout(void *arg1, void *arg2, boolean_t byteswap)
{
return (_zfs_replay_renameat2(arg1, arg2, byteswap, RENAME_WHITEOUT));
}

static int
zfs_replay_write(void *arg1, void *arg2, boolean_t byteswap)
{
Expand Down Expand Up @@ -998,6 +981,4 @@ zil_replay_func_t *zfs_replay_vector[TX_MAX_TYPE] = {
zfs_replay_create, /* TX_MKDIR_ATTR */
zfs_replay_create_acl, /* TX_MKDIR_ACL_ATTR */
zfs_replay_write2, /* TX_WRITE2 */
zfs_replay_exchange, /* TX_EXCHANGE */
zfs_replay_whiteout, /* TX_WHITEOUT */
};

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