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ceph: simplify arguments and return semantics of try_get_cap_refs
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The return of this function is rather complex. It can return 0 or 1,
and in the case of a 1 return, the "err" pointer will be filled out.
This necessitates a lot of copying of values.

We can achieve the same effect by just returning 0, 1 or a negative
error code, and drop the "err" argument from this function.

Signed-off-by: Jeff Layton <[email protected]>
Reviewed-by: "Yan, Zheng" <[email protected]>
Signed-off-by: Ilya Dryomov <[email protected]>
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@jtlayton @idryomov
jtlayton authored and idryomov committed May 7, 2019
1 parent a452bc0 commit 1199d7d
Showing 1 changed file with 30 additions and 46 deletions.
76 changes: 30 additions & 46 deletions fs/ceph/caps.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2525,9 +2525,14 @@ static void __take_cap_refs(struct ceph_inode_info *ci, int got,
* to (when applicable), and check against max_size here as well.
* Note that caller is responsible for ensuring max_size increases are
* requested from the MDS.
*
* Returns 0 if caps were not able to be acquired (yet), a 1 if they were,
* or a negative error code.
*
* FIXME: how does a 0 return differ from -EAGAIN?
*/
static int try_get_cap_refs(struct ceph_inode_info *ci, int need, int want,
loff_t endoff, bool nonblock, int *got, int *err)
loff_t endoff, bool nonblock, int *got)
{
struct inode *inode = &ci->vfs_inode;
struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
Expand All @@ -2547,8 +2552,7 @@ static int try_get_cap_refs(struct ceph_inode_info *ci, int need, int want,
if ((file_wanted & need) != need) {
dout("try_get_cap_refs need %s file_wanted %s, EBADF\n",
ceph_cap_string(need), ceph_cap_string(file_wanted));
*err = -EBADF;
ret = 1;
ret = -EBADF;
goto out_unlock;
}

Expand All @@ -2569,10 +2573,8 @@ static int try_get_cap_refs(struct ceph_inode_info *ci, int need, int want,
if (endoff >= 0 && endoff > (loff_t)ci->i_max_size) {
dout("get_cap_refs %p endoff %llu > maxsize %llu\n",
inode, endoff, ci->i_max_size);
if (endoff > ci->i_requested_max_size) {
*err = -EAGAIN;
ret = 1;
}
if (endoff > ci->i_requested_max_size)
ret = -EAGAIN;
goto out_unlock;
}
/*
Expand Down Expand Up @@ -2607,8 +2609,7 @@ static int try_get_cap_refs(struct ceph_inode_info *ci, int need, int want,
* task isn't in TASK_RUNNING state
*/
if (nonblock) {
*err = -EAGAIN;
ret = 1;
ret = -EAGAIN;
goto out_unlock;
}

Expand Down Expand Up @@ -2637,8 +2638,7 @@ static int try_get_cap_refs(struct ceph_inode_info *ci, int need, int want,
if (session_readonly) {
dout("get_cap_refs %p needed %s but mds%d readonly\n",
inode, ceph_cap_string(need), ci->i_auth_cap->mds);
*err = -EROFS;
ret = 1;
ret = -EROFS;
goto out_unlock;
}

Expand All @@ -2647,16 +2647,14 @@ static int try_get_cap_refs(struct ceph_inode_info *ci, int need, int want,
if (READ_ONCE(mdsc->fsc->mount_state) ==
CEPH_MOUNT_SHUTDOWN) {
dout("get_cap_refs %p forced umount\n", inode);
*err = -EIO;
ret = 1;
ret = -EIO;
goto out_unlock;
}
mds_wanted = __ceph_caps_mds_wanted(ci, false);
if (need & ~(mds_wanted & need)) {
dout("get_cap_refs %p caps were dropped"
" (session killed?)\n", inode);
*err = -ESTALE;
ret = 1;
ret = -ESTALE;
goto out_unlock;
}
if (!(file_wanted & ~mds_wanted))
Expand Down Expand Up @@ -2707,23 +2705,16 @@ static void check_max_size(struct inode *inode, loff_t endoff)
int ceph_try_get_caps(struct ceph_inode_info *ci, int need, int want,
bool nonblock, int *got)
{
int ret, err = 0;
int ret;

BUG_ON(need & ~CEPH_CAP_FILE_RD);
BUG_ON(want & ~(CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO|CEPH_CAP_FILE_SHARED));
ret = ceph_pool_perm_check(ci, need);
if (ret < 0)
return ret;

ret = try_get_cap_refs(ci, need, want, 0, nonblock, got, &err);
if (ret) {
if (err == -EAGAIN) {
ret = 0;
} else if (err < 0) {
ret = err;
}
}
return ret;
ret = try_get_cap_refs(ci, need, want, 0, nonblock, got);
return ret == -EAGAIN ? 0 : ret;
}

/*
Expand All @@ -2734,7 +2725,7 @@ int ceph_try_get_caps(struct ceph_inode_info *ci, int need, int want,
int ceph_get_caps(struct ceph_inode_info *ci, int need, int want,
loff_t endoff, int *got, struct page **pinned_page)
{
int _got, ret, err = 0;
int _got, ret;

ret = ceph_pool_perm_check(ci, need);
if (ret < 0)
Expand All @@ -2744,21 +2735,19 @@ int ceph_get_caps(struct ceph_inode_info *ci, int need, int want,
if (endoff > 0)
check_max_size(&ci->vfs_inode, endoff);

err = 0;
_got = 0;
ret = try_get_cap_refs(ci, need, want, endoff,
false, &_got, &err);
if (ret) {
if (err == -EAGAIN)
continue;
if (err < 0)
ret = err;
} else {
false, &_got);
if (ret == -EAGAIN) {
continue;
} else if (!ret) {
int err;

DEFINE_WAIT_FUNC(wait, woken_wake_function);
add_wait_queue(&ci->i_cap_wq, &wait);

while (!try_get_cap_refs(ci, need, want, endoff,
true, &_got, &err)) {
while (!(err = try_get_cap_refs(ci, need, want, endoff,
true, &_got))) {
if (signal_pending(current)) {
ret = -ERESTARTSYS;
break;
Expand All @@ -2767,19 +2756,14 @@ int ceph_get_caps(struct ceph_inode_info *ci, int need, int want,
}

remove_wait_queue(&ci->i_cap_wq, &wait);

if (err == -EAGAIN)
continue;
if (err < 0)
ret = err;
}
if (ret < 0) {
if (err == -ESTALE) {
/* session was killed, try renew caps */
ret = ceph_renew_caps(&ci->vfs_inode);
if (ret == 0)
continue;
}
if (ret == -ESTALE) {
/* session was killed, try renew caps */
ret = ceph_renew_caps(&ci->vfs_inode);
if (ret == 0)
continue;
return ret;
}

Expand Down

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