[Devel] [PATCH RHEL7 COMMIT] fs/fuse kio: cosmetic changes in pcs_fuse_prep_rw()
Konstantin Khorenko
khorenko at virtuozzo.com
Fri May 31 19:10:43 MSK 2019
The commit is pushed to "branch-rh7-3.10.0-957.12.2.vz7.96.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-957.12.2.vz7.96.10
------>
commit a4c0a32b5b78d6f542003b1917b1ab252db2ae16
Author: Pavel Butsykin <pbutsykin at virtuozzo.com>
Date: Fri May 31 19:10:40 2019 +0300
fs/fuse kio: cosmetic changes in pcs_fuse_prep_rw()
This is preparation patch with cosmetic changes in pcs_fuse_prep_rw(),
it will be needed for the next patch.
At first glance it seems there is no reason in performing pcs_fuse_prep_io()
under di->lock, but it makes sense when kio request is queued to di->size.queue.
If we release di->lock before pcs_fuse_prep_io(), then non-initialized request
can begin to be processed in fuse_size_grow_work(). The same goes for
inode_dio_begin(). This patch makes this point a little more obvious.
Signed-off-by: Pavel Butsykin <pbutsykin at virtuozzo.com>
---
fs/fuse/kio/pcs/pcs_fuse_kdirect.c | 117 +++++++++++++++++++++++--------------
1 file changed, 74 insertions(+), 43 deletions(-)
diff --git a/fs/fuse/kio/pcs/pcs_fuse_kdirect.c b/fs/fuse/kio/pcs/pcs_fuse_kdirect.c
index 4dad29418e0d..50c39c0ab8e7 100644
--- a/fs/fuse/kio/pcs/pcs_fuse_kdirect.c
+++ b/fs/fuse/kio/pcs/pcs_fuse_kdirect.c
@@ -857,18 +857,34 @@ static bool kqueue_insert(struct pcs_dentry_info *di, struct fuse_file *ff,
return true;
}
+static inline int req_wait_grow_queue(struct pcs_fuse_req *r,
+ struct fuse_file *ff, u16 type,
+ off_t offset, size_t size)
+{
+ struct pcs_dentry_info *di = get_pcs_inode(r->req.io_inode);
+
+ if (!kqueue_insert(di, ff, &r->req))
+ return -EIO;
+
+ pcs_fuse_prep_io(r, type, offset, size, 0);
+ inode_dio_begin(r->req.io_inode);
+ wait_grow(r, di, offset + size);
+ return 1;
+}
+
/*
* Check i size boundary and deffer request if necessary
* Ret code
* 0: ready for submission
- * -1: should fail request
+ * -EIO: should fail request
+ * -EPERM: Nope
* 1: request placed to pended queue
*/
static int pcs_fuse_prep_rw(struct pcs_fuse_req *r, struct fuse_file *ff)
{
- struct fuse_inode *fi = get_fuse_inode(r->req.io_inode);
- struct pcs_dentry_info *di = pcs_inode_from_fuse(fi);
- int ret = 0;
+ struct fuse_req *req = &r->req;
+ struct pcs_dentry_info *di = get_pcs_inode(req->io_inode);
+ int ret;
spin_lock(&di->lock);
/* Deffer all requests if shrink requested to prevent livelock */
@@ -880,38 +896,45 @@ static int pcs_fuse_prep_rw(struct pcs_fuse_req *r, struct fuse_file *ff)
}
wait_shrink(r, di);
ret = 1;
- goto out;
+ goto pending;
}
- if (r->req.in.h.opcode == FUSE_READ) {
+
+ switch (req->in.h.opcode) {
+ case FUSE_READ: {
size_t size;
- struct fuse_read_in *in = &r->req.misc.read.in;
+ struct fuse_read_in *in = &req->misc.read.in;
size = in->size;
if (in->offset + in->size > di->fileinfo.attr.size) {
if (in->offset >= di->fileinfo.attr.size) {
- r->req.out.args[0].size = 0;
+ req->out.args[0].size = 0;
ret = -EPERM;
- goto out;
+ goto fail;
}
size = di->fileinfo.attr.size - in->offset;
}
+ spin_unlock(&di->lock);
+
pcs_fuse_prep_io(r, PCS_REQ_T_READ, in->offset, size, 0);
- } else if (r->req.in.h.opcode == FUSE_WRITE) {
- struct fuse_write_in *in = &r->req.misc.write.in;
+ break;
+ }
+ case FUSE_WRITE: {
+ struct fuse_write_in *in = &req->misc.write.in;
if (in->offset + in->size > di->fileinfo.attr.size) {
- if (!kqueue_insert(di, ff, &r->req)) {
- ret = -EIO;
- goto out;
- }
- wait_grow(r, di, in->offset + in->size);
- ret = 1;
+ ret = req_wait_grow_queue(r, ff, PCS_REQ_T_WRITE,
+ in->offset, in->size);
+ goto pending;
}
+ spin_unlock(&di->lock);
+
pcs_fuse_prep_io(r, PCS_REQ_T_WRITE, in->offset, in->size, 0);
- } else if (r->req.in.h.opcode == FUSE_IOCTL) {
+ break;
+ }
+ case FUSE_IOCTL: {
size_t size;
- struct fiemap const *in = r->req.in.args[1].value;
- struct fiemap *out = r->req.out.args[1].value;
+ struct fiemap const *in = req->in.args[1].value;
+ struct fiemap *out = req->out.args[1].value;
*out = *in;
out->fm_mapped_extents = 0;
@@ -920,40 +943,48 @@ static int pcs_fuse_prep_rw(struct pcs_fuse_req *r, struct fuse_file *ff)
if (in->fm_start + size > di->fileinfo.attr.size) {
if (in->fm_start >= di->fileinfo.attr.size) {
ret = -EPERM;
- goto out;
+ goto fail;
}
size = di->fileinfo.attr.size - in->fm_start;
}
- pcs_fuse_prep_io(r, PCS_REQ_T_FIEMAP, in->fm_start, in->fm_extent_count*sizeof(struct fiemap_extent),
+ spin_unlock(&di->lock);
+
+ pcs_fuse_prep_io(r, PCS_REQ_T_FIEMAP, in->fm_start,
+ in->fm_extent_count*sizeof(struct fiemap_extent),
in->fm_extent_count);
r->exec.io.req.size = size;
- } else {
- struct fuse_fallocate_in const *in = r->req.in.args[0].value;
-
- if (in->offset + in->length > di->fileinfo.attr.size) {
- if (!kqueue_insert(di, ff, &r->req)) {
- ret = -EIO;
- goto out;
- }
- wait_grow(r, di, in->offset + in->length);
- ret = 1;
- }
+ break;
+ }
+ case FUSE_FALLOCATE: {
+ struct fuse_fallocate_in const *in = req->in.args[0].value;
+ u16 type;
if (in->mode & FALLOC_FL_PUNCH_HOLE)
- pcs_fuse_prep_io(r, PCS_REQ_T_WRITE_HOLE, in->offset, in->length, 0);
+ type = PCS_REQ_T_WRITE_HOLE;
else if (in->mode & FALLOC_FL_ZERO_RANGE)
- pcs_fuse_prep_io(r, PCS_REQ_T_WRITE_ZERO, in->offset, in->length, 0);
+ type = PCS_REQ_T_WRITE_ZERO;
else {
- if (ret) {
- pcs_fuse_prep_fallocate(r);
- } else {
- ret = -EPERM;
- goto out;
- }
+ ret = -EPERM;
+ goto fail;
}
+
+ if (in->offset + in->length > di->fileinfo.attr.size) {
+ ret = req_wait_grow_queue(r, ff, type, in->offset,
+ in->length);
+ goto pending;
+ }
+ spin_unlock(&di->lock);
+
+ pcs_fuse_prep_io(r, type, in->offset, in->length, 0);
+ break;
}
- inode_dio_begin(r->req.io_inode);
-out:
+ default:
+ BUG();
+ }
+ inode_dio_begin(req->io_inode);
+ return 0;
+fail:
+pending:
spin_unlock(&di->lock);
return ret;
}
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