aboutsummaryrefslogtreecommitdiffstats
path: root/fs/fuse/file.c
diff options
context:
space:
mode:
authorMiklos Szeredi <mszeredi@suse.cz>2009-04-02 08:25:34 -0400
committerMiklos Szeredi <mszeredi@suse.cz>2009-04-02 08:25:34 -0400
commitf4975c67dd9ad8eb47a4c77af0521a2b16ee0197 (patch)
tree4d4642e04e40f4835df9a18192da53b98b206bf8 /fs/fuse/file.c
parent833bb3046b6cb320e775ea2160ddca87d53260d5 (diff)
fuse: allow kernel to access "direct_io" files
Allow the kernel read and write on "direct_io" files. This is necessary for nfs export and execute support. The implementation is simple: if an access from the kernel is detected, don't perform get_user_pages(), just use the kernel address provided by the requester to copy from/to the userspace filesystem. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Diffstat (limited to 'fs/fuse/file.c')
-rw-r--r--fs/fuse/file.c42
1 files changed, 30 insertions, 12 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 4e340fedf768..78a2c8333700 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -386,7 +386,6 @@ void fuse_read_fill(struct fuse_req *req, struct file *file,
386 req->in.numargs = 1; 386 req->in.numargs = 1;
387 req->in.args[0].size = sizeof(struct fuse_read_in); 387 req->in.args[0].size = sizeof(struct fuse_read_in);
388 req->in.args[0].value = inarg; 388 req->in.args[0].value = inarg;
389 req->out.argpages = 1;
390 req->out.argvar = 1; 389 req->out.argvar = 1;
391 req->out.numargs = 1; 390 req->out.numargs = 1;
392 req->out.args[0].size = count; 391 req->out.args[0].size = count;
@@ -453,6 +452,7 @@ static int fuse_readpage(struct file *file, struct page *page)
453 attr_ver = fuse_get_attr_version(fc); 452 attr_ver = fuse_get_attr_version(fc);
454 453
455 req->out.page_zeroing = 1; 454 req->out.page_zeroing = 1;
455 req->out.argpages = 1;
456 req->num_pages = 1; 456 req->num_pages = 1;
457 req->pages[0] = page; 457 req->pages[0] = page;
458 num_read = fuse_send_read(req, file, inode, pos, count, NULL); 458 num_read = fuse_send_read(req, file, inode, pos, count, NULL);
@@ -510,6 +510,8 @@ static void fuse_send_readpages(struct fuse_req *req, struct file *file,
510 struct fuse_conn *fc = get_fuse_conn(inode); 510 struct fuse_conn *fc = get_fuse_conn(inode);
511 loff_t pos = page_offset(req->pages[0]); 511 loff_t pos = page_offset(req->pages[0]);
512 size_t count = req->num_pages << PAGE_CACHE_SHIFT; 512 size_t count = req->num_pages << PAGE_CACHE_SHIFT;
513
514 req->out.argpages = 1;
513 req->out.page_zeroing = 1; 515 req->out.page_zeroing = 1;
514 fuse_read_fill(req, file, inode, pos, count, FUSE_READ); 516 fuse_read_fill(req, file, inode, pos, count, FUSE_READ);
515 req->misc.read.attr_ver = fuse_get_attr_version(fc); 517 req->misc.read.attr_ver = fuse_get_attr_version(fc);
@@ -621,7 +623,6 @@ static void fuse_write_fill(struct fuse_req *req, struct file *file,
621 inarg->flags = file ? file->f_flags : 0; 623 inarg->flags = file ? file->f_flags : 0;
622 req->in.h.opcode = FUSE_WRITE; 624 req->in.h.opcode = FUSE_WRITE;
623 req->in.h.nodeid = get_node_id(inode); 625 req->in.h.nodeid = get_node_id(inode);
624 req->in.argpages = 1;
625 req->in.numargs = 2; 626 req->in.numargs = 2;
626 if (fc->minor < 9) 627 if (fc->minor < 9)
627 req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE; 628 req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
@@ -695,6 +696,7 @@ static int fuse_buffered_write(struct file *file, struct inode *inode,
695 if (IS_ERR(req)) 696 if (IS_ERR(req))
696 return PTR_ERR(req); 697 return PTR_ERR(req);
697 698
699 req->in.argpages = 1;
698 req->num_pages = 1; 700 req->num_pages = 1;
699 req->pages[0] = page; 701 req->pages[0] = page;
700 req->page_offset = offset; 702 req->page_offset = offset;
@@ -771,6 +773,7 @@ static ssize_t fuse_fill_write_pages(struct fuse_req *req,
771 size_t count = 0; 773 size_t count = 0;
772 int err; 774 int err;
773 775
776 req->in.argpages = 1;
774 req->page_offset = offset; 777 req->page_offset = offset;
775 778
776 do { 779 do {
@@ -935,21 +938,28 @@ static void fuse_release_user_pages(struct fuse_req *req, int write)
935} 938}
936 939
937static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf, 940static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
938 unsigned nbytes, int write) 941 unsigned *nbytesp, int write)
939{ 942{
943 unsigned nbytes = *nbytesp;
940 unsigned long user_addr = (unsigned long) buf; 944 unsigned long user_addr = (unsigned long) buf;
941 unsigned offset = user_addr & ~PAGE_MASK; 945 unsigned offset = user_addr & ~PAGE_MASK;
942 int npages; 946 int npages;
943 947
944 /* This doesn't work with nfsd */ 948 /* Special case for kernel I/O: can copy directly into the buffer */
945 if (!current->mm) 949 if (segment_eq(get_fs(), KERNEL_DS)) {
946 return -EPERM; 950 if (write)
951 req->in.args[1].value = (void *) user_addr;
952 else
953 req->out.args[0].value = (void *) user_addr;
954
955 return 0;
956 }
947 957
948 nbytes = min(nbytes, (unsigned) FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT); 958 nbytes = min(nbytes, (unsigned) FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
949 npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT; 959 npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
950 npages = clamp(npages, 1, FUSE_MAX_PAGES_PER_REQ); 960 npages = clamp(npages, 1, FUSE_MAX_PAGES_PER_REQ);
951 down_read(&current->mm->mmap_sem); 961 down_read(&current->mm->mmap_sem);
952 npages = get_user_pages(current, current->mm, user_addr, npages, write, 962 npages = get_user_pages(current, current->mm, user_addr, npages, !write,
953 0, req->pages, NULL); 963 0, req->pages, NULL);
954 up_read(&current->mm->mmap_sem); 964 up_read(&current->mm->mmap_sem);
955 if (npages < 0) 965 if (npages < 0)
@@ -957,6 +967,15 @@ static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
957 967
958 req->num_pages = npages; 968 req->num_pages = npages;
959 req->page_offset = offset; 969 req->page_offset = offset;
970
971 if (write)
972 req->in.argpages = 1;
973 else
974 req->out.argpages = 1;
975
976 nbytes = (req->num_pages << PAGE_SHIFT) - req->page_offset;
977 *nbytesp = min(*nbytesp, nbytes);
978
960 return 0; 979 return 0;
961} 980}
962 981
@@ -979,15 +998,13 @@ static ssize_t fuse_direct_io(struct file *file, const char __user *buf,
979 998
980 while (count) { 999 while (count) {
981 size_t nres; 1000 size_t nres;
982 size_t nbytes_limit = min(count, nmax); 1001 size_t nbytes = min(count, nmax);
983 size_t nbytes; 1002 int err = fuse_get_user_pages(req, buf, &nbytes, write);
984 int err = fuse_get_user_pages(req, buf, nbytes_limit, !write);
985 if (err) { 1003 if (err) {
986 res = err; 1004 res = err;
987 break; 1005 break;
988 } 1006 }
989 nbytes = (req->num_pages << PAGE_SHIFT) - req->page_offset; 1007
990 nbytes = min(nbytes_limit, nbytes);
991 if (write) 1008 if (write)
992 nres = fuse_send_write(req, file, inode, pos, nbytes, 1009 nres = fuse_send_write(req, file, inode, pos, nbytes,
993 current->files); 1010 current->files);
@@ -1163,6 +1180,7 @@ static int fuse_writepage_locked(struct page *page)
1163 fuse_write_fill(req, NULL, ff, inode, page_offset(page), 0, 1); 1180 fuse_write_fill(req, NULL, ff, inode, page_offset(page), 0, 1);
1164 1181
1165 copy_highpage(tmp_page, page); 1182 copy_highpage(tmp_page, page);
1183 req->in.argpages = 1;
1166 req->num_pages = 1; 1184 req->num_pages = 1;
1167 req->pages[0] = tmp_page; 1185 req->pages[0] = tmp_page;
1168 req->page_offset = 0; 1186 req->page_offset = 0;