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authorMiklos Szeredi <mszeredi@suse.cz>2008-05-12 14:02:32 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-05-13 08:02:26 -0700
commit78bb6cb9a890d3d50ca3b02fce9223d3e734ab9b (patch)
tree330cc4fd17af9176ae9e2ee833e1097638fd1b30 /fs/fuse
parent0f146a764ff08c4c210c04239c5e6784b4b77485 (diff)
downloadconfigs-78bb6cb9a890d3d50ca3b02fce9223d3e734ab9b.tar.gz
fuse: add flag to turn on big writes
Prior to 2.6.26 fuse only supported single page write requests. In theory all fuse filesystem should be able support bigger than 4k writes, as there's nothing in the API to prevent it. Unfortunately there's a known case in NTFS-3G where big writes cause filesystem corruption. There could also be other filesystems, where the lack of testing with big write requests would result in bugs. To prevent such problems on a kernel upgrade, disable big writes by default, but let filesystems set a flag to turn it on. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Szabolcs Szakacsits <szaka@ntfs-3g.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/fuse')
-rw-r--r--fs/fuse/file.c2
-rw-r--r--fs/fuse/fuse_i.h3
-rw-r--r--fs/fuse/inode.c5
3 files changed, 9 insertions, 1 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index f28cf8b46f8..8092f0d9fd1 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -804,6 +804,8 @@ static ssize_t fuse_fill_write_pages(struct fuse_req *req,
if (offset == PAGE_CACHE_SIZE)
offset = 0;
+ if (!fc->big_writes)
+ break;
} while (iov_iter_count(ii) && count < fc->max_write &&
req->num_pages < FUSE_MAX_PAGES_PER_REQ && offset == 0);
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index dadffa21a20..bae948657c4 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -404,6 +404,9 @@ struct fuse_conn {
/** Is bmap not implemented by fs? */
unsigned no_bmap : 1;
+ /** Do multi-page cached writes */
+ unsigned big_writes : 1;
+
/** The number of requests waiting for completion */
atomic_t num_waiting;
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 79b61587383..fb77e096213 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -576,6 +576,8 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
fc->no_lock = 1;
if (arg->flags & FUSE_ATOMIC_O_TRUNC)
fc->atomic_o_trunc = 1;
+ if (arg->flags & FUSE_BIG_WRITES)
+ fc->big_writes = 1;
} else {
ra_pages = fc->max_read / PAGE_CACHE_SIZE;
fc->no_lock = 1;
@@ -599,7 +601,8 @@ static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
arg->major = FUSE_KERNEL_VERSION;
arg->minor = FUSE_KERNEL_MINOR_VERSION;
arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
- arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC;
+ arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
+ FUSE_BIG_WRITES;
req->in.h.opcode = FUSE_INIT;
req->in.numargs = 1;
req->in.args[0].size = sizeof(*arg);