diff options
Diffstat (limited to 'include/fuse_common.h')
-rw-r--r-- | include/fuse_common.h | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/include/fuse_common.h b/include/fuse_common.h index b6613a8..4363e40 100644 --- a/include/fuse_common.h +++ b/include/fuse_common.h @@ -149,8 +149,22 @@ struct fuse_file_info { #define FUSE_CAP_IOCTL_DIR (1 << 11) /** - * Indicates that the filesystem supports automatic invalidation of - * cached pages. + * Traditionally, while a file is open the FUSE kernel module only + * asks the filesystem for an update of the file's attributes when a + * client attempts to read beyond EOF. This is unsuitable for + * e.g. network filesystems, where the file contents may change + * without the kernel knowing about it. + * + * If this flag is set, FUSE will check the validity of the attributes + * on every read. If the attributes are no longer valid (i.e., if the + * *attr_timeout* passed to fuse_reply_attr() or set in `struct + * fuse_entry_param` has passed), it will first issue a `getattr` + * request. If the new mtime differs from the previous value, any + * cached file *contents* will be invalidated as well. + * + * This flag should always be set when available. If all file changes + * go through the kernel, *attr_timeout* should be set to zero to + * avoid unneccessary getattr() calls. */ #define FUSE_CAP_AUTO_INVAL_DATA (1 << 12) |