From 68ce7bfcd995a8a393b1b14fa67dbc16fa3dc784 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Fri, 8 Jan 2016 16:01:25 -0500 Subject: [PATCH] fs: clean up the flags definition in uapi/linux/fs.h Add an explanation for the flags used by FS_IOC_[GS]ETFLAGS and remind people that changes should be revised by linux-fsdevel and linux-api. Add flags that are used on-disk for ext4, and remove FS_DIRECTIO_FL since it was used only by gfs2 and support was removed in 2008 in commit c9f6a6bbc28 ("The ability to mark files for direct i/o access when opened normally is both unused and pointless, so this patch removes support for that feature.") Now we have _two_ remaining flags left. But since we want to discourage people from assigning new flags, that's OK. Signed-off-by: Theodore Ts'o --- include/uapi/linux/fs.h | 31 +++++++++++++++++++++++++++---- 1 file changed, 27 insertions(+), 4 deletions(-) diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h index f15d980249b5..c5083d2e2c02 100644 --- a/include/uapi/linux/fs.h +++ b/include/uapi/linux/fs.h @@ -2,8 +2,11 @@ #define _UAPI_LINUX_FS_H /* - * This file has definitions for some important file table - * structures etc. + * This file has definitions for some important file table structures + * and constants and structures used by various generic file system + * ioctl's. Please do not make any changes in this file before + * sending patches for review to linux-fsdevel@vger.kernel.org and + * linux-api@vger.kernel.org. */ #include @@ -172,6 +175,23 @@ struct inodes_stat_t { /* * Inode flags (FS_IOC_GETFLAGS / FS_IOC_SETFLAGS) + * + * Note: for historical reasons, these flags were originally used and + * defined for use by ext2/ext3, and then other file systems started + * using these flags so they wouldn't need to write their own version + * of chattr/lsattr (which was shipped as part of e2fsprogs). You + * should think twice before trying to use these flags in new + * contexts, or trying to assign these flags, since they are used both + * as the UAPI and the on-disk encoding for ext2/3/4. Also, we are + * almost out of 32-bit flags. :-) + * + * We have recently hoisted FS_IOC_FSGETXATTR / FS_IOC_FSSETXATTR from + * XFS to the generic FS level interface. This uses a structure that + * has padding and hence has more room to grow, so it may be more + * appropriate for many new use cases. + * + * Please do not change these flags or interfaces before checking with + * linux-fsdevel@vger.kernel.org and linux-api@vger.kernel.org. */ #define FS_SECRM_FL 0x00000001 /* Secure deletion */ #define FS_UNRM_FL 0x00000002 /* Undelete */ @@ -185,8 +205,8 @@ struct inodes_stat_t { #define FS_DIRTY_FL 0x00000100 #define FS_COMPRBLK_FL 0x00000200 /* One or more compressed clusters */ #define FS_NOCOMP_FL 0x00000400 /* Don't compress */ -#define FS_ECOMPR_FL 0x00000800 /* Compression error */ /* End compression flags --- maybe not all used */ +#define FS_ENCRYPT_FL 0x00000800 /* Encrypted file */ #define FS_BTREE_FL 0x00001000 /* btree format dir */ #define FS_INDEX_FL 0x00001000 /* hash-indexed directory */ #define FS_IMAGIC_FL 0x00002000 /* AFS directory */ @@ -194,9 +214,12 @@ struct inodes_stat_t { #define FS_NOTAIL_FL 0x00008000 /* file tail should not be merged */ #define FS_DIRSYNC_FL 0x00010000 /* dirsync behaviour (directories only) */ #define FS_TOPDIR_FL 0x00020000 /* Top of directory hierarchies*/ +#define FS_HUGE_FILE_FL 0x00040000 /* Reserved for ext4 */ #define FS_EXTENT_FL 0x00080000 /* Extents */ -#define FS_DIRECTIO_FL 0x00100000 /* Use direct i/o */ +#define FS_EA_INODE_FL 0x00200000 /* Inode used for large EA */ +#define FS_EOFBLOCKS_FL 0x00400000 /* Reserved for ext4 */ #define FS_NOCOW_FL 0x00800000 /* Do not cow file */ +#define FS_INLINE_DATA_FL 0x10000000 /* Reserved for ext4 */ #define FS_PROJINHERIT_FL 0x20000000 /* Create with parents projid */ #define FS_RESERVED_FL 0x80000000 /* reserved for ext2 lib */ -- 2.20.1