From b383a73f2b832491a2f9e6e8ada26aad53b5763d Mon Sep 17 00:00:00 2001
From: Ira Weiny <ira.weiny@intel.com>
Date: Thu, 28 May 2020 08:00:02 -0700
Subject: [PATCH] fs/ext4: Introduce DAX inode flag
Git-commit: b383a73f2b832491a2f9e6e8ada26aad53b5763d
Patch-mainline: v5.8-rc2
References: jsc#SLE-12982
Add a flag ([EXT4|FS]_DAX_FL) to preserve FS_XFLAG_DAX in the ext4
inode.
Set the flag to be user visible and changeable. Set the flag to be
inherited. Allow applications to change the flag at any time except if
it conflicts with the set of mutually exclusive flags (Currently VERITY,
ENCRYPT, JOURNAL_DATA).
Furthermore, restrict setting any of the exclusive flags if DAX is set.
While conceptually possible, we do not allow setting EXT4_DAX_FL while
at the same time clearing exclusion flags (or vice versa) for 2 reasons:
1) The DAX flag does not take effect immediately which
introduces quite a bit of complexity
2) There is no clear use case for being this flexible
Finally, on regular files, flag the inode to not be cached to facilitate
changing S_DAX on the next creation of the inode.
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20200528150003.828793-9-ira.weiny@intel.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Acked-by: Jan Kara <jack@suse.cz>
---
fs/ext4/ext4.h | 15 +++++++++++----
fs/ext4/inode.c | 2 +-
fs/ext4/ioctl.c | 42 +++++++++++++++++++++++++++++++++++++++++-
fs/ext4/super.c | 3 +++
include/uapi/linux/fs.h | 1 +
5 files changed, 57 insertions(+), 6 deletions(-)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -405,13 +405,14 @@ struct flex_groups {
#define EXT4_EXTENTS_FL 0x00080000 /* Inode uses extents */
#define EXT4_EA_INODE_FL 0x00200000 /* Inode used for large EA */
#define EXT4_EOFBLOCKS_FL 0x00400000 /* Blocks allocated beyond EOF */
+#define EXT4_DAX_FL 0x02000000 /* Inode is DAX */
#define EXT4_INLINE_DATA_FL 0x10000000 /* Inode has inline data. */
#define EXT4_PROJINHERIT_FL 0x20000000 /* Create with parents projid */
#define EXT4_CASEFOLD_FL 0x40000000 /* Casefolded file */
#define EXT4_RESERVED_FL 0x80000000 /* reserved for ext4 lib */
-#define EXT4_FL_USER_VISIBLE 0x704BDFFF /* User visible flags */
-#define EXT4_FL_USER_MODIFIABLE 0x604BC0FF /* User modifiable flags */
+#define EXT4_FL_USER_VISIBLE 0x724BDFFF /* User visible flags */
+#define EXT4_FL_USER_MODIFIABLE 0x624BC0FF /* User modifiable flags */
/* Flags we can manipulate with through EXT4_IOC_FSSETXATTR */
#define EXT4_FL_XFLAG_VISIBLE (EXT4_SYNC_FL | \
@@ -419,14 +420,16 @@ struct flex_groups {
EXT4_APPEND_FL | \
EXT4_NODUMP_FL | \
EXT4_NOATIME_FL | \
- EXT4_PROJINHERIT_FL)
+ EXT4_PROJINHERIT_FL | \
+ EXT4_DAX_FL)
/* Flags that should be inherited by new inodes from their parent. */
#define EXT4_FL_INHERITED (EXT4_SECRM_FL | EXT4_UNRM_FL | EXT4_COMPR_FL |\
EXT4_SYNC_FL | EXT4_NODUMP_FL | EXT4_NOATIME_FL |\
EXT4_NOCOMPR_FL | EXT4_JOURNAL_DATA_FL |\
EXT4_NOTAIL_FL | EXT4_DIRSYNC_FL |\
- EXT4_PROJINHERIT_FL | EXT4_CASEFOLD_FL)
+ EXT4_PROJINHERIT_FL | EXT4_CASEFOLD_FL |\
+ EXT4_DAX_FL)
/* Flags that are appropriate for regular files (all but dir-specific ones). */
#define EXT4_REG_FLMASK (~(EXT4_DIRSYNC_FL | EXT4_TOPDIR_FL | EXT4_CASEFOLD_FL |\
@@ -438,6 +441,9 @@ struct flex_groups {
/* The only flags that should be swapped */
#define EXT4_FL_SHOULD_SWAP (EXT4_HUGE_FILE_FL | EXT4_EXTENTS_FL)
+/* Flags which are mutually exclusive to DAX */
+#define EXT4_DAX_MUT_EXCL (EXT4_ENCRYPT_FL | EXT4_JOURNAL_DATA_FL)
+
/* Mask out flags that are inappropriate for the given type of inode. */
static inline __u32 ext4_mask_flags(umode_t mode, __u32 flags)
{
@@ -477,6 +483,7 @@ enum {
EXT4_INODE_EXTENTS = 19, /* Inode uses extents */
EXT4_INODE_EA_INODE = 21, /* Inode used for large EA */
EXT4_INODE_EOFBLOCKS = 22, /* Blocks allocated beyond EOF */
+ EXT4_INODE_DAX = 25, /* Inode is DAX */
EXT4_INODE_INLINE_DATA = 28, /* Data in inode. */
EXT4_INODE_PROJINHERIT = 29, /* Create with parents projid */
EXT4_INODE_RESERVED = 31, /* reserved for ext4 lib */
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4767,7 +4767,7 @@ static bool ext4_should_enable_dax(struc
if (test_opt(inode->i_sb, DAX_ALWAYS))
return true;
- return false;
+ return ext4_test_inode_flag(inode, EXT4_INODE_DAX);
}
void ext4_set_inode_flags(struct inode *inode, bool init)
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -292,6 +292,33 @@ static int ext4_ioctl_check_immutable(st
return 0;
}
+static void ext4_dax_dontcache(struct inode *inode, unsigned int flags)
+{
+ struct ext4_inode_info *ei = EXT4_I(inode);
+
+ if (S_ISDIR(inode->i_mode))
+ return;
+
+ if (test_opt2(inode->i_sb, DAX_NEVER) ||
+ test_opt(inode->i_sb, DAX_ALWAYS))
+ return;
+
+ if ((ei->i_flags ^ flags) & EXT4_DAX_FL)
+ d_mark_dontcache(inode);
+}
+
+static bool dax_compatible(struct inode *inode, unsigned int oldflags,
+ unsigned int flags)
+{
+ if ((flags & EXT4_DAX_FL) && (oldflags & EXT4_DAX_MUT_EXCL))
+ return false;
+
+ if ((flags & EXT4_DAX_MUT_EXCL) && (oldflags & EXT4_DAX_FL))
+ return false;
+
+ return true;
+}
+
static int ext4_ioctl_setflags(struct inode *inode,
unsigned int flags)
{
@@ -320,6 +347,12 @@ static int ext4_ioctl_setflags(struct in
if (!capable(CAP_SYS_RESOURCE))
goto flags_out;
}
+
+ if (!dax_compatible(inode, oldflags, flags)) {
+ err = -EOPNOTSUPP;
+ goto flags_out;
+ }
+
if ((flags ^ oldflags) & EXT4_EXTENTS_FL)
migrate = 1;
@@ -377,6 +410,8 @@ static int ext4_ioctl_setflags(struct in
if (err)
goto flags_err;
+ ext4_dax_dontcache(inode, flags);
+
for (i = 0, mask = 1; i < 32; i++, mask <<= 1) {
if (!(mask & EXT4_FL_USER_MODIFIABLE))
continue;
@@ -537,12 +572,15 @@ static inline __u32 ext4_iflags_to_xflag
xflags |= FS_XFLAG_NOATIME;
if (iflags & EXT4_PROJINHERIT_FL)
xflags |= FS_XFLAG_PROJINHERIT;
+ if (iflags & EXT4_DAX_FL)
+ xflags |= FS_XFLAG_DAX;
return xflags;
}
#define EXT4_SUPPORTED_FS_XFLAGS (FS_XFLAG_SYNC | FS_XFLAG_IMMUTABLE | \
FS_XFLAG_APPEND | FS_XFLAG_NODUMP | \
- FS_XFLAG_NOATIME | FS_XFLAG_PROJINHERIT)
+ FS_XFLAG_NOATIME | FS_XFLAG_PROJINHERIT | \
+ FS_XFLAG_DAX)
/* Transfer xflags flags to internal */
static inline unsigned long ext4_xflags_to_iflags(__u32 xflags)
@@ -561,6 +599,8 @@ static inline unsigned long ext4_xflags_
iflags |= EXT4_NOATIME_FL;
if (xflags & FS_XFLAG_PROJINHERIT)
iflags |= EXT4_PROJINHERIT_FL;
+ if (xflags & FS_XFLAG_DAX)
+ iflags |= EXT4_DAX_FL;
return iflags;
}
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1287,6 +1287,9 @@ static int ext4_set_context(struct inode
if (WARN_ON_ONCE(IS_DAX(inode) && i_size_read(inode)))
return -EINVAL;
+ if (ext4_test_inode_flag(inode, EXT4_INODE_DAX))
+ return -EOPNOTSUPP;
+
res = ext4_convert_inline_data(inode);
if (res)
return res;
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -309,6 +309,7 @@ struct fscrypt_key {
#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_DAX_FL 0x02000000 /* Inode is DAX */
#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 */