[PATCH v2 1/2] ntdll/directory: Add support for EXT4 case folding per directory
Gabriel Ivăncescu
gabrielopcode at gmail.com
Wed May 22 12:32:11 CDT 2019
Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=47099
Signed-off-by: Gabriel Ivăncescu <gabrielopcode at gmail.com>
---
v2: Fix mistake with fstatat return value.
This patch just adds support for the case-insensitive attribute on ext4
with newer kernels -- so it should be safe for upstream (barring stylistic
and other changes).
It has some conditional processing for perf reasons. Checking for the
EXT4_CASEFOLD_FL attribute involves an ioctl, which operates on file
descriptors, while all the former checks operated directly on the dir name
(e.g. statfs).
Obviously, it's best to avoid looking up the directory multiple times (also
for correctness, so it refers to the same dir). So in the case that we *do*
use a file descriptor, then use it (e.g. fstatfs) everywhere.
However, to avoid a perf regression or downgrade on systems that don't
support the EXT2_IOC_GETFLAGS ioctl (e.g. MacOS, FreeBSD), we continue
using statfs and the like directly, this shaves off two syscalls (open/close).
But in the case the EXT4_CASEFOLD_FL is not supported on Linux (i.e. on
current kernels) or the directory doesn't have it (think of dirs outside
drive_c), this will unfortunately involve a bit more syscalls now, because
it has to open() and close() the fd. I'd really like if the fstatfs and
fstatat can stay if we do use the fd, to somehow make it less impactful on
current systems, so they won't have to lookup the directory again.
So that's basically why the GET_DIR_CASE_SENSITIVITY_USE_FD constant is there.
One last thing: as it is now, on Linux, we always set the EXT4_CASEFOLD_FL
flag ourselves since it does no harm even if it's not supported. Thus,
I can of course remove the .ciopfs old code and keep just the fstatat()
call by assuming we always use fd on Linux, if you prefer it that way. I
didn't remove it because I didn't want to "hardcode" this assumption,
so I'm waiting for feedback.
dlls/ntdll/directory.c | 66 ++++++++++++++++++++++++++++++++++++++++--
1 file changed, 63 insertions(+), 3 deletions(-)
diff --git a/dlls/ntdll/directory.c b/dlls/ntdll/directory.c
index bbdbbe9..e5fa48d 100644
--- a/dlls/ntdll/directory.c
+++ b/dlls/ntdll/directory.c
@@ -115,6 +115,8 @@ WINE_DEFAULT_DEBUG_CHANNEL(file);
/* just in case... */
#undef VFAT_IOCTL_READDIR_BOTH
+#undef EXT2_IOC_GETFLAGS
+#undef EXT4_CASEFOLD_FL
#ifdef linux
@@ -130,6 +132,12 @@ typedef struct
/* Define the VFAT ioctl to get both short and long file names */
#define VFAT_IOCTL_READDIR_BOTH _IOR('r', 1, KERNEL_DIRENT [2] )
+/* Define the ext2 ioctl for handling extra attributes */
+#define EXT2_IOC_GETFLAGS _IOR('f', 1, long)
+
+/* Case-insensitivity attribute */
+#define EXT4_CASEFOLD_FL 0x40000000
+
#ifndef O_DIRECTORY
# define O_DIRECTORY 0200000 /* must be directory */
#endif
@@ -977,6 +985,25 @@ static char *get_device_mount_point( dev_t dev )
}
+/***********************************************************************
+ * get_dir_case_sensitivity_ioctl
+ *
+ * Checks if the specified directory is case sensitive or not. Uses ioctl(2).
+ */
+static int get_dir_case_sensitivity_ioctl(int fd)
+{
+#define GET_DIR_CASE_SENSITIVITY_USE_FD 1
+#if defined(EXT2_IOC_GETFLAGS) && defined(EXT4_CASEFOLD_FL)
+ int flags;
+ if (ioctl(fd, EXT2_IOC_GETFLAGS, &flags) != -1 && (flags & EXT4_CASEFOLD_FL))
+ return FALSE;
+#else
+#undef GET_DIR_CASE_SENSITIVITY_USE_FD
+#define GET_DIR_CASE_SENSITIVITY_USE_FD 0
+#endif
+ return -1;
+}
+
#if defined(HAVE_GETATTRLIST) && defined(ATTR_VOL_CAPABILITIES) && \
defined(VOL_CAPABILITIES_FORMAT) && defined(VOL_CAP_FMT_CASE_SENSITIVE)
@@ -1115,12 +1142,16 @@ static int get_dir_case_sensitivity_attr( const char *dir )
* Checks if the volume containing the specified directory is case
* sensitive or not. Uses statfs(2) or statvfs(2).
*/
-static BOOLEAN get_dir_case_sensitivity_stat( const char *dir )
+static BOOLEAN get_dir_case_sensitivity_stat( const char *dir, int fd )
{
#if defined(__APPLE__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
struct statfs stfs;
+#if GET_DIR_CASE_SENSITIVITY_USE_FD
+ if (fstatfs( fd, &stfs ) == -1) return FALSE;
+#else
if (statfs( dir, &stfs ) == -1) return FALSE;
+#endif
/* Assume these file systems are always case insensitive on Mac OS.
* For FreeBSD, only assume CIOPFS is case insensitive (AFAIK, Mac OS
* is the only UNIX that supports case-insensitive lookup).
@@ -1157,7 +1188,11 @@ static BOOLEAN get_dir_case_sensitivity_stat( const char *dir )
#elif defined(__NetBSD__)
struct statvfs stfs;
+#if GET_DIR_CASE_SENSITIVITY_USE_FD
+ if (fstatvfs( fd, &stfs ) == -1) return FALSE;
+#else
if (statvfs( dir, &stfs ) == -1) return FALSE;
+#endif
/* Only assume CIOPFS is case insensitive. */
if (strcmp( stfs.f_fstypename, "fusefs" ) ||
strncmp( stfs.f_mntfromname, "ciopfs", 5 ))
@@ -1170,7 +1205,11 @@ static BOOLEAN get_dir_case_sensitivity_stat( const char *dir )
char *cifile;
/* Only assume CIOPFS is case insensitive. */
+#if GET_DIR_CASE_SENSITIVITY_USE_FD
+ if (fstatfs( fd, &stfs ) == -1) return FALSE;
+#else
if (statfs( dir, &stfs ) == -1) return FALSE;
+#endif
if (stfs.f_type != 0x65735546 /* FUSE_SUPER_MAGIC */)
return TRUE;
/* Normally, we'd have to parse the mtab to find out exactly what
@@ -1180,6 +1219,13 @@ static BOOLEAN get_dir_case_sensitivity_stat( const char *dir )
* This will break if somebody puts a file named ".ciopfs" in a non-
* CIOPFS directory.
*/
+ if (GET_DIR_CASE_SENSITIVITY_USE_FD)
+ {
+ if (fstatat( fd, ".ciopfs", &st, AT_NO_AUTOMOUNT ) == 0)
+ return FALSE;
+ return TRUE;
+ }
+
cifile = RtlAllocateHeap( GetProcessHeap(), 0, strlen( dir )+sizeof("/.ciopfs") );
if (!cifile) return TRUE;
strcpy( cifile, dir );
@@ -1205,12 +1251,26 @@ static BOOLEAN get_dir_case_sensitivity_stat( const char *dir )
*/
static BOOLEAN get_dir_case_sensitivity( const char *dir )
{
+ int case_sensitive, fd = -1;
+
#if defined(HAVE_GETATTRLIST) && defined(ATTR_VOL_CAPABILITIES) && \
defined(VOL_CAPABILITIES_FORMAT) && defined(VOL_CAP_FMT_CASE_SENSITIVE)
- int case_sensitive = get_dir_case_sensitivity_attr( dir );
+ case_sensitive = get_dir_case_sensitivity_attr( dir );
if (case_sensitive != -1) return case_sensitive;
#endif
- return get_dir_case_sensitivity_stat( dir );
+
+ if (GET_DIR_CASE_SENSITIVITY_USE_FD)
+ {
+ if ((fd = open(dir, O_RDONLY | O_NONBLOCK | O_LARGEFILE)) == -1)
+ return TRUE;
+ if ((case_sensitive = get_dir_case_sensitivity_ioctl(fd)) != -1)
+ goto end;
+ }
+ case_sensitive = get_dir_case_sensitivity_stat(dir, fd);
+
+end:
+ if (GET_DIR_CASE_SENSITIVITY_USE_FD) close(fd);
+ return case_sensitive;
}
--
2.21.0
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