[PATCH v3 1/2] ntdll/directory: Add support for EXT4 case folding per directory
Gabriel Ivăncescu
gabrielopcode at gmail.com
Fri May 24 07:09:34 CDT 2019
This adds support for checking the case-insensitive attribute on ext4 with
newer kernels so that Wine can rely on it for performance.
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 pathname
(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*
have a file descriptor, then use it everywhere, with e.g. fstatfs.
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, this will unfortunately
involve a bit more syscalls now, because it has to open() and close() the fd,
but it shouldn't be too much of a problem. (the fstatfs and fstatat make it
less impactful somewhat, so they won't have to lookup the directory again,
hopefully mitigating some of it)
Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=47099
Signed-off-by: Gabriel Ivăncescu <gabrielopcode at gmail.com>
---
v3: Clean up the code and don't have unused parameters in any case.
GET_DIR_CASE_SENSITIVITY_USE_FD is used so it can be as generic as possible
for fast tweaking and future expansion on other platforms, if they get
something similar.
As it is now, on Linux, we always set the EXT4_CASEFOLD_FL flag
ourselves. 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, to keep the code smaller. I didn't remove it because I didn't
want to "hardcode" this assumption, so please let me know if that should
be done or not.
dlls/ntdll/directory.c | 73 +++++++++++++++++++++++++++++++++++++-----
1 file changed, 65 insertions(+), 8 deletions(-)
diff --git a/dlls/ntdll/directory.c b/dlls/ntdll/directory.c
index bbdbbe9..354c00f 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
@@ -130,12 +132,25 @@ 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
#endif /* linux */
+/* Use a file descriptor for the case-sensitivity check if we have to */
+#if defined(EXT2_IOC_GETFLAGS) && defined(EXT4_CASEFOLD_FL)
+#define GET_DIR_CASE_SENSITIVITY_USE_FD 1
+#else
+#define GET_DIR_CASE_SENSITIVITY_USE_FD 0
+#endif
+
#define IS_OPTION_TRUE(ch) ((ch) == 'y' || (ch) == 'Y' || (ch) == 't' || (ch) == 'T' || (ch) == '1')
#define IS_SEPARATOR(ch) ((ch) == '\\' || (ch) == '/')
@@ -1109,18 +1124,35 @@ static int get_dir_case_sensitivity_attr( const char *dir )
}
#endif
+/***********************************************************************
+ * 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)
+{
+#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;
+#endif
+ return -1;
+}
+
/***********************************************************************
* get_dir_case_sensitivity_stat
*
* Checks if the volume containing the specified directory is case
- * sensitive or not. Uses statfs(2) or statvfs(2).
+ * sensitive or not. Uses (f)statfs(2), (f)statvfs(2), or fstatat(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 (statfs( dir, &stfs ) == -1) return FALSE;
+ if (fd != -1 && fstatfs( fd, &stfs ) == -1) return FALSE;
+ if (fd == -1 && statfs( dir, &stfs ) == -1) return FALSE;
+
/* 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 +1189,9 @@ static BOOLEAN get_dir_case_sensitivity_stat( const char *dir )
#elif defined(__NetBSD__)
struct statvfs stfs;
- if (statvfs( dir, &stfs ) == -1) return FALSE;
+ if (fd != -1 && fstatvfs( fd, &stfs ) == -1) return FALSE;
+ if (fd == -1 && statvfs( dir, &stfs ) == -1) return FALSE;
+
/* Only assume CIOPFS is case insensitive. */
if (strcmp( stfs.f_fstypename, "fusefs" ) ||
strncmp( stfs.f_mntfromname, "ciopfs", 5 ))
@@ -1170,7 +1204,9 @@ static BOOLEAN get_dir_case_sensitivity_stat( const char *dir )
char *cifile;
/* Only assume CIOPFS is case insensitive. */
- if (statfs( dir, &stfs ) == -1) return FALSE;
+ if (fd != -1 && fstatfs( fd, &stfs ) == -1) return FALSE;
+ if (fd == -1 && statfs( dir, &stfs ) == -1) return FALSE;
+
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 +1216,13 @@ 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 (fd != -1)
+ {
+ 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 );
@@ -1201,16 +1244,30 @@ static BOOLEAN get_dir_case_sensitivity_stat( const char *dir )
* get_dir_case_sensitivity
*
* Checks if the volume containing the specified directory is case
- * sensitive or not. Uses statfs(2) or statvfs(2).
+ * sensitive or not. Uses multiple methods, depending on platform.
*/
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 (fd != -1) close(fd);
+ return case_sensitive;
}
--
2.21.0
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