Attachment 60764 Details for Bug 25535 – Fix-cache-aging-for-fonts-on-FAT-filesystem-under-Linux

[patch] Fix-cache-aging-for-fonts-on-FAT-filesystem-under-Linux

0002-Fix-cache-aging-for-fonts-on-FAT-filesystem-under-Li.patch (text/plain), 6.95 KB, created by Mikhail Gusarov on 2012-04-29 05:15:11 UTC

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Creator: Mikhail Gusarov

Created: 2012-04-29 05:15:11 UTC

Size: 6.95 KB

patch

obsolete

>From 39727bf598ef2563d6b8246d484fa7be041cd6c2 Mon Sep 17 00:00:00 2001
>From: Mikhail Gusarov <dottedmag@dottedmag.net>
>Date: Sun, 29 Apr 2012 13:06:02 +0200
>Subject: [PATCH 2/2] Fix cache aging for fonts on FAT filesystem under Linux
>
>Windows does not update mtime of directory on FAT filesystem when
>file is added to it or removed from it. Fontconfig uses mtime of
>directory to check cache file aging and hence fails to detect
>newly added or recently removed files.
>
>This changeset detects FAT filesystem (currently implemented for
>Linux) and adds generating checksum of directory entries instead
>of using mtime which guarantees proper cache rebuild.
>
>For non-FAT filesystems this patch adds single syscall per directory
>which is negligeable overhead.
>
>This fixes bug https://bugs.freedesktop.org/show_bug.cgi?id=25535
>
>Signed-off-by: Mikhail Gusarov <dottedmag@dottedmag.net>
>---
> src/fccache.c |   14 +++---
> src/fcdir.c   |    2 +-
> src/fcint.h   |    5 ++-
> src/fcstat.c  |  133 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 145 insertions(+), 9 deletions(-)
>
>diff --git a/src/fccache.c b/src/fccache.c
>index dfe5b83..76e10cb 100644
>--- a/src/fccache.c
>+++ b/src/fccache.c
>@@ -229,7 +229,7 @@ FcDirCacheProcess (FcConfig *config, const FcChar8 *dir,
>     struct stat file_stat, dir_stat;
>     FcBool	ret = FcFalse;
> 
>-    if (FcStat (dir, &dir_stat) < 0)
>+    if (FcStatChecksum (dir, &dir_stat) < 0)
>         return FcFalse;
> 
>     FcDirCacheBasename (dir, cache_base);
>@@ -556,14 +556,14 @@ FcCacheTimeValid (FcCache *cache, struct stat *dir_stat)
> 
>     if (!dir_stat)
>     {
>-	if (FcStat (FcCacheDir (cache), &dir_static) < 0)
>+	if (FcStatChecksum (FcCacheDir (cache), &dir_static) < 0)
> 	    return FcFalse;
> 	dir_stat = &dir_static;
>     }
>     if (FcDebug () & FC_DBG_CACHE)
>-	printf ("FcCacheTimeValid dir \"%s\" cache time %d dir time %d\n",
>-		FcCacheDir (cache), cache->mtime, (int) dir_stat->st_mtime);
>-    return cache->mtime == (int) dir_stat->st_mtime;
>+	printf ("FcCacheTimeValid dir \"%s\" cache checksum %d dir checksum %d\n",
>+		FcCacheDir (cache), cache->checksum, (int) dir_stat->st_mtime);
>+    return cache->checksum == (int) dir_stat->st_mtime;
> }
> 
> /*
>@@ -727,7 +727,7 @@ FcDirCacheValidateHelper (int fd, struct stat *fd_stat, struct stat *dir_stat, v
> 	ret = FcFalse;
>     else if (fd_stat->st_size != c.size)
> 	ret = FcFalse;
>-    else if (c.mtime != (int) dir_stat->st_mtime)
>+    else if (c.checksum != (int) dir_stat->st_mtime)
> 	ret = FcFalse;
>     return ret;
> }
>@@ -802,7 +802,7 @@ FcDirCacheBuild (FcFontSet *set, const FcChar8 *dir, struct stat *dir_stat, FcSt
>     cache->magic = FC_CACHE_MAGIC_ALLOC;
>     cache->version = FC_CACHE_CONTENT_VERSION;
>     cache->size = serialize->size;
>-    cache->mtime = (int) dir_stat->st_mtime;
>+    cache->checksum = (int) dir_stat->st_mtime;
> 
>     /*
>      * Serialize directory name
>diff --git a/src/fcdir.c b/src/fcdir.c
>index 4399afc..2b476e8 100644
>--- a/src/fcdir.c
>+++ b/src/fcdir.c
>@@ -245,7 +245,7 @@ FcDirCacheScan (const FcChar8 *dir, FcConfig *config)
>     if (FcDebug () & FC_DBG_FONTSET)
> 	printf ("cache scan dir %s\n", dir);
> 
>-    if (FcStat (dir, &dir_stat) < 0)
>+    if (FcStatChecksum (dir, &dir_stat) < 0)
> 	goto bail;
> 
>     set = FcFontSetCreate();
>diff --git a/src/fcint.h b/src/fcint.h
>index ff655a4..c93a67b 100644
>--- a/src/fcint.h
>+++ b/src/fcint.h
>@@ -348,7 +348,7 @@ struct _FcCache {
>     intptr_t	dirs;		    /* offset to subdirs */
>     int		dirs_count;	    /* number of subdir strings */
>     intptr_t	set;		    /* offset to font set */
>-    int		mtime;		    /* low bits of directory mtime */
>+    int		checksum;	    /* checksum of directory state */
> };
> 
> #undef FcCacheDir
>@@ -997,6 +997,9 @@ FcMatrixFree (FcMatrix *mat);
> FcPrivate int
> FcStat (const FcChar8 *file, struct stat *statb);
> 
>+FcPrivate int
>+FcStatChecksum (const FcChar8 *file, struct stat *statb);
>+
> /* fcstr.c */
> FcPrivate void
> FcStrSetSort (FcStrSet * set);
>diff --git a/src/fcstat.c b/src/fcstat.c
>index 195878a..2663648 100644
>--- a/src/fcstat.c
>+++ b/src/fcstat.c
>@@ -26,6 +26,10 @@
> #include "fcint.h"
> #include "fcarch.h"
> #include <dirent.h>
>+#ifdef __linux__
>+#  include <sys/vfs.h>
>+#  include <linux/magic.h>
>+#endif
> 
> #ifdef _WIN32
> 
>@@ -114,3 +118,132 @@ FcStat (const FcChar8 *file, struct stat *statb)
> }
> 
> #endif
>+
>+/*
>+ * Checking for FAT filesystem which broken mtime handling. There is no
>+ * cross-platform filesystem type query call, so resort to OS-specific calls.
>+ */
>+#ifdef __linux__
>+static FcBool
>+FcFsMtimeBroken (const FcChar8 *file)
>+{
>+    int ret;
>+    struct statfs fs_stat;
>+
>+    if (FcDebug () & FC_DBG_CACHE)
>+	printf ("FcFsMtimeBroken %s\n", file);
>+
>+    ret = statfs ((const char *)file, &fs_stat);
>+    if (ret == -1)
>+	return FcFalse;
>+
>+    if (FcDebug () & FC_DBG_CACHE)
>+	printf ("FcFsMtimeBroken f_type %ld MSDOS_SUPER_MAGIC %d\n",
>+	        fs_stat.f_type, MSDOS_SUPER_MAGIC);
>+
>+    if (fs_stat.f_type == MSDOS_SUPER_MAGIC)
>+	return FcTrue;
>+
>+    return FcFalse;
>+}
>+#endif
>+
>+/*
>+ * This is to be enabled on all systems which support checking for FAT
>+ * filesystem, not just Linux, so change this #if after updating
>+ * FcFsMtimeBroken.
>+ */
>+#ifdef __linux__
>+
>+/* Adler-32 checksum implementation */
>+struct Adler32 {
>+    int a;
>+    int b;
>+};
>+
>+static void
>+Adler32Init (struct Adler32 *ctx)
>+{
>+    ctx->a = 1;
>+    ctx->b = 0;
>+}
>+
>+static void
>+Adler32Update (struct Adler32 *ctx, const char *data, int data_len)
>+{
>+    while (data_len--)
>+    {
>+	ctx->a = (ctx->a + *data++) % 65521;
>+	ctx->b = (ctx->b + ctx->a) % 65521;
>+    }
>+}
>+
>+static int
>+Adler32Finish (struct Adler32 *ctx)
>+{
>+    return ctx->a + (ctx->b << 16);
>+}
>+
>+/* dirent.d_type can be relied upon on FAT filesystem */
>+static FcBool
>+FcDirChecksumScandirFilter(const struct dirent *entry)
>+{
>+    return entry->d_type != DT_DIR;
>+}
>+
>+static int
>+FcDirChecksumScandirSorter(const struct dirent **lhs, const struct dirent **rhs)
>+{
>+    return strcmp((*lhs)->d_name, (*rhs)->d_name);
>+}
>+
>+static int
>+FcDirChecksum (const FcChar8 *dir, time_t *checksum)
>+{
>+    struct Adler32 ctx;
>+    struct dirent **files;
>+    int n;
>+
>+    Adler32Init (&ctx);
>+
>+    n = scandir ((const char *)dir, &files,
>+                 &FcDirChecksumScandirFilter,
>+                 &FcDirChecksumScandirSorter);
>+    if (n == -1)
>+        return -1;
>+
>+    while (n--)
>+    {
>+        Adler32Update (&ctx, files[n]->d_name, strlen(files[n]->d_name) + 1);
>+        Adler32Update (&ctx, (char *)&files[n]->d_type, sizeof(files[n]->d_type));
>+        free(files[n]);
>+    }
>+    free(files);
>+
>+    *checksum = Adler32Finish (&ctx);
>+    return 0;
>+}
>+#endif
>+
>+#ifdef __linux__
>+int
>+FcStatChecksum (const FcChar8 *file, struct stat *statb)
>+{
>+    if (FcStat (file, statb) == -1)
>+        return -1;
>+
>+    if (FcFsMtimeBroken (file))
>+    {
>+        if (FcDirChecksum (file, &statb->st_mtime) == -1)
>+            return -1;
>+    }
>+
>+    return 0;
>+}
>+#else
>+int
>+FcStatChecksum (const FcChar8 *file, struct stat *statb)
>+{
>+    return FcStat (flie, statb);
>+}
>+#endif
>-- 
>1.7.9.5
>

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Attachments on bug 25535: 32209 | 43671 | 43672 | 60763 | 60764 | 61532 | 61533 | 61534

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