lib-fs / posix: If create/link/rename fails with ENOENT, try creating parent dir...

This avoids random failures when the parent dir happens to be removed at
just the right time.

diff --git a/src/lib-fs/fs-posix.c b/src/lib-fs/fs-posix.c
index c8032bb5cee8bb598a024293bda21ddd52da8b50..193b92e9e50a02d5c3de243b2149ebceac6f407a 100644 (file)
--- a/src/lib-fs/fs-posix.c
+++ b/src/lib-fs/fs-posix.c
@@ -18,6 +18,7 @@
 #include <sys/stat.h>
 
 #define FS_POSIX_DOTLOCK_STALE_TIMEOUT_SECS (60*10)
+#define MAX_MKDIR_RETRY_COUNT 5
 
 enum fs_posix_lock_method {
        FS_POSIX_LOCK_METHOD_FLOCK,
@@ -85,13 +86,16 @@ static int fs_posix_create_parent_dir(struct fs *fs, const char *path)
 
        fname = strrchr(path, '/');
        if (fname == NULL)
-               return 0;
+               return 1;
        dir = t_strdup_until(path, fname);
-       if (mkdir_parents(dir, 0700) < 0 && errno != EEXIST) {
+       if (mkdir_parents(dir, 0700) == 0)
+               return 0;
+       else if (errno == EEXIST)
+               return 1;
+       else {
                fs_set_error(fs, "mkdir_parents(%s) failed: %m", dir);
                return -1;
        }
-       return 0;
 }
 
 static int
@@ -101,6 +105,7 @@ fs_posix_create(struct posix_fs *fs, const char *path, enum fs_open_flags flags,
        struct fs *_fs = &fs->fs;
        string_t *str = t_str_new(256);
        const char *slash = strrchr(path, '/');
+       unsigned int try_count = 0;
        int fd;
 
        if (slash != NULL)
@@ -108,10 +113,13 @@ fs_posix_create(struct posix_fs *fs, const char *path, enum fs_open_flags flags,
        str_append(str, fs->temp_file_prefix);
 
        fd = safe_mkstemp_hostpid(str, 0600, (uid_t)-1, (gid_t)-1);
-       if (fd == -1 && errno == ENOENT && (flags & FS_OPEN_FLAG_MKDIR) != 0) {
+       while (fd == -1 && errno == ENOENT &&
+              try_count <= MAX_MKDIR_RETRY_COUNT &&
+              (flags & FS_OPEN_FLAG_MKDIR) != 0) {
                if (fs_posix_create_parent_dir(_fs, path) < 0)
                        return -1;
                fd = safe_mkstemp_hostpid(str, 0600, (uid_t)-1, (gid_t)-1);
+               try_count++;
        }
        if (fd == -1) {
                fs_set_error(_fs, "safe_mkstemp(%s) failed: %m", str_c(str));
@@ -454,13 +462,16 @@ static int fs_posix_stat(struct fs *fs, const char *path, struct stat *st_r)
 
 static int fs_posix_link(struct fs *fs, const char *src, const char *dest)
 {
+       unsigned int try_count = 0;
        int ret;
 
        ret = link(src, dest);
-       if (ret < 0 && errno == ENOENT) {
+       while (ret < 0 && errno == ENOENT &&
+              try_count <= MAX_MKDIR_RETRY_COUNT) {
                if (fs_posix_create_parent_dir(fs, dest) < 0)
                        return -1;
                ret = link(src, dest);
+               try_count++;
        }
        if (ret < 0) {
                fs_set_error(fs, "link(%s, %s) failed: %m", src, dest);
@@ -471,13 +482,16 @@ static int fs_posix_link(struct fs *fs, const char *src, const char *dest)
 
 static int fs_posix_rename(struct fs *fs, const char *src, const char *dest)
 {
+       unsigned int try_count = 0;
        int ret;
 
        ret = rename(src, dest);
-       if (ret < 0 && errno == ENOENT) {
+       while (ret < 0 && errno == ENOENT &&
+              try_count <= MAX_MKDIR_RETRY_COUNT) {
                if (fs_posix_create_parent_dir(fs, dest) < 0)
                        return -1;
                ret = rename(src, dest);
+               try_count++;
        }
        if (ret < 0) {
                fs_set_error(fs, "link(%s, %s) failed: %m", src, dest);