New upstream version 1.4.0

[sven/fuse-exfat.git] / libexfat / io.c

diff --git a/libexfat/io.c b/libexfat/io.c
index 0fc35d28b7cca2c7687869115c4e5eaf12cf812a..7af5316da70b4b968474b9679271b359026c5a6a 100644 (file)
--- a/libexfat/io.c
+++ b/libexfat/io.c
@@ -3,7 +3,7 @@
        exFAT file system implementation library.
 
        Free exFAT implementation.
-       Copyright (C) 2010-2018  Andrew Nayenko
+       Copyright (C) 2010-2023  Andrew Nayenko
 
        This program is free software; you can redistribute it and/or modify
        it under the terms of the GNU General Public License as published by
@@ -390,27 +390,43 @@ ssize_t exfat_pwrite(struct exfat_dev* dev, const void* buffer, size_t size,
 ssize_t exfat_generic_pread(const struct exfat* ef, struct exfat_node* node,
                void* buffer, size_t size, off_t offset)
 {
-       uint64_t newsize = offset;
+       uint64_t uoffset = offset;
        cluster_t cluster;
        char* bufp = buffer;
        off_t lsize, loffset, remainder;
 
        if (offset < 0)
                return -EINVAL;
-       if (newsize >= node->size)
+       if (uoffset >= node->size)
                return 0;
        if (size == 0)
                return 0;
 
-       cluster = exfat_advance_cluster(ef, node, newsize / CLUSTER_SIZE(*ef->sb));
+       if (uoffset + size > node->valid_size)
+       {
+               ssize_t bytes = 0;
+
+               if (uoffset < node->valid_size)
+               {
+                       bytes = exfat_generic_pread(ef, node, buffer,
+                                       node->valid_size - uoffset, offset);
+                       if (bytes < 0 || (size_t) bytes < node->valid_size - uoffset)
+                               return bytes;
+               }
+               memset(buffer + bytes, 0,
+                               MIN(size - bytes, node->size - node->valid_size));
+               return MIN(size, node->size - uoffset);
+       }
+
+       cluster = exfat_advance_cluster(ef, node, uoffset / CLUSTER_SIZE(*ef->sb));
        if (CLUSTER_INVALID(*ef->sb, cluster))
        {
                exfat_error("invalid cluster 0x%x while reading", cluster);
                return -EIO;
        }
 
-       loffset = newsize % CLUSTER_SIZE(*ef->sb);
-       remainder = MIN(size, node->size - newsize);
+       loffset = uoffset % CLUSTER_SIZE(*ef->sb);
+       remainder = MIN(size, node->size - uoffset);
        while (remainder > 0)
        {
                if (CLUSTER_INVALID(*ef->sb, cluster))
@@ -432,13 +448,13 @@ ssize_t exfat_generic_pread(const struct exfat* ef, struct exfat_node* node,
        }
        if (!(node->attrib & EXFAT_ATTRIB_DIR) && !ef->ro && !ef->noatime)
                exfat_update_atime(node);
-       return MIN(size, node->size - newsize) - remainder;
+       return MIN(size, node->size - uoffset) - remainder;
 }
 
 ssize_t exfat_generic_pwrite(struct exfat* ef, struct exfat_node* node,
                const void* buffer, size_t size, off_t offset)
 {
-       uint64_t newsize = offset;
+       uint64_t uoffset = offset;
        int rc;
        cluster_t cluster;
        const char* bufp = buffer;
@@ -446,29 +462,29 @@ ssize_t exfat_generic_pwrite(struct exfat* ef, struct exfat_node* node,
 
        if (offset < 0)
                return -EINVAL;
-       if (newsize > node->size)
+       if (uoffset > node->size)
        {
-               rc = exfat_truncate(ef, node, newsize, true);
+               rc = exfat_truncate(ef, node, uoffset, true);
                if (rc != 0)
                        return rc;
        }
-       if (newsize + size > node->size)
+       if (uoffset + size > node->size)
        {
-               rc = exfat_truncate(ef, node, newsize + size, false);
+               rc = exfat_truncate(ef, node, uoffset + size, false);
                if (rc != 0)
                        return rc;
        }
        if (size == 0)
                return 0;
 
-       cluster = exfat_advance_cluster(ef, node, newsize / CLUSTER_SIZE(*ef->sb));
+       cluster = exfat_advance_cluster(ef, node, uoffset / CLUSTER_SIZE(*ef->sb));
        if (CLUSTER_INVALID(*ef->sb, cluster))
        {
                exfat_error("invalid cluster 0x%x while writing", cluster);
                return -EIO;
        }
 
-       loffset = newsize % CLUSTER_SIZE(*ef->sb);
+       loffset = uoffset % CLUSTER_SIZE(*ef->sb);
        remainder = size;
        while (remainder > 0)
        {
@@ -487,6 +503,7 @@ ssize_t exfat_generic_pwrite(struct exfat* ef, struct exfat_node* node,
                bufp += lsize;
                loffset = 0;
                remainder -= lsize;
+               node->valid_size = MAX(node->valid_size, uoffset + size - remainder);
                cluster = exfat_next_cluster(ef, node, cluster);
        }
        if (!(node->attrib & EXFAT_ATTRIB_DIR))