Modified the ext4fs_write function to create a new file that inherits the inode->mode of existing file. To fix an issue where file permissions are changed after modifying the contents of an existing file. --- fs/ext4/ext4_write.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/ext4_write.c b/fs/ext4/ext4_write.c index ea4c5d4157..6da4a26b71 100644 --- a/fs/ext4/ext4_write.c +++ b/fs/ext4/ext4_write.c @@ -847,6 +847,7 @@ int ext4fs_write(const char *fname, const char *buffer, { int ret = 0; struct ext2_inode *file_inode = NULL; + struct ext2_inode *existing_file_inode = NULL; unsigned char *inode_buffer = NULL; int parent_inodeno; int inodeno; @@ -900,6 +901,16 @@ int ext4fs_write(const char *fname, const char *buffer, /* check if the filename is already present in root */ existing_file_inodeno = ext4fs_filename_unlink(filename); if (existing_file_inodeno != -1) { + existing_file_inode = (struct ext2_inode *)zalloc(fs->inodesz); + if (!existing_file_inode) + goto fail; + ret = ext4fs_iget(existing_file_inodeno, existing_file_inode); + if (ret) + { + free(existing_file_inode); + goto fail; + } + ret = ext4fs_delete_file(existing_file_inodeno); fs->first_pass_bbmap = 0; fs->curr_blkno = 0; @@ -948,8 +959,13 @@ int ext4fs_write(const char *fname, const char *buffer, sizebytes = 0; } } else { - file_inode->mode = cpu_to_le16(S_IFREG | S_IRWXU | S_IRGRP | - S_IROTH | S_IXGRP | S_IXOTH); + if(existing_file_inode) { + file_inode->mode = existing_file_inode->mode; + free(existing_file_inode); + } else { + file_inode->mode = cpu_to_le16(S_IFREG | S_IRWXU | S_IRGRP | + S_IROTH | S_IXGRP | S_IXOTH); + } } /* ToDo: Update correct time */ file_inode->mtime = cpu_to_le32(timestamp); 2.18.0