Update configuration documentation page (#727)

* Update CONFIGURATION.md update the file modifications and deletions section with the release of overwrites Signed-off-by: andrewatamzn <[email protected]> * Update doc/CONFIGURATION.md Co-authored-by: Daniel Carl Jones <[email protected]> Signed-off-by: James Bornholt <[email protected]> --------- Signed-off-by: andrewatamzn <[email protected]> Signed-off-by: James Bornholt <[email protected]> Co-authored-by: James Bornholt <[email protected]> Co-authored-by: Daniel Carl Jones <[email protected]>
awslabs · Feb 2, 2024 · 778aad3 · 778aad3
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commit 778aad3
Showing 1 changed file with 8 additions and 4 deletions.
diff --git a/doc/CONFIGURATION.md b/doc/CONFIGURATION.md
@@ -174,11 +174,15 @@ Mountpoint automatically configures reasonable defaults for file system settings
 
 ### File modifications and deletions
 
-By default, Mountpoint allows creating new files, and does not allow deleting existing objects or overwriting existing objects. You can adjust these defaults in two ways:
-* If you want to allow file deletion, use the `--allow-delete` command-line flag. When you delete a file from your Mountpoint file system with this flag enabled, the corresponding object is immediately deleted from your S3 bucket.
-* If you want to forbid all mutating actions on your S3 bucket, use the `--read-only` command-line flag.
+By default, Mountpoint allows creating new files but does not allow deleting or overwriting existing objects.
 
-You cannot currently use Mountpoint to overwrite existing objects. However, if you use the `--allow-delete` flag, you can first delete the object and then create it again.
+Writes to existing files are allowed if `--allow-overwrite` flag is set at mount time, but only when the `O_TRUNC` flag is used at open time to truncate the existing file. All writes must start from the beginning of the file and must be made sequentially.
+
+If you want to allow file deletion, use the `--allow-delete` flag at mount time. Delete operations immediately delete the object from S3, even if the file is being read from.
+
+If you want to forbid all mutating actions on your S3 bucket via Mountpoint, use the `--read-only` command-line flag.
+
+For more details on the behavior of file operations with Mountpoint, see the [file operations section](https://github.com/awslabs/mountpoint-s3/blob/main/doc/SEMANTICS.md#file-operations) of the semantics documentation for more information. 
 
 ### S3 storage classes