CC: linux-doc@xxxxxxxxxxxxxxx
CC: Rob Landley <rob@xxxxxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxx>
---
Documentation/filesystems/fiemap.txt | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/Documentation/filesystems/fiemap.txt b/Documentation/filesystems/fiemap.txt
index 1b805a0efbb0..353f299bcbeb 100644
--- a/Documentation/filesystems/fiemap.txt
+++ b/Documentation/filesystems/fiemap.txt
@@ -83,7 +83,9 @@ struct fiemap_extent {
__u64 fe_physical; /* physical offset in bytes for the start
* of the extent */
__u64 fe_length; /* length in bytes for the extent */
- __u64 fe_reserved64[2];
+ __u64 fe_phys_length; /* physical length in bytes, may be different from
+ * fe_length and sets additional extent flags */
+ __u64 fe_reserved64;
__u32 fe_flags; /* FIEMAP_EXTENT_* flags for this extent */
__u32 fe_reserved[3];
};
@@ -93,7 +95,10 @@ for an extents logical offset to start before the request or its logical
length to extend past the request. Unless FIEMAP_EXTENT_NOT_ALIGNED is
returned, fe_logical, fe_physical, and fe_length will be aligned to the
block size of the file system. With the exception of extents flagged as
-FIEMAP_EXTENT_MERGED, adjacent extents will not be merged.
+FIEMAP_EXTENT_MERGED, adjacent extents will not be merged. The value of
+fe_phys_length is always set. It may be different from fe_length and sets
+additional extent flags that indicate the reason, eg. for compression it's
+FIEMAP_EXTENT_DATA_COMPRESSED.
The fe_flags field contains flags which describe the extent returned.
A special flag, FIEMAP_EXTENT_LAST is always set on the last extent in
@@ -143,6 +148,12 @@ unmounted, and then only if the FIEMAP_EXTENT_ENCODED flag is
clear; user applications must not try reading or writing to the
filesystem via the block device under any other circumstances.
+* FIEMAP_EXTENT_DATA_COMPRESSED
+ - This will also set FIEMAP_EXTENT_ENCODED
+The data in this extent has been compressed by the file system. When
+set, fe_phys_length contains the physical extent length in bytes. The
+value may be rounded depending on the filesystem implementation.
+
* FIEMAP_EXTENT_DATA_ENCRYPTED
- This will also set FIEMAP_EXTENT_ENCODED
The data in this extent has been encrypted by the file system.
--
1.8.4.5
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