chattr: Add extent conversion support

This patch adds new option, +e to chattr. The +e option
is used to convert the ext3 format (non extent) file
to ext4 (extent) format. This can be used to migrate
the ext3 file system to ext4 file system.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/misc/chattr.1.in b/misc/chattr.1.in
index d1c4cb5..e1e6a85 100644 (file)
--- a/misc/chattr.1.in
+++ b/misc/chattr.1.in
@@ -19,7 +19,7 @@ chattr \- change file attributes on a Linux second extended file system
 .B chattr
 changes the file attributes on a Linux second extended file system.
 .PP
-The format of a symbolic mode is +-=[ASacDdIijsTtu].
+The format of a symbolic mode is +-=[ASacDdeIijsTtu].
 .PP
 The operator `+' causes the selected attributes to be added to the
 existing attributes of the files; `-' causes them to be removed; and
@@ -74,10 +74,8 @@ although it can be displayed by
 .BR lsattr (1).
 .PP
 The 'e' attribute indicates that the file is using extents for mapping
-the blocks on disk.  It may not be set or reset using
-.BR chattr (1),
-although it can be displayed by
-.BR lsattr (1).
+the blocks on disk.  It may not be removed using
+.BR chattr (1).
 .PP
 The 'I' attribute is used by the htree code to indicate that a directory
 is being indexed using hashed trees.  It may not be set or reset using 

diff --git a/misc/chattr.c b/misc/chattr.c
index 3d67519..de33b08 100644 (file)
--- a/misc/chattr.c
+++ b/misc/chattr.c
@@ -82,7 +82,7 @@ static unsigned long sf;
 static void usage(void)
 {
        fprintf(stderr,
-               _("Usage: %s [-RVf] [-+=AacDdijsSu] [-v version] files...\n"),
+               _("Usage: %s [-RVf] [-+=AacDdeijsSu] [-v version] files...\n"),
                program_name);
        exit(1);
 }
@@ -99,6 +99,7 @@ static const struct flags_char flags_array[] = {
        { EXT2_APPEND_FL, 'a' },
        { EXT2_COMPR_FL, 'c' },
        { EXT2_NODUMP_FL, 'd' },
+       { EXT4_EXTENTS_FL, 'e'},
        { EXT2_IMMUTABLE_FL, 'i' },
        { EXT3_JOURNAL_DATA_FL, 'j' },
        { EXT2_SECRM_FL, 's' },
@@ -191,6 +192,7 @@ static int change_attributes(const char * name)
 {
        unsigned long flags;
        STRUCT_STAT     st;
+       int extent_file = 0;
 
        if (LSTAT (name, &st) == -1) {
                if (!silent)
@@ -199,7 +201,22 @@ static int change_attributes(const char * name)
                return -1;
        }
 
+       if (fgetflags(name, &flags) == -1) {
+               if (!silent)
+                       com_err(program_name, errno,
+                                       _("while reading flags on %s"), name);
+               return -1;
+       }
+       if (flags & EXT4_EXTENTS_FL)
+               extent_file = 1;
        if (set) {
+               if (extent_file && !(sf & EXT4_EXTENTS_FL)) {
+                       if (!silent)
+                               com_err(program_name, 0,
+                               _("Clearing extent flag not supported on %s"),
+                                       name);
+                       return -1;
+               }
                if (verbose) {
                        printf (_("Flags of %s set as "), name);
                        print_flags (stdout, sf, 0);
@@ -208,30 +225,31 @@ static int change_attributes(const char * name)
                if (fsetflags (name, sf) == -1)
                        perror (name);
        } else {
-               if (fgetflags (name, &flags) == -1) {
+               if (rem)
+                       flags &= ~rf;
+               if (add)
+                       flags |= af;
+               if (extent_file && !(flags & EXT4_EXTENTS_FL)) {
                        if (!silent)
-                               com_err (program_name, errno,
-                                        _("while reading flags on %s"), name);
+                               com_err(program_name, 0,
+                               _("Clearing extent flag not supported on %s"),
+                                       name);
                        return -1;
-               } else {
-                       if (rem)
-                               flags &= ~rf;
-                       if (add)
-                               flags |= af;
-                       if (verbose) {
-                               printf (_("Flags of %s set as "), name);
-                               print_flags (stdout, flags, 0);
-                               printf ("\n");
-                       }
-                       if (!S_ISDIR(st.st_mode))
-                               flags &= ~EXT2_DIRSYNC_FL;
-                       if (fsetflags (name, flags) == -1) {
-                               if (!silent)
-                                       com_err(program_name, errno,
+               }
+               if (verbose) {
+                       printf(_("Flags of %s set as "), name);
+                       print_flags(stdout, flags, 0);
+                       printf("\n");
+               }
+               if (!S_ISDIR(st.st_mode))
+                       flags &= ~EXT2_DIRSYNC_FL;
+               if (fsetflags(name, flags) == -1) {
+                       if (!silent) {
+                               com_err(program_name, errno,
                                                _("while setting flags on %s"),
                                                name);
-                               return -1;
                        }
+                       return -1;
                }
        }
        if (set_version) {