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ovl: fix some xino configurations

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Fix up two bugs in the coversion to xino_mode:
1. xino=off does not always end up in disabled mode
2. xino=auto on 32bit arch should end up in disabled mode

Take a proactive approach to disabling xino on 32bit kernel:
1. Disable XINO_AUTO config during build time
2. Disable xino with a warning on mount time

As a by product, xino=on on 32bit arch also ends up in disabled mode.
We never intended to enable xino on 32bit arch and this will make the
rest of the logic simpler.

Fixes: 0f831ec85e ("ovl: simplify ovl_same_sb() helper")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Amir Goldstein 2020-02-21 16:34:42 +02:00 committed by Miklos Szeredi
parent 531d3040bc
commit 53afcd310e
2 changed files with 9 additions and 1 deletions
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1
fs/overlayfs/Kconfig
View File

@ -93,6 +93,7 @@ config OVERLAY_FS_XINO_AUTO
bool "Overlayfs: auto enable inode number mapping" bool "Overlayfs: auto enable inode number mapping"
default n default n
depends on OVERLAY_FS depends on OVERLAY_FS
depends on 64BIT
help help
If this config option is enabled then overlay filesystems will use If this config option is enabled then overlay filesystems will use
unused high bits in undelying filesystem inode numbers to map all unused high bits in undelying filesystem inode numbers to map all

9
fs/overlayfs/super.c
View File

@ -1411,6 +1411,8 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs,
if (ofs->config.xino == OVL_XINO_ON) if (ofs->config.xino == OVL_XINO_ON)
pr_info("\"xino=on\" is useless with all layers on same fs, ignore.\n"); pr_info("\"xino=on\" is useless with all layers on same fs, ignore.\n");
ofs->xino_mode = 0; ofs->xino_mode = 0;
} else if (ofs->config.xino == OVL_XINO_OFF) {
ofs->xino_mode = -1;
} else if (ofs->config.xino == OVL_XINO_ON && ofs->xino_mode < 0) { } else if (ofs->config.xino == OVL_XINO_ON && ofs->xino_mode < 0) {
/* /*
* This is a roundup of number of bits needed for encoding * This is a roundup of number of bits needed for encoding
@ -1623,8 +1625,13 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
sb->s_stack_depth = 0; sb->s_stack_depth = 0;
sb->s_maxbytes = MAX_LFS_FILESIZE; sb->s_maxbytes = MAX_LFS_FILESIZE;
/* Assume underlaying fs uses 32bit inodes unless proven otherwise */ /* Assume underlaying fs uses 32bit inodes unless proven otherwise */
if (ofs->config.xino != OVL_XINO_OFF) if (ofs->config.xino != OVL_XINO_OFF) {
ofs->xino_mode = BITS_PER_LONG - 32; ofs->xino_mode = BITS_PER_LONG - 32;
if (!ofs->xino_mode) {
pr_warn("xino not supported on 32bit kernel, falling back to xino=off.\n");
ofs->config.xino = OVL_XINO_OFF;
}
}
/* alloc/destroy_inode needed for setting up traps in inode cache */ /* alloc/destroy_inode needed for setting up traps in inode cache */
sb->s_op = &ovl_super_operations; sb->s_op = &ovl_super_operations;