1 # SPDX-License-Identifier: GPL-2.0-only << 2 config OVERLAY_FS 1 config OVERLAY_FS 3 tristate "Overlay filesystem support" 2 tristate "Overlay filesystem support" 4 select FS_STACK << 5 select EXPORTFS << 6 help 3 help 7 An overlay filesystem combines two f 4 An overlay filesystem combines two filesystems - an 'upper' filesystem 8 and a 'lower' filesystem. When a na 5 and a 'lower' filesystem. When a name exists in both filesystems, the 9 object in the 'upper' filesystem is 6 object in the 'upper' filesystem is visible while the object in the 10 'lower' filesystem is either hidden 7 'lower' filesystem is either hidden or, in the case of directories, 11 merged with the 'upper' object. 8 merged with the 'upper' object. 12 9 13 For more information see Documentati !! 10 For more information see Documentation/filesystems/overlayfs.txt 14 << 15 config OVERLAY_FS_REDIRECT_DIR << 16 bool "Overlayfs: turn on redirect dire << 17 depends on OVERLAY_FS << 18 help << 19 If this config option is enabled the << 20 redirects when renaming directories << 21 still possible to turn off redirects << 22 "redirect_dir=off" module option or << 23 with the "redirect_dir=off" mount op << 24 << 25 Note, that redirects are not backwar << 26 an overlay which has redirects on a << 27 feature will have unexpected results << 28 << 29 If unsure, say N. << 30 << 31 config OVERLAY_FS_REDIRECT_ALWAYS_FOLLOW << 32 bool "Overlayfs: follow redirects even << 33 default y << 34 depends on OVERLAY_FS << 35 help << 36 Disable this to get a possibly more << 37 might not be backward compatible wit << 38 << 39 If backward compatibility is not an << 40 recommended to say N here. << 41 << 42 For more information, see Documentat << 43 << 44 If unsure, say Y. << 45 << 46 config OVERLAY_FS_INDEX << 47 bool "Overlayfs: turn on inodes index << 48 depends on OVERLAY_FS << 49 help << 50 If this config option is enabled the << 51 the index directory to map lower ino << 52 In this case it is still possible to << 53 "index=off" module option or on a fi << 54 "index=off" mount option. << 55 << 56 The inodes index feature prevents br << 57 up. << 58 << 59 Note, that the inodes index feature << 60 That is, mounting an overlay which h << 61 that doesn't support this feature wi << 62 << 63 If unsure, say N. << 64 << 65 config OVERLAY_FS_NFS_EXPORT << 66 bool "Overlayfs: turn on NFS export fe << 67 depends on OVERLAY_FS << 68 depends on OVERLAY_FS_INDEX << 69 depends on !OVERLAY_FS_METACOPY << 70 help << 71 If this config option is enabled the << 72 the index directory to decode overla << 73 In this case, it is still possible t << 74 globally with the "nfs_export=off" m << 75 instance basis with the "nfs_export= << 76 << 77 The NFS export feature creates an in << 78 directory. This full index is used << 79 inconsistencies on lookup, like redi << 80 the same lower dir. The full index << 81 time, especially when verifying that << 82 stale. << 83 << 84 Note, that the NFS export feature is << 85 That is, mounting an overlay which h << 86 that doesn't support this feature wi << 87 << 88 Most users should say N here and ena << 89 case basis with the "nfs_export=on" << 90 << 91 Say N unless you fully understand th << 92 << 93 config OVERLAY_FS_XINO_AUTO << 94 bool "Overlayfs: auto enable inode num << 95 default n << 96 depends on OVERLAY_FS << 97 depends on 64BIT << 98 help << 99 If this config option is enabled the << 100 unused high bits in underlying files << 101 inodes to a unified address space. << 102 might not be compatible with applica << 103 << 104 If compatibility with applications t << 105 issue, then it is safe and recommend << 106 << 107 For more information, see Documentat << 108 << 109 If unsure, say N. << 110 << 111 config OVERLAY_FS_METACOPY << 112 bool "Overlayfs: turn on metadata only << 113 depends on OVERLAY_FS << 114 select OVERLAY_FS_REDIRECT_DIR << 115 help << 116 If this config option is enabled the << 117 copy up only metadata where appropri << 118 happen when a file is opened for WRI << 119 possible to turn off this feature gl << 120 module option or on a filesystem ins << 121 "metacopy=off" mount option. << 122 << 123 Note, that this feature is not backw << 124 mounting an overlay which has metaco << 125 that doesn't support this feature wi << 126 << 127 If unsure, say N. << 128 << 129 config OVERLAY_FS_DEBUG << 130 bool "Overlayfs: turn on extra debuggi << 131 default n << 132 depends on OVERLAY_FS << 133 help << 134 Say Y here to enable extra debugging << 135 << 136 If unsure, say N. <<
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